Estimation of Seismic Ground Motions and Attendant Potential Human Fatalities from a Scenario Earthquake on the Hsincheng Active Fault in Taohsin Area, Taiwan

Abstract

The purpose of this study is to assess seismic hazards in the 29 administration districts of Taohsin area (Taoyuan City, Hsinchu County and Hsinchu City), Taiwan in the form of ShakeMaps as well as to estimate potential human fatalities from a scenario earthquake Mw 6.77 on the Hsincheng active fault in this area. The PGA contour map using historical seismic data and four active faults to calculate the ground motions shows that the areas where the PGA is greater than 400 gal are in the following regions: (1) Southwestern Longtan. (2) Southwestern Hukou, southern Sinfong, southeastern Sinpu, northern and central Jhubei, northern Guansi, central Cyonglin, central Jhudong, western Beipu, southern Baoshan and Emei. (3) The northeastern Bei District and the northern Dong District. Furthermore, the PGV contour map shows that the areas greater than 40cm/s is located in the central Jhubei, western Beipu, southern Baoshan, Emei, and northern and western Dong District of Hsinchu City. In addition, we calculate the probability of earthquake intensity show that the regions with the highest potential for earthquake hazards are located in the area surrounded by Beipu, Baoshan and Emei, as well as the area surrounded by Hukou, Sinfong, Jhubei, Bei Distruct and Xiangshan. The corresponding probability of earthquake intensity exceeding MMI VIII during the period of 50 years is above 35%. Finally, from estimation of potential human fatalities for a scenario earthquake on the Hsincheng fault, the fatalities are 367, 848 and 809 in Taoyuan City, Hsinchu County and Hsinchu City, respectively. Moreover, it is noted that potential fatalities increase rapidly for people above age 45. Total fatalities reach a high peak in age groups of 55–64. Especially, the area surrounded by Jhubei of Hsinchu County, Bei District and Dong District of Hsinchu City with both high population density and high site amplification factor for PGA and PGV, the local governments should be pay more attention on seismic hazard mitigation in this highly urbanized area with large number of buildings.