JP6291648B2 - Method and system for determining the arrival of major earthquake motions - Google Patents
Method and system for determining the arrival of major earthquake motions Download PDFInfo
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本発明は、地震発生時に観測された初期微動から、当該地震の主要動が到達する時刻を地震発生初期段階において判定するための地震の主要動の到達判定方法およびこれを用いた判定システムに関するものである。 TECHNICAL FIELD The present invention relates to an arrival determination method of an earthquake main motion and a determination system using the same for determining, in an initial stage of an earthquake occurrence, the time at which the main motion of the earthquake arrives from the initial tremor observed at the time of the earthquake occurrence. It is.
周知のように、地震動は、図１０に示すように、大別して初期微動（以下、Ｐ波と略す。）と主要動（以下、Ｓ波と略す。）に分類することができる。そして、地震による被害は、その殆どがＳ波による地震動によって引き起こされるものである。 As is well known, as shown in FIG. 10, seismic motion can be broadly classified into initial fine motion (hereinafter abbreviated as P wave) and main motion (hereinafter abbreviated as S wave). And most of the damage caused by earthquakes is caused by earthquake motion caused by S waves.
一方、Ｓ波は、Ｐ波よりも伝搬速度が遅いことから、地震発生時には、先ずＰ波の到達が観測され、一定時間が経過した後にＳ波が到達する。したがって、地震発生後、早期に生産能力を回復することが求められる工場などの生産設備においては、地震が発生した際に、Ｐ波の情報から、後に到達するＳ波の強さの大小を判別し、当該Ｓ波が到達した時点で既に機器の緊急停止の要否判定を終えていることが望ましい。 On the other hand, since the propagation speed of the S wave is slower than that of the P wave, the arrival of the P wave is first observed when an earthquake occurs, and the S wave arrives after a certain period of time has elapsed. Therefore, in a production facility such as a factory that is required to recover its production capacity early after an earthquake occurs, the magnitude of the intensity of the S wave that arrives later is determined from the P wave information when the earthquake occurs. However, it is desirable that the necessity determination of the emergency stop of the device has already been completed when the S wave arrives.
そこで、例えば下記特許文献１においては、Ｐ波の加速度最大値を用いて、Ｓ波の速度最大値を判定する方法が提案されており、下記特許文献２においては、Ｐ波の情報を用いて、Ｓ波の強さを判定する警報システムが提案されている。 Therefore, for example, in Patent Document 1 below, a method for determining the maximum speed value of the S wave using the maximum acceleration value of the P wave is proposed, and in Patent Document 2 below, information on the P wave is used. An alarm system for determining the intensity of the S wave has been proposed.
しかしながら、これらの従来技術は、地震発生後、予め設定された数秒間におけるＰ波の波形情報に基づいて判定を行うものであるために、特に震源が遠方の地震のように、Ｐ波の地震波形が数十秒かけて成長するような地震に対しては、当該Ｐ波の強さが充分に大きくなりきらない時点で判定を行うことになり、この結果やがて到達するＳ波の強さを過小評価する傾向があった。 However, since these conventional techniques make a determination based on waveform information of a P wave for a few seconds set in advance after the occurrence of an earthquake, an earthquake of a P wave, particularly an earthquake with a far epicenter. For earthquakes in which the waveform grows over several tens of seconds, determination is made when the intensity of the P wave does not become sufficiently large. As a result, the intensity of the S wave that will eventually arrive is determined. There was a tendency to underestimate.
本発明は、上記事情に鑑みてなされたものであり、地震動のＰ波の強さを適切に評価するために、現地地震計で得られた地震波の情報から、震源などの情報を介すことなく、簡易にかつ高い精度でＳ波の到達を判定することができる地震の主要動の到達判定方法および判定システムを提供することを課題とするものである。 The present invention has been made in view of the above circumstances, and in order to appropriately evaluate the strength of the P wave of seismic motion, the information about the epicenter, etc. is passed from the information on the seismic wave obtained by the local seismometer. Therefore, it is an object of the present invention to provide an arrival determination method and a determination system for main motion of an earthquake that can easily determine the arrival of an S wave with high accuracy.
上記課題を解決するため、請求項１に記載の発明は、判定の対象となる現地に設置した地震計で検知された地震のＰ波の振動波形から、上記現地へのＳ波の到達を判定するための地震の主要動の到達判定方法であって、上記現地の地震計で計測された振動波形から連続的にＳＴＡ／ＬＴＡを算出し、得られた値が予め設定されたＰ波検知用の閾値を越えた際に上記Ｐ波の到達を検知し、次いで引き続き当該Ｐ波の振動波形を計測するとともにＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＳ波検知用の閾値を越えた際に上記Ｓ波が到達したと判定することを特徴とするものである。 In order to solve the above problem, the invention according to claim 1 determines the arrival of the S wave to the site from the vibration waveform of the P wave of the earthquake detected by the seismometer installed at the site to be judged. Is a method for determining the arrival of the main motion of an earthquake, and for calculating the STA / LTA continuously from the vibration waveform measured by the local seismometer, and for the P wave detection in which the obtained value is preset. The arrival of the P wave is detected when the threshold value is exceeded, and then the vibration waveform of the P wave is continuously measured and the STA / LTA is calculated, and the obtained value is used for S wave detection set in advance. When the threshold value is exceeded, it is determined that the S wave has arrived.
ここで、ＳＴＡ／ＬＴＡとは、波形振幅（加速度、速度、変位等）の絶対値の短時間移動平均ＳＴＡと、長時間移動平均ＬＴＡの比である。すなわち、図３（ａ）に示す地震に対する波形振幅の絶対値のグラフにおいて、ＳＴＡとＬＴＡとの比を算出して、同様に時間軸で示せば、図３（ｂ）のように表される。図３は、加速度振幅に対して、ＳＴＡの移動平均間隔を０．１秒、ＬＴＡの移動平均間隔を５．０秒とした例である。 Here, STA / LTA is the ratio of the short-time moving average STA of the absolute value of the waveform amplitude (acceleration, speed, displacement, etc.) to the long-time moving average LTA. That is, in the graph of the absolute value of the waveform amplitude with respect to the earthquake shown in FIG. 3A, if the ratio of STA to LTA is calculated and similarly shown on the time axis, it is expressed as shown in FIG. . FIG. 3 shows an example in which the STA moving average interval is 0.1 seconds and the LTA moving average interval is 5.0 seconds with respect to the acceleration amplitude.
なお、ＳＴＡ／ＬＴＡを用いた技術に関しては、例えば上記非特許文献１において開示されている。そして、本発明は、上記ＳＴＡ／ＬＴＡの値を、Ｐ波およびＳ波の到達の判定に使用するものである。 The technology using STA / LTA is disclosed in Non-Patent Document 1, for example. In the present invention, the STA / LTA value is used to determine the arrival of the P wave and the S wave.
次いで、請求項２に記載の発明は、請求項１に記載の発明において、予め、過去に発生した複数の地震のデータから、各々の上記地震の計測地点におけるＰ波の観測波形から算出したＳＴＡ／ＬＴＡの最大値と当該計測地点における上記Ｐ波の継続時間との関係式を求めておき、上記現地の地震計がＰ波の到達を検知した後、ＳＴＡ／ＬＴＡの最大値と上記関係式とから上記Ｐ波の継続時間を予測し、上記Ｐ波の継続時間と上記Ｐ波の検知時刻を用いて上記Ｓ波の到達時刻を判定することを特徴とするものである。 Next, the invention according to claim 2 is the STA according to the invention according to claim 1, wherein the STA is calculated in advance from the data of a plurality of earthquakes that occurred in the past from the observed waveform of the P wave at each of the earthquake measurement points. After obtaining the relational expression between the maximum value of / LTA and the duration of the P wave at the measurement point, and after the local seismometer detects the arrival of the P wave, the maximum value of STA / LTA and the above relational expression The duration of the P wave is predicted from the above, and the arrival time of the S wave is determined using the duration of the P wave and the detection time of the P wave.
また、請求項３に記載の本発明に係る地震の主要動の到達判定システムは、判定の対象となる現地に設置された地震動の波形情報検出手段と、この波形情報検出手段によって計測されたＰ波の観測波形からＳ波の到達を判定する判定手段とを備えてなり、上記判定手段は、上記波形情報検出手段から送られてくる上記Ｐ波の観測波形から連続的にＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＰ波検知用の閾値を越えた際に上記Ｐ波の到達を検知し、次いで引き続き送られてくる当該Ｐ波の振動波形から連続的にＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＳ波検知用の閾値を越えた際に上記Ｓ波が到達したと判定する波形処理部を備えていることを特徴とするものである。 According to a third aspect of the present invention, there is provided an earthquake ground motion arrival determination system according to the present invention, wherein an earthquake motion waveform information detecting means installed in a site to be determined and a P measured by the waveform information detecting means. Determining means for determining the arrival of the S wave from the observed waveform of the wave, and the determining means continuously calculates the STA / LTA from the observed waveform of the P wave sent from the waveform information detecting means. Then, when the obtained value exceeds a preset threshold for P wave detection, the arrival of the P wave is detected, and then the STA / A waveform processing unit that calculates the LTA and determines that the S wave has arrived when the obtained value exceeds a preset threshold for S wave detection is provided. .
さらに、請求項４に記載の発明は、請求項３に記載の発明において、上記判定手段は、過去に発生した複数の地震のデータから、各々の上記地震の計測地点におけるＰ波の観測波形から算出したＳＴＡ／ＬＴＡの最大値と当該計測地点における上記Ｐ波の継続時間との関係式を格納したデータベースを有し、かつ上記波形処理部は、上記現地の地震計がＰ波の到達を検知した後、ＳＴＡ／ＬＴＡの最大値と上記関係式とから上記Ｐ波の継続時間を予測し、上記Ｐ波の継続時間と上記Ｐ波の検知時刻を用いて上記Ｓ波の到達時刻を判定することを特徴とするものである。 Furthermore, the invention according to claim 4 is the invention according to claim 3, wherein the determination means is based on a plurality of earthquake data that have occurred in the past, and from an observed waveform of a P wave at each of the earthquake measurement points. It has a database that stores the relational expression between the calculated maximum value of STA / LTA and the duration of the P wave at the measurement point, and the waveform processing unit detects the arrival of the P wave by the local seismometer After that, the duration of the P wave is predicted from the maximum value of STA / LTA and the relational expression, and the arrival time of the S wave is determined using the duration of the P wave and the detection time of the P wave. It is characterized by this.
なお、本発明において、初期微動をＰ波と略称して用い、主要動をＳ波と略称して用いているため、請求項２および請求項４に記載の発明における上記Ｐ波継続時間とは、Ｐ波到達検知時刻からＳ波到達時刻までの時間をいうものである。 In the present invention, the initial fine movement is abbreviated as P wave and the main movement is abbreviated as S wave. Therefore, the P wave duration in the inventions according to claim 2 and claim 4 The time from the P wave arrival detection time to the S wave arrival time.
請求項１〜４のいずれかに記載の発明によれば、地震計で計測された振動波形から連続的にＳＴＡ／ＬＴＡを算出し、順次更新されるＳＴＡ／ＬＴＡの値がＰ波検知用の閾値を越えた際にＰ波の到達を検知し、次いでＰ波の振動波形を計測するとともにＳＴＡ／ＬＴＡを算出して、同様に順次更新されるＳＴＡ／ＬＴＡの値がＳ波検知用の閾値を越えた際にＳ波が到達したと判定しているために、直下型地震のように、Ｓ波がすぐに到達する地震に対しても、Ｓ波の到達を高い精度で判定することができる。 According to the invention described in any one of claims 1 to 4, STA / LTA is continuously calculated from the vibration waveform measured by the seismometer, and the sequentially updated STA / LTA value is used for P-wave detection. The arrival of the P wave is detected when the threshold value is exceeded, then the vibration waveform of the P wave is measured and the STA / LTA is calculated. Similarly, the sequentially updated STA / LTA value is the threshold value for detecting the S wave. Since it is determined that the S wave has arrived when exceeding S, it is possible to determine the arrival of the S wave with high accuracy even for an earthquake that immediately reaches the S wave, such as a direct earthquake. it can.
さらに、請求項２または４に記載の発明によれば、予め過去に発生した複数の地震のデータ、好ましくは判定対象に回避すべき災害をもたらす虞のある複数の大地震のデータから、各地震の計測地点におけるＰ波の観測波形から算出したＳＴＡ／ＬＴＡの最大値と当該計測地点における上記Ｐ波の継続時間との関係式を求めておき、地震発生時に得られたＰ波の観測波形から連続的にＳＴＡ／ＬＴＡを算出し、その最大値と上記関係式からＳ波の到達時刻を判定しているので、簡易な演算処理によって地震発生初期段階にＳ波の到達時刻を判定することができる。 Further, according to the invention described in claim 2 or 4, each earthquake is obtained from a plurality of earthquake data that have occurred in the past in advance, preferably a plurality of large earthquake data that may cause a disaster to be judged. A relational expression between the maximum value of STA / LTA calculated from the observed waveform of the P wave at the measurement point and the duration of the P wave at the measured point is obtained, and from the observed waveform of the P wave obtained at the time of the earthquake occurrence Since the STA / LTA is continuously calculated and the arrival time of the S wave is determined from the maximum value and the above relational expression, it is possible to determine the arrival time of the S wave at the initial stage of occurrence of the earthquake by simple arithmetic processing. it can.
この際に、一般に震源が判定対象となる現地から近距離である場合には、Ｐ波が上記現地に到達するまでの間の分散や減衰が少ないことから、ＳＴＡ／ＬＴＡの値の立ち上がりが明確に現れ、そのまま最大値を記録した後は徐々に低下する。これに対して、震源が遠距離である場合には、到達するまでのＰ波の分散や減衰により、ＳＴＡ／ＬＴＡの値が徐々に立ち上がったり、あるいは極大値が段階的に複数観測されたりして、当該ＳＴＡ／ＬＴＡの値の最大値が判別し難くなる傾向にある。 At this time, in general, when the epicenter is a short distance from the site to be judged, since the dispersion and attenuation until the P wave reaches the site are small, the rise of the STA / LTA value is clear. Appears and gradually decreases after the maximum value is recorded. On the other hand, when the epicenter is at a long distance, the STA / LTA value gradually rises or multiple local maximum values are observed in stages due to the dispersion and attenuation of the P wave until it reaches. Therefore, the maximum value of the STA / LTA tends to be difficult to distinguish.
この点、本発明においては、Ｐ波を連続的に計測するとともにＳＴＡ／ＬＴＡを算出して、順次得られるＳＴＡ／ＬＴＡの最大値と上記関係式とから、Ｐ波の継続時間を予測してＳ波の到達時刻を判定しているために、震源が近距離の地震のみならず、遠距離の地震に対しても、高い精度でＳ波の到達時刻を判定することができる。 In this regard, in the present invention, the P wave is continuously measured and the STA / LTA is calculated, and the duration of the P wave is predicted from the sequentially obtained maximum value of STA / LTA and the above relational expression. Since the arrival time of the S wave is determined, it is possible to determine the arrival time of the S wave with high accuracy not only for a short distance earthquake but also for a long distance earthquake.
加えて、Ｐ波の到達を検知した後に、併行してＳＴＡ／ＬＴＡの値がＳ波検知用の閾値を越えた際にＳ波が到達したと判定しているために、ＳＴＡ／ＬＴＡの最大値と上記関係式からＰ波の継続時間を実際よりも長く予測した場合においても、確実にＳ波の到達を把握することができる。 In addition, after detecting the arrival of the P wave, it is determined that the S wave has arrived when the value of the STA / LTA exceeds the threshold for detecting the S wave. Even when the duration of the P wave is predicted to be longer than actual from the value and the above relational expression, the arrival of the S wave can be reliably grasped.
以下、図１〜図９に基づいて、本発明に係る地震の主要動の到達判定方法および判定システムの一実施形態について説明する。
図１は、上記判定システムの概略構成を示すもので、この判定システムは、判定の対象となる現地に設置された地震動の波形情報検出部（波形情報検出手段）１と、この波形情報検出部１によって計測されたＰ波の観測波形から、後に到達するＳ波の強さ（最大加速度や最大速度）を判定するパーソナルコンピュータ（判定手段、以下ＰＣと略す。）２と、このＰＣからＳ波の最大値が閾値を超えた際に制御信号を関係機器類等に送信する送信ライン３とから概略構成されたものである。
Hereinafter, based on FIGS. 1-9, one Embodiment of the arrival determination method and determination system of the main motion of the earthquake which concerns on this invention is described.
FIG. 1 shows a schematic configuration of the above-described determination system. This determination system includes a seismic motion waveform information detection unit (waveform information detection means) 1 installed on a site to be determined, and the waveform information detection unit. A personal computer (determination means, hereinafter abbreviated as PC) 2 for determining the intensity (maximum acceleration or maximum speed) of the S wave that arrives later from the observed waveform of the P wave measured by 1, and the S wave from this PC And a transmission line 3 that transmits a control signal to related devices and the like when the maximum value of exceeds a threshold value.
ここで、本実施形態においては、波形情報検出部１として１または複数の地震計が用いられており、当該地震計によって観測された時刻歴波形がＰＣ２の波形処理部４に送信されるようになっている。 Here, in the present embodiment, one or a plurality of seismometers are used as the waveform information detection unit 1, and the time history waveform observed by the seismometer is transmitted to the waveform processing unit 4 of the PC 2. It has become.
このＰＣ２は、全体を統括制御するＣＰＵ（主制御部）に、入出力制御部を介して実行プログラムを記録したハードディスク等の記憶装置、キーボードやマウス等の入力装置が接続されることによって上記波形処理部４が構成されるとともに、当該波形処理部４に入出力データを表示するモニタおよび判定結果などを記録する記憶装置（出力部）５、データベース６を格納した記憶装置および送信ライン３が接続されたものである。 The PC 2 has the above-described waveform when a storage device such as a hard disk and an input device such as a keyboard and a mouse, which record an execution program, are connected to a CPU (main control unit) that performs overall control. The processing unit 4 is configured, and the waveform processing unit 4 is connected to a monitor for displaying input / output data and a storage device (output unit) 5 for recording determination results, a storage device for storing the database 6, and a transmission line 3. It has been done.
そして、データベース６内には、図６に示す過去の大地震のデータから得られたＳ波の到達時刻を判定するための第１の関係式と、各々の上記大地震の計測地点でＰ波到達検知後における複数のＰ波の経過率（Ｐ波到達検知時から各々の判定時までの経過時間／Ｐ波の継続時間）について当該経過率の経過時間までのＰ波の観測波形の最大値とＳ波到達後のＳ波の観測波形の最大値との第２の関係式が格納されている。なお、Ｐ波到達検知時とは、本実施形態においては、各々の地震の計測地点におけるＰ波の観測波形からＳＴＡ／ＬＴＡを算出し、初めて閾値を超えた時刻とした。 In the database 6, the first relational expression for determining the arrival time of the S wave obtained from the data of the past large earthquake shown in FIG. 6 and the P wave at each measurement point of the large earthquake are shown. The maximum value of the observed waveform of the P wave up to the elapsed time of the elapsed rate with respect to the elapsed rate of the plurality of P waves after the arrival detection (the elapsed time from the detection of the arrival of the P wave to each determination time / the duration of the P wave) And a second relational expression between the maximum value of the observed waveform of the S wave after the arrival of the S wave. In this embodiment, the P wave arrival detection time is calculated as STA / LTA from the observed waveform of the P wave at each earthquake measurement point, and the time when the threshold value is exceeded for the first time.
ちなみに、図６に示す過去の大地震は、予め過去に発生した複数の地震のデータのうちから、判定の対象となる現地（例えば、振動を嫌う多数の精密機械が設置された工場）において、回避すべき災害をもたらす虞のあるものとして抽出されたものである。具体的には、観測点での加速度最大値、計測震度が一定値以上となるものを用いた。 By the way, the past large earthquakes shown in FIG. 6 are determined in advance from the data of a plurality of earthquakes that occurred in the past in advance (for example, factories where many precision machines that dislike vibrations are installed) It was extracted as something that could cause a disaster to be avoided. Specifically, the maximum acceleration value and the measured seismic intensity at the observation point were over a certain value.
そして、第１の関係式は、図６に示す複数の大地震のデータから、各々の地震の計測地点におけるＰ波の観測波形からＳＴＡ／ＬＴＡを算出し、その最大値と当該計測地点における上記Ｐ波の継続時間との関係を求めたものである。 The first relational expression calculates the STA / LTA from the observed waveform of the P wave at each earthquake measurement point from the data of a plurality of large earthquakes shown in FIG. The relationship with the duration of the P wave is obtained.
これを具体的に説明すると、先ず前提となるＳＴＡ／ＬＴＡとは、波形振幅（加速度、速度、変位等）の絶対値の短時間移動平均ＳＴＡと、長時間移動平均ＬＴＡの比である。すなわち、図３（ａ）に示す地震に対する波形振幅の絶対値のグラフにおいて、ＳＴＡとＬＴＡとの比を算出して、同様に時間軸で示せば、図３（ｂ）のように表される。図３は、加速度振幅に対して、ＳＴＡの移動平均間隔を０．１秒、ＬＴＡの移動平均間隔を５．０秒とした例である。なお、ＳＴＡ／ＬＴＡを用いた技術に関しては、例えば上記非特許文献１において開示されている。本発明は、上記ＳＴＡ／ＬＴＡの値を、Ｓ波到達の判定およびＳ波到達時刻の判定に使用するものである。 Specifically, the premise STA / LTA is the ratio of the short-time moving average STA of the absolute value of the waveform amplitude (acceleration, velocity, displacement, etc.) and the long-time moving average LTA. That is, in the graph of the absolute value of the waveform amplitude with respect to the earthquake shown in FIG. 3A, if the ratio of STA to LTA is calculated and similarly shown on the time axis, it is expressed as shown in FIG. . FIG. 3 shows an example in which the STA moving average interval is 0.1 seconds and the LTA moving average interval is 5.0 seconds with respect to the acceleration amplitude. The technology using STA / LTA is disclosed in Non-Patent Document 1, for example. In the present invention, the STA / LTA value is used for the determination of the arrival of the S wave and the determination of the arrival time of the S wave.
すなわち、図７は、図６に示した大地震の発生時に観測されたＰ波の加速度波形についてＳＴＡ／ＬＴＡを算出し、その最大値と当該計測地点における上記Ｐ波の継続時間とをグラフにプロットしたものである。なお、図７においては、後述するＳ波の到達判定によって、Ｓ波が到達したと判定されたデータは除外してある。 That is, FIG. 7 is a graph showing the STA / LTA for the acceleration waveform of the P wave observed at the occurrence of the large earthquake shown in FIG. 6, and the maximum value and the duration of the P wave at the measurement point. It is a plot. In FIG. 7, data determined to have reached the S wave by the S wave arrival determination described later is excluded.
そして、ＳＴＡ／ＬＴＡの最大値ＰＲＳＬと、Ｐ波到達検知時刻からＳ波到達時刻までの時間であるＰ波の継続時間ｄＴＰ（秒）との間には、概略下式で表される関係がある。
ｄＴＰ＝α１ｌｏｇ１０（ＰＲＳＬ）＋β１
ここで、α１、β１は、判定に用いる係数である。
The maximum value PR SL of STA / LTA and the P wave duration dT P (seconds), which is the time from the P wave arrival detection time to the S wave arrival time, are roughly expressed by the following equation. There is a relationship.
dT P = α 1 log 10 (PR SL ) + β 1
Here, α 1 and β 1 are coefficients used for determination.
そこで、図７に示す過去の地震観測記録の分析結果から、最小二乗法を用いて係数α１、β１を決定する。図７中実線で示す曲線は、このようにして求めた上記第１の関係式を示すものである。 Therefore, the coefficients α 1 and β 1 are determined from the analysis result of the past earthquake observation record shown in FIG. 7 using the least square method. A curve indicated by a solid line in FIG. 7 indicates the first relational expression thus obtained.
また、第２の関係式は、図６に示す各々の大地震の計測地点における複数のＰ波の経過率（本実施形態においては、図８に示すように、０．２、０．４、０．６、０．８、１．０、１．２、１．４および１．６）について算出した当該経過率の経過時間までのＰ波の観測波形の最大値とＳ波の観測波形の最大値との関係を示すものである（図５参照。）。 Further, the second relational expression is an elapsed rate of a plurality of P waves at each large earthquake measurement point shown in FIG. 6 (in this embodiment, as shown in FIG. 8, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6), the maximum value of the observed waveform of the P wave and the observed waveform of the S wave up to the elapsed time of the elapsed rate The relationship with the maximum value is shown (see FIG. 5).
より具体的には、判定対象であるＳ波の強さＰＡｅは、Ｐ波の到達検知時刻（ＴＰ）からＰ波継続時間に対する上記経過率（Ｐ波経過率ＬＰ）に至る時刻（Ｔ）までの観測波形の最大値ＰＡと、上記経過率ＬＰを以下の式に代入することで判定される。
ＰＡｅ＝１０^（α２（ＬＰ）*ｌｏｇ１０（ＰＡ）＋β２（ＬＰ））
ＬＰ＝（Ｔ−ＴＰ）／（ＴＳｅ−ＴＰ）
ここで、α２、β２は判定式で用いる係数であり、Ｐ波経過率ＬＰごとに定まる値である。また、ＴＳｅは、上記第１の関係式を用いて判定されたＳ波到達時刻である。
More specifically, the intensity PA e of S-wave to be determined, the time ranging from the arrival detection time of P-wave (T P) in the course rate for P-wave duration (P-wave passed ratio L P) ( the maximum value PA of the observed waveforms up T), the elapsed ratio L P is determined by substituting in the following equation.
PA e = 10 ^ (α 2 (L P ) * log 10 (PA) + β 2 (L P ))
L P = (T−T P ) / (T Se −T P )
Here, alpha 2, beta 2 is a coefficient used in the determination equation is a value determined for each P-wave passed ratio L P. T Se is the S wave arrival time determined using the first relational expression.
そして、図８は、図６に示す過去の地震観測記録の分析結果から、各々の経過率について横軸をＰＡ（加速度３成分最大値）とし、縦軸をＰＡｅ（主要動の加速度水平成分最大値）とした場合の各Ｐ波経過率に対応する時刻までの関係図を示すものであり、この結果から経過率毎に最小二乗法を用いて上記係数α２、β２を決定する。図８中実線で示す曲線は、このようにして求めた上記第２の関係式を示すものである。 FIG. 8 shows the results of analysis of past earthquake observation records shown in FIG. 6, with the horizontal axis representing PA (maximum acceleration three component value) and the vertical axis representing PA e (acceleration horizontal component of main motion). FIG. 6 shows a relationship diagram up to the time corresponding to each P-wave elapsed rate in the case of the maximum value), and the coefficients α 2 and β 2 are determined for each elapsed rate using the least square method. A curve indicated by a solid line in FIG. 8 represents the second relational expression obtained in this way.
次に、図２に基づいて、ＰＣ２の波形処理部４における機能とともに、本発明に係る地震の主要動の到達判定方法の一実施形態について説明する。
先ず、地震発生後、波形情報検出部１から送られてくる振動の波形情報からＰ波の到達を検知した時点で、Ｓ波の強さの判定を開始する。ここで、Ｐ波の到達を検知するには、本実施形態においては、上記波形情報からＳＴＡ／ＬＴＡを算出し、初めて閾値を超えた場合にＰ波が到達したものと判断する。
Next, an embodiment of the method for determining the arrival of major earthquake motion according to the present invention will be described based on FIG. 2 together with the function of the waveform processing unit 4 of the PC 2.
First, after the occurrence of an earthquake, when the arrival of a P wave is detected from the waveform information of vibrations sent from the waveform information detector 1, the determination of the strength of the S wave is started. Here, in order to detect the arrival of the P wave, in this embodiment, STA / LTA is calculated from the waveform information, and it is determined that the P wave has arrived when the threshold value is exceeded for the first time.
その第１段階として、上記Ｐ波の波形情報からＳ波の到達時刻を判定する。先ず、連続的に当該Ｐ波の観測波形のＳＴＡ／ＬＴＡを算出する。
そして、図４（ｂ）に示すように、Ｐ波到達検知時刻のＳＴＡ／ＬＴＡの値と、上記第１の関係式とから、Ｐ波の継続時間ｄＴＰを算出して、Ｓ波の到達時刻ＴＳｅ（秒）を次式を用いて判定する。
ＴＳｅ＝ＴＰ＋ｄＴＰ
ここで、ＴＰは、Ｐ波到達検知時刻（秒）である。
次いで、図４（ｃ）に示すように、順次得られるＳＴＡ／ＬＴＡの値から最大値が得られた場合に、さらに当該最大値と上記関係式とからＰ波の継続時間ｄＴＰを更新して、新たなＳ波の到達時刻ＴＳｅを判定する。
As the first step, the arrival time of the S wave is determined from the waveform information of the P wave. First, the STA / LTA of the observed waveform of the P wave is calculated continuously.
Then, as shown in FIG. 4 (b), the value of STA / LTA of P-wave arrival detection time, and a said first relationship, to calculate the duration dT P of P-wave arrival S-wave The time T Se (seconds) is determined using the following equation.
T Se = T P + dT P
Here, TP is the P wave arrival detection time (seconds).
Then, as shown in FIG. 4 (c), when the maximum value is obtained from the values of successively obtained STA / LTA, further updates the duration dT P P wave from the said maximum value and the relationship Then, the arrival time T Se of the new S wave is determined.
ちなみに、仮に図４（ｃ）に示す最大値を検知した後に、より大きな最大値が算出された場合には、再び当該最大値と上記関係式とからＰ波の継続時間ｄＴＰを更新して、新たなＳ波の到達時刻を判定する工程を繰り返す。 Incidentally, if after detecting a maximum value shown in FIG. 4 (c), if it is greater maximum value is calculated, updates the duration dT P P wave from again the maximum value and the relationship The process of determining the arrival time of a new S wave is repeated.
これと併行して、図９に示すように、Ｐ波検出後に波形情報検出部１から送られてくる振動の波形情報からＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＳ波検知用の閾値を越えた際にＳ波が到達したと判定する。具体的には、Ｐ波検出後のＳＴＡ／ＬＴＡの最小値Ｐ２を順次更新するとともに最大値Ｐ３も順次更新し、これらの差（Ｐ３−Ｐ２）を連続的に算出して、その値が予め設定されたＳ波検知用の閾値を越えた時に、Ｓ波が到達したと判定して、送信ライン３から生産機器等へ制御信号送信先に、例えば当該生産機器類を緊急に停止させる等の制御命令を送信する。 In parallel with this, as shown in FIG. 9, the STA / LTA is calculated from the waveform information of the vibration sent from the waveform information detector 1 after the P wave is detected, and the obtained value is set in advance. It is determined that the S wave has reached when the wave detection threshold is exceeded. Specifically, also sequentially updated maximum value P 3 while sequentially updating the minimum value P 2 of the STA / LTA after P wave detection, to calculate these differences a (P 3 -P 2) continuously, When the value exceeds a preset threshold for S wave detection, it is determined that an S wave has arrived, and the control signal is transmitted from the transmission line 3 to the production equipment, for example, the production equipment is urgently transmitted. Send a control command to stop.
他方、ＳＴＡ／ＬＴＡが予め設定されたＳ波検知用の閾値を越えていない間は、上述したＳ波の到達時刻ＴＳｅの判定を順次更新しつつ、第２段階として、判定されたＳ波到達時刻ＴＳｅおよびＰ波の到達検知時刻から、現在時刻ＴまでのＰ波経過率ＬＰ（＝（Ｔ−ＴＰ）／（ＴＳｅ−ＴＰ））を算出する。 On the other hand, while the STA / LTA does not exceed the preset threshold for S wave detection, the determination of the S wave arrival time T Se described above is sequentially updated, and the determined S wave is determined as the second stage. From the arrival time T Se and the arrival detection time of the P wave, the P wave elapsed rate L P (= (T−T P ) / (T Se −T P )) up to the current time T is calculated.
次いで、上記時刻Ｔまでの観測波形の最大値ＰＡを用いて、当該経過率ＬＰにおける上記第２の関係式から、これから到達するＳ波の強さＰＡｅを判定する。また、判定されたＳ波強さＰＡｅ等の情報を、モニタ５での表示および記録装置５への出力を行うとともに、上記Ｓ波強さＰＡｅが、予め設定されている閾値を超えた時点で、送信ライン３から生産機器等へ制御信号送信先に、例えば当該生産機器類を緊急に停止させる等の制御命令を送信する。 Then, using the maximum value PA of the observed waveforms up the time T, from the second relational expression of the elapsed index L P, determines the strength PA e of S waves now reached. Further, information such as the determined S wave intensity PA e is displayed on the monitor 5 and output to the recording device 5, and the S wave intensity PA e exceeds a preset threshold value. At the time, a control command for urgently stopping the production equipment is transmitted from the transmission line 3 to the production equipment or the like to the control signal transmission destination.
なお、上記実施形態においては、地震の振動波形として応答加速度を用いた場合についてのみ示したが、本発明はこれに限定されるものではなく、地震動に対する応答速度や計測震度などを用いても、同様の精度で判定が行えるものと考えられる。また、Ｓ波の到達時刻の判定についても、上記実施形態において示したものに限らず、例えば緊急地震情報等を利用して判定することもできる。 In the above embodiment, only the case where the response acceleration is used as the vibration waveform of the earthquake is shown, but the present invention is not limited to this, even if using the response speed or the measured seismic intensity for the earthquake motion, It is considered that determination can be made with similar accuracy. Also, the determination of the arrival time of the S wave is not limited to that shown in the above embodiment, and can be determined using, for example, emergency earthquake information.
以上説明したように、上記構成からなる地震の主要動の到達判定方法および判定システムにおいては、地震計１で計測された振動波形から連続的にＳＴＡ／ＬＴＡを算出し、順次更新されるＳＴＡ／ＬＴＡの値がＰ波検知用の閾値を越えた際にＰ波の到達を検知し、次いでＰ波の振動波形を計測するとともにＳＴＡ／ＬＴＡを算出して、同様に順次更新されるＳＴＡ／ＬＴＡの値がＳ波検知用の閾値を越えた際にＳ波が到達したと判定しているために、直下型地震のように、Ｓ波がすぐに到達する地震に対して、当該Ｓ波の到達を高い精度で判定することができる。 As described above, in the method and system for determining the arrival of the main motion of the earthquake having the above configuration, the STA / LTA is continuously calculated from the vibration waveform measured by the seismometer 1, and the STA / When the LTA value exceeds the threshold value for detecting the P wave, the arrival of the P wave is detected, then the vibration waveform of the P wave is measured, the STA / LTA is calculated, and the STA / LTA is sequentially updated in the same manner. Since the S wave has been determined to have reached when the value of S exceeds the threshold for S wave detection, the S wave of the S wave can be detected against an earthquake that reaches the S wave immediately, such as a direct earthquake. The arrival can be determined with high accuracy.
これに加えて、予め過去に発生した複数の地震のデータ、好ましくは判定対象に回避すべき災害をもたらす虞のある複数の大地震のデータから、各地震の計測地点におけるＰ波の観測波形から算出したＳＴＡ／ＬＴＡの最大値と当該計測地点における上記Ｐ波の継続時間との関係式を求めておき、地震発生時に得られたＰ波の観測波形から連続的にＳＴＡ／ＬＴＡを算出し、その最大値と上記関係式からＳ波の到達時刻を判定しているので、簡易な演算処理によって地震発生初期段階にＳ波の到達時刻を判定することができる。 In addition to this, from the data of a plurality of earthquakes that occurred in the past in advance, preferably from the data of a plurality of large earthquakes that may cause a disaster to be judged, from the observed waveform of the P wave at each earthquake measurement point Obtain a relational expression between the calculated maximum value of STA / LTA and the duration of the P wave at the measurement point, continuously calculate the STA / LTA from the observed waveform of the P wave obtained at the time of the earthquake, Since the arrival time of the S wave is determined from the maximum value and the above relational expression, the arrival time of the S wave can be determined at the initial stage of occurrence of the earthquake by a simple calculation process.
また、ＳＴＡ／ＬＴＡの最大値と上記関係式からＰ波の継続時間を実際よりも長く予測した場合においても、ＳＴＡ／ＬＴＡの値がＳ波検知用の閾値を越えた際にＳ波が到達したと判定しているために、確実にＳ波の到達を知らせることができる。 Further, even when the P wave duration is predicted to be longer than the actual value from the maximum value of STA / LTA and the above relational expression, the S wave arrives when the STA / LTA value exceeds the threshold for S wave detection. Therefore, it is possible to reliably notify the arrival of the S wave.
１ 波形情報検出手段（地震計）
２ ＰＣ（判定手段）
３ 送信ライン
４ 波形処理部
６ データベース
1 Waveform information detection means (Seismometer)
2 PC (determination means)
3 Transmission line 4 Waveform processing unit 6 Database
Claims (4)
上記現地の地震計で計測された振動波形から連続的にＳＴＡ／ＬＴＡを算出し、得られた値が予め設定されたＰ波検知用の閾値を越えた際に上記Ｐ波の到達を検知し、次いで引き続き当該Ｐ波の振動波形を計測するとともにＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＳ波検知用の閾値を越えた際に上記Ｓ波が到達したと判定することを特徴とする地震の主要動の到達判定方法。 A method for determining the arrival of the main motion of an earthquake for determining the arrival of an S wave to the site from the vibration waveform of the P wave of the earthquake detected by a seismometer installed at the site to be judged,
The STA / LTA is continuously calculated from the vibration waveform measured by the local seismometer, and the arrival of the P wave is detected when the obtained value exceeds a preset threshold for P wave detection. Subsequently, the vibration waveform of the P wave is continuously measured and STA / LTA is calculated, and it is determined that the S wave has reached when the obtained value exceeds a preset threshold for S wave detection. A method for determining the arrival of major earthquake motions.
上記現地の地震計がＰ波の到達を検知した後、ＳＴＡ／ＬＴＡの最大値と上記関係式とから上記Ｐ波の継続時間を予測し、上記Ｐ波の継続時間と上記Ｐ波の検知時刻を用いて上記Ｓ波の到達時刻を判定することを特徴とする請求項１に記載の地震の主要動の到達判定方法。 A relational expression between the maximum value of STA / LTA calculated from the observed waveform of the P wave at each of the earthquake measurement points and the duration of the P wave at the measurement point from the data of a plurality of earthquakes that occurred in the past in advance. Seeking
After the local seismometer detects the arrival of the P wave, the P wave duration is predicted from the maximum STA / LTA value and the relational expression, and the P wave duration and the P wave detection time are predicted. The arrival determination method of the main motion of the earthquake according to claim 1, wherein the arrival time of the S wave is determined by using.
上記判定手段は、上記波形情報検出手段から送られてくる上記Ｐ波の観測波形から連続的にＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＰ波検知用の閾値を越えた際に上記Ｐ波の到達を検知し、次いで引き続き送られてくる当該Ｐ波の振動波形から連続的にＳＴＡ／ＬＴＡを算出して、得られた値が予め設定されたＳ波検知用の閾値を越えた際に上記Ｓ波が到達したと判定する波形処理部を備えていることを特徴とする地震の主要動の到達判定システム。 Waveform information detecting means for seismic motion installed in the site to be determined, and determining means for determining the arrival of the S wave from the observed waveform of the P wave measured by the waveform information detecting means,
The determination means continuously calculates the STA / LTA from the observed waveform of the P wave sent from the waveform information detection means, and the obtained value exceeds a preset threshold for P wave detection. When the P wave arrives, the STA / LTA is continuously calculated from the vibration waveform of the P wave that is subsequently sent, and the obtained value is used for the S wave detection set in advance. An arrival determination system for main motion of an earthquake, comprising a waveform processing unit for determining that the S wave has reached when a threshold value is exceeded.
かつ上記波形処理部は、上記現地の地震計がＰ波の到達を検知した後、ＳＴＡ／ＬＴＡの最大値と上記関係式とから上記Ｐ波の継続時間を予測し、上記Ｐ波の継続時間と上記Ｐ波の検知時刻を用いて上記Ｓ波の到達時刻を判定することを特徴とする請求項３に記載の地震の主要動の到達判定システム。 The determination means includes a maximum STA / LTA value calculated from an observed waveform of a P wave at each of the earthquake measurement points, and a duration of the P wave at the measurement point, from data of a plurality of earthquakes that have occurred in the past. Has a database that stores the relational expression of
The waveform processing unit predicts the duration of the P wave from the maximum value of the STA / LTA and the relational expression after the local seismometer detects the arrival of the P wave, and the duration of the P wave. The arrival determination system of the main motion of the earthquake according to claim 3, wherein the arrival time of the S wave is determined using the detection time of the P wave and the detection time of the P wave.
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