1994 Taiwan Strait earthquake
The 1994 Taiwan Strait earthquake occurred on 16 September 1994, at 14:20 local time in the southern Taiwan Strait. The magnitude of this earthquake was given as 6.8 by the USGS and 7.3 by Fujian Seismological Bureau. The epicenter was located about 150 to 180 km from the coast of the border of Guangdong and Fujian, and about 150 km southwest of Taiwan.
Geology
The earthquake occurred in the transition zone from the continental margin to the continent-ocean transitional crust. In this region, the depth of the Moho interface decreases from about 28 km in the west to about 20 km in the east. The transition between continental and oceanic crusts is reflected in the variation of the depth of the Moho interface.There are several NW trending faults in the Taiwan Strait, including the Ningde-Sandiaojiao fault zone, the Taichung-Jinjiang fault zone, and the Bashi fault zone. In addition, there are several faults in the NE direction, including the Binhai Fault Zone . Some sources suggested that the earthquake was related to the activity of the Bashi fault system. However, there are still disputes over whether the fault plane should have been in the NW or the NE direction.
A paper of Fujian Seismological Bureau showed that the earthquake was caused by left-lateral strike slip of a normal fault.
The earthquake had a maximum slip of 14 m in the hypocentral region. The source duration was about 4 s, which is short for an event with magnitude about 6.7. From the slip amplitude and the source duration, it was suggested that this earthquake began as a breaking of a strong asperity with low dynamic friction, had high stress drop, and was stopped by large friction around the asperity.