Major earthquakes around Taipei and a seismic hazard assessment with Monte Carlo simulation

The region around Taiwan is known for high seismicity. Under the circumstances, seismic hazard assessments and proper earthquake-resistant designs are essential to the region. From a well-studied earthquake catalog, this paper presents the statistics of major earthquakes (i.e., moment magnitude Mw≥5.5 and distance ≤200km) around the most important city in Taiwan (i.e., Taipei). The analysis shows that the mean annual rate of the major earthquakes is 2.79 around the city, with mean magnitude and SD equal to Mw 6.12 and 0.68, respectively, and mean source-to-site distance and SD equal to 129 and 39 km, respectively. With the earthquake statistics and local ground motion models, a seismic hazard assessment was conducted with Monte Carlo simulations (MCSs). The analysis shows the mean rate for peak ground acceleration ≥0.23g (where g is gravitational acceleration) should be around 0.013 per year, indicating that the current design peak ground acceleration in Taipei. From this paper, the current seismic design in Taipei might not be as conservative as expected, and a review and revision could be needed for assuring the city's seismic safety against high seismicity in the region.