Parametric Criteria in Onsite Earthquake Early Warning System

نوع مقاله: مقاله تحقیقی‌ (پژوهشی‌)

نویسندگان

1 عضو هیئت علمی دانشگاه

2 گروه ژئوفیزیک، دانشگاه آزاد اسلامی واحد علوم و تحقیقات، تهران،ایران

چکیده

تخمین سریع جنبش‌های نیرومند زمین بر اساس بخش اولیه موج P، یکی از مهمترین اهداف سامانه هشدار سریع زلزله است. در این مطالعه با استفاده ترکیبی از پارامتر‌های جنبش زمین و نیز شیب منحنی رشد دامنه امواج در چند ثانیه اول سیگنال، ۵ پارامتر آستانه معرفی شده‌اند که به عنوان‌ ابزاری مفید در تشخیص زودهنگام بیشینه جنبش‌ سرعت زمین بیشتر از ۱۰ سانتی‌متر بر ثانیه کاربرد دارد. این حد آستانه منطبق بر شدت مرکالی اصلاح شده بیشتر از ۶ است که عموما با خسارات مالی و تلفات جانی همراه است.
Rapid detection of peak ground motion and consequently intensity based on few seconds of the initial part of P wave is considered to be the initial stage in most onsite Earthquake Early Warning (EEW) systems. In the current study, five parametric criteria including A, B, B*P_a, B*P_v and B*P_d are proposed for rapid detection of destructive strong motions at a target based on amplitude of the first 4 seconds of Japan event waveform where A and B parameters represent the characteristics of P wave envelope curve in a simple function with the form of Bt.exp(-At). P_a, P_v and P_d are the initial peak ground acceleration, velocity and displacement, respectively. The current study represent five thresholds parameters including A, B, B*P_a, B*P_v and B*P_d in order to warn a Peak Ground Velocity (PGV) greater than about 10 cm/sec which are clustered in strong shaking with Modified Mercalli Intensity (MMI) larger than VI.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Parametric Criteria in Onsite Earthquake Early Warning System

نویسندگان [English]

  • Reza Heidari 1
  • Reza Heidari 2
1 Assistant Professor of seismology,
2 هیئت علمی
چکیده [English]

In recent years, rapid estimation of Peak Ground Motion (PGM) and Modified Mercalli Intensity (MMI) based on few seconds of the initial portion of P wave has been studied as the most important part of the onsite Earthquake Early Warning (EEW) systems studies. To establish an onsite EEW, we need the empirical relationship between earthquake size, PGM and epicentral distance in real-time mode. In some EEWs, the epicentral distance are estimated from the amplitude growth rate of few seconds of P waves. Many studies have empirically confirmed that the growth rate becomes smaller as epicentral distance becomes far. This relation is true regardless of the earthquake size. In the current study, five parametric criteria including A, B, B*P_a, B*P_v and B*P_d are proposed for quick detection of destructive oncoming strong motions at a specific target based on ground motions of the first 4 seconds of Japan event waveforms where A and B parameters represent the characteristics of P wave envelope curve in a simple function with the form of Bt.exp(-At). In this study, B parameter is inversely proportional to epicentral distance which can be readily estimated within a given short time after P waves arrival. P_a, P_v and P_d are the initial peak ground acceleration, velocity and displacement, respectively. The current study represent five thresholds parameters including A, B, B*P_a, B*P_v and B*P_d in order to warn a Peak Ground Velocity (PGV) greater than about 10 cm/sec which are clustered in strong shaking with Modified Mercalli Intensity (MMI) larger than VI. Therefore, destructive earthquakes can be detected form the maximum amplitudes and growth rate of few seconds of P waves by using mentioned parametric criteria.
In recent years, rapid estimation of Peak Ground Motion (PGM) and Modified Mercalli Intensity (MMI) based on few seconds of the initial portion of P wave has been studied as the most important part of the onsite Earthquake Early Warning (EEW) systems studies. To establish an onsite EEW, we need the empirical relationship between earthquake size, PGM and epicentral distance in real-time mode. In some EEWs, the epicentral distance are estimated from the amplitude growth rate of few seconds of P waves. Many studies have empirically confirmed that the growth rate becomes smaller as epicentral distance becomes far. This relation is true regardless of the earthquake size. In the current study, five parametric criteria including A, B, B*P_a, B*P_v and B*P_d are proposed for quick detection of destructive oncoming strong motions at a specific target based on ground motions of the first 4 seconds of Japan event waveforms where A and B parameters represent the characteristics of P wave envelope curve in a simple function with the form of Bt.exp(-At). In this study, B parameter is inversely proportional to epicentral distance which can be readily estimated within a given short time after P waves arrival. P_a, P_v and P_d are the initial peak ground acceleration, velocity and displacement, respectively.

کلیدواژه‌ها [English]

  • Onsite earthquake early warnings
  • KiK-net
  • P wave
  • PGV
  • Parametric criteria