Why are there so many earthquakes in Chengdu?

It is not that there are many earthquakes in Chengdu, but that there are many earthquakes around Chengdu, which has affected Chengdu.

The Qingbaijiang earthquake with a magnitude of 5. 1 occurred early this morning, and the main city of Chengdu felt a strong earthquake. This earthquake is the closest to the main city of Chengdu since 1900, only 38 kilometers. The epicentre also includes Jintang County, qingbaijiang district and Guanghan City, which are densely populated.

There are many mountains in the west of Sichuan and basins in the middle. The earthquake-prone areas are mostly concentrated in the western mountainous areas, which are distributed in a straight line and parallel at the junction of mountainous areas and basins. Among them, Longmenshan fault is the most famous-it is a huge crustal fault system, which runs through the lithosphere, extending more than 500 kilometers from north to south and 70 kilometers wide. The culprit of 5 12 is this fault zone.

There are several fault zones around Chengdu. Pujiang-Xinjin-Shuangliu-Chengdu-Xindu-Guanghan-Deyang fault zone passes through the main urban areas of Chengdu and Deyang, and an earthquake occurred on June 2 1. 0943; 2. Guangyuan-Anxian-Guankou-Dayi-Ya 'an fault zone; 3. Longquanshan fault zone; 4. Dayi-Jintang fault zone; 5. Ya 'an-Emei-Pujiang-Dayi-Pengzhou fault zone; 6. Pengzhou-Dujiangyan fault zone; 7. Qionglai-Dayi-Pixian-Pengzhou-Shifang-Mianzhu-Jiange fault zone; 8. Deyang-Zhongjiang fault zone; 9. Wenjiang-Pixian fault zone; 10, Hanyuan-Chengdu-Jiange fault zone; 1 1, Shuangliu-Qionglai fault zone. In addition, there are earthquake-prone active areas in the western Sichuan Plateau.

Chengdu is not in the seismic activity zone, and belongs to the Yangtze plate with a stable history of 800-900 million years. Located on the Yangtze platform, it has excellent damping layer and is the most stable area. The earthquake zones of Longmenshan, Songpan and Mao Wen, which are closest to Chengdu, have the greatest impact on Chengdu, with the intensity of 7 degrees during the Wenchuan earthquake.

Who says there are many earthquakes in Chengdu? During the earthquake, Guawazi said that these places could not be counted. Why? Didn't it say "Dujiangyan, Sichuan" at the beginning? It has nothing to do with Chengdu, and it is the same this time. But when it comes to economy, population, tourism, even heat maps, light spots, Deyang, Meishan and Ziyang all belong to Chengdu, Jiuzhaigou and Emei Mountain … Why do you say that the earthquake belongs to Chengdu!

Because Chengdu is located at the junction of the Asia-Europe plate and the Indian Ocean plate, Sichuan Province has a special geographical position. The west is the eastern end of the Qinghai-Tibet Plateau, mostly mountainous. There is a Longmenshan fault zone here. The crust in this place is active, and every high-intensity earthquake will be accompanied by aftershocks, so there are many earthquakes in Chengdu and its vicinity.

There is an alluvial plain below Chengdu, and there is no rock slab, which has a damping effect. Just like a person sitting on a sofa, the earthquake can't be so severe. Like the 5 12 earthquake, Chengdu didn't suffer any big losses.

Near the Longmenshan active fault zone!

This earthquake is in the suburbs of Chengdu, not Chengdu.

But to calculate the population output value, Chengdu must be counted, and Sichuan can also be counted.

The Indian Ocean plate drifted northeast and collided with the Eurasian plate. The Indian Ocean plate is embedded under the Eurasian plate, which lifts Eurasia and forms the Himalayas and the Qinghai-Tibet Plateau. Under this collision, a series of east-west mountains were formed in the northern part of the Qinghai-Tibet Plateau, and the Hengduan mountains in the north-south direction were formed in the eastern part. This series of mountains is the Eurasian plate fold caused by the collision of two major plates, forming a fault zone. Until today, the Indian Ocean plate is still drifting to the northeast. Under the action of this force, the fault zone is constantly under pressure. When it reaches a certain level, it will cause dislocations and earthquakes. Such a big earthquake will happen every few decades or hundreds of years, while a small earthquake will happen at any time. Chengdu is located in the west of Sichuan Basin, close to Longmen Mountain, the easternmost part of Hengduan Mountains, with Longmen Fault Zone at the foot of the mountain. Earthquakes can happen at any time. Coincidentally, Chengdu is located on alluvial stratum, just like a big cushion, which greatly cushioned the impact of the earthquake on Chengdu. Moreover, the plate below Chengdu alluvium is complete, without fracture, and there will be no earthquake in itself. Therefore, although the Longquanshan fault in the east of Chengdu will have a small vibration, the Longmen Mountain in the west will have a big vibration every few decades. Chengdu has been safe for thousands of years, and everyone can rest assured to live here, even if it is an earthquake.

There are two major seismic belts around Chengdu, Longmen seismic belt and Longquanshan seismic belt.

Maybe it's in the earthquake zone.

First of all, it is undeniable that there are many earthquakes in Sichuan. In 2065438+2009, there were nearly 100 small earthquakes of magnitude 2-5, and most earthquakes below magnitude 5 were not felt. Secondly, the earthquakes around Chengdu are felt in Chengdu. There were only two earthquakes in Chengdu in 20 19, including this one in 2020. Finally, attach the 20 19 Chongqing earthquake: ask me why I should attach it to Chongqing, so that the questioner can satisfy his inner "frankness" about Chongqing.