Estimation of Seismic Ground Motions and Attendant Potential Human Fatalities from Scenario Earthquakes on the Sanchiao Fault in Taipei City, Taiwan

Kun-Sung Liu

doi:10.11648/j.earth.20190802.12

Abstract

The purpose of this study is to estimate maximum ground motions in Taipei city in the form of ShakeMaps as well as to assess potential human fatalities from scenario earthquakes on the Sanchiao active faults in this area. Analysis of seismic hazard potential becomes necessary in Taipei City for the Central Geological Survey (CGS) announced the Sanchiao active fault as Category II. The resultant ShakeMap patterns of maximum ground motion by using ground motion prediction equation (GMPE) method in a case of Mw6.88 show the areas of PGA above 400 gals are located in the northern and western parts of Taipei. Furthermore, the areas of PGA above 500 gals are located in these regions: Beitou, Shihlin, Datong, Wanhua, Jhongjheng, northern Neihu, western Jhongshan, western Daan and western Sinyi. In addition, seismic hazards in terms of PGA and PGV in the vicinity of the Sanchiao fault are not completely dominated by the Sanchiao fault. The main reason is that some areas located in the vicinity of the Sanchiao fault are marked with low site response amplification values of 0.55 and 0.67 for PGA and PGV, respectively. Finally, from estimation of potential human fatalities from scenario earthquakes on the Sanchiao active fault, it is noted that potential fatalities increase rapidly in people above age 45. Total fatalities reach a high peak in age groups of 55–64. Another to pay special attention is Taipei City has hundreds of thousands of households whose residences over 40 years old. When a strong earthquake strikes, these old houses are vulnerable to collapse. In light of the results of this study, the author urge both the municipal and central governments to take effective seismic hazard mitigation measures in the highly urbanized areas with a large number of old buildings in Taipei city. The results of this study will show which areas with higher earthquake hazard potential in Taipei City. It will help mitigate Taipei City earthquake disaster loss in the future, as well as provide critical information for emergency response plans.

Highlights

Taiwan is located along the circum-Pacific seismic belt
(2) The above-mentioned areas with high peak ground acceleration (PGA) and peak ground velocity (PGV) are due to the combined effects of the Sanchiao fault and large site response factors
From the study of Pai et al [22] showed the primary cause of death for the According to above results and discussion, some findings are summarized as follows: From the maximum PGA ShakeMap for an Mw6.88 scenario earthquake on the Sanchiao active fault in Taipei City, the results reveal that high PGA areas greater than 400 gals are located in the northern and western parts of Taipei

Summary

Introduction

Taiwan is located along the circum-Pacific seismic belt. During the last four hundred years, 20 damaging earthquakes had occurred in Taipei area. There were three damaging earthquakes, 1986 Hualien earthquake, 1999 Chi-Chi earthquake and 2002 Hualien earthquake during the last century had resulted in heavy loss of human lives in Taipei They occurred primarily at shallow depths, and were mostly associated with active faults that ruptured the ground surface. The assessment of potential seismic hazards has become increasingly important in Taipei city since the Central Geological Survey upgraded the Sanchiao active fault from suspected fault to Category II in 2010 [1]. It poses a high potential for seismic disaster in the event of a large magnitude earthquake on the fault that most likely could cause serious damage. The governments need to put in more efforts on earthquake disaster prevention in these areas to reduce probably earthquake losses

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