Repeating earthquakes and seismic potential along the northern Longitudinal Valley fault of eastern Taiwan

Abstract

The northern Longitudinal Valley fault in eastern Taiwan creeps at the surface with a small rate of ∼1 cm/yr but slips in large earthquakes. To improve seismic hazard assessment, it is important to comprehend the slip deficit rate distribution at depth. We discovered 25 ML 2.1-4.6 repeating earthquakes in this area and inverted GPS measurements for producing an image of the along-strike spatial distribution of deep fault slip rates. The repeating events are located at the depths of 10-22 kin with 24.9-77.5 mm/yr slip rates, which are comparable with the GPS-derived slip rates of 47.5 ± 5.8 mm/yr at similar depth ranges. Based on distribution of GPS-derived slip deficits, since 1951, the northern Longitudinal Valley fault has become capable of releasing stored strain in a future Mw = 7.3 earthquake. Copyright 2007 by the American Geophysical Union.