대한해협에서의 지진해일 전파특성과 지진해일고의 확률적 기술

Characteristics of Tsunami Propagation through the Korean Straits and Statistical Description of Tsunami Wave Height

  • 조용준 (서울시립대학교 토목공학과) ;
  • 이재일 (서울시립대학교 토목공학과)
  • Cho, Yong-Jun (Dept. of Civil Engineering, University of Seoul) ;
  • Lee, Jae-Il (Dept. of Civil Engineering, University of Seoul)
  • 발행 : 2006.12.31

초록

본 연구에서는 강건한 지진해일모형인 비선형 천수 방정식에 기초하여 대한해협을 통과하는 지진해일의 전파특성에 관해 연구하였다. 지진해일은 쓰시마-고토 단층대에서 우리나라에 영향을 미친 지진 중 비교적 출현 빈도가 높은 리히터 규모 7.5의 지진에 의해 발생하는 것으로 가정하였다. 수치모의 결과 지진해일의 선도파랑이 대한해협을 횡단하는데 60분 정도가 소요되며 이는 지진해일 경보 시스템이 대피시간의 부족으로 인해 그 기능을 발휘하지 못할 수도 있음을 시사한다. 또한 전 쓰시마-고토 단층대에서 동일한 생기빈도를 가지는 지진사상에 대해 Kajiura(1963)의 동수역학 모형과 간단한 지진학적 모형을 활용한 지진해일 재해 모형이 제시되었다. 제시된 지진해일 재해 모형을 활용하여 우리나라 남해안 마산, 여수, 통영, 고흥 전면 해역에서의 각 수위별 지진해일고의 초과확률이 제시되었다. 이와 더불어 본고에서 제시한 지진해일 재해모형의 검증은 관측자료가 비교적 풍부한 동해 동연 오쿠시리 해령에서 1993년에 발생한 북해도 남서외해 지진해일과 Akita and Fukaura 두 곳에서 관측된 수위자료를 대상으로 수행되어 매우 고무적인 결과를 얻었다. 이 연구 결과들은 지진해일의 위험에 대한 연안방계 시스템의 설계기준의 수정을 위한 가치 있는 자료들로 활용될 수 있으리라 판단된다.

We numerically studied tsunami propagation characteristics through Korean Straits based on nonlinear shallow water equation, a robust wave driver of the near field tsunamis. Tsunamis are presumed to be generated by the earthquake in Tsuhima-Koto fault line. The magnitude of earthquake is chosen to be 7.5 on Richter scale, which corresponds to most plausible one around Korean peninsula. It turns out that it takes only 60 minutes for leading waves to cross Korean straits, which supports recently raised concerns at warning system might be malfunctioned due to the lack of evacuation time. We also numerically obtained the probability of tsunami inundation of various levels, usually referred as tsunami hazard, along southern coastal area of Korean Peninsula based on simple seismological and Kajiura (1963)'s hydrodynamic model due to tsunami-generative earthquake in Tsuhima-Koto fault line. Using observed data at Akita and Fukaura during Okushiri tsunami in 1993, we verified probabilistic model of tsunami height proposed in this study. We believe this inundation probability of various levels to give valuable information for the amendment of current building code of coastal disaster prevention system to tame tsunami attack.

키워드

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