JP2007298446A - Seismometer, seismometer system, earthquake alarm issuing method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seismometer, a seismometer system, an earthquake alarm issuing method and a program, capable of estimating a range requiring an alarm, and capable of calculating highly reliably the range requiring the alarm. <P>SOLUTION: The seismometer 3 includes an acceleration sensor 7 and a processor 9. The acceleration sensor 7 measures all the time an acceleration as to each component of two vertical-directional and horizontal-directional (meridional and zonal) components, and acquires an acceleration value to be transmitted to the processor 9. The processor 9 performs a waveform processing function, a magnitude estimation function, a required alarm range estimation function, an information transmission function and an alarm output function, based on the acceleration value received from the acceleration sensor 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, a seismometer, a seismometer system, an earthquake warning issuing method, and a program for calculating an alarm required range based on an initial tremor (P wave) of an earthquake.

Seismic motion can be broadly divided into initial fine motion (P wave) and main motion (S wave) that arrives thereafter. Of these, the S-waves actually cause earthquake damage in most cases. Therefore, conventionally, a technique for estimating an earthquake damage range based on a P wave before an S wave arrives and issuing an earthquake warning in the range has been studied. For example,
(A) For the Tokaido Shinkansen, etc., the magnitude is estimated from the period of the P wave initial motion of the earthquake, the epicenter distance is estimated from the estimated magnitude and amplitude, and the extent of damage is estimated from the estimated magnitude and epicenter position. , There is a system for issuing an alarm (see Patent Documents 1 to 5, Non-Patent Document 1).

(B) For the Tokaido Shinkansen, the epicenter distance is estimated from the magnitude of the amplitude increase of the P wave initial motion of the earthquake, the epicenter direction is estimated from the incident direction of the earthquake motion, and the epicenter position is estimated from the epicenter distance and epicenter direction, and the estimation There is a system that estimates the magnitude from the epicenter position and amplitude, and further estimates the extent of damage from the estimated magnitude and epicenter position and issues a warning (see Patent Documents 6 to 7 and Non-Patent Documents 2 to 3) .
Japanese Patent No. 1249924 Japanese Patent No. 1285667 Japanese Patent No. 1510592 Japanese Patent No. 1636955 Japanese Patent No. 1610622 Japanese Patent Laid-Open No. 2002-277557 Japanese Patent Laid-Open No. 2005-10041 Nakamura et al., "Research on comprehensive earthquake disaster prevention system", Journal of Japan Society of Civil Engineers, January 1996 Tsukada et al., “Early Earthquake Specification Estimation Method Using P-wave Envelope Shape”, Earthquake No. 2 pp. 351-361, 2004 Motoya et al., “Establishing an early earthquake warning system for the Tokaido Shinkansen”, Summary of the 60th Annual Conference of Japan Society of Civil Engineers, September 2005

  However, in the techniques (a) and (b), since a plurality of data is used and processing is performed using an average value for a relatively long time (for example, 1 second), after the P wave arrives, It takes time to estimate the magnitude and epicenter position, and to estimate the extent of damage, and as a result, the timing for issuing an alarm is delayed. Therefore, there is a problem that it is not possible to secure a sufficient time until the S wave arrives after issuing an alarm. In particular, in the case of a direct earthquake, since the time from the arrival of the P wave to the arrival of the S wave is short, the above problem becomes serious.

  Further, in the techniques (a) and (b), there is a case where the reliability in calculating the damage range is insufficient. This is because, in the technique (a) described above, the initial motion period used for magnitude estimation also depends on the distance from the epicenter to the seismometer, and therefore the magnitude may be underestimated depending on the distance. is there. Further, in the technique (b), the epicenter position may be estimated farther than actual with respect to a direct earthquake.

  The present invention has been made in view of the above points. A seismometer, a seismometer system, a method for issuing an earthquake warning, and a program that can estimate a range requiring an alarm early and have high reliability in calculating the range that requires an alarm. The purpose is to provide.

(1) The invention of claim 1
Acceleration detecting means for detecting the acceleration A caused by the earthquake P wave, magnitude calculating means for calculating the magnitude M of the earthquake by applying the acceleration A to the equation (1), and the magnitude M with the equation (2) An essential point is a seismometer including an alarm range calculation means for calculating an alarm range Δ required to be applied to the above.

Formula (1): M = αlogA + β
Formula (2): logΔ = γlogM + δ
As a result of earnest research, the inventor of the present application has found that there is a relationship of the equation (1) between the acceleration A caused by the P wave of the earthquake and the magnitude M of the earthquake, as shown in FIG.
Since the seismometer of the present invention can calculate the magnitude M in a very short time using the equation (1) and does not need to perform a long-time process as in the prior art, The required alarm range Δ can be calculated in a very short time from reaching. Therefore, it is possible to issue an earthquake warning at an early stage within the alarm required range Δ, and to secure a time from the earthquake warning issuance to the arrival of the S wave, so that damage caused by the earthquake can be reduced. The seismometer of the present invention is particularly useful for a direct earthquake with a short time from arrival of a P wave to arrival of an S wave.

  Further, since the alarm range Δ required by the seismometer of the present invention is set according to the magnitude M of the earthquake, if an earthquake alarm is issued within the alarm range Δ, an originally unnecessary place The earthquake warning is not issued at the site, and conversely, the earthquake warning is not issued at the necessary place. In other words, when the alarm required range Δ is fixed, when a small earthquake occurs, even if no alarm is normally required, an alarm is issued uniformly within the alarm required range Δ, and a large earthquake occurs. When it occurs, even if an alarm is originally required, the alarm will not be issued if it is out of the alarm range Δ required. However, according to the seismometer of the present invention, such an adverse effect does not occur. .

In addition, the seismometer of the present invention can accurately calculate the alarm required range Δ in the case of a direct earthquake.
The alarm required range Δ means that within the range, strong shaking due to an earthquake occurs and damages to the structure, etc., but outside the range, the shaking is weak and damage to the structure does not occur. .

In the formulas (1) and (2), α, β, γ, and δ are constants. These values can be determined by statistical processing from a large number of earthquake data. These values can be, for example, α = 1.69, β = 2.81, γ = 0.71, and δ = −3.2.
(2) The invention of claim 2
The seismometer according to claim 1, further comprising an earthquake occurrence information transmitting means for transmitting earthquake occurrence information representing the occurrence of the earthquake when the acceleration A and / or the magnitude M is equal to or greater than a predetermined value. And

  Since the seismometer of the present invention transmits earthquake occurrence information, other facilities that have received the earthquake occurrence information (for example, other seismometers, facilities that issue earthquake warnings according to earthquake occurrence information) An earthquake warning can be issued based on the information.

Examples of the predetermined value related to the acceleration A include a value in a range of 40 gal or more. The predetermined value related to the magnitude M includes a value in the range of 5.5 or more, for example.
(3) The invention of claim 3
The seismometer according to claim 2, wherein the earthquake occurrence information transmitting means selectively transmits the earthquake occurrence information only within the alarm required range Δ.

Since the seismometer of the present invention selectively transmits earthquake occurrence information only within the alarm required range Δ, an earthquake alarm is issued based on this earthquake occurrence information in facilities within the alarm required range Δ (for example, , Other seismometers, facilities that issue earthquake warnings in response to earthquake occurrence information), and have received earthquake occurrence information. Therefore, an earthquake warning is not issued at a place where it is not necessary, or conversely, an earthquake warning is not issued at a necessary place.
(4) The invention of claim 4
The seismometer according to any one of claims 1 to 3, further comprising an earthquake warning issuing means for issuing an earthquake warning when the acceleration A and / or the magnitude M is equal to or greater than a predetermined value. .

The seismometer of the present invention can issue an earthquake warning by itself. As an earthquake alarm, for example, a display device provided as a part of a seismometer or a sound, an image, or the like generated by a display device provided outside the seismometer. In addition, for example, an earthquake alarm is performed on a system in the vicinity of the seismometer, and measures for reducing earthquake damage (for example, shutting off power, gas, compressed air, etc., stopping operation of a train, etc.) ).
(5) The invention of claim 5
A seismometer system comprising a plurality of seismometers and a transmission means for transmitting information between the plurality of seismometers, wherein the seismometer detects an acceleration A caused by a P wave of an earthquake. An acceleration detection means for calculating the magnitude M of the earthquake by applying the acceleration A to the equation (1), and calculating the alarm required range Δ by applying the magnitude M to the equation (2). A warning range calculation means; a transmission means for transmitting earthquake occurrence information via the transmission means when the acceleration A and / or the magnitude M is equal to or greater than a predetermined value; and the earthquake occurrence information via the transmission means. Receiving means, and an earthquake warning issuing means for issuing an earthquake warning according to the earthquake occurrence information, and issuing the earthquake warning according to the earthquake occurrence information. A gist of a seismometer system, comprising: an alarm issuing range setting means for setting the seismometer to a seismometer within the alarm range Δ required calculated by the seismometer that is a transmission source of the earthquake occurrence information. To do.

Formula (1): M = αlogA + β
Formula (2): logΔ = γlogM + δ
The seismometer system of the present invention can calculate the alarm required range Δ in an extremely short time from the arrival of the P wave, and can issue an earthquake alarm early in the alarm required range Δ. Therefore, according to the seismometer system of the present invention, it is possible to secure the time from the earthquake warning issuance to the arrival of the S wave, and the damage caused by the earthquake can be reduced. The seismometer system of the present invention is particularly useful for a direct type earthquake in which the time from arrival of a P wave to arrival of an S wave is short.

  Further, the seismometer system of the present invention sets the alarm required range Δ for issuing an earthquake alarm according to the magnitude M of the earthquake, so that an alarm is issued at a place where an earthquake alarm is not necessary, or conversely, Earthquake warnings will not be issued in places where it is necessary.

Further, the seismometer system of the present invention can calculate the alarm required range Δ more accurately in the case of a direct earthquake.
As the alarm issuing range setting means, for example, there is a means for sending earthquake occurrence information to a seismometer within the alarm required range Δ but not to a seismometer outside the alarm required range Δ.

  Further, as the alarm issuing range setting means, for example, whether or not the seismometer that has received the earthquake occurrence information (may include a seismometer outside the alarm required range Δ) is within the alarm required range Δ. There is a means to judge and issue an earthquake warning if it is inside, but not to issue an earthquake warning if it is outside. At this time, if the earthquake occurrence information includes, for example, identification information of the source seismometer and information on the size of the alarm-required range Δ, the seismometer that has received the earthquake occurrence information It can be determined whether or not it is within Δ.

For example, the transmission means may transmit information directly from one seismometer to another. Or the information transmitted from each seismometer may be once collected in a control part, and information may be sent to the required seismometer from the control part.
(6) The invention of claim 6
The alarm issuing range setting means is a means for setting the transmission destination of the earthquake occurrence information as another seismometer within the alarm required range Δ calculated by the seismometer that is the transmission source of the earthquake occurrence information. A gist of the seismometer system according to claim 6.

In the present invention, the range where the earthquake warning is issued by setting the transmission destination of the earthquake occurrence information as another seismometer within the alarm required range Δ calculated by the seismometer that is the transmission source of the earthquake occurrence information. Can be within the alarm required range Δ. That is, as shown in FIG. 2, seismometers within the alarm range Δ require earthquake occurrence information and issue an earthquake alarm, but seismometers outside the alarm range Δ require earthquake occurrence information. Do not issue earthquake warnings.
(7) The invention of claim 7
The seismometer issues the earthquake warning by the earthquake warning issuing means when the acceleration A detected by the seismometer and / or the magnitude M calculated by the seismometer is equal to or greater than a predetermined value. The gist of the seismometer system according to claim 5 or 6, characterized in that.

In the seismometer system of the present invention, when the acceleration A, magnitude M, or both detected by a certain seismometer exceeds a predetermined value, the seismometer transmits earthquake occurrence information to another seismometer, The seismometer itself issues an earthquake warning.
(8) The invention of claim 8
The acceleration A due to the P wave of the earthquake is detected, the acceleration A is applied to the equation (1) to calculate the magnitude M of the earthquake, and the magnitude M is applied to the equation (2) to detect the alarm range Δ The gist of the method of issuing an earthquake warning is to issue an earthquake warning within the alarm required range Δ.

Formula (1): M = αlogA + β
Formula (2): logΔ = γlogM + δ
According to the present invention, it is possible to calculate the alarm required range Δ in an extremely short time from the arrival of the P wave, and to issue an earthquake alarm early in the alarm required range Δ. Therefore, according to the present invention, it is possible to secure the time from the earthquake warning issuance to the arrival of the S wave, and it is possible to reduce the damage caused by the earthquake. The present invention is particularly useful for a direct earthquake with a short time from arrival of a P wave to arrival of an S wave.

  In the present invention, since the alarm required alarm range Δ for issuing an earthquake alarm is set according to the magnitude M of the earthquake, an alarm is issued in a place where an earthquake alarm is not required, or conversely, a place where an earthquake alarm is required. The earthquake warning will not be issued.

Further, the present invention can more accurately calculate the alarm required range Δ in the case of a direct earthquake.
(9) The invention of claim 9
The gist of the present invention is a program that causes a computer to function as the acceleration detection means, the magnitude calculation means, and the alarm required range calculation means in claim 1.

  The program of the present invention can cause a computer to function as acceleration detection means, magnitude calculation means, and alarm required range calculation means in claim 1.

1. 1. First Embodiment (1-1) Configuration of Seismometer System The configuration of the seismometer system 1 will be described with reference to FIG. The seismometer system 1 includes a plurality of seismometers 3, which are distributed and arranged at a predetermined distance from each other. In FIG. 2, seismometers 3A, 3B, 3C, 3D, 3E,... Are displayed to identify individual seismometers 3.

  Further, the seismometer system 1 includes a transmission means 5 for transmitting information between the seismometers 3. In FIG. 2, for the sake of convenience, only the transmission means 5 between the seismometer 3A and the other seismometers is shown, but between the other seismometers, for example, between the seismometers 3B and 3C. The transmission means 5 is also provided between the seismometer 3C and the seismometer 3D, between the seismometer 3B and the seismometer 3E, and so on. The transmission means 5 may be, for example, a wired information transmission cable or a means for transmitting information by wireless communication.

  Next, the configuration of the seismometer 3 will be described with reference to FIG. The seismometer 3 includes an acceleration sensor 7 and a processing device 9. The acceleration sensor 7 constantly measures acceleration for each direction component in the vertical direction and the two horizontal directions (north-south direction and east-west direction), acquires the acceleration value, and transmits it to the processing device 9.

  The processing device 9 is a control means (computer) including a CPU, a ROM, a RAM, and the like, and a program for executing processing to be described later is recorded in the ROM. Based on the acceleration value received from the acceleration sensor 7, the processing device 9 performs a waveform processing function, a magnitude estimation function, a warning range estimation function, an information transmission / reception function, and an earthquake warning output function. The waveform processing function is normal filter processing performed on the acceleration waveform. Further, the magnitude estimation function, the alarm range estimation function, the information transmission / reception function, and the earthquake alarm output function will be described in detail later.

(1-2) Process Performed by Seismometer System 1 Next, the process performed by the processing device 9 of the seismometer 3 will be described based on the flowchart of FIG.

In step 100, based on the acceleration value received from the acceleration sensor 7, accelerations of three components (up and down, north and south, east and west) are acquired.
In step 110, the three-component acceleration acquired in step 100 is combined to calculate a three-component combined acceleration A3.

  In step 120, it is determined whether or not the state of the seismometer 3 is a normal state. The state of the seismometer 3 is one of a normal state and an earthquake state, and a transition between both states is performed based on the value of the resultant acceleration A3 in steps 140 and 190 described later. . If it is a normal state, the process proceeds to step 130, and if it is an earthquake state, the process proceeds to step 150.

  In step 130, it is determined whether or not the value of the resultant acceleration A3 is greater than a predetermined reference value 1. In the case of YES, the process returns to step 100 after shifting to the in-earthquake state at step 140. In the case of NO, the process returns to step 100 while maintaining the normal state.

On the other hand, if it is determined in step 120 that the state is not a normal state (that is, an earthquake state), the process proceeds to step 150.
In step 150, the resultant acceleration A3 is applied to equation (1) to calculate the magnitude M of the earthquake (magnitude estimation function).

Formula (1): M = αlogA + β
Here, the value of α is 1.69, and the value of β is 2.81.
In Step 160, the magnitude M calculated in Step 150 is applied to Equation (2) to calculate the alarm required range Δ (alarm required range estimation function).

Formula (2): logΔ = γlogM + δ
Here, the value of γ is 0.71, and the value of δ is −3.2.
In step 170, the earthquake occurrence information is transmitted via the transmission means 5 only to the seismometers 3 within the alarm required range Δ calculated in step 160 among the other seismometers 3 (of the information transmission / reception function). Information transmission function). For example, in the case shown in FIG. 2, the seismometer 3A calculates the alarm required range Δ. When viewed from the seismometer 3A, the seismometer 3B and the seismometer 3D are within the alarm range Δ, but the seismometer 3C and the seismometer 3E are outside the alarm range Δ. The seismometer 3A transmits the earthquake occurrence information 15 to the seismometer 3B and the seismometer 3D via the transmission means 5, but does not transmit the earthquake occurrence information 15 to the seismometer 3C and the seismometer 3E (alarm instruction range setting) means).

  In FIG. 2, only the alarm required range Δ calculated by the seismometer 3A and the earthquake occurrence information 15 sent out by the seismometer 3A are shown, but the other seismometers 3 also perform the processing shown in FIG. Is executed to calculate the alarm required range Δ, and the earthquake occurrence information is output to the other seismometers 3 within the alarm required range Δ as viewed from each seismometer.

  In step 180, it is determined whether or not the value of the resultant acceleration A3 is smaller than a predetermined reference value 2. If YES, the process returns to step 100 after shifting to the normal state in step 190. In the case of NO, the process returns to step 100 while maintaining the state during the earthquake.

(1-3) Earthquake Warning Issued by Seismometer 3 The seismometer 3 issues an earthquake warning when it is determined in step 130 of FIG. 4 that the value of the resultant acceleration A3 is greater than a predetermined reference value 1 ( Alarm output function). This earthquake warning is, for example, a display device provided as a part of the seismometer 3 that is determined that the value of the combined acceleration A3 is greater than a predetermined reference value 1, or a display device provided outside the seismometer 3 Means sound, images, etc. In addition, for example, an earthquake alarm is performed on a system in the vicinity of the seismometer 3 to reduce earthquake damage (for example, shut off power, gas, compressed air, etc., stop operation of a train, etc.) May be). Further, the seismometer 3 receives earthquake occurrence information from other seismometers 3 (reception function of the information transmission / reception function), and issues an earthquake alarm in the same manner as described above in response to the reception (alarm output) function).

(1-4) Effects of the seismometer system The seismometer system 1 can calculate the alarm required range Δ in a very short time from the arrival of the P wave, and can issue an earthquake alarm in the alarm required range Δ. . FIG. 5 is a diagram showing the time series of the arrival of the P wave, the warning issuance, the arrival of the S wave, the time when the shaking is maximum, and the end of the earthquake to the seismometer 3 closest to the epicenter. In FIG. 5, T ₁ represents the timing at which the seismometer system 1 of the first embodiment issues an alarm. As is clear from FIG. 5, the seismometer system 1 can issue an earthquake alarm within a very short time (for example, within one second from the arrival of the P wave) after the arrival of the P wave.

  As described above, according to the seismometer system 1, since an earthquake warning can be issued early, it is possible to secure time from the earthquake warning issuance to the arrival of the S wave, and to reduce damage caused by the earthquake. . The seismometer system 1 is particularly useful for a direct type earthquake in which the time from the arrival of the P wave to the arrival of the S wave is short.

  In addition, since the seismometer system 1 sets the alarm required range Δ for issuing an alarm according to the magnitude of the earthquake, it issues an earthquake alarm in a place where an earthquake alarm is not required, or conversely, an earthquake alarm is required. There will be no earthquake warnings issued at the location. In other words, if the alarm range is fixed, when a small earthquake occurs, even if a place where the earthquake alarm is not normally required, if it is within the alarm range, the earthquake alarm will be issued uniformly, When a large earthquake occurs, even if an earthquake warning is originally required, the earthquake warning will not be issued if it is out of the required alarm range. According to the seismometer system 1 of the present invention, Such harmful effects do not occur.

In addition, the seismometer system 1 can calculate the alarm required range Δ more accurately during a direct earthquake.
(1-5) Application of seismometer system 1 to railways The seismometer system 1 can be used in the field of railways. For example, as shown in FIG. 6, seismometers 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H,...

  In the example shown in FIG. 6, a direct type earthquake occurred immediately below the seismometer 3E, and the alarm required alarm range Δ was a range from the epicenter to 60 km (range from the seismometer 3B to the seismometer 3H). To do. At this time, the seismometer 3E calculates the alarm required range Δ in real time according to the magnitude of the earthquake, and the earthquake occurrence information is transmitted to the seismometers 3B to 3D and seismometers 3F to 3H within the alarm required range Δ. Send. The seismometers 3B to 3D and the seismometers 3F to 3H receive the earthquake occurrence information and issue an earthquake warning. In particular, the seismometer 3B issues a seismic warning to stop the train 11 that has been nearby. In the example shown in FIG. 6, the seismometer 3B can issue an earthquake warning only 4 seconds after the occurrence of the earthquake.

2. Second Embodiment Also in the second embodiment, the configuration of the seismometer system 1 is basically the same as that of the first embodiment, but the process executed by the seismometer system 1 is one. The parts are different. The difference will be mainly described with reference to FIGS.

As shown in FIG. 7, the processing device 9 has two types of functions for estimating the magnitude. The magnitude M ₁ estimation function is the same as that in the first embodiment. The magnitude M ₂ and the epicenter position estimation function will be described in detail later.

Next, processing executed by the processing device 9 will be described based on the flowchart of FIG.
In step 200, based on the acceleration value received from the acceleration sensor 7, accelerations of three components (up and down, north and south, east and west) are acquired.

In step 210, the three-component acceleration acquired in step 100 is combined to calculate a three-component combined acceleration A3.
In step 220, it is determined whether or not the state of the seismometer 3 is a normal state. If it is a normal state, the process proceeds to step 230, and if it is an earthquake state, the process proceeds to step 250.

  In step 230, it is determined whether or not the value of the resultant acceleration A3 is greater than a predetermined reference value 1. In the case of YES, the process returns to step 200 after shifting to the state during earthquake in step 240. In the case of NO, the process returns to step 200 while maintaining the normal state.

On the other hand, if it is determined in step 220 that the state is not the normal state (that is, the state is during an earthquake), the process proceeds to step 250.
In step 250, the resultant acceleration A3 is applied to Equation (1), to calculate the magnitude M ₁ earthquake.

Formula (1): M ₁ = αlogA + β
Here, the value of α is 1.69, and the value of β is 2.81.
In step 260, it is determined whether or not a certain period of time has elapsed since the time of arrival of the earthquake (the time of transition to the earthquake state). If yes, then continue with step 270, otherwise continue with step 280.

In step 270, earthquake / noise determination, magnitude M ₂ estimation, and epicenter position (seismic distance D) are performed. The processing in step 270 will be described in detail later.
In step 280, the magnitude M required is calculated by applying the magnitude M to the equation (2).

Formula (2): logΔ = γlogM + δ
Here, the value of γ is 0.71, and the value of δ is −3.2.
As the magnitude M to be substituted into the equation (2), when NO is determined in the immediately preceding step 260, the magnitude M ₁ calculated in the above step 250 is used, and YES is determined in the immediately preceding step 260. If it is determined, the magnitude M ₂ calculated in step 270 is used.

In step 290, the earthquake occurrence information is transmitted via the transmission means 5 only to the seismometers 3 within the alarm required range Δ calculated in step 280 among the other seismometers 3.
In step 300, it is determined whether or not the value of the resultant acceleration A3 is smaller than a predetermined reference value 2. If YES, the process returns to step 200 after shifting to the normal state at step 310. In the case of NO, the process returns to step 200 while maintaining the state during the earthquake.

Next, the process of step 270 will be described based on the flowchart of FIG.
In step 400, digital waveform data measured continuously for several seconds using the acceleration sensor 7 is acquired.

  In step 410, the offset is removed from the digital waveform data. In step 420, the absolute value of the digital waveform data is acquired. At this time, if the absolute value is less than or equal to a certain reference value, it is forcibly set to a predetermined minimum reference value.

In step 430, smoothing (for example, taking a waveform envelope) is performed on the digital waveform data.
In step 440, the digital waveform data is fitted to equation (3) to obtain coefficients X and Y. Here, t represents time (sec), and V (t) represents amplitude at time t.

Formula (3): V (t) = Yt exp (−Xt)
In step 450, noise determination threshold values T _X and T _Y for _X and _Y are set.
In step 460, the noise determination thresholds T _X and T _Y are used to identify whether it is earthquake motion or noise. Specifically, when X is smaller than T _X , it can be determined that there is a ground motion, and when X is equal to or greater than T _X , it can be determined that it is noise. Moreover, when Y is larger than T _Y , it can be determined that there is an earthquake motion, and when Y is equal to or less than T _Y , it can be determined that it is noise. The values of T _X and T _Y can be set to optimum values for determination based on a large number of earthquake data.

  In step 470, it is determined whether or not it is determined in step 460 that there is an earthquake motion. If YES, the process proceeds to step 480. If NO, the process is terminated, and the process proceeds to step 280 in FIG.

In step 480, the value of Y is substituted into equation (4) to calculate the epicenter distance D.
Formula (4): logD = ε ₁ logY + ε ₂
In step 490, the equation (5), by substituting the epicenter distance D and the maximum amplitude V _max, calculating the magnitude M _2.

Formula (5): M ₂ = ζ ₁ logV _mav + ζ ₂ logD + ζ ₃
Note that the magnitude M ₂ may be calculated using any one of the equations (6) to (9) instead of the equation (5).

Formula (6): M ₂ = η ₁ X + η ₂ logY + η ₃
Equation _{(7): M 2 = η} 1 logV max + η 2 logY + η 3
Formula (8): M ₂ = η ₁ X + η ₂ log (log Y) + η ₃
Formula (9): M ₂ = η ₁ logV _max + η ₂ log (log Y) + η ₃
Here, ε ₁ , ε ₂ , ζ ₁ , ζ ₂ , ζ ₃ , η ₁ , η ₂ , and η ₃ are parameters determined by statistical processing from a large number of earthquake data. After step 490, the process is terminated, and the process proceeds to step 280 in FIG.

  The seismometer system 1 according to the second embodiment has the same effect as the seismometer system 1 according to the first embodiment, and further provides an early warning for an earthquake that occurs at a position away from the seismometer. Also has the effect of securing.

3. Reference example 1
The seismometer system of Reference Example 1 includes a plurality of seismometers and transmission means for transmitting information between them, and the seismometer includes an acceleration sensor and a processing device, respectively. Although common to the embodiment, the processing to be executed is greatly different. Description will be made based on the flowchart of FIG.

In step 600, based on the acceleration value received from the acceleration sensor, acceleration of three components (vertical, north-south, east-west) is acquired.
In step 610, the three-component acceleration acquired in step 600 is synthesized, and the three-component synthesized acceleration A3 is calculated.

In step 620, it is determined whether the seismometer is in a normal state. If it is a normal state, the process proceeds to step 630, and if it is an earthquake state, the process proceeds to step 650.
In step 630, it is determined whether or not the value of the resultant acceleration A3 is greater than a predetermined reference value 1. In the case of YES, the process returns to step 600 after shifting to the state during earthquake at step 640. If NO, the process returns to step 600 while maintaining the normal state.

On the other hand, if it is determined in step 620 that the state is not a normal state (that is, an earthquake state), the process proceeds to step 650.
In step 650, it is determined whether or not the value of the resultant acceleration A3 is greater than a predetermined reference value 2. If yes, then continue with step 660, otherwise continue with step 670.

In step 660, the earthquake occurrence information is transmitted to only the seismometer within the preset range via the transmission means.
In step 670, it is determined whether or not the value of the resultant acceleration A3 is smaller than a predetermined reference value 3. If YES, the process returns to step 600 after shifting to the normal state in step 680. In the case of NO, the process returns to step 600 while maintaining the state during the earthquake.

  In the seismometer system of Reference Example 1, since the range for issuing an alarm is fixed, an alarm is issued at a place where no alarm is required, or conversely, an alarm is not issued at a place where an alarm is required. Sometimes. In other words, since the range for issuing warnings is fixed, when a small earthquake occurs, even if a place where originally no earthquake warning is required, the earthquake warning will be issued uniformly within the fixed range, When a major earthquake occurs, even if an earthquake alarm is necessary, the alarm will not be issued if it is outside the fixed range.

  Consider a case in which the seismometer system of Reference Example 1 is used in the field of railways. For example, as shown in FIG. 11, a plurality of seismometers (indicated by 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H,...) Are arranged along the line 10 at predetermined intervals. .

  In the example shown in FIG. 11, it is assumed that a direct earthquake occurs directly below the seismometer 3E, and the magnitude of the earthquake causes damage at a position 60 km from the epicenter (position of the seismometer 3B).

  The P-wave reaches the seismometer 3E close to the epicenter most quickly among the plurality of seismometers, but the seismometer 3E has a fixed range regardless of the magnitude of the earthquake (in the example of FIG. Since the earthquake occurrence information is sent only to a range of 20 km (total range of 40 km), the earthquake occurrence information is not sent to the seismometer 3B that is 60 km away. The earthquake warning is issued at the position of the seismometer 3B. It is necessary to wait until the P wave reaches the seismometer 3C far from the epicenter and the seismometer 3C sends the earthquake occurrence information to the seismometer 3B. In the example shown in FIG. 11, it takes 10 seconds from the occurrence of an earthquake until the seismometer 3B issues an earthquake warning.

4). Reference example 2
The seismometer system of the present Reference Example 2 is composed of a plurality of seismometers and transmission means for transmitting information between them, and the seismometers each include an acceleration sensor and a processing device. Although common to the embodiment, the processing to be executed is greatly different. The difference will be mainly described based on the flowchart of FIG.

In step 700, based on the acceleration value received from the acceleration sensor, acceleration of three components (vertical, north-south, east-west) is acquired.
In step 710, the three-component acceleration acquired in step 700 is synthesized to calculate a three-component synthesized acceleration A3.

In step 720, it is determined whether or not the seismometer is in a normal state. If it is a normal state, the process proceeds to step 730, and if it is an earthquake state, the process proceeds to step 750.
In step 730, it is determined whether or not the value of the resultant acceleration A3 is greater than a predetermined reference value 1. In the case of YES, the process returns to step 700 after transitioning to an earthquake state at step 740. If NO, the process returns to step 700 while maintaining the normal state.

On the other hand, if it is determined in step 720 that the state is not the normal state (that is, the state is in an earthquake), the process proceeds to step 750.
In step 750, it is determined whether or not a certain period of time has elapsed from the time of earthquake arrival (the time of transition to the earthquake state). If yes, then continue with step 760, otherwise continue with step 790.

In step 760, earthquake / noise determination, magnitude M ₂ estimation, and epicenter position (seismic distance D) are performed. The processing in step 760 is the same as the processing in step 270 in the second embodiment.

In step 770, the alarm required range Δ is calculated by applying the magnitude M ₂ calculated in step 760 to equation (2).
Formula (2): logΔ = γlogM + δ
Here, the value of γ is 0.71, and the value of δ is −3.2.

In step 780, the earthquake occurrence information is transmitted via the transmission means only to the seismometers within the alarm required range Δ calculated in step 770 among other seismometers.
In step 790, it is determined whether or not the value of the resultant acceleration A3 is smaller than a predetermined reference value 2. If YES, the process returns to the normal state at Step 800 and then returns to Step 700. In the case of NO, the process returns to Step 700 while maintaining the state during the earthquake.

  Since the seismometer system of the present reference example 2 cannot calculate the alarm range Δ required until a certain time has elapsed since the arrival of the earthquake (see step 750 in FIG. 12), the earthquake alarm is detected within the alarm range Δ required from the arrival of the P wave. It takes a long time to issue

FIG. 5 is a diagram showing the time series of the arrival of the P wave to the seismometer, the warning issuance, the arrival of the S wave, the maximum shaking, and the end of the earthquake. In FIG. 5, T ₂ represents a timing seismometer system of the present reference example 2 is issued earthquake alarm. Furthermore, T ₃ is the method described in Patent Documents 1 to 5 and Non-Patent Document 1, represents the timing of trigger an earthquake alarm.

As is clear from FIG. 5, the seismometer system of Reference Example 2 and the methods described in Patent Documents 1 to 5 and Non-Patent Document 1 are compared to the case of the first embodiment (T ₁ ). Therefore, the timing for issuing an earthquake warning will be delayed. Therefore, in the case of a direct type earthquake in which the time from the arrival of the P wave to the arrival of the S wave is short, it may not be possible to secure a sufficient time from the earthquake warning to the arrival of the S wave.

Needless to say, the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the present invention.
For example, the seismometer 3 may transmit earthquake occurrence information and issue an earthquake warning when the calculated magnitude M is greater than or equal to a predetermined value.

It is a graph showing the correlation of the magnitude of an earthquake and the maximum acceleration in a P wave. 1 is an explanatory diagram illustrating a configuration of a seismometer system 1. FIG. 2 is a block diagram showing a configuration of a seismometer 3. FIG. It is a flowchart showing the process which the processing apparatus 9 of the seismometer 3 performs. It is explanatory drawing showing the time series from a direct type earthquake occurrence to completion | finish. It is explanatory drawing showing the example of application to the railroad field | area of a seismometer system. 2 is a block diagram showing a configuration of a seismometer 3. FIG. It is a flowchart showing the process which the processing apparatus 9 of the seismometer 3 performs. It is a flowchart showing the process which the processing apparatus 9 of the seismometer 3 performs. It is a flowchart showing the process which the processing apparatus of a seismometer performs. It is explanatory drawing showing the example of application to the railroad field | area of a seismometer system. It is a flowchart showing the process which the processing apparatus of a seismometer performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seismometer system 3 ... Seismometer 5 ... Transmission means 7 ... Accelerometer 9 ... Processing apparatus 10 ... Track 11 ... Train 15 ... Earthquake occurrence information

Claims (9)

Acceleration detecting means for detecting acceleration A caused by the P wave of the earthquake;
Magnitude calculating means for calculating the magnitude M of the earthquake by applying the acceleration A to the equation (1);
An alarm range calculation means for calculating the alarm range Δ required by applying the magnitude M to the equation (2).
Formula (1): M = αlogA + β
Formula (2): logΔ = γlogM + δ   2. The seismometer according to claim 1, further comprising an earthquake occurrence information transmitting unit configured to transmit earthquake occurrence information indicating the occurrence of the earthquake when the acceleration A and / or the magnitude M is equal to or greater than a predetermined value.   The seismometer according to claim 2, wherein the earthquake occurrence information transmitting means selectively transmits the earthquake occurrence information only within the alarm required range Δ.   The seismometer according to claim 1, further comprising an earthquake warning issuing means for issuing an earthquake warning when the acceleration A and / or the magnitude M is equal to or greater than a predetermined value. A plurality of seismometers,
A transmission means for transmitting information between the plurality of seismometers,
The seismometer is
Acceleration detecting means for detecting acceleration A caused by the P wave of the earthquake;
Magnitude calculating means for calculating the magnitude M of the earthquake by applying the acceleration A to the equation (1);
An alarm required range calculating means for calculating the alarm required range Δ by applying the magnitude M to the equation (2);
When the acceleration A and / or the magnitude M is greater than or equal to a predetermined value, transmission means for transmitting earthquake occurrence information via the transmission means;
Receiving means for receiving the earthquake occurrence information via the transmission means;
In accordance with the earthquake occurrence information, with an earthquake warning issuing means for issuing an earthquake warning,
The alarm issuing range setting means that sets the seismometer that issues the earthquake warning according to the earthquake occurrence information as a seismometer within the alarm required range Δ calculated by the seismometer that is the transmission source of the earthquake occurrence information. A seismometer system characterized by comprising:
Formula (1): M = αlogA + β
Formula (2): logΔ = γlogM + δ   The alarm issuing range setting means is a means for setting the transmission destination of the earthquake occurrence information as another seismometer within the alarm required range Δ calculated by the seismometer that is the transmission source of the earthquake occurrence information. The seismometer system according to claim 6, wherein the seismometer system is provided.   The seismometer issues the earthquake warning by the earthquake warning issuing means when the acceleration A detected by the seismometer and / or the magnitude M calculated by the seismometer is equal to or greater than a predetermined value. The seismometer system according to claim 5 or 6, characterized in that. Detect acceleration A caused by earthquake P wave,
Applying the acceleration to equation (1) to calculate the magnitude M of the earthquake,
Applying the magnitude M to Equation (2) to calculate the alarm required range Δ,
An earthquake warning issuing method for issuing an earthquake warning within the alarm required range Δ.
Formula (1): M = αlogA + β
Formula (2): logΔ = γlogM + δ   A program that causes a computer to function as the acceleration detection means, the magnitude calculation means, and the alarm range calculation means according to claim 1.