JP2013113815A - Earthquake motion duration time prediction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earthquake motion duration time prediction system capable of predicting an earthquake motion duration time on an optional location at which earthquake motion observation data is not recorded.SOLUTION: An earthquake motion duration time prediction system 1 includes a storage part 5 for storing the coordinates of a target location and ground conditions of the target location, a regression expression calculation part 41 for preliminarily modeling aging characteristics of waveforms of a plurality of pieces of observation data of actual earthquake motion with an envelope function and representing an earthquake motion duration time by a regression expression calculated with a hypocentral distance and Meteorological Agency magnitude as parameters, a reception part 2 for receiving real-time earthquake information including the earthquake location and Meteorological Agency magnitude, a hypocentral distance calculation part 42 for calculating a hypocentral distance on the basis of the earthquake location of the real-time earthquake information and the stored coordinates of the target location, and a duration time calculation part 44 for substituting the ground conditions of the target location, the hypocentral distance, and the Meteorological Agency magnitude for the stored regression expression, and calculating an earthquake motion duration time.

Description

  The present invention relates to a seismic motion duration prediction system. Specifically, the present invention relates to a ground motion duration prediction system that predicts the duration of ground motion.

  Conventionally, the convergence of seismic motion is often determined based on the magnitude of seismic motion detected by a seismometer installed at a target point (see Patent Document 1). That is, in Patent Document 1, in order to perform elevator resumption control, a seismometer is installed on the site, and on the condition that the magnitude of seismic motion detected by this seismometer is smaller than a set threshold value, It is determined that the ground motion has converged.

  However, in addition to the introduction costs associated with the installation of seismometers, maintenance management running costs are required, so it is not easy to install seismometers at the target points.

  In view of this, an earthquake disaster prevention system has been developed that uses real-time earthquake information such as emergency earthquake warnings to predict the strength of ground motion at a target location and damage prediction of a building at the target location (see Patent Document 2). In this disaster prevention system, when an earthquake occurs, the duration of the earthquake motion is calculated using real-time earthquake information such as an emergency earthquake bulletin, and the damage of the building is predicted based on the duration of the earthquake motion.

Here, the duration of earthquake motion is obtained as follows.
That is, for earthquakes that have occurred in the past, a trend regarding the characteristics of the ground motion spectrum and duration is obtained by regression analysis or the like based on the position of the epicenter, the magnitude, and the observation data of each receiving area. Earthquakes that occur in the same seismic region occur with almost the same seismogenic mechanism, so the seismic source characteristics are similar, and the same seismic area has almost the same ground motion characteristics. In addition, a database of seismic motion spectrum characteristics and durations according to magnitude will be constructed.

  When real-time earthquake information (emergency earthquake warning) is received at the time of the earthquake, the combination of the source area of this earthquake and the receiving area to which the target point belongs is searched from the database, and the ground motion spectrum characteristics and the duration of the ground motion of the corresponding combination are searched. Is read. In this way, the duration of earthquake motion is obtained.

JP 2007-178202 A JP 2006-343578 A

  However, with the method disclosed in Patent Document 1, the duration of the earthquake motion can be predicted only for a combination of a specific source region and a seismic region stored in the database. For this reason, there was a problem that the duration of seismic motion could not be predicted in areas where seismic motion observation data was not recorded.

  An object of the present invention is to provide an earthquake motion duration prediction system capable of predicting the duration of an earthquake motion at an arbitrary point where the observation data of the earthquake motion is not recorded.

  The seismic motion duration prediction system according to claim 1 is a seismic motion duration prediction system that predicts the duration of seismic motion at a target point, and a storage unit that stores coordinates of the target point and ground conditions of the target point; The time-dependent characteristics of the waveforms of a plurality of observation data of actual seismic motion are modeled in advance using an envelope function, and the duration of the seismic motion is expressed as a regression equation using the epicenter distance and the JMA magnitude as parameters, and the regression equation is stored in the memory. A regression equation calculation unit to be stored in the unit, a reception unit that receives real-time earthquake information including the epicenter location and the JMA magnitude, and a hypocenter distance based on the source location of the real-time earthquake information and the stored coordinates of the target point In the epicenter distance calculation unit and the stored regression equation, the ground condition of the target point, the epicenter distance, and By substituting Zocho magnitude, characterized in that it comprises a duration calculation unit for calculating the duration of the ground motion, the.

According to the present invention, the storage unit stores the coordinates of the target point and the ground conditions of the target point. In addition, the regression equation calculation unit models the time-dependent characteristics of a plurality of actual seismic motion waveforms with an envelope function, and represents the regression equation using the epicenter distance and the Japan Meteorological Agency magnitude as parameters, and stores this regression equation in the storage unit. Let me.
Then, when the real-time earthquake information is received by the receiving unit, the epicenter distance calculation unit calculates the epicenter distance based on the epicenter position of the real-time earthquake information and the stored coordinates of the target point. Next, the duration calculation unit calculates the duration of the earthquake motion by substituting the ground condition of the target point, the epicenter distance, and the Japan Meteorological Agency magnitude into the stored regression equation.
Therefore, it is possible to predict the duration of seismic motion at any point and notify disaster prevention information such as the start of evacuation in the building.

  The earthquake motion duration prediction system according to claim 2 is characterized in that, as the regression equation, a regression equation in soft ground and a regression equation in hard ground are used.

  According to this invention, considering the ground conditions, the regression equation for the soft ground and the regression equation for the hard ground are used as the regression equations, so that the prediction accuracy of the seismic motion duration prediction system can be improved.

  According to the present invention, the storage unit stores the coordinates of the target point and the ground condition of the target point. In addition, a regression equation calculation unit models the time-dependent characteristics of a plurality of actual seismic motion waveforms with an envelope function, and represents the regression equation using the epicenter distance and the Japan Meteorological Agency magnitude as parameters, and stores this regression equation in the storage unit. Let me. Then, when the real-time earthquake information is received by the receiving unit, the epicenter distance calculation unit calculates the epicenter distance based on the epicenter position of the real-time earthquake information and the stored coordinates of the target point. Next, the duration calculation unit calculates the duration of the earthquake motion by substituting the ground condition of the target point, the epicenter distance, and the Japan Meteorological Agency magnitude into the stored regression equation. Therefore, it is possible to predict the duration of seismic motion at any point and notify disaster prevention information such as the start of evacuation in the building.

It is a block diagram of the earthquake motion duration prediction system concerning one embodiment of the present invention. It is a flowchart of operation | movement of the earthquake motion duration prediction system which concerns on the said embodiment. It is a figure which shows the epicenter distribution of the earthquake in the Kanto district. It is a figure which shows an example of the time-dependent characteristic of the waveform of an earthquake motion. It is a figure which shows the relationship between the epicenter distance and duration in a soft ground. It is a figure which shows the relationship between the epicenter distance and duration in a hard ground.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a seismic motion duration prediction system 1 according to an embodiment of the present invention.
The seismic motion duration prediction system 1 predicts the duration of seismic motion at a target point based on real-time earthquake information such as emergency earthquake bulletin, and includes a receiving unit 2, a display unit 3, an arithmetic processing unit 4, and a storage unit. 5 is provided.

The receiving unit 2 receives real-time earthquake information transmitted from the Japan Meteorological Agency.
The display unit 3 displays information received by the receiving unit 2 and information output from the arithmetic processing unit 4, and is, for example, a monitor.

The memory | storage part 5 memorize | stores various information, for example, is a hard disk. The storage unit 5 stores the coordinates (latitude / longitude) of the target point in advance, and stores the average S wave velocity V _S30 from the ground surface to a depth of 30 m as the ground condition of the target point. Further, the regression formula obtained by the regression formula calculation unit 41 of the arithmetic processing unit 4 described later is stored.

The arithmetic processing unit 4 reads out a program stored in the storage unit 5 and develops and executes it on an OS (Operating System) that performs operation control.
Specifically, the arithmetic processing unit 4 includes a regression equation calculation unit 41, an epicenter distance calculation unit 42, a predicted seismic intensity calculation unit 43, and a duration calculation unit 44.

  The regression equation calculation unit 41 models the time-dependent characteristics of the waveforms of a plurality of observation data of actual seismic motion with an envelope function, and represents the seismic source distance calculated by the predicted seismic intensity calculation unit 43 and the meteorological agency magnitude as parameters. Stored in the unit 5.

When receiving the real-time earthquake information, the epicenter distance calculation unit 42 calculates the epicenter distance based on the epicenter position of the real-time earthquake information and the coordinates of the target point stored in the storage unit 5.
The predicted seismic intensity calculation unit 43 substitutes the seismic source distance and the Japan Meteorological Agency magnitude calculated by the seismic source distance calculation unit 42 into the seismic intensity calculation formula (for example, the technical standards for forecasting work permission, the Meteorological Agency Seismic Volcano Department March 18, 2010). The predicted seismic intensity at the target point is calculated.

  When the real time earthquake information including the epicenter position and the JMA magnitude is received, the duration calculation unit 44 reads the regression equation from the storage unit 5 and calculates the ground condition of the target point and the epicenter distance calculation unit 42 to the regression equation. Substituting the epicenter distance and the Japan Meteorological Agency magnitude, the duration of the earthquake motion is calculated.

  FIG. 2 is a flowchart of an operation for calculating the duration of the earthquake motion of the earthquake motion duration prediction system 1.

In step S <b> 1, the receiver 2 receives real-time earthquake bulletin. That is, information such as the earthquake occurrence time t ₀ , the location of the epicenter (specifically, latitude, longitude, seismic source depth), and the Japan Meteorological Agency magnitude M _j are acquired from this real-time earthquake early warning.

In step S <b> 2, the epicenter distance calculation unit 42 calculates the epicenter distance X from the epicenter to the target point.
In step S3, the predicted seismic intensity calculation unit 43 calculates the predicted seismic intensity at the target point by substituting the epicenter distance X calculated by the seismic source distance calculation unit 42 and the Japan Meteorological Agency magnitude M _j into the seismic intensity calculation formula.

  In step S4, the predicted seismic intensity calculation unit 43 determines whether the predicted seismic intensity at the target point is 3 or more. If this determination is Yes, the process moves to step S5, and if it is No, the process ends.

In step S < _b > 5, the duration calculation unit 44 calculates a time ta at which the main motion of the earthquake motion reaches the target point based on the travel schedule of the Japan Meteorological Agency.

In step S _< b> 6, the duration calculation unit 44 reads the target point V _S30 from the storage unit 5, and determines whether or not the read V _S30 is 400 m / s or more. If this determination is No, the target point is soft ground, so the process proceeds to step S7. If Yes, the target point is hard ground, and the process proceeds to step S8.

  In step S <b> 7, the duration calculation unit 44 reads out the following regression equation (1) from the storage unit 5.

In the equation (1), a, b, c, d, and e are regression coefficients that vary depending on the region and ground conditions, and σ ₁ and σ ₂ are logarithmic standard deviations in the regression equation. Α is a coefficient that takes into account variations in the regression equation, and is a coefficient that is multiplied by the logarithmic standard deviations σ ₁ and σ ₂ .
Further, from the storage unit 5 reads out the ground conditions for soft ground, determine the duration t _d -t _a ground motion in soft ground. That is, a, b, c, d, e, σ ₁ , and σ ₂ are read and substituted into the equation (1).

On the other hand, in step S8, the duration calculation unit 44 reads the above-mentioned equation (1) from the storage unit 5 reads out the ground conditions for hard ground, the duration t _d -t _a ground motion in the hard soil Ask. That is, a, b, c, d, e, σ ₁ , and σ ₂ are read and substituted into the equation (1).

In step S9, the duration calculation unit 44, the main movement of the ground motion in addition the duration t _d -t _a ground motion at time t _a to reach the target point, to calculate the end time t _d of the ground motion.
In step S10, the display unit 3 to display the end time _{t d} of the ground motion.

Hereinafter, the procedure for obtaining the above equation (1) will be described by taking the Kanto region as an example.
As shown in FIG. 3, 18 submarine earthquakes with a magnitude of _Mj of 5.0 or more that occurred after 1996 were selected, and 2378 observation data of these 18 earthquakes were used. The circle in FIG. 3 indicates the position of the epicenter.
First, each observation data was classified into soft ground and hard ground. That is, the ground conditions at the target point were arranged using the average S wave velocity V _S30 from the ground surface to a depth of 30 m as an index. Specifically, V _S30 was estimated for each observation data, and V _S30 was 400 m / s or more as hard ground and less than 400 m / s as soft ground.

  Hereinafter, the duration of the ground motion is the time from the start of the main motion until the amplitude of the main motion is reduced to about 1/10 with respect to the envelope curve modeling the acceleration waveform of the ground motion on the ground surface.

  Therefore, for each observation data, for example, as shown in FIG. 4, the temporal characteristics of the waveform of the earthquake motion are modeled by a Jennings-type envelope E (t). Specifically, the waveform of the seismic motion was divided into a rising part, a strong earthquake part, and an attenuation part, and E (t) was configured by the following equations (2) to (5).

Here, t _a is the start time of the rising part, t _b is the end time of the rising part, that is, the start time of the strong earthquake part, t _c is the end time of the strong earthquake part, that is, the start time of the attenuation part, and t _d is the end time of the attenuation part. , A is the amplitude value of the strong motion part at E (t). Further, B = ln10 / (t _d −t _c ).

The envelope function thus modeled was subjected to regression analysis using the epicenter distance X and the Japan Meteorological Agency magnitude M _j as parameters, and the above-described equation (1) was obtained.
The regression coefficients a, b, c, d, e and logarithmic standard deviations σ ₁ and σ ₂ at this time are shown below.

FIG. 5A is a diagram showing the relationship between the duration t _c -t _b of the strong earthquake part and the epicenter distance X in soft ground. FIG. 5B is a diagram showing the relationship between the duration t _d -t _c of the attenuation part and the epicenter distance X in the soft ground.
FIG. 6A is a diagram showing the relationship between the duration t _c -t _b of the strong earthquake part and the epicenter distance X in the hard ground. FIG. 6B is a diagram showing the relationship between the duration t _d -t _c of the attenuation part and the epicenter distance X in the hard ground.

From FIG. 5 and FIG. 6, it can be seen that the duration t _c -t _b of the strong earthquake part becomes longer as M _j and X become larger. Further, it can be seen that the duration of the attenuation part does not depend much on M _j and becomes longer as X increases. Also, the duration _t c -t _b of strong motion portion, compared to the duration _t d -t _c of the damping unit, it can be seen that the variation is large.

According to this embodiment, there are the following effects.
(1) The storage unit 5 stores the coordinates of the target point and the ground conditions of the target point. In addition, the regression equation calculation unit 41 models in advance the time-dependent characteristics of a plurality of actual seismic motion waveforms with an envelope function, and represents the regression equation using the epicenter distance and the JMA magnitude as parameters, and this regression equation is stored in the storage unit 5. Remember me.
Then, when the real-time earthquake information is received by the receiving unit 2, the epicenter distance calculation unit 42 calculates the epicenter distance based on the epicenter position of the real-time earthquake information. Next, the duration calculation unit 44 calculates the duration of the earthquake motion by substituting the ground condition of the target point, the epicenter distance, and the Japan Meteorological Agency magnitude into the stored regression equation.
Therefore, it is possible to predict the duration of seismic motion at any point and notify disaster prevention information such as the start of evacuation in the building.

  (2) Considering the ground conditions, the regression equation for the soft ground and the regression equation for the hard ground are used as the regression equations, so that the prediction accuracy of the seismic motion duration prediction system 1 can be improved.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Earthquake motion duration prediction system 2 ... Reception part 3 ... Display part 4 ... Arithmetic processing part 5 ... Memory | storage part 41 ... Regression formula calculation part 42 ... Earthquake source distance calculation part 43 ... Prediction seismic intensity calculation part 44 ... Duration calculation part

Claims (2)

A seismic motion duration prediction system that predicts the duration of seismic motion at a target location,
A storage unit for storing coordinates of the target point and ground conditions of the target point;
The time-dependent characteristics of a plurality of observation data of actual seismic motion are modeled with an envelope function in advance, the duration of the seismic motion is expressed as a regression equation using the epicenter distance and the Japan Meteorological Agency magnitude as parameters, and the regression equation is stored in the storage unit A regression equation calculation unit to be stored in
A receiver for receiving real-time earthquake information including the location of the epicenter and the JMA magnitude;
An epicenter distance calculation unit for calculating an epicenter distance based on the epicenter position of the real-time earthquake information and the coordinates of the stored target point;
A seismic motion duration prediction unit comprising a duration calculation unit that calculates the duration of seismic motion by substituting the ground condition of the target point, the epicenter distance, and the Japan Meteorological Agency magnitude into the stored regression equation. system.   The earthquake motion duration prediction system according to claim 1, wherein a regression equation for soft ground and a regression equation for hard ground are used as the regression equation.

Images