China News Agency, Beijing, June 12 (Reporter Sun Zifa) June 12, 2020 is the 190th anniversary of the 7/1/2 magnitude earthquake that occurred in the magnetic county of Hebei, Henan, and Qing dynasties. Although preliminary research on the Cixian earthquake has achieved preliminary results, it is initially confirmed that the northwest-west trending Cixian-Daming fault west section (Nanshancun-Chakou fault) is the seismogenic fault of the earthquake, but there are still some Unresolved scientific issues are worth exploring.
The major scientific issues that still remained unresolved in the Cixian earthquake 190 years ago include: First, did the earthquake-generating fault Nanshan Village-Chakou fault record ancient earthquake events? What is the interval between recurrences of ancient earthquake events? What is the danger of a major earthquake in the future? The second is the eastern section of the Cixian-Daming fault hidden under the North China Plain. Is it an active fault? What is the nature of its activity and rate of movement? The third is the densely populated and huge national economy in the North China Plain, how to improve the ability to deal with earthquake disaster risks?
Earthquake experts said that these problems all require the unremitting efforts of seismic science and technology workers to explore and solve them.
The Public Service Department of the China Earthquake Administration said that the Cixian earthquake occurred at the boundary between the North China Plain and the Taihang Mountains. There are many faults in different directions hidden beneath the surface of the North China Plain. There are mainly two groups of northeast and northwest. The Cixian-Daming fault is a northwestern fault. Its western part enters the Taihang Mountain area and is exposed on the surface. It is called Nanshan Village-Chakou Fault. Geologists believe that the Nanshan Village-Chakou fault is an active fault (a fault that has been active since 120,000 years ago), and that along the fault, an earthquake fault swell with a height of 2-4 meters and a maximum height of about 7 meters was found. It is considered to be a trace of surface rupture of the 7 1/2 earthquake in Ci County in 1830.
After the big earthquake in Cixian that year, a series of aftershocks occurred in the vicinity of the epicenter area. Until modern times, many small and medium-sized earthquake activities can still be recorded near the epicenter. Geophysicists inferred from inversion calculations based on the seismic wave records of these small and medium earthquakes. The depth of the source body of the M7 7 1/2 earthquake in Cixian County in 1830 was about 15 kilometers. The source fault deep underground was a north-west-west high-dip strike-slip fault, spatially distributed with the Nanshan Village-Chakou active fault found on the surface. It is basically the same.
According to reports, on June 12, 1830 (Qing Daoguang Decade Leap April 22), a magnitude 7 and 1/2 earthquake occurred in Ci County between Hebei and Henan, and only the number of deaths recorded in Ci County It surpassed 10,000 people and caused a large number of houses to collapse or be destroyed in Linzhang, Anyang, Handan, Wu'an, Shexian, Linxian and other places. There are also a large number of casualties. The world cultural heritage "Yinxu" is far from the earthquake The epicenter was only a few tens of kilometers. Subsequent aftershocks of magnitude 5 1/2 to 5 3/4 occurred on June 13, 24 and 26, respectively, further aggravating the earthquake disaster. (Finish)