JP4472769B2 - Real-time seismometer and prediction method of seismic intensity using it - Google Patents

Description

  The present invention adopts seismic intensity instead of the conventionally used acceleration as a measure of the strength of shaking caused by an earthquake (hereinafter referred to as seismic motion), and in particular, seismic intensity measured by an existing seismometer that has passed the certification of the Japan Meteorological Agency. This invention relates to a real-time seismometer capable of measuring the seismic intensity corresponding to 1 in real time (hereinafter, the seismic intensity measured in this way is referred to as real-time seismic intensity) and a method for predicting seismic intensity using the seismic intensity meter.

  The main phases included in the seismic wave include a P wave (initial tremor) that travels in the ground, an S wave (main motion), and a surface wave that travels on the ground surface. The average propagation speed is the fastest for the P wave and slightly less than twice the S wave, and the surface wave is slightly slower than the S wave. For this reason, ground motion is first caused by P waves. In addition, the time required from the arrival of the P wave to the arrival of the S wave or the surface wave becomes longer as the distance from the epicenter. In addition, the intensity of seismic motion is greater for the S wave than for the P wave, and for the S wave and the surface wave, the surface wave may be greater than the S wave depending on conditions. Therefore, damage caused by earthquakes is mainly caused by S waves or surface waves.

  By utilizing such general properties of seismic waves, for example, if an earthquake or ground motion is detected and an alarm or control signal is issued before the arrival of an S wave or surface wave that causes a large seismic motion, Very useful for prevention and mitigation. However, for that purpose, it is necessary to predict the strength of the ground motion due to the S wave or the surface wave as soon as possible after the arrival of the P wave, and to strictly evaluate it with a scale associated with the damage.

  Conventionally, in an earthquake warning system that emits an alarm or control signal, acceleration is used as a measure of the intensity of earthquake motion, and when the measured value exceeds a predetermined threshold, an alarm or control signal is output. It was. However, in the above system, since acceleration is used as a measure of the strength of earthquake motion, the strength of the earthquake motion may be determined based on the amplitude of a high frequency band that is weakly related to damage. In addition, the threshold value is simply set regardless of the seismic source distance (the straight line distance connecting the observation point and the epicenter) and without reasonably predicting the intensity of ground motion due to S waves or surface waves. Since the configuration depends on it, there has been a problem that unnecessary alarms and control signals are output.

  In addition, control seismometers utilizing the fact that the maximum acceleration amplitude of the P wave and the maximum acceleration amplitude of the S wave are approximately proportional to each other have been used in equipment such as elevators. When the value exceeds a certain value, an alarm or control signal is issued before the arrival of the S wave, assuming that the S wave reaches a value that threatens the safety of the device. Therefore, the error is large, and it is difficult to accurately predict the earthquake motion due to the S wave. In order not to miss the strong shaking, it is necessary to set the monitoring level of the P wave low, which causes an unnecessary alarm or control signal.

Here, the “Seismic intensity class” adopted by the Japan Meteorological Agency as a measure of the strength of ground motion will be explained. The seismic intensity was historically determined based on the experience of the staff of the Japan Meteorological Agency rather than the measured value by the measuring instrument, but was later revised to be based on the measured value by the seismometer, and a new measured seismic intensity was defined. That is, the measured seismic intensity is a value determined on the basis of the measurement result obtained by an existing seismic intensity meter that has passed the certification of the Japan Meteorological Agency. In this way, one measured seismic intensity is determined for one earthquake. The seismic intensity is ○. It is written as “○” and may take a negative value in a small earthquake. At present, the seismic intensity class is determined based on the measured seismic intensity, and the calculation method for obtaining the measured seismic intensity from the measured values by the seismometer has been determined by the experience of the seismic intensity class obtained from the measured seismic intensity. It is devised to be consistent with the conventional “seismic intensity class”. In the present application, the measured seismic intensity is expressed as “Seismic intensity ○ or seismic intensity ○. ○” in arithmetical numbers, and the seismic intensity class is expressed as Roman numerals.
In the definition of measured seismic intensity determined in this way, the measured value of the acceleration of seismic motion obtained in a time series by the seismometer is lower than the frequency of 0.6 Hz (cycle 1.6 seconds) (long cycle) Side) and a frequency of 10 Hz (period 0.11 sec), a sharp cutoff filter is applied to the measured value on the higher frequency side (shorter period side), and the square root for the measured value of the frequency of 0.6 to 10 Hz. A filter proportional to the inverse of is applied.

FIG. 38 is a diagram showing the frequency characteristics of seismic intensity published by the Japan Meteorological Agency.
As shown in FIG. 38, the acceleration amplitude corresponding to each seismic intensity has a trough point with a period of 1.6 seconds, and both the short period side and the long period side increase with increasing distance from the trough point. This characteristic is determined by the Japan Meteorological Agency based on past earthquake observations and damage status, and represents the general frequency characteristics of a structure (relationship between seismic vibration frequency and structure strength). According to this figure, the general structure has a natural period of around 1.6 seconds, and the same as the dominant period of the ground motion (the period of the wave having the largest energy among the seismic waves) moves away from the natural period. It can be seen that the acceleration increases with the seismic intensity and can withstand strong ground motion.

  Thus, the risk of an earthquake is not determined only by the acceleration amplitude of the ground motion, but greatly depends on the relationship between the dominant period of the ground motion and the natural period of the building or equipment. The mechanism of damage caused by earthquake motion differs depending on the object to be damaged, but basically it is strongly influenced by the intensity and duration of the earthquake motion in the period near the natural period of the object. It is known that the seismic intensity has a relatively good correlation with the magnitude and presence / absence of damage compared to the maximum acceleration and maximum velocity of earthquake motion. Therefore, as described above, the Japan Meteorological Agency measures the acceleration of seismic motion and obtains the measured seismic intensity based on the result. However, in the conventional method performed by the Japan Meteorological Agency, there is a problem that a predetermined calculation time is required for data processing and that it is not easy to issue an alarm or a control signal depending on a measure associated with damage. In order to solve such problems, various researches and developments have been actively conducted on seismic intensity calculation methods and seismic intensity meters, and some inventions and devices have already been disclosed.

For example, Patent Document 1 discloses an invention relating to a seismic intensity meter that employs a method of calculating a seismic intensity with a name “Seismic Intensity Meter” that places a small burden on hardware.
The invention disclosed in Patent Document 1 includes an acceleration sensor that converts detected acceleration into an electric signal, a filter circuit that removes an analog signal output from the acceleration sensor except for a specific frequency region, and a filter circuit. A processing unit that converts the processed analog signal into a digital signal and calculates the seismic intensity and a display unit that displays the seismic intensity calculated by the calculating unit are provided.
In the seismometer having such a structure, since the output value from the acceleration sensor is processed by the filter circuit before being input to the calculation unit, it is not necessary to perform the Fourier transform and the inverse Fourier transform in the calculation unit. This has the effect of reducing the burden on the device. Thereby, the time required for calculating the seismic intensity can be shortened.

Patent Document 2 discloses an early earthquake specification estimation method and system capable of accurately estimating an earthquake specification using data for one second from the arrival of a P wave under the name “early earthquake specification estimation method and system”. An invention related to this is disclosed.
The invention disclosed in Patent Document 2 is based on 1-second data of coefficient B representing the degree of temporal change in the P-wave initial motion amplitude obtained using the function fitting method, and the maximum amplitude of initial fine motion in 1 second from the arrival of the P-wave. The epicenter distance (distance between the point just above the epicenter and the observation point) and the magnitude are estimated based on a predetermined formula.
According to such a method, it is possible to accurately estimate the specifications of a direct type earthquake in a short time using data for 1 second after arrival of the P wave, and to minimize the damage of the accident.
JP 2007-198812 A JP 2006-275696 A

  However, in the invention disclosed in Patent Document 1 which is the above-described prior art, although the seismic intensity of the earthquake that has occurred can be measured, it is not configured to be able to determine the type of earthquake, so the magnitude of the earthquake is predicted. Therefore, there is a problem that it is difficult to use it as a so-called control seismometer installed in equipment such as an elevator for the purpose of minimizing the occurrence of damage.

  Further, in the invention disclosed in Patent Document 2, since it is necessary to obtain the function parameter stably, there is a problem that a very large amount of data is required. Moreover, since the approximate function used cannot express the necessary part of the P wave initial motion without omission, the accuracy of the obtained information may be insufficient. Furthermore, although the epicenter distance and magnitude could be estimated, there was a problem that the scale of the earthquake could not be strictly evaluated on a scale associated with damage.

  The present invention has been made in response to such conventional circumstances, and measures seismic intensity corresponding to the seismic intensity measured by an existing seismometer that has passed the certification of the Japan Meteorological Agency in real time and at low cost, and the measurement result To provide a real-time seismometer that can be used as a control seismometer, and a method for predicting seismic intensity, etc. With the goal.

In order to achieve the above object, a real-time seismometer according to the first aspect of the present invention comprises an acceleration detection means for detecting three types of acceleration components respectively generated in three axial directions orthogonal to each other in association with an earthquake, and the acceleration detection An A / D converter that converts an analog signal output from the means into a first digital signal, and a first digital signal output from the A / D converter is weighted with respect to a predetermined frequency to obtain a second A digital IIR filter for converting the digital IIR signal into three digital signals, and three types of second digital signals output from the digital IIR filter are vector-synthesized and converted into a third digital signal, and based on the third digital signal. A calculation unit that calculates real-time seismic intensity and a determination unit that determines the type of earthquake based on the real-time seismic intensity. By comparing the reference value varies with time and said real-time seismic intensity is characterized in determining the type of the earthquake.
The real-time seismometer having the above-described configuration has an effect that the burden on hardware is reduced as compared with the FFT seismometer. Moreover, when using as a seismic intensity meter for control, it has the effect | action that an unnecessary operation | movement is prevented by including the information regarding the classification of an earthquake in a control signal.

The real-time seismometer according to claim 2 is an acceleration detection means for detecting three types of acceleration components respectively generated in three axial directions orthogonal to each other accompanying an earthquake, and is output from the acceleration detection means. An analog filter that weights the first analog signal and converts the first analog signal into a second analog signal, an A / D converter that converts the second analog signal into a first digital signal, An arithmetic unit that vector-synthesizes three types of first digital signals output from the A / D converter and converts them into a second digital signal, and calculates a real-time seismic intensity based on the second digital signal; and a determining unit a type of seismic based on this real-time seismic intensity, the determination unit compares the reference value and the real-time seismic intensity which varies with time It is characterized in determining the type of the earthquake.
The real-time seismometer having such a configuration has an effect that the load on hardware is smaller than that of the invention according to claim 1, although the range of seismic intensity that can be measured is narrower than when a digital filter is used. .

The invention according to claim 3 is the real-time seismometer according to claim 1, wherein the digital IIR filter is a characteristic of the structure or equipment that is subject to alarm or control for the predetermined frequency of the first digital signal. The weighting is performed according to a frequency characteristic set in advance based on the above.
When a real-time seismometer having such a configuration is used as a control seismometer, an alarm level is set in accordance with the frequency response limit strength of the target structure or equipment.

According to a fourth aspect of the present invention, in the real-time seismometer according to the second aspect, the analog filter has characteristics of a structure or equipment that is a target of alarm or control with respect to a predetermined frequency of the first analog signal. Based on this, weighting is performed in accordance with a preset frequency characteristic.
The real-time seismometer having such a configuration has the effect of reducing the burden on hardware in addition to the same operation as that of the third aspect of the invention.

The invention according to claim 5 is the real-time seismometer according to any one of claims 1 to 4, wherein the calculation unit obtains the maximum value of the real-time seismic intensity as the measured seismic intensity equivalent value. It is.
The real-time seismometer having such a configuration has an effect that the equivalent value of the measured seismic intensity prescribed by the Japan Meteorological Agency is accurately measured in real time with a simple configuration.

According to a sixth aspect of the present invention, in the real-time seismometer according to any one of the first to fifth aspects, the calculation unit calculates the epicenter distance based on the increase rate of the real-time seismic intensity in the P wave initial motion part. It is characterized by this.
The real-time seismometer having such a configuration has an effect that the epicenter distance is quickly calculated before the arrival of the S wave or the surface wave.

According to a seventh aspect of the present invention, in the real-time seismometer according to the fifth aspect, the calculation unit obtains the maximum value of the real-time seismic intensity, particularly in the P wave region.
The real-time seismometer having such a configuration has an effect that the measured seismic intensity equivalent value is easily and quickly calculated before the arrival of the S wave or the surface wave.

The invention described in claim 8 is characterized in that, in the real-time seismometer according to claim 5, the calculation unit obtains a maximum value within a predetermined time of the P wave initial motion portion in the real-time seismic intensity.
The real-time seismometer having such a configuration has an effect that the calculation time of the measured seismic intensity is shortened although the prediction accuracy of the measured seismic intensity is lower than that of the invention according to claim 7.

The invention according to claim 9 is the real-time seismometer according to any one of claims 1 to 4, wherein the computing unit changes the real-time seismic intensity from the first seismic intensity to the second seismic intensity in the P wave initial motion part. The epicenter distance or the measured seismic intensity equivalent value is calculated based on the time required to reach it.
The real-time seismometer having such a configuration has an effect that the epicenter distance and the measured seismic intensity equivalent value are accurately calculated in a shorter time than the inventions described in claims 5 to 8.

According to a tenth aspect of the present invention, a method for predicting seismic intensity or the like detects three types of acceleration components respectively generated in three axial directions orthogonal to each other accompanying an earthquake, and converts an analog signal representing the acceleration component into a digital signal. Convert, apply IIR filter processing, weight a predetermined frequency and vector synthesize, calculate real-time seismic intensity based on this synthesized digital signal, and calculate the reference value changing with time and this real-time seismic intensity. In comparison, the type of earthquake is determined.
Such a prediction method such as seismic intensity has an effect that the time required for signal processing is shortened as compared with a signal processing method using the FFT method. Further, by including information on the type of earthquake in the control signal, there is an effect that unnecessary operation of the control target device is prevented.

According to an eleventh aspect of the present invention, a method for predicting seismic intensity or the like detects three types of acceleration components respectively generated in three axial directions orthogonal to each other in accordance with an earthquake, and performs analog filter processing on analog signals representing the acceleration components. To give a weight to a predetermined frequency and convert it to a digital signal, vector synthesize this digital signal, calculate real-time seismic intensity based on this synthesized digital signal, and a reference value that changes with time and this The real-time seismic intensity is compared to determine the type of earthquake.
According to such a method for predicting seismic intensity or the like, there is an effect that the burden on the hardware used for the filter processing is less than that of the invention according to claim 10.

According to a twelfth aspect of the present invention, in the method for predicting seismic intensity or the like according to the tenth aspect of the present invention, a digital signal is converted into an IIR signal according to a frequency characteristic set in advance based on a characteristic of a structure or equipment to be alarmed or controlled. Filtering is performed to weight a predetermined frequency.
According to such a prediction method of seismic intensity or the like, there is an effect that the alarm level used when the control signal is issued is set according to the frequency corresponding limit intensity of the target structure or equipment.

According to a thirteenth aspect of the present invention, in the prediction method of the seismic intensity or the like according to the eleventh aspect, the analog signal is converted into an analog signal in accordance with a frequency characteristic set in advance based on the characteristic of the structure or equipment to be alarmed or controlled. Filtering is performed to weight a predetermined frequency.
In such a method for predicting seismic intensity or the like, in addition to the effect that the burden on the hardware used for the filtering process is smaller than that of the invention according to claim 10, the same effect as the invention according to claim 12 is obtained. Have.

The invention according to claim 14 is characterized in that, in the prediction method of seismic intensity and the like according to any one of claims 10 to 13, the maximum value of the real-time seismic intensity is obtained as the measured seismic intensity equivalent value. is there.
According to such a prediction method of seismic intensity and the like, there is an effect that an equivalent value of the measured seismic intensity defined by the Japan Meteorological Agency is measured in real time by a seismic intensity meter having a simple structure.

The invention according to claim 15 is the method for predicting seismic intensity according to any one of claims 10 to 14, wherein the seismic source distance is calculated based on the rate of increase of the real-time seismic intensity in the P wave initial motion part. It is characterized by.
Such a prediction method of seismic intensity or the like has an effect that the epicenter distance is predicted quickly before the arrival of the S wave or the surface wave.

The invention according to claim 16 is characterized in that, in the prediction method of seismic intensity and the like according to claim 14, the maximum value in the real time seismic intensity, particularly in the P wave region, is obtained.
According to such a prediction method of seismic intensity, the measured seismic intensity equivalent value is easily and quickly calculated before the arrival of the S wave or the surface wave.

The invention as set forth in claim 17 is characterized in that, in the method for predicting seismic intensity or the like as set forth in claim 14, the maximum value within a predetermined time of the P wave initial motion portion is obtained in the real time seismic intensity.
According to such a method for predicting seismic intensity or the like, although the prediction accuracy of the measured seismic intensity is lower than that of the invention described in claim 16, the calculation time of the measured seismic intensity is shortened.

The invention according to claim 18 is the prediction method of seismic intensity etc. according to any one of claims 10 to 13, wherein the real-time seismic intensity reaches the second seismic intensity from the first seismic intensity in the P wave initial motion part. The epicenter distance or the measured seismic intensity equivalent value is calculated on the basis of the time required until.
According to such a prediction method of seismic intensity and the like, the epicenter distance and the measured seismic intensity equivalent value are calculated more accurately in a shorter time than the inventions described in claims 14 to 17.

According to a nineteenth aspect of the present invention, in the real-time seismometer according to the third aspect, the digital IIR filter includes a plurality of filters having different pass frequency bands, and the calculation unit and the determination unit pass through the plurality of filters, respectively. It is characterized in that the signals can be individually processed.
The real-time seismometer having such a structure has an effect that the type of earthquake is individually determined based on signals having different frequency bands respectively output from the filters constituting the digital IIR filter.

The invention according to claim 20 is the real-time seismometer according to claim 4, wherein the analog filter is composed of a plurality of filters having different pass frequency bands, and the calculation unit and the determination unit are signals that have passed through the plurality of filters, respectively. Are configured to be individually processable.
The real-time seismometer having such a structure has an effect that the type of earthquake is individually determined based on signals having different frequency bands respectively output from the filters constituting the analog filter.

According to a twenty-first aspect of the present invention, in the prediction method of seismic intensity or the like according to the twelfth aspect, the IIR filter processing includes a plurality of filter processings having different pass frequency bands, and the signals subjected to the plurality of filter processings are respectively obtained. It is characterized by vector synthesis individually.
The method for predicting seismic intensity or the like according to the present invention has the same effect as the invention according to the nineteenth aspect since the invention according to the nineteenth aspect is regarded as a method invention.

According to a twenty-second aspect of the present invention, in the prediction method of seismic intensity or the like according to the thirteenth aspect, the analog filter processing includes a plurality of filter processings having different pass frequency bands. It is characterized by vector synthesis individually.
The method for predicting seismic intensity or the like according to the present invention has the same effect as the invention according to the twentieth aspect since the invention according to the twentieth aspect is regarded as a method invention.

  In the real-time seismometer according to claim 1 of the present invention, the hardware can be simplified as compared with the conventional type, and it is difficult for a failure to occur, and the manufacturing cost is reduced. In addition, accurate emergency control that eliminates unnecessary operations can be performed by controlling the operating state of equipment such as an elevator and a manufacturing apparatus based on seismic intensity (real-time seismic intensity) measured without delay with respect to seismic motion. In addition, it is possible to determine the type of earthquake, and it is possible to issue an alarm or control signal based on a scale associated with damage. As a result, the reliability of the earthquake information is increased, so that the occurrence of damage due to the earthquake can be minimized.

  Further, in the real-time seismometer according to claim 2 of the present invention, the seismic intensity measurement range is narrower than that of the invention according to claim 1, but the hardware can be further simplified and the product is made cheaper. be able to.

  In the real-time seismometer according to claim 3 of the present invention, emergency control is performed only for an earthquake having a truly harmful frequency spectrum. Thereby, it is possible to perform earthquake disaster prevention of appropriate equipment and the like.

  According to the real-time seismometer according to claim 4 of the present invention, it is possible to reduce the burden on hardware and to exert the same effect as the invention according to claim 3.

  In the real-time seismometer according to claim 5 of the present invention, the structure can be simplified as compared with a seismometer that has passed the certification of the Japan Meteorological Agency, so that the apparatus can be reduced in size and price.

  In the real-time seismometer according to claim 6 of the present invention, since the epicenter distance is calculated in a very short time, an effective alarm and control signal can be issued even in the vicinity of the epicenter where emergency earthquake warning is difficult to apply.

  In the real-time seismometer according to claim 7 of the present invention, the value equivalent to the measured seismic intensity is calculated in an extremely short time and easily, so that an effective alarm and control even in the vicinity of an epicenter where emergency earthquake warning is difficult to apply. A signal can be emitted.

  In the real-time seismometer according to claim 8 of the present invention, since the measured seismic intensity equivalent value is calculated in a shorter time than the invention according to claim 7, it is possible to issue a warning or control signal more effectively. Is possible.

  In the real-time seismometer according to the ninth aspect of the present invention, the alarm and control signal can be output in a shorter time than the inventions according to the fifth to eighth aspects. This makes it possible to take more accurate disaster prevention measures before the S wave or surface wave arrives.

  According to the prediction method for seismic intensity and the like according to claim 10 of the present invention, the real-time seismic intensity can be measured without a time delay with respect to the earthquake motion. Then, by sending a control signal based on the real-time seismic intensity to equipment such as an elevator or a manufacturing apparatus, it is possible to eliminate unnecessary operations and perform urgent control accurately. Furthermore, by including information on the type of earthquake in an alarm or control signal, it is possible to obtain an alarm or control signal based on a scale associated with damage. By using such alarms and control signals, it is possible to take appropriate disaster prevention measures to minimize the occurrence of damage caused by earthquakes.

  According to the prediction method for seismic intensity and the like according to claim 11 of the present invention, although the seismic intensity measurement range is narrower than that of the invention according to claim 10, an inexpensive measuring device equipped with simplified hardware is used. be able to.

  According to the method for predicting seismic intensity and the like according to claim 12 of the present invention, it is possible to take emergency control only for an earthquake having a truly harmful frequency spectrum and take an appropriate disaster prevention measure.

  According to the prediction method for seismic intensity and the like according to claim 13 of the present invention, in addition to the effect of the invention described in claim 11, the same effect as that of the invention described in claim 12 is exhibited.

  According to the method for predicting seismic intensity and the like according to claim 14 of the present invention, a highly reliable alarm and control signal based on the measured seismic intensity equivalent value can be issued in a short time. This makes it possible to take measures necessary to minimize earthquake damage before the arrival of S waves or surface waves.

  According to the method for predicting seismic intensity and the like described in claim 15 of the present invention, it is possible to predict the scale of an earthquake and take appropriate disaster prevention measures before arrival of S waves or surface waves.

  According to the method for predicting seismic intensity and the like according to claim 16 of the present invention, an effective alarm or control signal can be issued in a short time.

  According to the prediction method of seismic intensity and the like described in claim 17 of the present invention, the alarm and the control signal can be issued in a shorter time than the invention described in claim 16, so that the time required for disaster prevention measures is increased. Can take.

  According to the method for predicting seismic intensity and the like according to claim 18 of the present invention, it is possible to predict the seismic intensity in a shorter time as the earthquake has a stronger seismic intensity. Therefore, it is possible to take appropriate disaster prevention measures even in the vicinity of the epicenter where the earthquake early warning is particularly difficult to apply.

  When the real-time seismometer according to claim 19 of the present invention is used for facility management, the seismic intensity in the frequency band including the natural frequency of each facility can be accurately detected. Therefore, it is possible to take appropriate disaster prevention and mitigation measures for each facility.

  In the real-time seismometer according to the twentieth aspect of the present invention, it is possible to reduce the burden on the hardware and to exert the same effect as that of the twentieth aspect.

  According to the prediction method for seismic intensity and the like according to claim 21 of the present invention, the same effects as those of the invention according to claim 19 are obtained.

  According to the method for predicting seismic intensity and the like according to claim 22 of the present invention, the same effect as that of the invention according to claim 20 is obtained.

  Hereinafter, an example of a real-time seismometer according to the preferred embodiment of the present invention and a method of predicting seismic intensity using the real-time seismometer will be described with reference to FIGS.

The real-time seismometer of the first embodiment will be described with reference to FIGS. 1 to 20 (particularly, corresponding to claims 1, 3, 5, 7, 8, 10, 12, 14, 16, 17).
FIG. 1 is a configuration diagram of Example 1 of the real-time seismometer according to the embodiment of the present invention. Moreover, FIG. 2 is a figure which shows the frequency characteristic of the digital filter which comprises the real-time seismometer of Example 1. FIG.
As shown in FIG. 1, the real-time seismometer 1a of the present embodiment is detected by an acceleration detection means 2 that detects three types of acceleration components generated in the east-west direction, the north-south direction, and the up-down direction, and the acceleration detection means 2. An A / D converter 3 that converts a continuous time signal (analog signal) into a discrete acceleration signal (digital signal) by sampling a continuous time signal (analog signal) for every three types of acceleration components, and this A digital filter 4a that performs weighting processing as shown in FIG. 2 on a predetermined frequency of the acceleration signal, a vector synthesizer 5 that vector synthesizes a plurality of input signals, and a synthesized signal output from the vector synthesizer 5 Based on the seismic intensity calculation unit 6a that calculates the real-time seismic intensity J and the measured seismic intensity equivalent value, and the time waveform of the real-time seismic intensity J (hereinafter, real-time seismic intensity waveform and And a determination unit 7 that determines an earthquake type based on the earthquake disaster prevention signal 14 and outputs an earthquake disaster prevention signal 14, and an alarm unit 8 that issues an alarm including information on the earthquake type according to the earthquake disaster prevention signal 14. It is. That is, the vector synthesizer 5 and the seismic intensity calculation unit 6a constitute an arithmetic unit 9a that calculates the real-time seismic intensity J based on the output signal from the digital filter 4a.

The acceleration detection means 2 is a three-axis integrated ultra-small acceleration sensor based on MEMS (Micro Electro Mechanical System) technology, and detects the east-west direction component, north-south direction component, and up-down direction component of the acceleration caused by the earthquake, Output as analog signals 10a to 10c. The analog signals 10a to 10c are converted into digital signals 11a to 11c by a three-channel integrated delta-sigma A / D converter 3 based on LSI technology.
The digital filter 4a is a filter circuit (IIR filter) having an infinite impulse response function and has the frequency characteristics shown in FIG. The digital signals 11a to 11c are weighted as shown in FIG. 2 with respect to a predetermined frequency by the digital filter 4a, and then output as digital signals 12a to 12c. The vector synthesizer 5 performs a vector synthesis process on the digital signals 12a to 12c and outputs the resultant as a synthesized digital signal 13a.
The seismic intensity calculation unit 6a calculates the seismic intensity intermediate value I by substituting the synthesized digital signal 13a into “a” in the following equation, and then obtains the n-th value from the highest level for m consecutive seismic intensity intermediate values I in real time. Seismic intensity J. According to such a method, impulsive noise is eliminated, so that the real-time seismometer 1a is less likely to malfunction due to noise other than earthquakes. If the seismic intensity conversion time is 1 second and the sampling frequency is 100 Hz, and the values of m and n are 100 and 30, respectively, the duration of each data of the seismic intensity intermediate value I indicating a value greater than the real-time seismic intensity J per second The total is just 0.3 seconds.

In addition, log is a common logarithm, and b is a constant and is approximately 0.94.

The operation principle of the seismic intensity calculation unit 6a will be described with reference to FIG.
FIG. 3 is a diagram for explaining the operating principle of the seismic intensity calculation unit 6a constituting the real-time seismic intensity meter 1a of the first embodiment. Waveform D represents seismic intensity intermediate value I, and waveform E and waveform F represent real-time seismic intensity J. However, the waveform E is a 1-second seismic intensity (m = 100 (1 second), n = 30 (0.3 seconds)), and the waveform F is a 2-second seismic intensity (m = 200 (2 seconds), n = 30 (0 .3 seconds)).
As shown in FIG. 3, in order to determine a second seismic intensity at time T _1, horizontally assuming dashed P of one second back from the "○" in the time T _1, overlying than the dashed line P The height of the broken line P is adjusted until the total time occupied by the seismic intensity intermediate value I (waveform D) reaches 0.3 seconds. And the seismic intensity when the broken line P satisfies the above-mentioned conditions is defined as a 1-second seismic intensity. Further, even if the time T _2, obtaining a second seismic intensity, assuming a dashed Q of one second dating back from the "○" in the time T _2,, the time occupied by the seismic intensity intermediate value exceeds the dashed Q I (waveform D) The height of the broken line Q is adjusted so that the total of the total is 0.3 seconds, and the seismic intensity at that time is set to 1 second seismic intensity. Further, in the seek 2 seconds Intensity at time T _3, at time T ₃ of 2 seconds dating back from the "○" assumes the dashed line R, seismic intermediate value I of occupying time (waveform D) greater than the broken line R The height of the broken line R is adjusted so that the total is 0.3 seconds, and the seismic intensity at that time is defined as a 2-second seismic intensity.

Next, regarding the real-time seismic intensity calculated by the seismic intensity calculating unit 6a, k-net (National Disaster Prevention Science and Technology Center) concerning Chuetsu earthquake (October 23, 2004, magnitude: M6.8, epicenter depth: 13km) This will be explained using the observation data of the seismic observation network.
FIG. 4 is a diagram showing a real-time seismic intensity waveform (1 second seismic intensity) calculated based on observation data of the main earthquake of the Chuetsu earthquake. NIG017 to NIG020 are observation point codes, which indicate that the data that is the basis of each real-time seismic intensity waveform is observed at different points. NIG019 having the largest amplitude indicates a real-time seismic intensity waveform at the Ojiya observation point close to the epicenter. The horizontal axis represents the time (s) that has elapsed since the seismic intensity 1 was recorded, and the vertical axis represents the real-time seismic intensity. Further, the constituent elements or terms shown in FIG. 1 or FIG.
As shown in FIG. 4, the real-time seismic intensity (noise level) before the earthquake is normally -2 to -4, and when the P-wave reaches the installation point of the real-time seismometer 1a, the real-time seismic intensity rises rapidly and about 2 seconds later. The ground motion due to the P wave is maximized (point A). Thereafter, the S wave arrives and the real-time seismic intensity continues to increase. After about 4.5 seconds, the seismic motion due to the S wave reaches its maximum, and the real-time seismic intensity reaches 6.6 (point B). And the seismic motion due to the S wave starts to decrease, but at about 5.5 seconds, the amplitude of the surface wave prevails and the real-time seismic intensity starts to increase again. The maximum value is about 6.8 after about 8 seconds after the arrival of the P wave. (Point C). After that, the real-time seismic intensity also decreases with the decay of the seismic motion, and eventually returns to the noise level (seismic intensity -2 to -4) before the occurrence of the earthquake. In addition, a strong direct earthquake generally has such a seismic intensity waveform.

FIG. 5 is a diagram showing the seismic intensity intermediate value I calculated based on the observation data in Ojiya used in FIG. 4 and the real-time seismic intensity waveform (1 sec seismic intensity, 2 sec seismic intensity). The starting point of the time axis is 17:55:00 on October 23, 2004, and the noise level is about −3.5 in terms of seismic intensity. Waveform D represents the seismic intensity intermediate value I, and waveform E and waveform F represent the real-time seismic intensity. However, the waveform E is a 1-second seismic intensity (m = 100 (1 second), n = 30 (0.3 seconds)), and the waveform F is a 2-second seismic intensity (m = 200 (2 seconds), n = 30 (0 .3 seconds)).
As shown in FIG. 5, the P wave arrives approximately 2.75 seconds after the start of observation, and the seismic intensity exceeds 4 one second later, and the seismic intensity reaches 6.5 four seconds later. In addition, the delay at the rise of the P wave is approximately 0.3 seconds for both the 1 second seismic intensity (waveform E) and the 2 second seismic intensity (waveform F). Furthermore, comparing the 1-second seismic intensity (waveform E) with the 2-second seismic intensity (waveform F), the values are almost the same at the stage of increasing seismic intensity, but the 1-second seismic intensity (waveform E) is more effective in reducing the seismic motion. Excellent trackability. The maximum value of the 2-second seismic intensity (waveform F) is slightly larger, and the 2-second seismic intensity (waveform F) is delayed by about 1 second with respect to the 1-second seismic intensity (waveform E) when the ground motion is attenuated.

Next, the result of comparing the 1-second seismic intensity with the 5-second seismic intensity will be described.
FIG. 6 is a partially enlarged view of FIG. 5 in which the 2-second seismic intensity is replaced with the 5-second seismic intensity. In addition, about the waveform shown in FIG. 5, the same code | symbol is attached | subjected and the description is abbreviate | omitted. The waveform G has a seismic intensity of 5 seconds (m = 500 (5 seconds), n = 30 (0.3 seconds)).
As shown in FIG. 6, both the 1-second seismic intensity (waveform E) and the 5-second seismic intensity (waveform G) show almost the same value at the stage of increasing seismic intensity, but the maximum value is 5 from the 1-second seismic intensity (waveform E). The second seismic intensity (waveform G) is slightly larger. In addition, the delay of the 5-second seismic intensity (waveform G) with respect to the 1-second seismic intensity (waveform E) when the ground motion is attenuated is about 4 seconds.

Further, the responsiveness of the real-time seismic intensity meter 1a will be described using data at three points (observation point codes: TTRH02, SMNH01, TTR007) of the Tottori-ken Seibu earthquake (magnitude 4.2).
Figures 7 (a) to 7 (d) compare the real-time seismic intensity waveform (one-second seismic intensity) calculated based on the main shock and aftershock data of the Tottori-ken Seibu Earthquake and seismic intensity waveforms calculated using the same method as the conventional seismometer. FIG. 7 (a) and 7 (b) are based on the data of the main shock at the observation point codes (TTRH02, SMNH01), respectively, and FIGS. 7 (c) and (d) are the observation point codes (TTRH02, TTR007). Based on aftershock data. The solid line is the real-time seismic intensity calculated by the real-time seismic intensity meter 1a, and “●” is the seismic intensity of the conventional seismic intensity meter. Since the conventional seismometer uses an FFT (Fast Fourier Transform) algorithm in a 10-second section, the data to be processed is the time from “●” to 10 seconds before. In the figure, “●” indicates a value obtained by repeating this process every second.
As shown in FIGS. 7A to 7D, the real-time seismic intensity and the seismic intensity obtained by the conventional seismic intensity meter have different followability with respect to the attenuation of the ground motion. And when the seismic intensity of the conventional seismic intensity meter is compared with the real-time seismic intensity, the delay when the seismic motion is attenuated is approximately 10 seconds. Since the FFT processing section is determined in relation to the lower limit frequency of the filter processing, the delay at the time of earthquake motion attenuation cannot be shortened. Although it is possible to achieve a processing frequency equivalent to that of a real-time seismic intensity meter (10 times or more per second), it is not practical because a very large amount of data processing is required.

Real-time seismic intensity based on k-net observation data (number of earthquakes: 18, number of data: 2739) for major earthquakes from the Tottori-ken Seibu earthquake in October 2000 to the Chuetsu-oki earthquake in July 2007 The result of calculating the maximum value of (second seismic intensity) will be described with reference to FIG.
FIG. 8 is a diagram showing the relationship between the maximum real-time seismic intensity (1 second seismic intensity) and the measured seismic intensity. The horizontal axis is the measured seismic intensity measured with an existing seismometer using the FFT method as a filter for weighting for seismic intensity conversion, and the vertical axis is the maximum real-time seismic intensity obtained using the real-time seismometer 1a. .
As shown in FIG. 8, the maximum real-time seismic intensity is in good agreement with the measured seismic intensity. Therefore, in the real-time seismic intensity meter 1a of the present embodiment, the maximum value of the real-time seismic intensity is obtained in the seismic intensity calculation unit 6a as the measured seismic intensity equivalent value.

Here, based on k-net observation data (4678) that recorded seismic intensity 0 or more in 18 earthquakes that occurred from the Tottori-ken Seibu Earthquake in October 2000 to the Chuetsu-oki Earthquake in July 2007. The results of obtaining the real-time seismic intensity (1-second seismic intensity) of the area until the wave reaches (hereinafter referred to as P-wave area) will be described with reference to FIGS.
FIG. 9A is a diagram showing the relationship between the maximum value of the real-time seismic intensity (1 second seismic intensity) and the measured seismic intensity in the entire P wave region, and FIG. 9B is the real time from the arrival of the P wave to 1 second later. It is the figure which showed the relationship between the maximum value of a seismic intensity (1 second seismic intensity), and a measured seismic intensity. Moreover, Fig.10 (a) is the figure which showed the relationship between the maximum value of the real-time seismic intensity (1 second seismic intensity) from the arrival of the P wave to 2 seconds later, and the measured seismic intensity. It is the figure which showed the relationship between the maximum value of the real-time seismic intensity (1 second seismic intensity) until 3 seconds, and a measured seismic intensity. 9 and 10, the horizontal axis represents the measured seismic intensity measured with an existing seismometer that uses the FFT method for the weighting filter for seismic intensity conversion, and the vertical axis is obtained using the real-time seismic intensity meter 1a. Represents real-time seismic intensity.
As shown in FIG. 9A, a strong correlation is recognized between the maximum value of the real-time seismic intensity in the entire P wave region and the measured seismic intensity obtained by the existing method for each earthquake occurring inland or on the coast. However, the Tokachi-oki earthquake (magnitude 8) and the southeastern Mie prefecture offshore (magnitude 7.4) have different characteristics.
Therefore, for inland or coastal earthquakes, the relationship between the maximum value of the real-time seismic intensity and the measured seismic intensity in the entire P-wave region is obtained in advance as shown by the broken line approximation formula before the arrival of the S wave. The measured seismic intensity can be estimated for the observed earthquake.
As shown in FIG. 9B, for each earthquake occurring inland or on the coast, there is a correlation between the maximum real-time seismic intensity from the arrival of the P wave and one second after the arrival of the P wave and the measured seismic intensity. Therefore, it is possible to estimate the measured seismic intensity for the earthquake to be observed before the arrival of the S wave by obtaining in advance the relationship between the maximum value of the real time seismic intensity and the measured seismic intensity 1 second after the arrival of the P wave. is there. In this case, although the prediction accuracy of the measured seismic intensity is lower than in the case of FIG. 9A, there is an advantage that the time required for calculating the measured seismic intensity is shortened.
Further, in FIG. 10A, the data variation is somewhat improved compared to FIG. 9B. Therefore, when the maximum real-time seismic intensity from the arrival of the P wave to 2 seconds later is used, the measured seismic intensity is predicted with higher accuracy than when the maximum real-time seismic intensity from the arrival of the P wave to 1 second later is used. Can do.
Further, in FIG. 10B, the data variation is further improved as compared with FIG. 9B. Therefore, when using the maximum value of the real-time seismic intensity from 3 seconds after the arrival of the P wave, the prediction accuracy of the measured seismic intensity is further improved compared to the case of using the maximum value of the real-time seismic intensity from 1 second after the arrival of the P wave. . However, since the time required to calculate the measured seismic intensity increases, the time from when an alarm or the like is issued until the S wave arrives (margin time) is shortened.
That is, when an earthquake that occurs inland or on the coast is to be observed, the real-time seismometer 1a of the present embodiment is selected from the maximum value in the P-wave region or the arrival of the P-wave in the seismic intensity calculator 6a. The measurement seismic intensity equivalent value can be calculated from the maximum value of the real-time seismic intensity within the time.

  The determination unit 7 determines the type of earthquake shown in Table 1 based on the real-time seismic intensity waveform, and for earthquakes with an estimated seismic intensity IV (measured seismic intensity 3.5) or higher in the seismic intensity class set by the Japan Meteorological Agency shown in Table 2. In response, an earthquake disaster prevention signal 14 corresponding to the type of earthquake is issued. The alarm unit 8 issues a different alarm for each type of earthquake according to the earthquake disaster prevention signal 14.

Next, a method for determining the type of earthquake in the determination unit 7 will be described using k-net observation data.
FIGS. 11 to 13 show real-time seismic intensity waveforms (1) calculated based on observation data at points of epicenter distances of 15 to 32 km, 20 to 42 km, 42 to 120 km, and 96 to 214 km in the same Chuetsu earthquake as in FIG. Fig. 14 shows the real-time seismic intensity waveform calculated based on the observation data at the epicenter distance of 96 to 214 km in the Tokachi-oki earthquake (magnitude: M8.0, epicenter depth: 45 km). (1 second seismic intensity). That is, FIG. 11 is a diagram showing a real-time seismic intensity waveform immediately below or near each observation point, and FIG. 12 is a diagram showing a real-time seismic intensity waveform for earthquakes in the vicinity. FIG. 13 is a diagram showing a real-time seismic intensity waveform in a teleseismic earthquake occurring inland or on the coast, and FIG. 14 is a diagram showing a real-time seismic intensity waveform in a trench-type seismic earthquake. NIG017 and the like are observation point codes, which indicate that seismic intensity waveforms are observed at different points. The horizontal axis represents the time (s) that has elapsed since the seismic intensity 1 was recorded, and the vertical axis represents the real-time seismic intensity. Furthermore, the broken lines indicated by (1) to (5) are alarm determination criteria. In the determination unit 7 of the real-time seismometer 1a of the present embodiment, the seismic intensity waveform is within the broken line (1)-(2) within 0.5 seconds. When (seismic intensity 2) is exceeded, it is determined to be a direct earthquake, and within 5 seconds the broken line (3)-(4) (seismic intensity 3.3) is determined to be a near-field earthquake, and after 5 seconds the broken line When (5)-(6) (seismic intensity 4.5) is exceeded, it is determined to be a far-field earthquake and an earthquake disaster prevention signal 14 is output.

As shown in FIG. 11, the seismic intensity waveforms of NIG017 to NIG020 all exceed the broken line (1)-(2) (seismic intensity 2) within 0.5 seconds. Therefore, if the real-time seismometer 1a is installed at the time of this earthquake, the determination unit 7 determines that the type of earthquake is a direct earthquake and outputs the earthquake disaster prevention signal 14, and the alarm unit 8 outputs the earthquake disaster prevention signal 14 Will issue a warning indicating a direct earthquake. For the observation point code NIG019 (Ojiya), the time from when the determination unit 7 of the real-time seismometer 1a detects the P wave until the alarm unit 8 issues an alarm reaches 0.1 seconds, and reaches the maximum amplitude after the alarm is output. Time (hereinafter referred to as margin time) is 7.8 seconds. Similarly, the margin times of NIG017, NIG018, and NIG020 are 5.2 seconds, 21.5 seconds, and 5.9 seconds, respectively. As already described, since there is a time delay of approximately 0.3 seconds between the real-time seismic intensity calculated by the seismic intensity calculation unit 6a of the real-time seismic intensity meter 1a and the ground motion, the output time of the earthquake disaster prevention signal 14 It is necessary to add 0.3 seconds and subtract 0.3 seconds from the surplus time.
In FIG. 12, the seismic intensity waveforms of NIG021, NIG022, NIG028, and FSK028 all exceed the broken line (3)-(4) (seismic intensity 3.3) within 5 seconds. If the real-time seismometer 1a is installed in the same manner as described above, the determination unit 7 determines that the type of earthquake is a near-field earthquake, outputs an earthquake disaster prevention signal 14, and receives the earthquake disaster prevention signal 14 as an alarm unit 8 Emits a warning indicating a nearby earthquake. The margin times of NIG021, NIG022, NIG028, and FSK028 are 3.2 seconds, 2.6 seconds, 6.5 seconds, and 4.6 seconds, respectively.
Moreover, in FIG. 13, all the seismic intensity waveforms exceed the broken line (5)-(6) (seismic intensity 4.5) after 5 seconds. In this case as well, if the real-time seismometer 1a is installed as in FIG. 11, the determination unit 7 determines that the earthquake type is a far-field earthquake and outputs an earthquake disaster prevention signal 14, and the alarm unit 8 causes the earthquake disaster prevention. In response to the service signal 14, an alarm indicating a far-field earthquake is issued. The margin time at this time is 0.0 to 8.4 seconds.
Furthermore, also in FIG. 14, all seismic intensity waveforms exceed the broken lines (5)-(6) (seismic intensity 4.5) after 5 seconds. Therefore, if the real-time seismometer 1a is installed as in the case of FIG. 11, the determination unit 7 determines the type of earthquake as a far-field earthquake and outputs an earthquake disaster prevention signal 14. The alarm unit 8 receives the earthquake disaster prevention signal 14 and issues an alarm indicating a far-field earthquake. The margin time at this time is 0.7 to 17.3 seconds.

The real-time seismometer 1a having the above structure has an effect that the burden on hardware is reduced as compared with the FFT seismometer. In addition, the measured seismic intensity equivalent value can be accurately measured in real time from the maximum real-time seismic intensity with a simple configuration. Then, when the seismic intensity calculation unit 6a is configured to obtain a maximum value in the P-wave region in the real-time seismic intensity and set it as a measured seismic intensity equivalent value, the measured seismic intensity equivalent value is an S wave or surface wave. It has the effect of being easily and quickly calculated before reaching. Further, when the seismic intensity calculation unit 6a is configured to obtain the maximum value within a predetermined time of the P wave initial motion part among the real time seismic intensity as the measured seismic intensity equivalent value, the maximum value of the real time seismic intensity in the P wave region is obtained. Although the prediction accuracy of the measured seismic intensity is lower than in the case, the calculation time is shortened.
Furthermore, if the real-time seismometer 1a is used as a control seismometer, it is possible to have a configuration for generating a control signal including information on the type of earthquake. In this case, the control target device is unnecessary. The operation is prevented.

  As described above, the real-time seismometer 1a according to the present embodiment is less likely to fail because the burden on hardware is small. In addition, by controlling the operating state of equipment such as elevators and manufacturing equipment based on seismic intensity (real-time seismic intensity) measured without time delay with respect to earthquake motion, accurate emergency control that eliminates unnecessary operations is possible. It is. Furthermore, it has a configuration capable of determining the type of earthquake, and can issue an alarm or control signal based on a scale associated with damage. As a result, the reliability of the earthquake information is increased, so that the occurrence of damage due to the earthquake can be minimized. In addition, since the structure of the seismic intensity meter can be simplified, it is possible to reduce the size and cost of the device. Further, if the seismic intensity calculation unit 6a is configured to obtain the maximum value in the P wave region in the real-time seismic intensity and set it as a value corresponding to the measured seismic intensity, it is effective even in the vicinity of the epicenter where the emergency earthquake warning is difficult to apply. Alarms and control signals can be issued. Then, when the seismic intensity calculation unit 6a is configured to obtain the maximum value within a predetermined time of the P wave initial motion portion among the real-time seismic intensity as the measured seismic intensity equivalent value, the measured seismic intensity equivalent in a shorter time than the above case. Since the value is calculated, it is possible to issue a warning and a control signal more effectively. In addition, the real-time seismometer 1a analyzes the P-wave initial motion part and predicts (highly dangerous) direct earthquakes, near-field earthquakes, and far-field earthquakes above a certain seismic intensity before reaching the main motion. It is possible to issue a warning or control signal based on a scale associated with damage. As a result, the reliability of the earthquake information is increased, so that the occurrence of damage due to the earthquake can be minimized. When using as a control seismometer for devices that can be controlled instantaneously, such as switching off a switch or solenoid valve, stop the devices when the seismic intensity reaches a critical seismic intensity that can be safely operated. Therefore, excessive operation can be completely prevented. Thus, since the real-time seismometer 1a functions autonomously with respect to any earthquake, it does not incur communication costs like a device that uses emergency earthquake alerts, and is most suitable for earthquake disaster prevention of direct earthquakes. .

  Here, real-time observation data (4678) of k-net that recorded seismic intensity 1 or higher in 18 major earthquakes that occurred from the Tottori-ken Seibu earthquake in October 2000 to the Chuetsu-oki earthquake in July 2007. Table 3 shows the results of processing with the seismic intensity meter 1a. The numbers in the table are the number of observation points that output an alarm, and “G” and “NG” mean “normal operation” and “illegal operation”, respectively. “T” means the time from the alarm output to the maximum seismic intensity (margin time).

  As shown in Table 3, there are a total of 48 earthquakes (23 earthquakes with seismic intensity V or more), of which 3 are seismic intensity III (3.3 (2), 3.4 (1) )), A warning is issued (correct answer rate: 94%). In addition, there are a total of 64 earthquakes classified into nearby areas (21 earthquakes with seismic intensity V or higher), and one of them has issued a warning with seismic intensity III (3.4) (correct answer rate: 98%). Furthermore, there were a total of 276 earthquakes classified into remote areas (56 earthquakes with seismic intensity V or higher), 14 of which were seismic intensity V or higher with a margin time of less than 3 seconds. In other words, when the margin time is 3 seconds or more and “normal operation” is set, the correct answer rate is 91%. In addition, although the probability is low, among the earthquakes that are classified directly below or in the vicinity, excessive operations have occurred particularly in inland earthquakes with a small magnitude.

Next, the operation of the real-time seismometer 1a according to the present embodiment will be described using the k-net observation data related to the Chuetsu earthquake while comparing it with the prior art.
FIG. 15 is a diagram in which the vertical acceleration component waveforms recorded at observation points (327 locations) during the Chuetsu earthquake are plotted in the vertical axis direction according to the epicenter distance. That is, the vertical axis represents the epicenter distance (km), and the horizontal axis represents the elapsed time (s). Also, the origin of the horizontal axis (elapsed time 0 s) and the time when the earthquake occurred at the epicenter (hereinafter referred to as the epicenter time (O)) do not match. In addition, the broken line in a figure shows the time (henceforth P wave arrival point (P)) and the time of S wave arrival (henceforth S wave arrival point (S)) when the P wave arrived in each data. Are connected to each other.
Referring to FIG. 15, as the observation point is farther from the epicenter, the time of the P wave arrival point (P) is delayed and the time difference between the P wave arrival point (P) and the S wave arrival point (S) is larger. . In addition, although the scale of each data is automatically adjusted so that the amplitude of the waveform does not shake out, when the epicenter distance exceeds 200 km, the waveform gradually begins to break and the epicenter distance exceeds 230 km. Waveform breaks at the observation points. And the waveform is sparse at the observation point where the epicenter distance exceeds 290 km. This indicates that the earthquake has been overlooked.

FIG. 16 is a diagram in which real-time seismic intensity waveforms calculated from the same observation data as in FIG. 15 using the real-time seismic intensity meter 1a of this embodiment are plotted along the vertical axis according to the epicenter distance. The vertical axis and the horizontal axis indicate the epicenter distance (km) and the elapsed time (s), respectively, and the origin (elapsed time 0 s) and the epicenter time (O) on the horizontal axis do not match. In addition, the P wave arrival point (P) and the S wave arrival point (S) in each data are shown connected by broken lines.
As shown in FIG. 16, when the distance from the epicenter is reached, the time of the P wave arrival point (P) is delayed, the time difference between the P wave arrival point (P) and the S wave arrival point (S) is increased, and the seismic intensity gradually decreases. I understand. In this embodiment, since the seismic intensity recording sensitivity is set to a constant value regardless of the epicenter distance, as shown in FIG. 16, the strength of the seismic motion is directly expressed as the amplitude of the real-time seismic intensity waveform. Therefore, the arrival point of the P wave and S wave can be clearly read. In addition, at the observation point with a long epicenter distance, a head cut of the real-time seismic intensity waveform occurs as in FIG.

FIGS. 17A to 17T are diagrams respectively showing real-time seismic intensity waveforms at 20 observation points whose epicenter distance is shorter than 62 km among those shown in FIG. FIGS. 18A to 18T are diagrams individually showing real-time seismic intensity waveforms at 20 observation points whose epicenter distance is longer than 198 km among those shown in FIG. The vertical and horizontal axes are seismic intensity (real-time seismic intensity) and elapsed time (s), respectively. In FIGS. 17 and 18, (a) shows data at an observation point closest to the epicenter, and (t) shows data at an observation point farthest from the epicenter.
17 and 18, the seismic intensity before reaching the seismic wave is about -4. However, when the P wave arrives, the seismic intensity increases rapidly and reaches its maximum after the arrival of the S wave. The seismic intensity increases gradually as the epicenter distance increases. Moreover, since FIG. 17 is the data of the observation point close to the epicenter, the real-time seismic intensity waveform is not truncated, but since FIG. 18 is the data of the observation point far from the epicenter, (a), (d), In the diagrams (h), (k), (p), and (q), the real-time seismic intensity waveform is broken.
In addition, in FIG. 18, when the data which the head breakage of the real-time seismic intensity waveform has occurred and the data which does not have the head breakage are compared, there is no difference in the S / N ratio of both. Therefore, it is considered that the phenomenon of real-time seismic intensity waveform cut-off seen in these figures occurred due to insufficient capability of the conventional device used for observation. Moreover, according to the real-time seismic intensity meter 1a of the present embodiment, a known technique for automatically adjusting the threshold value is used in combination, and the threshold value is set to about +2 of the noise level in seismic intensity. Even in this case, it is possible to reliably detect the rise of the P wave by preventing data from being cut off at all observation points.

Furthermore, the effect | action which removes noises other than an earthquake which the real-time seismometer 1a of a present Example has is demonstrated.
Generally, since an earthquake sensor represented by an acceleration sensor or the like responds to all ground vibrations other than earthquakes, various devices have been devised to remove noises other than those earthquakes. For example, a method of providing a so-called noise removal filter that removes noise using a difference in frequency between an earthquake sensor and an earthquake detector, or a method of automatically adjusting a threshold for judging an earthquake in conjunction with a noise level It has been known. In addition, by setting to detect only vibration that has continued for a certain period of time, earthquakes are detected only when there is a method for removing noise that occurs only once, such as lightning strikes, or when multiple seismic sensors detect simultaneously. There is also a method for determining that it has occurred.
On the other hand, the real-time seismometer 1a of the present embodiment includes the digital filter 4a as described above, and the digital filter 4a has the frequency characteristics shown in FIG. That is, the digital filter 4a suppresses the sensitivity of the frequency components on both sides centering on 0.7 Hz where the destructive force of the earthquake is large, and in particular, noise of frequency components of 10 Hz or more is removed. Further, as already described, the real-time seismometer 1a is configured to select a value that lasts for a certain period of time (for example, 0.3 seconds) in the calculation of the seismic intensity calculator 6a. It has the effect that it is hardly affected by the noise generated once.

FIG. 19A shows acceleration data during a lightning strike observed by a conventional accelerometer, and FIG. 19B shows data after passing through the seismic intensity filter of the real-time seismometer 1a of the present embodiment. ) Is a real-time seismic intensity waveform calculated from the acceleration data of FIG. FIGS. 19A and 19B are time waveforms of acceleration components in three directions of up and down, north and south, and east and west, and the vertical axis and the horizontal axis are acceleration (gal) and time (s), respectively.
As shown in FIG. 19 (a), when a lightning strike occurs near the observation point, electrical noise (noise near 52 seconds) is generated due to surge current, and ground vibration (noise near 53 seconds) caused by thunder sound is generated. appear. When these noises are passed through the seismic intensity filter, the high frequency components are removed as shown in FIG. 19B, but the low frequency components remain without being removed. At this time, as shown in FIG. 19 (c), the maximum value of the pulsed seismic intensity waveform is seismic intensity 0, but in the real-time seismic intensity meter 1a of the present embodiment, the threshold value for determining an earthquake is set to seismic intensity 2 or higher. Therefore, noise generated by lightning can be reliably removed.

FIG. 20A shows acceleration data when passing through a snowplow observed by a conventional accelerometer, and FIG. 20B shows data after passing the seismic intensity filter of the real-time seismometer 1a of the present embodiment. (C) is a real-time seismic intensity waveform calculated from the acceleration data of FIG. 20A and 20B are time waveforms of acceleration components in three directions of up and down, north and south, and east and west, and the vertical axis and the horizontal axis are acceleration (gal) and time (s), respectively.
As shown in FIG. 20A, when the snowplow passes near the observation point, large vibration noise is continuously generated. When this noise is passed through the seismic intensity filter, the high frequency component is removed as shown in FIG. At this time, the maximum value of the pulsed seismic intensity waveform is −0.7 or less as shown in FIG. Also in this case, by using the real-time seismic intensity meter 1a of the present embodiment and setting the threshold value to, for example, seismic intensity 2 or higher, it is possible to reliably remove vibration noise accompanying the passing of the snowplow.

  The structure of the real-time seismometer of the present invention is not limited to this embodiment. For example, the calculation of the real-time seismic intensity by the calculation unit 9a does not have to be performed every sampling, and may be performed at a necessary frequency (about 10 Hz). Further, the same result can be obtained even if the order of the vector synthesizer 5 and the seismic intensity calculation unit 6a is changed. However, in this case, the n consecutive seismic intensity intermediate values I for each of the three types of time series data obtained by substituting the digital signals 12a to 12c into “a” in the equation (1) from the top n The second value is obtained and used as the real-time seismic intensity. In this way, the same result can be obtained by either method, but the number of digits of the numerical value handled in the case of the first embodiment is smaller.

  In general, manufacturing equipment such as semiconductors can be used to prevent or reduce damage to the equipment by an emergency stop in the event of an earthquake. However, if the equipment is shut down urgently, it is necessary to dispose of products on the line (work in process). May result in significant losses. Therefore, in these facilities, etc., there is a problem that “I want to avoid emergency stops other than when they are really necessary” as much as possible. Therefore, as a countermeasure, the frequency characteristic of the digital filter 4a of the present embodiment can be set to “corresponding to the limit intensity at each frequency of the target equipment or the like” instead of FIG. That is, the digital signals 11a to 11c described with reference to FIG. 1 are weighted with respect to a predetermined frequency by the digital filter 4a according to the frequency characteristics set in advance based on the characteristics of the structure or equipment to be alarmed or controlled. It is set as such. In this case, it is equivalent to setting the alarm level according to the frequency response limit strength of the target equipment etc., and it becomes possible to perform emergency control only for earthquakes with a truly harmful frequency spectrum, Earthquake disaster prevention such as more precise equipment is possible.

  Also, earthquake classifications and judgment criteria are not limited to those shown in the present embodiment, and can be appropriately changed according to the purpose of use. However, if the seismic intensity level of the broken line (1)-(2) of the alarm judgment standard is lowered, an alarm can be issued in a shorter time, but an unnecessary operation may occur in a small earthquake of less than M5 that occurs immediately below. However, if the seismic intensity level of the broken line (1)-(2) is increased, the possibility of unnecessary operation in a small earthquake of less than M5 is further reduced, but the time for issuing an alarm will be delayed. Become. And when the determination time of the broken line (2)-(3) is delayed, the possibility that an unnecessary operation occurs in an earthquake with a low seismic intensity increases, and conversely, when the determination time of the broken line (2)-(3) is increased, The earthquake in the immediate subdivision changes to the neighborhood, and the warning time is delayed. Therefore, it is desirable to set the seismic intensity level of the broken lines (1)-(2) and the determination time of the broken lines (2)-(3) by a trade-off between the alarm output time and the unnecessary operation.

A real-time seismometer according to the second embodiment will be described with reference to FIG. 21 (particularly, corresponding to claims 2, 4, 11, and 13).
FIG. 21 is a configuration diagram of Example 2 of the real-time seismometer according to the embodiment of the present invention. In addition, about the component demonstrated using FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
As shown in FIG. 21, the real-time seismometer 1b of the present embodiment includes an analog filter 4b instead of the digital filter 4a in the real-time seismometer 1a of the first embodiment. That is, the analog signals 10a to 10c output from the acceleration detecting means 2 are input to the analog filter 4b, weighted as shown in FIG. 2 with respect to a predetermined frequency, and then output as analog signals 15a to 15c. . The analog signals 15a to 15c are converted into digital signals 16a to 16c by the A / D converter 3, respectively, are vector-synthesized by the vector synthesizer 5, and are output as a synthesized digital signal 13b.
In the real-time seismometer 1b having such a configuration, the range of seismic intensity that can be measured is narrower than when the digital filter 4a is used, but the burden on hardware is smaller than that of the real-time seismometer 1a according to the first embodiment. In addition, the load required for the filtering process is reduced. Therefore, it can be made cheaper than the real-time seismic intensity meter 1a.

  In the real-time seismometer 1b according to the present embodiment, the frequency characteristic of the analog filter 4b can be set to “corresponding to the limit intensity at each frequency of the target equipment or the like” instead of FIG. When such a real-time seismometer 1b is used as a control seismometer, an alarm level is set according to the frequency response limit intensity of the target equipment and the like, which is truly harmful. Emergency control can be performed only for earthquakes having a frequency spectrum. Thereby, accurate earthquake disaster prevention of equipment and the like becomes possible.

A real-time seismometer according to the third embodiment will be described with reference to FIGS. 22 to 27 (particularly, corresponding to claims 6, 9, 15, and 18).
FIG. 22 is a configuration diagram of Example 3 of the real-time seismometer according to the embodiment of the present invention. In FIG. 22, an epicenter distance calculation unit 6b is added to FIG. Also, the same components as those described with reference to FIG.

Here, the relationship between the real-time seismic intensity waveform (1 second seismic intensity) and the magnitude of the earthquake will be described using observation data of k-net of the main shock and aftershock of the Aki-Nada earthquake.
FIG. 23 is a diagram showing a real-time seismic intensity waveform calculated based on observation data of the Aki Pass earthquake. For aftershocks, we selected those with the same epicenter distance (approximately 50 km) as the main shock.
As shown in FIG. 23, the real-time seismic intensity increases sharply with the arrival of the P-wave, and the growth duration of the real-time seismic intensity after reaching the P-wave (the time to reach the maximum seismic intensity in the P-wave region) increases as the magnitude of the earthquake increases. The maximum value of seismic intensity that is finally reached is also large. In addition, although the maximum values of the P wave and S wave fluctuate depending on the magnitude, the rise (speed and rate of increase) of the real-time seismic intensity waveform is hardly affected by the magnitude. Further, the maximum increase rate of the real-time seismic intensity waveform is recorded within 0.5 seconds after the arrival of the P wave.

Next, the relationship between the rate of increase in real-time seismic intensity (1 second seismic intensity) and the epicenter distance will be described with reference to FIG.
24A to 24F are diagrams in which the maximum value of the increase rate at the time of rising of the real-time seismic intensity waveform is plotted for many earthquakes. The horizontal axis is the epicenter distance (km), and the vertical axis is the real-time seismic intensity increase rate (seismic intensity / second), both of which are logarithmic axes. For example, if “the time required for the seismic intensity to increase by 1 is 0.05 seconds”, “increase rate = 20”. Further, diff X (0.01 seconds) in the figure indicates that the difference time is 0.01 seconds. Note that the description of the dots in FIGS. 24A to 24E is the same as that in FIG. 24F, and the difference in dot shape indicates that the magnitude of the earthquake is different.
24 (a) to 24 (f), it can be seen that the rate of increase in real-time seismic intensity is inversely proportional to the epicenter distance, and does not depend on the magnitude of the magnitude.

Furthermore, the relationship between the rise time of the real-time seismic intensity waveform (1 second seismic intensity) and the epicenter distance will be described with reference to FIG.
FIGS. 25A to 25I are graphs in which the rise time of the real-time seismic intensity waveform is plotted for many earthquakes. The description of the dots in these figures is shown in the lower right corner. The horizontal axis is the epicenter distance (km), the vertical axis is the rise time (s) of the real-time seismic intensity waveform, and both are logarithmic axes. In addition, the difference in dot shape indicates that the seismic intensity (seismic intensity class) is different. Note that TimeDJma (−2 to 0) means data when the real-time seismic intensity value changes from “−2” to “0”.
As shown in FIGS. 25A to 25I, the rise time of the real-time seismic intensity waveform is proportional to the epicenter distance, but is not affected by the seismic intensity. The data when the real-time seismic intensity value changes from “0” to “1” has the smallest variation.

FIG. 26 is a diagram showing the relationship between the rise time of the real-time seismic intensity waveform and the epicenter distance when the value of the real-time seismic intensity (1 second seismic intensity) changes from “0” to “1”. The horizontal axis is the epicenter distance (km), and the vertical axis is the rise time (s) of the real-time seismic intensity waveform.
FIG. 26 shows that the rise time of the real-time seismic intensity waveform is shorter as the epicenter distance is closer. Note that the data shown in FIG. 26 varies widely, so it is difficult to accurately estimate the epicenter distance based on the rise time of the real-time seismic intensity waveform. 50-100 km), and it is possible to predict the category of teleseismic earthquakes (100 km or more).

Real-time data from 15 earthquakes from October 2000 Tottori-ken Seibu Earthquake to March 2006 Fukuoka-ken Seiho-Oki Earthquake using seismic intensity 3 or higher (1149). The relationship between the rise time of the seismic intensity waveform (1 second seismic intensity) and the measured seismic intensity will be described.
FIGS. 27A and 27B show the relationship between the rise time of the real-time seismic intensity waveform and the measured seismic intensity when the real-time seismic intensity value changes from “0” to “2” and from “0” to “3”, respectively. It is a figure. The horizontal axis is the measured seismic intensity, and the vertical axis is the rise time (s) of the real-time seismic intensity waveform. In addition, the legend represents “earthquake name”, “magnitude”, and depth (km) of the epicenter.
As shown in FIGS. 27 (a) and 27 (b), the rise time of the real-time seismic intensity waveform becomes shorter as the seismic intensity increases. In addition, there is a correlation between the rise time of the real-time seismic intensity waveform and the measured seismic intensity. Therefore, for example, if an approximate expression (broken line) as shown by a broken line is prepared in advance, the measured seismic intensity equivalent value can be obtained from the rise time of the real-time seismic intensity waveform before the arrival of the S wave by using this approximate expression. However, even in the case of an earthquake with a small magnitude, the rise of the real-time seismic intensity waveform becomes sharp when the epicenter distance is short, so there are cases where the above approximate expression cannot be predicted as in the data surrounded by the broken line in FIG. is there. In this case, for example, as shown in FIG. 27B, the measured seismic intensity is predicted based on the rise time of the real-time seismic intensity waveform when the real-time seismic intensity value changes from “0” to “3”. The effects of the aforementioned small magnitude earthquakes are reduced or eliminated.
In FIG. 27 (b), the M7 class earthquake immediately below or in the vicinity has a short rise time in the real-time seismic intensity waveform, and the arrival seismic intensity is large, while the earthquake in the immediately below M5 class has a short rise time in the real-time seismic intensity waveform, The measured seismic intensity is small. In addition, the seismic intensity of the M7 class in the remote area is slightly longer in the rise time of the real-time seismic intensity waveform, and the measured seismic intensity is smaller. Yes. Therefore, “P-wave growth duration and seismic intensity growth” differ between “directly or nearby M7 class earthquakes” and “directly M5 class earthquakes”. It is possible to output an appropriate alarm by distinguishing between the two using. Further, long-distance earthquakes of M7 class or higher can be distinguished from far-field earthquakes by appropriately selecting the determination condition of “arrival seismic intensity and arrival time”. Thus, it is highly likely that an earthquake whose rise time of the real-time seismic intensity waveform is within 2 seconds is a major earthquake immediately below, and an earthquake whose rise time of the real-time seismic intensity waveform is within 2 to 10 seconds is a local earthquake. Probability is high. In addition, since the characteristics of trench-type earthquakes such as the Tokachi-oki earthquake (magnitude 8 or 7.1) are different from those of other earthquakes, another judgment is necessary.

The real-time seismometer 1c of the present embodiment uses the characteristics of the real-time seismic intensity waveform described above. In particular, in the real-time seismometer 1a of the first embodiment, the real-time seismic intensity is changed from the first seismic intensity to the second seismic intensity in the P wave initial motion part. The seismic intensity calculation unit 6a calculates a value corresponding to the measured seismic intensity based on the time required to reach the seismic intensity, and the epicenter distance calculation unit 6b calculates the real-time seismic intensity increase rate or the real-time seismic intensity from the first seismic intensity to the second seismic intensity. The epicenter distance is calculated based on the time required to reach the seismic intensity. That is, the epicenter distance calculation part 6b comprises the calculating part 9a with the vector synthesizer 5 and the seismic intensity calculation part 6a.
In the real-time seismometer 1c having such a configuration, the intensity of the seismic motion due to the S wave or the surface wave is quickly predicted before the arrival of the S wave or the surface wave. That is, since the epicenter distance and the measured seismic intensity equivalent value can be predicted in a very short time, it is possible to issue an effective alarm and control signal even in the vicinity of the epicenter where emergency earthquake warning is particularly difficult to apply. This makes it possible to take appropriate disaster prevention measures.

A real-time seismometer according to the fourth embodiment will be described with reference to FIGS. 28 to 37 (particularly corresponding to claims 19 to 22).
FIG. 28 is a configuration diagram of Example 4 of the real-time seismometer according to the embodiment of the present invention. FIG. 29 is a diagram showing frequency characteristics of a digital filter constituting the real-time seismometer of the fourth embodiment. In addition, about the component demonstrated using FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
As shown in FIG. 28, the real-time seismometer 1d according to the present embodiment is the same as the real-time seismometer 1a according to the first embodiment, in which digital signals 11a to 11c are alarmed or controlled with respect to a predetermined frequency by the digital filter 4a. This corresponds to one of the modifications in which the weighting is performed according to the frequency characteristics set in advance based on the characteristics of the structure or equipment. Specifically, the real-time seismometer 1d includes three filters 17a to 17c having different pass frequency bands in place of the digital filter 4a, the calculation unit 9a, the determination unit 7, and the alarm unit 8 in the real-time seismometer 1, and these A calculation unit 9b that processes a signal that has passed through the filter, determination units 20a to 20c, and alarm units 21a to 21c are provided. Further, the calculation unit 9b includes vector synthesizers 18a to 18c and seismic intensity calculation units 19a to 19c, and is configured to be able to individually process signals that have passed through the filters 17a to 17c. The filters 17a to 17c have frequency characteristics shown in FIGS. 29 (a) to 29 (c), respectively.

  The digital signals 11a to 11c output from the A / D converter 3 are cut into frequency components of 0.333 Hz or more by the filter 17a to become digital signals 22a to 22c. The digital signals 11a to 11c input to the filter 17b are output as digital signals 23a to 23c after the frequency components other than 0.333 Hz to 2 Hz are cut off. Further, the digital signals 11a to 11c input to the filter 17c are each output with the frequency components of 2 Hz or less cut as digital signals 24a to 24c. The digital signals 22a to 22c, the digital signals 23a to 23c, and the digital signals 24a to 24c are vector-synthesized by the vector synthesizers 18a to 18c, respectively, to become combined digital signals 25a to 25c. The seismic intensity calculators 19a to 19c calculate real-time seismic intensity J1 to J3 based on the combined digital signals 25a to 25c, respectively, and the determination units 20a to 20c determine the type of earthquake based on the real-time seismic intensity J1 to J3 and the earthquake. The disaster prevention signals 26a to 26c are respectively output, and the alarm units 21a to 21c respectively issue alarms including information on the type of earthquake according to the earthquake disaster prevention signals 26a to 26c.

  Some earthquakes have a biased frequency spectrum and some have a long vibration period. In such a case, since the conventional seismometer uses a seismic intensity filter determined by the Japan Meteorological Agency, there is a possibility that an appropriate result cannot be obtained. On the other hand, the real-time seismometer 1d of the present embodiment has an effect that the type of earthquake is individually determined based on the signals of three types of frequency bands passing through the filters 17a to 17c. Therefore, if the real-time seismometer 1d of this embodiment is used for facility management, the seismic intensity in the frequency band including the natural frequency of each facility can be accurately detected. This makes it possible to take appropriate disaster prevention measures and mitigation measures for each facility.

Here, k-net observation data on the Iwate-Miyagi inland earthquake that occurred in June 2008, the Niigata Chuetsu earthquake that occurred in October 2004, and the Tokachi-oki earthquake that occurred in September 2003 are recorded in real time seismometer 1d. The processing results will be described with reference to FIGS.
FIG. 30A is a frequency spectrum obtained by processing observation data (observation point is Ichikansai) of the surface vertical motion component related to the Iwate-Miyagi inland earthquake using the real-time seismometer 1d of Example 4. b) is the real-time seismic intensity waveform of FIG. 31 (a) to 31 (c) are based on signals subjected to filtering processing such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more in the same observation data as FIG. It is a real-time seismic intensity waveform calculated by FIGS. 31A to 31C correspond to the above-described real-time seismic intensity J1 to J3, respectively. In addition, both the horizontal axis and the vertical axis in FIG. 30A are logarithmic axes.
As shown in FIG. 30A, the frequency component of 0.333 Hz or less is small, the frequency component of 0.333 to 2 Hz is slightly small, and the frequency component of 2 Hz or more is large. Moreover, as shown in FIG.30 (b), the maximum value of real-time seismic intensity has reached 6.3.
As shown to Fig.31 (a), the time when the seismic intensity exceeded 1 in the frequency band below 0.333 Hz is less than 60 second. Therefore, it can be seen that there was little possibility of long-term damage. Moreover, in FIG.31 (b), the maximum value of a real-time seismic intensity is less than 6, and it turns out that there was little influence on a wooden house. Furthermore, as shown in FIG. 31 (c), the seismic intensity in the frequency band of 2 Hz or higher is the largest. This confirms that there was little influence on the wooden house as in FIGS. 31 (a) and 31 (b).

FIG. 32A is a frequency spectrum obtained by processing the observation data (observation point is Ojiya) of the east-west motion component related to the Niigata Chuetsu earthquake using the real-time seismic intensity meter 1d of Example 4, and FIG. It is a real-time seismic intensity waveform of (a). 33 (a) to 33 (c) are based on signals that have been subjected to filter processing such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more in the same observation data as FIG. It is a real-time seismic intensity waveform calculated by 33A to 33C correspond to the above-described real-time seismic intensity J1 to J3, respectively. Moreover, both the horizontal axis and the vertical axis in FIG. 32A are logarithmic axes.
As shown in FIG. 32A, the frequency component of 0.333 to 2 Hz is mainly used, and the frequency component of 0.333 Hz or less is slightly increased. Moreover, as shown in FIG.32 (b), the maximum value of real-time seismic intensity has reached 6.8.
As shown in FIG. 33 (a), the maximum value of the seismic intensity reaches 4 in the frequency band of 0.333 Hz or less, and the state where the seismic intensity exceeds 1 continues for about 150 seconds. Therefore, there is a risk that the long-period structure is damaged. Moreover, in FIG.33 (b), the frequency component of 0.333-2Hz is outstanding, and it turns out that the influence on a wooden house was great. As shown in FIG. 33 (c), frequency components of 2 Hz or higher are relatively small.

FIG. 34 (a) is a frequency spectrum obtained by processing the north-south motion component observation data (observation points are Tokyo and Shinozaki) regarding the Niigata Chuetsu earthquake using the real-time seismometer 1d of Example 4, and (b) is It is a real-time seismic intensity waveform in FIG. 35 (a) to 35 (c) are based on signals that have been subjected to filter processing such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more in the same observation data as FIG. It is a real-time seismic intensity waveform calculated by FIGS. 35A to 35C correspond to the above-described real-time seismic intensity J1 to J3, respectively. Further, both the horizontal axis and the vertical axis in FIG. 34 (a) are logarithmic axes.
As shown in FIG. 34A, the frequency component of 0.333 Hz or higher is attenuated, and the frequency component of 0.333 Hz or lower is dominant. As shown in FIG. 34 (b), the maximum real-time seismic intensity is about 3.3.
As shown in FIG. 35 (a), a state where the seismic intensity exceeds 1 continues for 200 seconds or more in a frequency band of 0.333 Hz or less. Therefore, there is a risk of damage to elevators in skyscrapers. Further, from FIGS. 35B and 35C, it can be seen that the maximum shaking of this earthquake was short in time but was due to a frequency component of 0.333 to 2 Hz.

FIG. 36A is a frequency spectrum obtained by processing east-west motion component observation data (observation point is Tomakomai) regarding the Tokachi-oki earthquake using the real-time seismometer 1d of Example 4, and FIG. It is a real-time seismic intensity waveform of (a). 37 (a) to (c) are based on a signal subjected to filter processing such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more in the same observation data as FIG. It is a real-time seismic intensity waveform calculated by 37A to 37C correspond to the above-described real-time seismic intensity J1 to J3, respectively. In addition, the horizontal axis and the vertical axis in FIG. 36A are both logarithmic axes.
As shown in FIG. 36A, frequency components of 0.333 Hz or less are outstanding. Moreover, as shown in FIG.36 (b), the maximum value of a real-time seismic intensity is 4.4.
As shown in FIG. 37 (a), in the frequency band of 0.333 Hz or less, the state of seismic intensity 1 or more continues for about 270 seconds, and the state of seismic intensity 3 or more continues for about 60 seconds. Therefore, there is a risk that extremely serious damage has occurred to the skyscraper and large oil tank. Also, from FIGS. 37B and 37C, it can be seen that the maximum shake of this earthquake was short in time but was due to a frequency component of 0.333 to 2 Hz.

  The real-time seismometer 1d according to the present embodiment has a configuration in which the frequency band of the digital filter 4a according to the first embodiment is divided into three and all the frequency bands of the digital filter 4a are shared by using the filters 17a to 17c. The frequency band division and the number of divisions and the number of filters used therefor are not limited to those shown in this embodiment, and can be changed as appropriate. Further, instead of the first embodiment, the frequency band of the analog filter 4b of the second embodiment is divided into three, and the entire frequency band of the analog filter 4b is shared by three analog filters corresponding to the filters 17a to 17c. You can also. In this case, the burden on hardware is reduced, and the same operations and effects as the real-time seismometer 1d of the present embodiment are exhibited.

  The inventions described in claims 1 to 22 of the present invention are particularly effective in facilities and areas where it is necessary to predict the type and scale of an earthquake in a short time and to take appropriate disaster prevention measures.

It is a block diagram of Example 1 of the real-time seismometer according to the embodiment of the present invention. It is a figure which shows the frequency characteristic of the digital filter which comprises the real-time seismometer of Example 1. FIG. It is a figure for demonstrating the principle of operation of the seismic intensity calculation part which comprises the real-time seismometer of Example 1. FIG. It is a figure which shows the real-time seismic intensity waveform (1 second seismic intensity) calculated based on the observation data of the Chuetsu earthquake main shock. It is a figure which shows the seismic intensity intermediate value computed by the real-time seismic intensity meter of Example 1, and a real-time seismic intensity waveform (1 second seismic intensity, 2 second seismic intensity). It is the figure which expanded FIG. 5 partially and replaced the 2-second seismic intensity with the 5-second seismic intensity. Figures (a) to (d) are a comparison of real-time seismic intensity waveforms (one-second seismic intensity) calculated based on the main shock and aftershock data of the Tottori-ken Seibu Earthquake and seismic intensity waveforms calculated using the same method as a conventional seismometer. It is. It is the figure which showed the relationship between the maximum value of a real-time seismic intensity (1 second seismic intensity), and a measured seismic intensity. (A) is the figure which showed the relationship between the maximum value of the real-time seismic intensity (1 second seismic intensity) and the measured seismic intensity in the whole P wave region, and (b) is the real time seismic intensity from the arrival of the P wave to 1 second ( It is the figure which showed the relationship between the maximum value of 1 second seismic intensity) and measured seismic intensity. (A) is a diagram showing the relationship between the maximum real-time seismic intensity (1 second seismic intensity) and measured seismic intensity up to 2 seconds after the arrival of the P wave, and (b) shows 3 seconds after the arrival of the P wave. It is the figure which showed the relationship between the maximum value of real-time seismic intensity (1 second seismic intensity) and measured seismic intensity. It is the figure which showed the real-time seismic intensity waveform directly under or near each observation point. It is the figure which showed the real-time seismic intensity waveform in the earthquake of a near district. It is the figure which showed the real-time seismic intensity waveform in the teleseismic earthquake which occurs inland or the coast. It is the figure which showed the real-time seismic intensity waveform in a trench type teleseismic earthquake. It is the figure which arranged the waveform of the acceleration component of the up-and-down direction recorded in the observation point (327 places) in the case of the Chuetsu earthquake along with the vertical axis according to the epicenter distance. It is the figure which arranged the real-time seismic intensity waveform computed from the same observation data as FIG. 15 using the real-time seismic intensity meter of a present Example along with the vertical axis direction according to epicenter distance, and plotted. (A) thru | or (t) are the figures which showed the real-time seismic intensity waveform separately about 20 observation points whose epicenter distance is shorter than 62 km among what was shown in FIG. (A) thru | or (t) are the figures which showed the real-time seismic intensity waveform separately about 20 observation points whose epicenter distance is longer than 198 km among what was shown in FIG. (A) is the acceleration data at the time of a lightning strike observed by a conventional accelerometer, (b) is the data after passing through the seismic intensity filter of the real-time seismometer of this embodiment, (c) is the same as FIG. It is a real-time seismic intensity waveform calculated from the acceleration data in FIG. (A) is the acceleration data at the time of passing through the snowplow observed by a conventional accelerometer, and (b) in the figure is the data after passing through the seismic intensity filter of the real-time seismometer of this embodiment, (c) in the figure. Is a real-time seismic intensity waveform calculated from the acceleration data of FIG. It is a block diagram of Example 2 of the real-time seismic intensity meter according to the embodiment of the present invention. It is a block diagram of Example 3 of the real-time seismometer according to the embodiment of the present invention. It is a figure which shows the real-time seismic intensity waveform calculated based on the observation data of the Aki-an earthquake. (A) thru | or (f) is the figure which plotted the maximum value of the increase rate at the time of the rising of a real-time seismic intensity waveform about many earthquakes. (A) thru | or (i) is the figure which plotted the rise time of the real-time seismic intensity waveform about many earthquakes. It is the figure which showed the relationship between the rise time of a real-time seismic intensity waveform, and a hypocenter distance when the value of a real-time seismic intensity (1 second seismic intensity) changes from "0" to "1". (A) and (b) are diagrams showing the relationship between the rise time of the real-time seismic intensity waveform and the measured seismic intensity when the real-time seismic intensity value changes from “0” to “2” and from “0” to “3”, respectively. It is. It is a block diagram of Example 4 of the real-time seismometer according to the embodiment of the present invention. It is a figure which shows the frequency characteristic of the digital filter which comprises the real-time seismometer of Example 4. (A) is a frequency spectrum obtained by processing observation data of the vertical motion component of the surface layer related to the Iwate-Miyagi inland earthquake using the real-time seismometer of Example 4 (observation point is Kansai), (b) It is a real-time seismic intensity waveform in FIG. (A) thru | or (c) were calculated based on the signal which performed the filter process which will be 0.333 Hz or less, 0.333-2 Hz, and 2 Hz or more in the same observation data as FIG. Real-time seismic intensity waveform. (A) is the frequency spectrum calculated | required by processing the observation data (observation point is Ojiya) regarding the Niigata Chuetsu earthquake using the real-time seismic intensity meter of Example 4, (b) is the same figure (a). It is a real-time seismic intensity waveform. (A) to (c) were calculated based on the same observation data as in FIG. 32 based on a signal subjected to filter processing such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more. Real-time seismic intensity waveform. (A) is a frequency spectrum obtained by processing observation data (observation points are Tokyo and Shinozaki) for the Niigata Chuetsu earthquake using the real-time seismic intensity meter of Example 4, and (b) is the figure ( It is a real-time seismic intensity waveform of a). (A) to (c) were calculated based on the same observation data as FIG. 34 based on the signal subjected to the filtering process such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more. Real-time seismic intensity waveform. (A) is the frequency spectrum calculated | required by processing the observation data (observation point is Tomakomai) regarding the Tokachi-oki earthquake using the real-time seismic intensity meter of Example 4, (b) is the figure (a). It is a real-time seismic intensity waveform. (A) to (c) were calculated based on the same observation data as in FIG. 36 based on a signal subjected to filter processing such that the pass frequency band is 0.333 Hz or less, 0.333 to 2 Hz, or 2 Hz or more. Real-time seismic intensity waveform. It is a figure which shows the frequency characteristic of the seismic intensity published by the Japan Meteorological Agency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1d ... Real time seismometer 2 ... Acceleration detection means 3 ... A / D converter 4a ... Digital filter 4b ... Analog filter 5 ... Vector synthesizer 6a ... Seismic intensity calculation part 6b ... Epicenter distance calculation part 7 ... Determination part 8 ... Alarm Units 9a, 9b ... arithmetic units 10a-10c ... analog signals 11a-11c ... digital signals 12a-12c ... digital signals 13a, 13b ... composite digital signals 14 ... earthquake disaster prevention signals 15a-15c ... analog signals 16a-16c ... digital signals 17a to 17c, filter 18a to 18c, vector synthesizer 19a to 19c, seismic intensity calculation unit 20a to 20c, determination unit 21a to 21c, alarm unit 22a to 22c, digital signal 23a to 23c, digital signal 24a to 24c, digital signal 25a ... 25 c... Synthesized digital signal 26 a to 26 c. Shin Disaster signal D-G ... waveform I ... seismic intermediate value J ... real time seismic J1 to J3 ... real time seismic P～R ... broken lines

Claims (22)

Acceleration detecting means for detecting three types of acceleration components respectively generated in three axis directions orthogonal to each other accompanying an earthquake, and A / D conversion for converting an analog signal output from the acceleration detecting means into a first digital signal A digital IIR filter that converts the first digital signal output from the A / D converter to a second digital signal by weighting the first digital signal to a predetermined frequency, and the digital IIR filter The three types of second digital signals are vector-synthesized and converted into a third digital signal, a calculation unit for calculating a real-time seismic intensity based on the third digital signal, and an earthquake based on the real-time seismic intensity and a determining unit type, the determination unit may land by comparing the real-time seismic intensity with a reference value which varies with time Real-time seismic intensity meter and judging the type. Acceleration detecting means for detecting three types of acceleration components respectively generated in three axial directions orthogonal to the earthquake, and the first analog signal output from the acceleration detecting means is weighted to a predetermined frequency. An analog filter for converting to a second analog signal, an A / D converter for converting the second analog signal to a first digital signal, and the three types of the first output from the A / D converter An arithmetic unit that vector-synthesizes the digital signal and converts it into a second digital signal and calculates a real-time seismic intensity based on the second digital signal; a determination unit that determines the type of earthquake based on the real-time seismic intensity; the provided, characterized in that the determination unit is that by comparing the real-time seismic intensity with a reference value which varies with time to determine the type of seismic real -Time seismic intensity meter.   The digital IIR filter weights a predetermined frequency of the first digital signal in accordance with a frequency characteristic set in advance based on a characteristic of a structure or equipment to be alarmed or controlled. The real-time seismic intensity meter according to claim 1.   The analog filter performs weighting on a predetermined frequency of the first analog signal according to a frequency characteristic set in advance based on a characteristic of a structure or equipment to be alarmed or controlled. The real-time seismic intensity meter according to claim 2. The arithmetic unit, the real-time seismic intensity meter according to any one of claims 1 to 4, characterized in that for obtaining the maximum value of the real-time seismic as measured seismic intensity equivalent value.   The real-time seismometer according to any one of claims 1 to 5, wherein the calculation unit calculates an epicenter distance based on an increase rate of the real-time seismic intensity in a P wave initial motion portion.   6. The real-time seismometer according to claim 5, wherein the arithmetic unit obtains a maximum value in the P-wave region, among the real-time seismic intensity.   6. The real-time seismometer according to claim 5, wherein the calculation unit obtains a maximum value within a predetermined time of the P-wave initial motion portion in the real-time seismic intensity.   2. The calculation unit calculates an epicenter distance or a measured seismic intensity equivalent value based on a time required for the real-time seismic intensity to reach a second seismic intensity from a first seismic intensity in a P wave initial motion part. The real-time seismometer according to claim 1. Detects three types of acceleration components that occur in three axial directions orthogonal to each other in response to an earthquake, converts analog signals representing these acceleration components into digital signals, applies IIR filter processing, and weights predetermined frequencies Seismic intensity, etc. characterized by calculating the real-time seismic intensity based on the synthesized digital signal and comparing the reference value changing with time with this real-time seismic intensity Prediction method. Detects three types of acceleration components that occur in three axial directions orthogonal to each other in response to an earthquake, applies analog filter processing to the analog signal representing this acceleration component, weights a predetermined frequency, and converts it into a digital signal Convert, digitally synthesize this digital signal, calculate real-time seismic intensity based on this synthesized digital signal, compare the real-time seismic intensity with the reference value that changes with time, and determine the type of earthquake Prediction method such as seismic intensity.   The digital signal is subjected to IIR filter processing according to a frequency characteristic set in advance based on a characteristic of a structure or equipment to be alarmed or controlled, and a predetermined frequency is weighted. Item 10. Prediction method for seismic intensity, etc.   The analog signal is subjected to analog filter processing in accordance with a frequency characteristic set in advance based on a characteristic of a structure or equipment to be alarmed or controlled, and a predetermined frequency is weighted. The prediction method of seismic intensity etc. of claim | item 11. The method for predicting seismic intensity or the like according to any one of claims 10 to 13, wherein a maximum value of the real-time seismic intensity is obtained as a measured seismic intensity equivalent value.   The seismic intensity prediction method according to any one of claims 10 to 14, wherein an epicenter distance is calculated based on an increase rate of the real-time seismic intensity in a P-wave initial motion portion.   15. The method for predicting seismic intensity and the like according to claim 14, wherein a maximum value in the P wave region is obtained from the real-time seismic intensity.   15. The method for predicting seismic intensity and the like according to claim 14, characterized in that a maximum value within a predetermined time of a P wave initial motion portion is obtained from the real-time seismic intensity.   14. The epicenter distance or the measured seismic intensity equivalent value is calculated based on the time required for the real-time seismic intensity to reach the second seismic intensity from the first seismic intensity in the P wave initial motion part. The prediction method of seismic intensity etc. of any one item.   The digital IIR filter includes a plurality of filters having different pass frequency bands, and the calculation unit and the determination unit are configured to be able to individually process signals that have passed through the plurality of filters. Item 3. Real-time seismic intensity meter.   The analog filter includes a plurality of filters having different pass frequency bands, and the calculation unit and the determination unit are configured to be able to individually process signals that have passed through the plurality of filters. 4. Real-time seismic intensity meter according to 4.   13. The method for predicting seismic intensity and the like according to claim 12, wherein the IIR filter process comprises a plurality of filter processes having different pass frequency bands, and individually vector-synthesizes the signals subjected to the plurality of filter processes. .   14. The method for predicting seismic intensity and the like according to claim 13, wherein the analog filter processing includes a plurality of filter processings having different pass frequency bands, and individually vector-synthesizes the signals subjected to the plurality of filter processings. .