On June 24 , a sudden landslide occurred in Xinma Village, Diexi Town, Mao County, Sichuan Province, which caused more than 40 households and more than 100 people to be buried. The river channel blocked 2 kilometers, and more than 1600 meters of road was buried . The amount of landslide is about 800. Million cubic meters . After learning about the disaster, the relevant units of the Ministry of Land and Resources and the China Geological Survey took immediate action and actively devoted themselves to rescue operations.

After learning about the disaster, the Ministry of Land and Resources immediately upgraded the level-3 emergency response of the earlier geological disasters to Level II. Minister of Land and Resources Jiang Daming first inquired about the disaster by telephone and gave instructions, and sent the Deputy Director of Ministry of Land and Resources Ling Yueming to lead the team. The expert group traveled to Sichuan to guide rescue operations.

The Office of the Ministry of Land and Resources issued the first urgent notice regarding the actual prevention of geological disasters and required the relevant departments to attach great importance to it, intensify investigations, implement responsibilities, actively avoid risks, decisively withdraw, strengthen its duty, and improve the speed of disasters. Reporting system. Effective measures must be taken to prevent sticking to death and to prevent and reduce casualties caused by geological disasters.

According to expert analysis, this is a high-level remote landslide-induced debris flow disaster induced by rainfall.

The function and phenomenon that a part of rock and soil on a slope of a mountain slope moves along a certain weak structural plane (band) to move down the slope as a whole, commonly known as “walking the mountain”, is one of common geological disasters.

The earthquakes in western Sichuan and western Yunnan have always been relatively active. In the western Sichuan area, an earthquake of magnitude 6-7 occurs every 20 years, and in the western Yunnan area , the 6-7 level occurs once every 10 years. There are complementary situations in these two regions. One is weak and the other is strong.

Congenital deficiency

The landslide is actually the effect of the hidden disaster compounded by the 1933 Diexi earthquake and the 2008 Wenchuan earthquake, and is the result of the plateau movement of the Qinghai-Tibet Plateau.

Note: The Songpinggou in the Didaxi Town where the landslide is located is a place where the fault of the Diezha earthquake passed in 1933. This earthquake caused more damage to the slope than the 2008 Wenchuan earthquake.

Long-term accumulation

See the complete stone on the surface, it may have layers or cracks underneath it. The rock formations become loose after encountering external factors such as earthquakes, and then penetrate the rainwater to reduce the frictional resistance between the rock formations and break the original static state. Or multiple accumulating factors such as rainfall, and repeated impact on the original structure of the rock formation, reaching a certain critical point, it will start landslides, mudslides and other disasters.

Explanation: The landslide disaster is not caused by a single factor, but is a natural process of long-term, multi-factor intersections, including internal forces such as earthquakes and crustal movements, and external forces such as rainfall and ice and snow melting.

The last straw: rainfall

Judging from the accident situation, "rain induced" is the "last straw" that produces landslides. A continuous drizzle is like pouring oil on a broken rock, breaking a rock that is already in a critical state and causing a landslide.

The landslide body of this disaster is about 8 million cubic meters. In 100 seconds, the plane sliding distance is about 2500 meters to 3000 meters . The types of landslides are rocky landslides and landslides, as well as high-speed and low-speed conditions.

In the area of ​​high mountains and valleys, the landslide is a subgrade metamorphic sandstone landslide with an altitude of about 3,400 meters and a height difference of more than 1,000 meters . The slope is between 50 and 60 degrees, and it is a high-speed bedding landslide.

Explanation: The high landslides often have a fast impact and a large area. It is also because of the high level and high speed that the landslide body will form debris after falling, and its impact on the ground is not integral, but it forms a debris flow consisting of many rock blocks, that is, a “slug-slip-debris flow”. The scope of the disaster caused by the region is also greater.

Early warning: long-term research is needed

Many people think that after the earthquake, there is no problem if there is no place to collapse. However, the effects of the earthquake and the effects of instability are actually long-term and must be taken seriously.

Landslides can be judged primarily by surface deformation. However, rocky landslides are bursty and invisible, and are often difficult to predict.

Hard rocky landslides

The identification of potential rocky landslide points cannot be achieved through simple remote sensing techniques, satellite images, etc., but it requires long-term research, mainly including two aspects. One is the renewal of geological survey techniques and the other is the theoretical study of disasters. In-depth.

Note: For early warning of rocky landslides, acoustic emission or micro-seismic technology can be used for rocky landslide disaster point monitoring. This is a technology that monitors the acoustic signals generated during rock deformation and fracture, but requires professional technical equipment. Higher costs often make it difficult to cover a large area and a wide range of geological hazards in high-risk areas.

As for post-disaster reconstruction, the two sides of the Minjiang River are still relatively dangerous. We must pay attention to the stability of the surrounding areas. We must take measures to ensure the safety of residents as much as possible.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.