Prehistoric earthquakes along the Shanchiao fault, Taipei Basin, northern Taiwan

Stratigraphic relations recorded in boreholes drilled along the Shanchiao fault, a normal fault that bounds the western margin of metropolitan Taipei, reveal evidence of early–mid Holocene subsidence and active extension of the Taipei Basin. Paleoseismic data suggest that the maximum displacement for each subsidence event ranges from 2.3 to 4.5 m. Despite large uncertainties, the large offsets imply earthquake magnitudes that range in size from 6.9 to 7.1. Our results suggest that large magnitude earthquakes along the Shanchiao fault are one of the major seismic hazards in the metropolitan Taipei area.