第68回統計地震学セミナー / The 68th Statistical Seismology Seminar

Date&Time
2018年1月31日(水)
/ 31 January, 2018 (Wed) 13:30 – 14:30

Admission Free,No Booking Necessary

Place
統計数理研究所 セミナー室6 (A508)
/ Seminar room 6 (A508) @ The Institute of Statistical Mathematics
区切り線
Speaker
Prof. Kuo-Fong Ma
(Department of Earth Sciences, National Central University, Taiwan)
Title
Probability on Seismic Hazard Assessment of Taiwan: Progress and Challenge
Abstract
Taiwan Earthquake Model published the first public PSHA map of Taiwan in late 2015, and had been widely discussed and adopted in a way toward seismic hazard mitigation and risk assessment. The model adopts the source parameters of 38 seismogenic structures under a single fault segment basis, and shallow areal source for crustal events, and, intraplate, and interplate subduction events. To evaluate the potential ground-shaking resulting from each seismic source, the corresponding ground-motion prediction equations for crustal and subduction earthquakes are adopted. The highest hazard probability is evaluated to be in Southwestern Taiwan and the Longitudinal Valley of Eastern Taiwan. Right after the publication of PSHA2015, a damaging earthquake of 2016 Meinong M6.6 earthquake occurred in southwestern Taiwan from non-identified seismogenic structure. Historically, significant crustal damaging earthquakes in Taiwan mostly were from complicated fault system rather than from a single fault segment (e.g. 1935 M7.5 Hsinchu-Taichung, and 1906 M7.1 Meishan earthquakes). Technically, the 2016 M6.6 Meinong earthquake could be categorized into areal source event. The 1906 M7.1 Meishan earthquake, recently, had been resolved to be from a fault system of blind NE strike thrust with EW surface breaching fault (one of the identified seismogenic structures). These events suggest that a single fault segment evaluation for seismic hazard might be inadequate. Despite the difficulty in giving slip rate of a single segment into the probability calculation, how to deal with the slip rate in probability from complex fault system is a challenge. In the same time, PSHA evaluation of ground motion from areal source and active fault might double count the hazard for an event involved from the both category. How to determine the maximum magnitude events from areal source, and the delineation of the involvement of the areal source event to complex fault system brought another attention on the source categorization and its partition in probability for seismic hazard assessment.