"6·" Landslide disaster in Guanlinggang Wuzhen, Guizhou

At around 14:00 on June 28, 2010, due to the continuous heavy rainfall, a severe landslide occurred in Dazhai Village, Gangwu Town, Guanling County, Guizhou Province, resulting in the death of 42 people and the disappearance of 57 people in Dazhai Village. .

Full picture of the landslide

After on-site investigation, the geological disaster emergency expert team of the Ministry of Land and Resources concluded that the Gangwuzhen landslide in Guanling County was a rare and extremely large landslide debris flow compound disaster, showing a high-speed Long-range sliding characteristics: After the sliding mountain moved forward for about 500 meters, it violently collided with a small hillside in the Yongwo Village Group of Dazhai Village, Gangwu Town. After deflecting 90°, it transformed into a high-speed debris flow, slid down at a right angle at high speed, and shoveled The surface accumulation in the Dazhai Village Group area eventually resulted in this rare large landslide-debris flow disaster.

The formation of this huge geological disaster is mainly due to the following four reasons:

First, the local geological structure is relatively special. The top of the mountain is made of relatively hard limestone and dolomite. However, it has good water permeability and is easy to form caves; the terrain in the lower part of the mountain is relatively gentle, and the lithology of the strata is mudstone and sandstone that can easily form water-rich zones. This kind of "hard top and soft bottom" geological structure is not only easy to form landslides, but also prone to collapse. and other geological disasters.

Secondly, before this disaster occurred, the local area experienced rare heavy rainfall. On the 27th and 28th alone, the rainfall reached 310 millimeters, including 8:00 pm on the 27th and 11:00 on the 28th. In the past 15 hours, the rainfall reached 237 millimeters, exceeding all previous local meteorological records.

Third, the local terrain is special. The mountain where the landslide occurred is a "boot-shaped terrain" with a steep top and a gentle bottom. The relative height difference of the topography is 400 meters to 500 meters. Therefore, the momentum after the landslide slides is huge, which not only forms Debris flow, and the sliding distance is as long as 1.5 kilometers.

Fourthly, Guizhou suffered from a rare drought in history last year in summer, autumn, winter and spring. Heavy rainfall is more likely to quickly penetrate into the mudstone and sandstone in the lower part of the mountain.