The crust is divided into six plates, namely, the Pacific plate, the Indian Ocean plate, the Eurasian plate, the American plate, the African plate and the Antarctic plate. Earthquake is the process that the movement of these six plates leads to the collision and compression between plates, which leads to the dislocation and rupture of plate boundaries and interior, thus releasing a lot of energy to the outside world. The energy released during an earthquake mainly propagates outward in the form of seismic waves, which are divided into longitudinal waves and shear waves. Longitudinal waves travel faster than shear waves, so in an earthquake, we first feel the shaking up and down, and then the shaking left and right. The damage of longitudinal wave is weak, but the damage of shear wave is great, so when we feel the earthquake, we still have a certain reaction time in theory, and we can quickly go to a safe place to avoid danger.

Simply put, it can be understood that two peerless masters released a lot of energy in the process of fighting, and then caused innocent people around them to get hurt. In fact, earthquakes on the earth have been very active. According to relevant statistics, the number of earthquakes of magnitude 6 or above in the world in the 1970s was 89 1, in the 1980s it was 933, in the 1990s it was 1203, and in the 20th century it was 1025 and 10 to 65438+. It is not difficult to see from the data that earthquakes have been quite frequent. Then why do we feel that earthquakes are becoming more and more frequent?

Sichuan, located in the north-south seismic belt of China, is one of the earthquake-prone areas in China.

Starting from Ningxia, China, passing through eastern Gansu, western Sichuan and even Yunnan, there is an earthquake-intensive zone that runs through Chinese mainland in a general north-south direction, which is called the China North-South Seismic Zone, or the North-South Seismic Zone for short. The belt can extend north to Mongolia and south to Myanmar.

Formation of the North-South Seismic Belt: The North-South Seismic Belt is a new structural entity, with the crust of the Qinghai-Tibet Plateau as the main body, merging with the west of the Yangtze block, and the boundary is dispersed. The giant anti-S-shaped or slow-arc structural belt, the arc structure with the central arc facing south and the spiral structure developed near the eastern boundary, which constitute its basic framework, have become the three major structural characteristics of the north-south seismic belt, all of which are the products of plastic extension and flow.

First, it is an objective fact that earthquakes are relatively frequent, because the earth has entered a relatively active period and is currently in a period of frequent plate activity. On the other hand, with the development of science and technology and the arrival of the media age, the speed of news dissemination is getting faster and faster. There was an earthquake before, and it may take a long time for people in other places to receive the news. What happens one second now can spread all over the world the next, so people will feel more and more frequent.

The third reason is that China is located at the junction of the Asia-Europe plate, the Pacific plate and the Indian Ocean plate, just in the world's two major seismic activity zones (the Pacific Rim seismic zone and the Mediterranean Sea? Between Himalayan seismic belts), Sichuan is located in the Mediterranean? Himalayan seismic belt, so the frequency of seismic activity is high. In addition, in the past, everyone was hungry and warm, and their minds were focused on the problem of food and clothing, and they didn't care so much about what happened in the distance. Now that people's living standards have improved, they are beginning to pay attention to our surrounding environment.