Example:1September 23, 945, Luanxian County, Hebei Province, M = 6.25 earthquake. Aftershocks lasted for half a year and did not subside until the following spring. 1After the Tangshan earthquake of magnitude 7.8 at 3: 42 am on July 28th, 976, two strong aftershocks occurred that day, with magnitudes of magnitude 6.5 and 7. 1 respectively. Aftershocks of magnitude 5-6 or even stronger will continue to occur along the active fault zones of Ninghe, Tangshan and Luanxian. For example, an earthquake of magnitude 6.9 occurred in the northeast of Ninghe River on June 5438+0 15, and the strong aftershock will remain active until the following spring (1977). As for 5.
Abroad, the 1870 Greek earthquake lasted for three years, during which 750,000 earthquakes occurred. Generally speaking, aftershocks always decrease and weaken gradually, but sometimes there may be bigger aftershocks and cause damage. It is particularly noteworthy that the epicenter of the aftershock will not be too far from the epicenter of the main shock. Many buildings became unstable after being hit by the main earthquake, although they were not damaged. At this time, if another strong aftershock occurs, although the magnitude is smaller than the main shock, it may cause more damage than the main shock.
In the California 1952 Kern County earthquake, the main shock was completely destroyed in Bakersfield. Sometimes, an aftershock just over magnitude 3 can knock down some houses. Therefore, after the main earthquake has passed, we should be alert to aftershocks and strengthen the prediction and prevention work, and we should not take it lightly. 1974 in may 1 1 day, an earthquake of magnitude 7. 1 occurred in Zhaotong, Yunnan. After the earthquake, two aftershocks of magnitude 5 or above were predicted before the earthquake. Although it caused damage, there were few casualties.
Facing aftershocks, we should pay attention to:
People's Daily Online, Beijing, May 15:
The leader of the the State Council Emergency Management Expert Group, the Deputy Director of the Expert Committee of the National Disaster Reduction Committee, and the Counselor Dan of the State Council visited the Powerful Country Forum today to talk about matters that should be paid attention to in the face of aftershocks.
He said that first of all, we must rely on advanced scientific monitoring equipment to strengthen monitoring. Then, for the people affected by the disaster or in the earthquake zone, when the aftershocks occur, we should first calm down and not panic.
In addition, it should be noted that everyone has different positions. For example, if you are in a house, where should you focus on avoiding disasters? It is safer in houses with small spans or triangles.
Another understanding was recently told to us by an American rescue expert. He said that some of us ran under the table and bed as soon as we talked about the earthquake. He said that this should be paid special attention to, which is not necessarily correct. They have done many experiments, that is, put the mannequin under the table and then put it next to the solid table and bed. Finally, after the house collapsed, the bottom was crushed and the side was intact. This means that in such a crowded space, buildings often leave you a living space, that is, we try to squat down in the room below the height of the bed and table, but don't climb in, which may reduce casualties.
If you are on the street, avoid tall buildings, especially some glass curtain walls, and avoid high-voltage lines.
If you want to avoid steep cliffs in mountainous areas, try to go to open areas, so you should take different ways to avoid disasters in different places to reduce casualties.