Journal of the Korean Society of Hazard Mitigation (한국방재학회 논문집)

Korean Society of Hazard Mitigation (한국방재학회)
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Crustal Structure Beneath Korea Seismic Stations (Inchon, Wonju and Pohang) Using Receiver function

수신함수에 의한 한국 지진관측소(인천, 원주 포항) 하부의 지각구조 연구

  • Published : 2004.12.31
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Abstract

The broadband receiver functions are developed from teleseismic P waveforms recorded at Wonju(KSRS), Inchon(IRIS), and Pohang(PHN), and are analyzed to examine the crustal structure beneath these stations. The teleseismic receiver functions are inverted in the time domain of the vertical P wave velocity structures beneath the stations. Clear P-to-S converted phases from the Moho interface are observed in teleseismic seismograms recorded at these stations. The crustal velocity structures beneath the stations are estimated by using the receiver function inversion method(Ammon et al., 1990). The general features of inversion results are as follows: (1) For the Inchon station, the Conrad discontinuity exists at 17.5 Km(SW) deep and the Moho discontinuity exists at 29.5 Km(NW) and 30.5 Km(SE, SW) deep. (2) The shallow crustal structure beneath Wonju station may be covered with a sedimentary rock of a 3 Km thickness. The average Moho depth is assumed about 33.0 Km, and the Conrad discontinuity may exist at 17.0 Km(NE) and 21.0 Km(NW) deep. (3) For Pohang station, the thickness of shallow sedimentary layer is a 3.0 Km in the direction of NE and NW. The Moho depth is 28.0 Km in the direction of the NE and NW. The Conrad discontinuity can be estimated to be existed at 21.0 Km deep for the NE and NW directions.

광역 수신 함수가 원주, 인천, 포항 관측소에서 원격 지진 P파로 개발된다. 그리고, 이들 관측소 하부의 지각 구조 해석을 위해서 분석된다. 원격 수신 함수는 관측소 하부 P 파 속도 구조를 위한 시간 영역에서 역산된다. 모호 불연속면에서 P파에서 전환된 S 파가 이들 관측소에서 관측되었다. 관측소의 지하 지각구조는 수신함수 역산으로 산출된다. 1) 인천 관측소에서 Conrad 불연속면은 남서방향에서 17.5Km이고, Moho 불연속면은 북서방향에서 29.5Km와 남동 및 밤서 방향에서 30.5Km이다. 2) 원주 관측소의 경우 천부층의 퇴적층 두께는 3Km인 것으로 해석된다. Moho 깊이는 3.0Km, Conrad 깊이는 북동쪽에서는 17.0Km로, 북서쪽에서는 21.04km이다. 3) 포항 관측소의 경우, 천부 퇴적암 두께 3Km가 북동 및 북서 방향에서 발견되었다. Moho 깊이는 북동쪽과 북서방향에서 28.04km인 것으로 해석되며, Conrad 불연속면은 북동과 북서방향에서 21.0Km인 것으로 산출되었다.

Keywords

References

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