由兩起0206強震反思近斷層地動研究在台灣的重要性與挑戰

RETHINKING THE IMPORTANCE AND CHALLENGE OF NEAR-FUALT GROND MOTION STUDIES IN TAIWAN FROM TWO FEBUARY 6TH EVENTS

何丞穎(Cheng-Ying Ho) ； 林哲民(Che-Min Lin) ； 郭俊翔(Chun-Hsiang Kuo) ； 饒瑞鈞(Ruey-Juin Rau) ； 溫國樑(Kuo-Liang Wen)

《中國土木水利工程學刊》 31卷5期 (2019/09) Pp. 501-511

https://doi.org/10.6652/JoCICHE.201909_31(5).0008

摘要

美濃地震為盲斷層錯動引起，有顯著的破裂方向性並引致速度脈衝，花蓮地震則是米崙斷層錯動而造成近斷層速度脈衝，兩起地震分別造成台南市及花蓮市嚴重傷亡與災損。米崙斷層回歸期僅約70年，基於此地質證據及實際案例（1951年和2018年兩次地震），花蓮市之地震危害度應重新評估，且本次花蓮地震近斷層測站的記錄應作為花蓮市設計地震檢討更新之依據。本研究也證實處理過後的高頻GPS記錄已能夠應用在近斷層區域的地動特性分析。我們相信盲斷層及極短回歸期活動斷層的地動特性是台灣近斷層地動研究的重點與挑戰。

關鍵字

近斷層速度脈衝 ； 高頻GPS ； 盲斷層

並列摘要

Meinong earthquake was caused by a blind fault with significant rupture directivity effect as well as induced pulse-like velocities. As for Hualien earthquake, Milun fault ruptured and generated velocity pulses at near-fault region. The two earthquakes therefore left serious casualties and damages. The return period of Milun fault is only about 70 years and reevaluation of seismic hazard analysis for Hualien City is essential according to geological evidence and the real cases of earthquakes in 1951 and 2018. The current design earthquake for Hualien City should be reviewed and adjusted in the light of the observed strong motion records of the 2018 Hualien earthquake. We also validated the application of High-rate GPS records on near-fault ground motion analysis. We are convinced that to understand and predict strong motions caused by blind faults and active faults with very short return period are key points and challenges for near-fault strong motions in Taiwan.

並列關鍵字

Near-fault Velocity Pulse ； High-rate GPS ； Blind Fault