China News Service, Beijing, April 3 (Reporter Sun Zifa) The reporter learned from the China Earthquake Administration that after a 7.3-magnitude earthquake occurred in the waters of Hualien County, Taiwan on the morning of April 3, experts from the China Seismological Network Center organized research and analysis and believed that the earthquake occurred On the northern section of the Huadong Longitudinal Valley Fault in Taiwan, preliminary focal mechanism analysis results show that this earthquake was a thrust rupture.
This earthquake broke the 17-year calm of earthquakes above magnitude 7 since the 2006 magnitude 7.2 earthquake in Pingtung, Taiwan. Seismological experts said that from the perspective of long-term strain release, this 7.3-magnitude earthquake was a normal ups and downs of strong seismic activity in Taiwan. From a statistical point of view, after an earthquake of magnitude 7 or above occurs in Taiwan, it has little significance in predicting a strong earthquake of magnitude 7 in the mainland in the short term.
Taiwan has a history of active strong earthquakes. Since 1970, 19 earthquakes of magnitude 7 or above have occurred within 300 kilometers of the epicenter. The largest earthquake was an 8.0-magnitude earthquake off the coast of Taitung County, Taiwan, on January 25, 1972, which was about 146 kilometers away. ; The closest time is the 7.2-magnitude earthquake off the coast of Pingtung County, Taiwan, on December 26, 2006, about 251 kilometers away from this earthquake; the closest spatial distance is the 7.0-magnitude earthquake off the coast of Hualien County, Taiwan, on December 14, 1990, about 251 kilometers away from this earthquake The earthquake was about 13 kilometers away.
Why has there been no earthquake of magnitude 7 or above in Taiwan for more than ten years? Seismological experts analyzed that Taiwan is located in the hub area where the Eurasian Plate, the Pacific Plate and the Philippine Subplate converge. The tectonic environment is very complex and it is one of the most seismically active regions in the world. On the one hand, its strong earthquake activity is limited by the Pacific Rim. In the tectonic activity in the western belt, the temporal inhomogeneity of moderately strong earthquakes is very significant; on the other hand, although there was a long period of calm for magnitude 7 earthquakes after the 2006 magnitude 7.2 earthquake in the Pingtung Sea, seismic activity above magnitude 6 occurred during this period. It is still very active, with a total of 33 earthquakes of magnitude 6 or above.
The earthquake in Taiwan was clearly felt in Fujian, Guangdong, Zhejiang, Shanghai, Anhui and other places. What impact will it have on the mainland? Seismological experts interpreted that there are significant differences in the geodynamic characteristics of Taiwan and the mainland. The main sources of power in the mainland are the northeastward compression and push of the Indian Plate in the west and the westward subduction of the Pacific Plate in the east. From a statistical point of view, after an earthquake of magnitude 7 or above occurs in Taiwan, it has little significance in predicting a strong earthquake of magnitude 7 in the mainland in the short term.
According to the official measurement of the China Seismological Network, at 7:58 on April 3, Beijing time, a magnitude 7.3 earthquake occurred in the waters of Hualien County, Taiwan (23.81 degrees north latitude, 121.74 degrees east longitude), with a focal depth of 12 kilometers and a distance of about 23 kilometers from Hualien County. (over)