Microzonation of Seismic Hazard Potential in Southwestern Taiwan

Abstract:

Majority of southwestern Taiwan is densely populated in alluvial plains. Medium- and high-story buildings are increasing. Reconstruction speed of old buildings in some communities is slow. However, in southwestern Taiwan has repeatedly been struck by large earthquakes such as 1736 Tainan earthquake, 1792 Chiayi earthquake, 1839 Chiayi earthquake, 1862 Tainan earthquake, 1906 Meishan earthquake, 1941 Jhongpu earthquake, 1946 Hsinhua earthquake, 1964 Baihe earthquake, 1988 Rueili earthquake and 1999 Chiayi earthquake. In addition, at least nine active faults are distributed in this area, we can foresee very high earthquake hazard potential. In this study, a catalog of 2041 shallow earthquakes occurred from 1900 to 2010 with M_w magnitudes ranging from 5.0 to 8.2, and 11 disastrous earthquakes occurred from 1683-1899 as well as 3 active faults are used to estimate the seismic hazard potential in southwestern Taiwan for seismic microzonation. Furthermore, the probabilities of seismic intensity exceeding CWB intensity 5, 6, 7 and MMI VI, VII, VIII in 10, 30, and 50-year periods in above areas are also analyzed for the seismic microzonation. Finally, by comparing with the seismic zoning map of Taiwan in current building code that was revised after 921 earthquakes. Results of this study show high earthquake hazard potential in southwestern Taiwan. They provide a valuable database for the seismic design of critical facilities. It will help mitigate Chianan earthquake disaster loss in the future, as well as provide critical information for emergency response plans.