Thursday 25 June 2015

Landslide causes tsunami on the Daning River in Chongqing, China.

A huge landslide has triggered a tsunami on the Daning River (a tributary of the Yangtze) in Wushan County in Yangqing Municipality, China. The landslip occurred on the north bank of the river at at about 6.40 pm local time on Wednesday 24 June 2015, and involved about 2000 cubic meters of sediments collapsing into the river, triggering a series of waves up to six meters high, which overturned a total of thirteen vessels on the river, predominantly small fishing craft but including one fourteen meter patrol boat. One person has been confirmed dead following the incident and four more to have been injured. The area of river around the incident has been closed to shipping and 196 people have been evacuated from homes close to the site as a precaution.

The 24 June 2015 Daning River landslide. Zhu Yunping/Xinhua.

Most landslides are triggered by soil water logging, when flooding or high rainfall cause sediments to lose their cohesion, triggering collapses. However the sediments of the Daning River landslide appear dry, and the river is low, suggesting that this may not be the case in this incident, and leading to speculation that the event may be linked to the construction of the Three Gorges Dam, which is about 110 km downriver of the incident, and which may have altered the distribution of geological stress in the area.

Vessels on the Daning River washed ashore by the 24 June 2015 tsunami. Zhu Yunping/Xinhua.

Wushan County is noted for its fertile loess soils, however these also leave it exposed to dangerous earth movements. Loess soils are formed by wind-blown sediments from arid regions settling in moister areas, those in Wushan typically being Pleistocene soils from Central Asia. However such sediments are notoriously loosely packed, and move much more freely than other sediments, creating a higher risk of landslides across much of Central and Northern China.

See also...

The China Earthquake Networks Center recorded a Magnitude 5.5 Earthquake at a depth of 7 km in Jianhe County in southeastern Guizhou Province, China...


The United States Geological Survey recorded a Magnitude 4.2 Earthquake at a depth of 13.8 km in southeastern Guizhou Province, China, slightly...


The China Earthquake Networks Center recorded a Magnitude 6.3 Earthquake in about 25 km to the northwest of Kanding in eastern Sichuan Province, slightly before 11.20 pm local time (slightly before...


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