According to the China Seismological Network, at 5:00 on May 29, Beijing time, a magnitude 3.2 earthquake occurred in the junction area of Tangshan City and Luan County, Hebei Province, with a focal depth of 6 kilometers.
Related reports: At 10:22:52 am on May 28, Beijing time, a 4.8-magnitude felt earthquake occurred at the junction of Tangshan City and Luan County, Hebei Province.
Extended reading: Experts explain the aftershocks of the Tangshan earthquake that lasted for 36 years
Beijing News (Reporter Jin Yu) Yesterday morning, a 4.8-magnitude earthquake occurred in Tangshan. There has been no report of casualties. It has been 36 years since the Tangshan earthquake. The China Seismological Network Center explained that the earthquake was an aftershock of the Tangshan earthquake. Officials say there will be no damaging earthquakes in the Tangshan area in the short term.
Cracks appeared in individual houses in Tangshan
Yesterday at 10:22, a magnitude 4.8 earthquake occurred at the junction of the municipal district of Tangshan City, Hebei Province and Luan County (39.7 degrees north latitude, 118.5 degrees east longitude), with a focal depth of 8 kilometers. The epicenter of the earthquake was only 180 kilometers away from Beijing, and the earthquake was felt in Beijing, Tianjin, Qinhuangdao and other places.
According to the Tangshan Earthquake Bureau, according to preliminary investigations, there were no obvious casualties or property losses. Some houses in Guzhi District of Tangshan City had cracks and light bulbs fell off; two houses in Luan County had cracks. The earthquake was felt in Tangshan Douhe Reservoir, 15 kilometers away from downtown Tangshan, but there was no damage.
According to the Tangshan Earthquake Bureau, the earthquake was clearly felt near the epicenter of Tangshan, especially in Tanghai, Luanxian and Tangshan urban areas. An official from the Luannan County Earthquake Bureau said, "I felt a bit strong when I saw the chair shaking and the house was fine."
The consultation room of the Beijing Municipal Seismological Bureau said that the main feeling of the earthquake in Beijing was that they saw things in the house shaking, some things fell, and some people felt that the house shook momentarily. It is estimated that the earthquake intensity in the Beijing area is about four to five degrees.
Thirty-six years later, there are still aftershocks of that year
The earthquake situation report of the Tangshan Earthquake Bureau stated that "it is initially believed that the earthquake is a normal fluctuation of aftershocks in the old earthquake area of Tangshan"; "According to the analysis of the overall characteristics of the Tangshan earthquake sequence type, this earthquake is mainly an aftershock type earthquake, and it is the main aftershock type earthquake in our city. Seismic activity fluctuates normally. The possibility of a destructive earthquake in our city is low. "Tangshan had two earthquakes in 2010. At that time, experts said in an interview with Xinhua News Agency reporters that these two earthquakes were also aftershocks after the 7.8-magnitude Tangshan earthquake in 1976.
Jiang Haikun, deputy director of the Earthquake Forecasting Department of the China Seismological Network Center, said that this earthquake was an aftershock of the 1976 Tangshan earthquake. This Tangshan earthquake, like the earthquake that occurred in 2010, is in the energy attenuation period of the Tangshan earthquake, and its time and space characteristics are consistent with the characteristics of aftershocks.
Number of aftershocks of the Tangshan Earthquake
According to the China Seismological Network Center
Earthquake magnitudes from the 1990s to the present 2000
1-1.9 magnitude, an average of 418 times, an average of 325 times
2-2.9 magnitude, an average of 102 times An average of 56 times
Level 3-3.9 An average of 10.1 times An average of 6 times
A level 4-4.9 An average of 1.4 times An average of 0.97 times
Experts say that aftershocks have a decay period, and the frequency will become lower and lower as time goes by
Jiang Haikun, deputy director of the Earthquake Forecast Department of the China Seismological Network Center, explained that after a major earthquake occurs, energy will accumulate and aftershocks will appear. This is related to the "strain" of the plate. The so-called "strain" can be understood as the speed at which the plate moves. Southwest my country belongs to the Indian Ocean Plate, which moves a few centimeters every year. The strain is rapid, causing energy to be released quickly. Aftershocks may end in a relatively short period of time, such as decades. In contrast, the movement speed in the eastern region is only a few millimeters, and the strain force is very slow, so the energy release is also slow, and the aftershocks may last for hundreds of years.
In addition, the duration of aftershocks is also related to the magnitude of the major earthquake.Jiang Haikun said that the Wenchuan earthquake and the Tangshan earthquake were one level different in magnitude and more than 30 times different in energy. "A magnitude 7 earthquake is equivalent to 33 magnitude 6 earthquakes." At present, there are many aftershocks from the Wenchuan earthquake.
Jiang Haikun explained that aftershocks have a decay period. Taking Tangshan as an example, as time goes by, the frequency of aftershocks will become less and less.
