China News Service, Chengdu, May 20 (Reporter Liu Zhongjun) The reporter learned from the Sichuan Seismological Bureau on the 20th that the 4.8-magnitude earthquake that occurred in Hanyuan County, Ya'an City, the province was a strike-slip earthquake, with the epicenter located in Hanyuan- The northern section of the Ganluo fault.

The fire rescue force arrived at the toll station of Hanyuan Jiuxiang Expressway.

Photo courtesy of Sichuan Expressway Public Security

  Du Fang, a researcher at the Sichuan Earthquake Administration, said in an interview with a reporter from that the Hanyuan M4.8 earthquake was a strike-slip type earthquake with the epicenter located in the northern segment of the Hanyuan-Ganluo fault, and the focal mechanism solution was basically consistent with the seismogenic structure.

The Hanyuan-Ganluo fault starts from the northwest of Luding Gasyingpan, passes through Jinping and Huochangba, and ends at the southwest of Hanyuan. It is about 90 kilometers long. It is mainly developed between the Jinning granite and the Mesozoic strata and inside the Paleozoic strata. , this fault is not a Holocene active fault, but a late Pleistocene active fault, and the fault movement is strike-slip and thrust.

  Du Fang said that the Hanyuan-Ganluo fault that triggered the M4.8 earthquake is the Hanyuan-Ganluo fault, which has the ability to generate moderate-intensity earthquakes, and there are moderate-intensity earthquakes in historical records.

Since 1970, three earthquakes of magnitude 4.0 (including aftershocks) have occurred within 50 kilometers of the epicenter.

Among them, there were two earthquakes of magnitude 4.0-4.9 and one earthquake of magnitude 5.0-5.9.

Among these earthquakes, the largest and most recent earthquake is the M5.0 earthquake in the northwest of Shimian on June 9, 1989, which is about 38 kilometers away from the M4.8 Hanyuan earthquake on May 20, 2022; the closest earthquake in space is 1970 The Tianquan M4.0 earthquake on June 27 is about 27 kilometers away from the May 20, 2022 Hanyuan M4.8 earthquake.