Why does the Tangshan earthquake 44 years ago still have aftershocks? Expert interpretation

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 Why does the Tangshan earthquake 44 years ago still have aftershocks? Expert interpretation


He explained that after the occurrence of a large earthquake, it will cause a quite long fracture zone. The adjustment of the stress and strain of the fracture zone will last for a long time. In the process of adjustment, many small fractures will occur, and many aftershocks will occur. There are many aftershocks in 1966 Xingtai earthquake in Hebei Province, Haicheng earthquake in 1975, Tangshan earthquake in 1976 and Wenchuan earthquake in 2008. The long-term aftershocks are called long-term aftershocks. Of course, most of the long-term aftershocks have smaller magnitudes, with magnitudes of 2, 3 or even smaller, but some larger long-term aftershocks will occur, reaching more than magnitude 4 or 5. The Guye earthquake occurred in the rupture zone of Tangshan earthquake, so it can be judged as aftershock of Tangshan earthquake.

According to the experts progress, the earthquake with M = 5.1 occurred in Guye District, which was the largest aftershock in Tangshan area in recent years. To be exact, this aftershock should be called the long-term strong aftershock of 1976 Tangshan earthquake. Aftershocks will occur on Tangshan seismic belt in the future, but the long-term aftershocks will become smaller and fewer. However, it is not ruled out that there will be some long-term aftershocks in Tangshan aftershock area in the future, such as the aftershocks with magnitude 4 or even magnitude 5.

A total of 24 earthquakes with m u2265 3 have occurred in Hebei Province in the past five years, the largest of which is this one, the China Seismological Network Express said on the 12th.

The earthquake activity in the aftershock area of Tangshan earthquake is very rich, fluctuating and decaying, and there are still about 4 or 5 earthquakes, the official microblog of Beijing Seismological Bureau said at noon on the 12th. According to expert consultation and analysis, it is unlikely that an earthquake of magnitude 5 or above will occur in the original area of the earthquake in recent days.

After the earthquake occurred in Guye District, the Seismological Bureau of Hebei Province and the Seismological Bureau of Tianjin successively sent teams to the earthquake area to carry out emergency response work. The emergency management department launched the four level emergency response for earthquake disasters, and the Hebei Provincial Peoples government launched the third level emergency response.

In the afternoon of July 12, the China Earthquake Network Center held a briefing on the Tangshan Guye earthquake with a magnitude of 5.1, China News Network reported. Liu Jie, deputy director of the center, said at the meeting that the Guye earthquake occurred in the old earthquake area of Tangshan with M = 7.8 in July 1976, which is a normal seismic fluctuation activity in the old earthquake area of Tangshan, and is also another aftershock with m u2265 5 or above after the Tangshan Guye MS5.0 earthquake in October 1995.

Liu Jie stressed that according to the current observation data and analysis of earthquake cases, it is unlikely that an earthquake of magnitude 5 or above will occur again in the old Tangshan earthquake area in the short term. He also said that according to the worlds research, the duration of aftershock activity is generally the loading activity of the main shock structure, that is, about 10% of the incubation time of the main earthquake. The preparation time of the Tangshan earthquake is thousands of years, so it is relatively normal for the aftershock activity in Tangshan aftershock area to last for more than 100 years..

The surging news noted that as early as March 12, 2010, when the China Seismological Bureau interpreted the recent earthquake situation for the public and introduced relevant knowledge, it referred to the Tangshan aftershock and how to define the aftershock. When answering a reporters question at that time, Liu Jie said that after the occurrence of a large earthquake, obvious increase of seismic activity will be observed in its focal area and adjacent areas. These obviously increased earthquakes are generally called aftershocks. At present, there is no effective scientific method to identify whether an earthquake is an aftershock of a large earthquake or another new earthquake.

Surging journalist Liao Yan

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