JP6177628B2 - Immediate ground motion prediction method using underground ground motion - Google Patents

Description

  The present invention relates to an immediate ground motion prediction method using underground ground motion.

  In addition to hardware measures such as seismic reinforcement to improve the earthquake resistance of railway facilities in advance, railway earthquake countermeasures include early earthquake warnings to control train operations quickly and appropriately in the event of an earthquake, and railway facilities after an earthquake occurs. It is important to take soft measures such as seismic operation regulation that regulates train operation in the range where damage is expected.

  The methods used for early earthquake warnings in the railway field can be broadly divided into two. One is a method of outputting an alarm at a timing when an arbitrary seismic motion index calculated from observation values of a seismometer exceeds a predetermined value (specified value). The other method is to estimate the location and scale of the epicenter from the initial P wave detected by the seismometer and output an alarm for the affected area. The epicenter estimation method based on the initial P wave was first put into practical use as UrEDAS in 1992 (see Non-Patent Document 1 below). In UrEDAS, a method has been adopted in which the epicenter distance is estimated from the magnitude estimated from the prevailing frequency of the P wave initial motion for several seconds and the observed amplitude, the influence range is judged based on past railway damage examples, and an alarm is output. Yes. After that, the B-Δ method (see Non-Patent Documents 2 and 3 below) for estimating the epicenter distance using the relationship between the envelope shape of the amplitude of the P wave initial motion part and the epicenter distance is incorporated into a new early earthquake disaster prevention system. It has been used on some bullet trains in Japan from 2004 to the present.

Yutaka Nakamura: Research on comprehensive earthquake disaster prevention system, Journal of Japan Society of Civil Engineers, No. 531 / I-34, 1996, pp. 1-33. Odaka, T .; Ashiya, K .; Sato, S .; , Ohtake, K .; and Nozaka, D.A. : A new method of quickestimating epidistance distance and magnesium from single seismic record, Bulletin of the Seismological Society. 93, no. 1,2003, pp. 526-532. Koji Shibuya, Shinji Sato, Naotaka Iwata, Masahiro Korenaga, Hiromitsu Nakamura: Use of Earthquake Early Warnings in Railway Earthquake Warning Systems, Geophysical Exploration, Vol. 60, no. 5, 2007, pp. 387-397. Shuichi Sotani, Shigeru Nakajima: Examination of measured seismic intensity for warning and predicted seismic intensity for warning, Proceedings of the 62nd Annual Scientific Lecture, Japan Society of Civil Engineers, 2007, pp. 1273-1274. Tatsuya Itoi, Yasuo Uchiyama, Masami Takagi, Takatoshi Sueda, Ichiro Nagashima: Development and performance evaluation of an earthquake disaster prevention system using emergency early warning information and initial tremor information of local seismometers, Architectural Institute of Japan Technical Report, Vol. 16, no. 33, 2010, pp. 827-832. Hoshiba, M .; : Real-time Prediction of Ground Motion by Kirchoff-Fresnel Boundary Integral Effort Method, Extended Front Detection Method. 118, 2013, pp. 1038-1050. Kurahashi Shu, Irikura Kojiro: Proposal of immediate prediction method of main motion waveform using vertical motion acceleration recording in earthquake early warning, 2013 Geoscience Union Meeting Proceedings, 2013, SSS23-P01. Cabinet Office: Central Disaster Prevention Council “Tokyo Metropolitan Earthquake Countermeasures Committee”, http: // www. Bousai. go. jp / kaigirep / chubou / senmon / shutochokkajishinsenmon /, accessed on June 26, 2013 Kentaro Mizushima: Introduction of SI value to Shinkansen earthquake operation regulations, new track, Vol. 60, no. 4, 2006, p. 25-27. Yugo Ito, Shuichi Other Tani: Optimization of driving regulation after the earthquake occurred, Japan Railway Facilities Association, Vol. 44, no. 10, 2006, p. 813-815. Junichi Horigoe: Earthquake countermeasures and outline of operation regulations in JR East, New Line, Vol. 60, no. 1, 2006, pp. 59-61. Kazuhiro Iwakiri, Mitsuyuki Hiba, Kazuo Otake, Toshihiro Shimoyama: Examination of utilization of KiK-net strong motion data around Minami Kanto for early earthquake warnings, test time signal, Vol. 75, 2012, pp. 37-59. Satoshi Takano, Yusuke Hamada: Examination of on-site earthquake warning system using borehole seismometer data-To prepare for a direct earthquake by compensating for the weak point of emergency earthquake warning-2011 Geoscience Union Meeting Proceedings 2011, HDS030 -02. Hiroki Hayashi, Keiji Kasahara, Naoki Kimura: Pre-Tertiary basement rocks distributed in the basement of the Kanto Plain, Journal of Geology, Vol. 112, no. 1, 2006, pp. 2-13. National Research Institute for Earth Science and Disaster Prevention: Strong motion observation network (K-NET, KiK-net), http: // www. kyoshin. bosai. go. jp / kyoshin /, accessed on March 23, 2013 Keiichi Kasahara: Dynamics of Earthquakes Introduction to Modern Seismology, Kashima Press, 1983

  In direct earthquakes, it has been pointed out that the time from the occurrence of the earthquake to the arrival of the main motion is short, and the alarm output is not in time. Therefore, as a method of predicting the main motion directly from the P wave without estimating the epicenter and outputting an alarm, it is determined by the alarm seismic intensity (see Non-Patent Document 4 above) obtained from the vertical motion where the P wave is dominant. A method of outputting an alarm according to the specified value has been put into practical use on some Shinkansen lines in Japan. Also, in fields other than railways, systems for production facilities have been developed that predict primary motion directly using the statistical relationship between the acceleration of the initial motion of the P wave and the velocity of the primary motion of the S wave (the above non-patent document). Reference 5). In recent years, a wave field that has been observed in real time using a boundary integral equation method using a boundary integral equation method as an actual value (see Non-Patent Document 6 above), or a P wave has reached a certain observation point. Research on methods for predicting S waves from P waves theoretically, such as a method for predicting S waves in areas where strong shaking has not yet arrived (see Non-Patent Document 7 above), has also been conducted. While the urgency of earthquakes directly under the Tokyo metropolitan area has been pointed out (see Non-Patent Document 8 above), expectations for improving the immediateness and accuracy of early earthquake warnings are increasing, and there is a need for a method for outputting warnings more quickly and reliably. Development is an urgent need.

  On the other hand, although railway railway operation control methods vary slightly among railway operators, they may be performed based on seismic motion index values calculated from seismometer observations installed at regular intervals along the railway. Many. When the seismic motion index value of a certain seismometer exceeds the operational regulation issuance reference value, operation regulation measures such as speed regulation and operation suspension are taken in a predetermined section for the seismometer. In the case of driving stoppage, security by walking etc. will be implemented for all sections subject to driving restrictions, and if there is no abnormality in the railway facility, driving will resume. The interval between seismometers along the railway varies depending on the route, but it is about 5 km for densely arranged routes and about 40 km for local lines. For this reason, when operation is canceled, it takes time for security by walking or the like, so even if the railway facility is harmless, it takes a long time to resume operation. In recent years, some railway operators have attempted to rationalize the operation regulation by changing the seismic motion index value used for the operation regulation to one that is highly related to damage (Non-Patent Document 9, above). 10). In addition, it is also practiced to add seismometers to subdivide the operation restriction section and shorten the guard target section when the operation is stopped (see Non-Patent Document 11). The current method does not evaluate the fluctuation of the ground motion within the operation restriction section, so if the distribution of the ground motion within the operation restriction section can be predicted with high accuracy immediately after the occurrence of the earthquake, the optimization of the guard range should be considered. It can be important information above.

  In view of the above-described situation, the present invention uses immediate ground motion using underground ground motion that can directly predict the amplitude of the S wave on the ground surface by using the amplitude of the P wave observed on the earthquake base. An object is to provide a prediction method.

In order to achieve the above object, the present invention provides
[1] In the immediate ground motion prediction method using underground ground motion,
(A) Regarding the relationship between the maximum acceleration or maximum velocity u _b ^s of the underground S wave and the maximum acceleration or maximum velocity u _s ^s of the surface S wave, the observed maximum acceleration of the underground S wave and the surface S wave for each observation point Alternatively, the parameter a ₁ is determined by fitting the expression log _s ^s = log _b ^s + a ₁ (expression 2) to the maximum observation speed relationship so that the error for all observation records is minimized by the least square method. And
(B) Regarding the relationship between the maximum acceleration or maximum velocity u _b ^p of underground P wave and the maximum acceleration or maximum velocity u _b ^s of underground S wave, observation of underground P wave and underground S wave for each observation point By fitting the equation log _b ^s = logu _b ^p + a ₂ (Equation 7) with respect to the relationship between the maximum acceleration or the observed maximum velocity, the parameter a ₂ Decide
(C) A parameter of an expression log _s ^s = logu _b ^p + a (expression 9) indicating the relationship between the maximum acceleration or maximum velocity of the underground P wave and the surface S wave obtained from the expression (2) and the expression (7). a is determined by a = a ₁ + a ₂ , and the maximum acceleration or maximum velocity u _s ^s of the surface S wave is directly calculated from the maximum acceleration or maximum velocity u _b ^{p of the} underground P wave using the above equation (9). Prediction.

  [2] Immediate ground motion prediction using ground motion, characterized in that in the method for predicting immediate ground motion using ground motion in [1] above, a warning can be output up to about 1 second faster than using ground motion. Method.

  [3] In the immediate ground motion prediction method using underground ground motion described in [1] above, the relationship between the maximum amplitude (acceleration, velocity) reflecting the influence of underground structure and the radiation characteristics of the epicenter is constructed. And

  [4] The immediate ground motion prediction method using underground ground motion according to [1] above, wherein the surface S wave is predicted in a plane using the underground S wave and the underground velocity structure.

  According to the present invention, by using the amplitude of the P wave observed on the earthquake base, the amplitude of the S wave on the ground surface can be directly predicted, and early earthquake motion prediction can be performed.

  In addition, surface S waves can be predicted in a plane using underground S waves and underground velocity structures.

  Furthermore, in the setting of control values using conventional surface earthquake records, in principle, the ground motion amplification effect due to the underground velocity structure could not be taken into account. Can be considered.

It is a schematic diagram which performs the immediate ground motion prediction using the underground ground motion of this invention. It is a distribution map of the KiK-net observation point of the Kanto plain. It is a figure which shows the epicenter distribution of the used earthquake. It is a figure which shows the histogram of the ground surface maximum acceleration [gal] of the used earthquake. As a waveform example, it is a figure which shows the acceleration waveform and velocity waveform of CHBH04 in the ground of the magnitude 6.0 and 73.0 km depth which occurred in the northwestern part of Chiba Prefecture on July 23, 2005. It is a figure which shows the arrival time difference of underground P wave and surface P wave. It is a figure which shows the relationship of the maximum acceleration of underground S wave and surface S wave. It is a figure which shows the relationship between the maximum velocity of underground S wave and surface S wave. It shows a comparison of the parameters a ₁ at each observation point. It is a figure which shows the relationship between the maximum acceleration of underground P wave and underground S wave. It is a figure which shows the relationship between the maximum velocity of underground P wave and underground S wave. It shows a comparison of the parameter a ₂ at each observation point. It is a figure which shows the relationship between the maximum acceleration of underground P wave and surface S wave. It is a figure which shows the relationship between the maximum velocity of underground P wave and surface S wave. It is a figure which shows the comparison of the parameter a in each observation point. It is a figure which shows the correlation coefficient of the maximum amplitude. It is a figure which shows the comparative example of the observation waveform of ground surface vibration in CHBH04, and a calculation waveform. It is a figure which shows the relationship between the observed value of underground S wave in each observation point, and the calculated value of surface S wave.

Immediate ground motion prediction method using underground seismic motion of the present invention, the relationship between (a) the maximum acceleration or the maximum speed of the underground S-wave u _b ^s and surface S-wave maximum acceleration or maximum velocity u _s ^s of observation points For each relationship between the observed maximum acceleration or the observed maximum velocity of the underground S wave and the surface S wave , the expression log _s ^s = log _b ^s + a ₁ (Expression 2) Parameter a ₁ is determined by fitting so that is minimized,
(B) Regarding the relationship between the maximum acceleration or maximum velocity u _b ^p of underground P wave and the maximum acceleration or maximum velocity u _b ^s of underground S wave, observation of underground P wave and underground S wave for each observation point By fitting the equation log _b ^s = logu _b ^p + a ₂ (Equation 7) with respect to the relationship between the maximum acceleration or the observed maximum velocity, the parameter a ₂ Decide
(C) A parameter of an expression log _s ^s = logu _b ^p + a (expression 9) indicating the relationship between the maximum acceleration or maximum velocity of the underground P wave and the surface S wave obtained from the expression (2) and the expression (7). a is determined by a = a ₁ + a ₂ , and the maximum acceleration or maximum velocity u _s ^s of the surface S wave is directly calculated from the maximum acceleration or maximum velocity u _b ^{p of the} underground P wave using the above equation (9). Predict.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a schematic diagram for performing an immediate ground motion prediction using the ground motion of the present invention. FIG. 1 (a) shows an immediate prediction of a surface S wave using an underground P wave, and FIG. It is a figure which shows the surface prediction of the surface S wave which used underground S wave.

In these figures, 1 is the seismic base, 2 is the sedimentary layer, 3 is the ground surface, 4 is a deep borehole reaching from the ground surface 3 to the seismic base 1, 5 is an underground seismometer placed on the seismic base 1, 6 is Surface seismometers placed on the ground surface 3, 7 is the epicenter, 8 is the P wave radiated from the epicenter 7, 9 is the S wave radiated from the seismic source 7, 11 is the P observed by the underground seismometer 5 Wave (P _BH ), 12 is S wave (S _BH ) observed by underground seismometer 5, 13 is P wave (PS _F ) observed by surface seismometer 6, and 14 is observed by surface seismometer 6 S wave (S _SF ).

As shown in this figure, by using the amplitude of the P wave (P _BH ) 11 observed by the underground seismometer 5 installed on the seismic base 1, it was observed by the surface seismometer 6 on the ground surface 3. A method of directly predicting the amplitude of the S wave (S _SF ) 14 is adopted.

  By this method, it is possible to increase the margin time as compared with the current system only by the time during which the seismic wave propagates through the thick deposition layer 2.

Therefore, using the data of KiK-net (Base Earthquake Strong Motion Observation Network of National Research Institute for Earth Science and Disaster Prevention) (see Non-Patent Document 15 above) in the Tokyo metropolitan area and surrounding areas for earthquakes directly under the metropolitan area, the P wave (P _BH ) 11 and the seismic base 1 S wave (S _BH ) 12, and the seismic base 1 S wave (S _BH ) 12 and the surface S wave (S _SF ) 14 are examined, and the seismic base P wave (P _BH ) We developed a method to predict the surface S wave (S _SF ) 14 according to 11 information.

  As described above, in the present invention, an underground earthquake record in the Kanto Plain is used in order to realize an immediate prediction method of surface ground motion for an earthquake directly below the capital.

  As shown in Fig. 1 (a), by predicting the surface S wave directly from the P wave (ground P wave) observed by the underground seismometer, It is possible to output an alarm faster and more reliably than the estimation method according to. In addition, as shown in Fig. 1 (b), by combining the S wave (underground S wave) observed with the underground seismometer and the underground velocity structure of the sedimentary layer, the surface S wave is predicted in a plane immediately after the occurrence of the earthquake. it can. In the study for speeding up and sophisticating the earthquake early warning (see Non-Patent Document 12 above), the applicability of the emergency earthquake early warning to the existing method and the extraction of the problem are performed. In addition, a method of predicting ground motion from the ground and ground motion index (see Non-Patent Document 13 above) has been proposed, but only shows a statistical relationship.

In the present invention, using the KiK-net observation point data of the National Research Institute for Earth Science and Disaster Prevention, consideration is given to the effects of seismic source characteristics, propagation path characteristics, and site amplification characteristics on the maximum amplitude of underground and surface earthquake records. In addition, we propose an immediate prediction method for ground motion.
(A) Observation points and data used Fig. 2 shows the distribution of KiK-net observation points in the Kanto Plain. Among the observation points in FIG. 2, the present invention uses the underground and surface earthquake records of 12 observation points (see Non-Patent Document 14 above) where the borehole has reached the Pre-New Tertiary System.

  In the present invention, in order to limit the earthquake to the epicenter around the Kanto Plain, an earthquake having an epicenter of 34.5 to 37.0 ° north latitude and 138.5 to 141.0 ° east longitude was used. In addition, 243 earthquakes with a magnitude of 4.5-7.0 were used because the earthquake motions were mainly observed over the entire Kanto Plain. Fig. 3 shows the epicenter distribution of the used earthquake. However, there are actually differences in the number of earthquakes used at each observation point due to the fact that there are cases where the epicenter distance is large and earthquakes are not observed.

  Next, FIG. 4 shows a histogram of the maximum ground acceleration [gal] of the earthquake used this time. According to FIG. 4, since most of the earthquakes used this time have a maximum acceleration of about several tens of gals, it is considered that there is little data affected by the non-linearity of the ground.

Using the acceleration waveform observed in the earthquake shown in FIG. 3, the arrival times of the P wave and the S wave were visually observed. Inspection was performed using a vertical component for the P wave and two horizontal components for the S wave. Next, the acceleration waveform was integrated to obtain a velocity waveform. The acceleration waveform was subjected to third-order Butterworth type bandpass filter processing with cutoff frequencies of 0.1 Hz and 20 Hz. Finally, the maximum amplitude of the P wave and S wave was determined for each of the acceleration waveform and the velocity waveform. The maximum amplitude of the P wave is the maximum absolute value of the vertical component in the time from the arrival of the P wave to the arrival of the S wave, and the maximum amplitude of the S wave is the maximum value of the horizontal two-component vector sum after arrival of the S wave. FIG. 5 shows the acceleration waveform and velocity waveform of CHBH04 in the ground and on the surface in an earthquake of magnitude 6.0 and depth of 73.0 km that occurred in the northwestern part of Chiba Prefecture on July 23, 2005 as a waveform example.
(B) Increase in margin time when using underground earthquake records Fig. 6 shows the arrival time difference between the underground P wave and the ground P wave at each observation point. At the observation points used this time, the arrival time difference is 0.1 to 1.2 seconds, and it can be seen that the observation points with deeper boreholes are larger. Therefore, it is possible to output an alarm about one second earlier than using an underground earthquake record.

Relationship between maximum amplitude in underground and surface earthquake records [1] Relationship between maximum amplitude of underground S-wave and surface S-wave In the present invention, an observation point where the borehole reaches the earthquake base is used. The relationship between the medium S wave and the surface S wave is expressed by equation (1) using the transfer function G (ω) between the earthquake base and the surface.

  Here, u represents the amplitude of the seismic wave. The superscript S represents the S wave, and the subscripts b and s represent the underground and the ground, respectively. Taking the logarithm of both sides of the above equation (1), equation (2) is obtained.

  here,

It is. In other words, if the underground S wave and the surface S wave have a linear relationship on the logarithmic axis and the transfer function between the earthquake base and the ground surface, that is, the parameter a ₁ representing the amplification factor from the earthquake base to the ground surface can be determined, It becomes possible to predict the surface S wave from the S wave.

The relationship between the observed values of the maximum acceleration and maximum velocity of the underground S wave and the surface S wave at each observation point is shown in FIGS. 7 and 8, respectively. The straight line in the figure is the result of fitting equation (2) to minimize the error for all observation records. A comparison of the parameter a ₁ at each observation point is shown in FIG. From FIG. 9, it can be seen that a ₁ has a maximum acceleration of 0.39 to 0.90 and a maximum speed of about 0.58 to 0.96, and varies depending on the observation point. This is because the site amplification characteristics are different for each observation point. The correlation coefficient between the maximum amplitude of the underground S wave and the surface S wave is 0.76 to 0.98 at the maximum acceleration and 0.83 to 0.99 at the maximum speed. The correlation coefficient exceeds 0.9 at many observation points, and the maximum amplitude of the surface S wave can be accurately predicted from the maximum amplitude of the underground S wave. This indicates the possibility that the surface S wave can be predicted with high accuracy from the underground S wave by giving an underground velocity structure directly below the observation point.

[2] Relationship between the maximum amplitude of underground P-wave and underground S-wave Assuming that the epicenter is a double couple, the wave fields of the P-wave and S-wave at the borehole observation point sufficiently away from the seismic source are given by equations (4) and (4), respectively. (5) (see Non-Patent Document 16 above).

Here, ρ is the density of the medium, V is the elastic wave velocity in the medium, r is the epicenter distance, f (t) is the force acting on the epicenter, and R θφ is the radiation coefficient. When the amplitude ratio of Expression (4) and Expression (5) is taken, Expression (6) is obtained.

  Taking the logarithm of both sides of equation (6), equation (7) is obtained.

  here,

It is. In other words, the ground P wave and the ground S wave have a linear relationship on the logarithmic axis, and the parameter a _{2 including} the influence of the radiation coefficient of each earthquake and the S wave / P wave velocity ratio of the earthquake occurrence area is determined. If it is possible, the underground S wave can be predicted from the underground P wave.

The relationship between the observed values of the maximum acceleration and maximum velocity of the underground P wave and underground S wave at each observation point is shown in FIGS. 10 and 11, respectively. The straight line in the figure is the result of fitting Equation (7) so that the error is minimized with respect to all observation records. A comparison of the parameter a ₂ at each observation point is shown in FIG. From FIG. 12, it can be seen that a ₂ has a maximum acceleration of 0.25 to 0.92 and a maximum speed of about 0.45 to 0.84, and varies depending on the observation point. This is because the influence of the S wave / P wave velocity ratio in the earthquake occurrence region and the difference in the radiation pattern of each earthquake differs at each observation point. The correlation coefficient between the maximum amplitude of the underground P wave and the underground S wave is 0.75 to 0.92 at the maximum acceleration and 0.73 to 0.92 at the maximum velocity, and is different for each observation point. The fact that the overall correlation is smaller than in the previous case is thought to be due to the effects of variations in the radiation pattern of each earthquake.

[3] Relationship between the maximum amplitude of underground P wave and ground surface S wave The relationship between underground P wave and ground surface S wave is obtained from the following equation from equations (2) and (7).

  here,

It is. That is, the parameter a includes the influence of the ground motion amplification due to the underground velocity structure, the radiation coefficient, and the S wave / P wave velocity ratio in the earthquake occurrence area.

The relationship between the observed values of the maximum acceleration and maximum velocity of the underground P wave and the surface S wave at each observation point is shown in FIGS. 13 and 14, respectively. The straight line in the figure is the result of fitting equation (9) so that the error is minimized with respect to all observation records. A comparison of the parameter a at each observation point is shown in FIG. As a result, it was confirmed from FIG. 15 that the parameter a is the sum of a ₁ and a ₂ as shown in Expression (10). FIG. 16 is a diagram showing the correlation coefficient of the maximum amplitude. From this figure, the correlation coefficient of the maximum amplitude of the underground P wave and the surface S wave is 0.68 to 0.89 at the maximum acceleration, and is 0.00 at the maximum speed. 74 to 0.91.

Prediction of ground motion using borehole seismograms and underground velocity structure From the above examination, it was found that surface earthquake motion may be predicted with high accuracy using underground S wave and underground velocity structure. In other words, even if there is no seismometer on the ground surface, it is possible that the ground motion can be estimated by using the nearby underground earthquake records if the underground velocity structure is estimated. Therefore, for the observation point where the underground velocity structure has been estimated in previous studies, the ground motion is calculated using the transfer function obtained by the one-dimensional overlapping reflection theory using the ground S wave as the input ground motion from the basement. Compare with observation records. Here, the Q value is given by Equation (11) as a frequency dependent type.

Here, Q ₀ is a damping constant and f is a frequency. Based on the result of pre-calculation in CHBH04, Q ₀ gives a value 1/25 of the S wave velocity [m / s].

  FIG. 17 shows a comparative example of the observed waveform and the calculated waveform of the ground motion in CHBH04. The maximum accelerations of observed and calculated waveforms are close to each other, indicating that the underground velocity structure and damping constant are generally appropriate. Next, FIG. 18 shows the relationship between the observed value of the underground S wave and the calculated value of the surface S wave at each observation point. The straight line in the figure represents the relationship between the observed values of the underground S wave and the ground S wave shown in FIG. In CHBH04 for which the pre-calculation was performed, the observed value and the calculated value coincide on average. On the other hand, at other observation points, it can be seen that the calculated value may overestimate or underestimate the observed value. This is thought to be due to the fact that the attenuation constant in the sedimentary layer differs depending on the observation point and the accuracy of the underground velocity structure is different. Therefore, it is necessary to clarify the underground velocity structure and attenuation structure in advance in order to accurately estimate the ground motion at a point where there is no seismometer.

  According to the present invention, since the immediate ground motion prediction method using underground earthquake records considers site amplification characteristics, it is possible to give different seismic motion control values for each observation point, which is finer than the conventional method. Regulation becomes possible.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The instantaneous ground motion prediction method using the ground motion of the present invention is capable of directly predicting the amplitude of the S wave on the ground surface by using the amplitude of the P wave observed on the earthquake base. It can be used as an immediate earthquake motion prediction method using

DESCRIPTION OF SYMBOLS 1 Seismic base 2 Sediment layer 3 Ground surface 4 Deep borehole 5 Subsurface seismometer 6 Surface seismometer 7 Epicenter 8 P wave radiated from hypocenter 9 S wave radiated from seismic source 11 P wave observed by subsurface seismometer (P _BH )
12 S wave (S _BH ) observed by underground seismometer
13 P wave ( _PSF ) observed by surface seismometer
14 S wave (S _SF ) observed by surface seismometer

Claims (4)

(A) Regarding the relationship between the maximum acceleration or maximum velocity u _b ^s of the underground S wave and the maximum acceleration or maximum velocity u _s ^s of the surface S wave, the observed maximum acceleration of the underground S wave and the surface S wave for each observation point Alternatively, the parameter a ₁ is determined by fitting the expression log _s ^s = log _b ^s + a ₁ (expression 2) to the maximum observation speed relationship so that the error for all observation records is minimized by the least square method. And
(B) Regarding the relationship between the maximum acceleration or maximum velocity u _b ^p of underground P wave and the maximum acceleration or maximum velocity u _b ^s of underground S wave, observation of underground P wave and underground S wave for each observation point By fitting the equation log _b ^s = logu _b ^p + a ₂ (Equation 7) with respect to the relationship between the maximum acceleration or the observed maximum velocity, the parameter a ₂ Decide
(C) A parameter of an expression log _s ^s = logu _b ^p + a (expression 9) indicating the relationship between the maximum acceleration or maximum velocity of the underground P wave and the surface S wave obtained from the expression (2) and the expression (7). a is determined by a = a ₁ + a ₂ , and the maximum acceleration or maximum velocity u _s ^s of the surface S wave is directly calculated from the maximum acceleration or maximum velocity u _b ^{p of the} underground P wave using the above equation (9). Prediction method for ground motion using underground ground motion, characterized by dynamic prediction.   2. The method for predicting immediate ground motion using ground motion according to claim 1, wherein an alarm can be output at a maximum of about 1 second earlier than using ground motion.   A method for predicting immediate ground motion using underground ground motion according to claim 1, wherein a relationship of maximum amplitude (acceleration, velocity) reflecting the influence of underground structure and the radiation characteristics of the hypocenter is constructed. Immediate ground motion prediction method using ground motion.   2. An immediate ground motion prediction method using underground ground motion according to claim 1, wherein the ground surface ground wave is predicted in a plane using the underground S wave and underground velocity structure. Prediction method.

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