About this Wenchuan earthquake

Experts explain in detail: Why is Wenchuan earthquake more destructive than Tangshan earthquake?

Wenchuan earthquake is the most destructive and widespread earthquake in China since 1949. The intensity and intensity of this earthquake exceeded 1976 Tangshan earthquake. China earthquake research and geological disaster research experts today analyzed the main reasons why Wenchuan earthquake is more destructive than Tangshan earthquake.

Mei Feng, an expert from the Basic Geology Research Office of the Institute of Geomechanics, Chinese Academy of Geological Sciences, pointed out that the Wenchuan earthquake was more destructive than the Tangshan earthquake when he visited the website of the Ministry of Land and Resources today. First of all, it can be seen from the magnitude that the Wenchuan earthquake was slightly stronger.

Internationally recognized Tangshan earthquake with magnitude 7.6 and Wenchuan earthquake with magnitude 8. Secondly, judging from the fault dislocation of geological mechanism, the Tangshan earthquake was extensional and the hanging wall collapsed. Wenchuan earthquake is upward, which has a greater impact than Tangshan earthquake.

Thirdly, the fault dislocation time of Tangshan earthquake is 12.9 seconds, and that of Wenchuan earthquake is 22.2 seconds. The longer the dislocation time, the longer people feel the strong earthquake, which means that the sway duration of buildings in Wenchuan earthquake is stronger than that in Tangshan earthquake.

Fourthly, from the index of earthquake tensor, the Tangshan earthquake was 2.7, and the Wenchuan earthquake was 9.4, which was quite different.

Fifth, the Wenchuan earthquake has a larger area than the Tangshan earthquake. Mei Feng said that this is mainly due to fault dislocation. Wenchuan earthquake is a compressive fault, and its dislocation direction is northeast, which means that the northeast of Wenchuan is greatly affected, but the situation in its west will be better.

Wenchuan earthquake affected a large area, and it is said that almost all of Southeast Asia and East Asia felt the earthquake. "The main reason is that the dislocation time of the Wenchuan earthquake is particularly long, which is even longer than the Tangshan earthquake. This is why although the Tangshan earthquake has a large number of deaths, the impact of the disaster is actually not as great as that of the Wenchuan earthquake. " Mei Feng said, because the disasters in Wenchuan are widely distributed.

Sixth, the geological disasters and secondary disasters induced by Wenchuan earthquake are much bigger than Tangshan earthquake. Cen Jiafa, a professor at the Senior Consulting and Research Center of the Ministry of Land and Resources, said that since the Tangshan earthquake mainly occurred in the plain area and the Wenchuan earthquake mainly occurred in the mountainous area, the types of secondary disasters and geological disasters were different, and the destructive collapses, rolling stones and landslides caused by the Wenchuan earthquake were much more serious than those caused by the Tangshan earthquake. In addition, because there is more water in Sichuan, the dammed lake is different from the Tangshan earthquake.

An Meijian, an expert from the Basic Geology Research Office of the Institute of Geomechanics, Chinese Academy of Geological Sciences, added that the magnitude of Wenchuan earthquake was slightly higher than that of Tangshan earthquake, and the energy difference was three times. The greater the energy of an earthquake, the farther it spreads and causes damage in a longer distance. In addition, the location of Wenchuan earthquake is also very special. Tangshan earthquake happened in the east of China. Because the delay line in the east is thin, the seismic wave attenuation in the east is serious, while the delay line in Sichuan is thick, so the seismic wave attenuation is slow. From these two perspectives, the impact of Wenchuan earthquake is greater than that of Tangshan.

Statistics show that 1976 Tangshan earthquake caused 242,000 deaths. Up to now, the Wenchuan earthquake has caused 324.77 million deaths.

Experts pointed out that compared with Tangshan earthquake, the death toll of Wenchuan earthquake was relatively small, mainly because Tangshan earthquake happened at night and most people were sleeping. Wenchuan earthquake mainly occurred in the daytime. In addition, Tangshan earthquake mainly occurred in urban areas, while Wenchuan earthquake mainly occurred in mountainous areas or rural areas with low population density.