Proceedings of the Earthquake Engineering Society of Korea Conference (한국지진공학회:학술대회논문집)

Earthquake Engineering Society of Korea (한국지진공학회)
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The study on rapid magnitude estimation using first arrival

초동 P파를 이용한 조기 규모추정에 관한 연구

  • 황의홍 (기상연구소 해양기상지진연구실) ;
  • 조봉곤 (전북대학교 지구환경과학부) ;
  • 류용규 (기상연구소 해양기상지진연구실) ;
  • 신동훈 (기상연구소 해양기상지진연구실) ;
  • 김수경 (기상연구소 해양기상지진연구실) ;
  • 윤용훈 (기상연구소 해양기상지진연구실)
  • Published : 2006.03.17
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Abstract

We have been conducting several studies on providing information to the public promptly as soon as earthquake occurs. Recently, JMA proposed a method for warning big earthquakes by observing the first 2 seconds after the first arrival. In this study, the envelope of the absolute value of the first 2 seconds after the first arrival is calculated, and then the relation of epicentral distance and slope of envelope, parameter B, is obtained. This result is applied to local magnitude equation of KMA, which then gives us a new magnitude equation from which can estimate the magnitude using maximum amplitude of P wave. We applied the method to two recent earthquakes; Uljin and Daegu. The results using only the vertical components show that the magnitudes are lower than those calculated by the local magnitude equation of KMA. However, when we apply the method to the 3 components of maximum displacements, the results corresponds with those obtained from the local magnitude equation.

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