The 1994 Taiwan Strait earthquake occurred on September 16, 1994 at 14:20 local time (06:20 UTC) in the southern Taiwan Strait. The magnitude of this earthquake was given as M_w 6.8 by USGS^[1] and M_s 7.3 by Fujian Seismological Bureau.^[2] The epicenter was located about 150 to 180 km from the coast of the border of Guangdong and Fujian, China, and about 150 km southwest of Taiwan.^[3]

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.^[2]

There are several NW trending faults in the Taiwan Strait, including the Ningde-Sandiaojiao fault zone ( - ), the Taizhong-Jinjiang fault zone ( - ), and the Bashi fault zone ( ).^[4] In addition, there are several faults in the NE direction, including the Binhai Fault Zone (or the Littoral Fault Zone) ( ).^[5] 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.^[2]

A paper of Fujian Seismological Bureau showed that the earthquake was caused by left-lateral strike slip of a normal fault.^[2]

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 M_w 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.^[6]

Damage

The intensities recorded in Taiwan were shindo 4 in Penghu, 3 in Kaohsiung, and 2 in Taipei. The earthquake could be felt in Hong Kong and Macau, and the intensity recorded in Hong Kong was MM V to VI.^[7][8] This earthquake was felt strongly in Guangdong and Fujian, China, with building damage and collapse reported. 3 deaths were reported in Guangdong and 1 in Fujian.^[2] Cities as north as Hefei and as west as Nanning were included in the felt range.^[9]

Tsunami

A tsunami was triggered by the earthquake. The heights of the tsunami were recorded as 38 cm in Penghu, Taiwan and 18 cm in Dongshan, Fujian, China.^[10]

References

fa: ( ) zh:1994