The image below, which was published by China News in the aftermath of the landslide<\/a>, provides an impression of the scale of this failure:<\/p>\n Panoramic view of the Hanyuan County landslide, which occurred in August 2020 in Sichuan, China. Image from China News<\/a> via Teller Report<\/a>.<\/p><\/div>\n .<\/p>\n He et al.<\/em> (2020)<\/a> report that the landslide, which is located at 29.341, 102.698, had a volume of about 5 million cubic metres, and dimensions of 880 m long, 280 m wide and a depth of about 20 m.<\/p>\n Prior to the landslide, Hanyuan County suffered two substantial rainfall events, on 16 August 2020 and 18 August 2020, which together deposited 149.5 mm of precipitation.\u00a0 Interestingly, He et al.<\/em> (2020)<\/a> report the following local observations of the development of failure:<\/p>\n “According to our visit to local villagers, intermittent ground deformation in the landslide area has been observed since August 17, 2020. From August 17 to 18, numerous cracks have developed on the ground, and the length and width of cracks increased slightly. On August 20, a series of new cracks appeared in the rear edge of the landslide area, and the crack depth exceeded 1 m. At 3:50 am on August 21, the sliding materials began to slip along the sliding surface, accompanied by \u201cswoosh\u201d sound and the sky of dust.”<\/em><\/p>\n Note the quite long gap between the rainfall and the final failure event.<\/p>\n He et al.<\/em> (2020)<\/a> indicate that the failure in Hanyuan County occurred in three stages, which initiated at the top of the slope.\u00a0 This initial failure loaded the material further down the slope, which progressively failed.\u00a0 Finally, the entire slope failed and underwent a fluidisation process (presumably static liquefaction) to generate a high mobility flow that was devastating to buildings in its path.<\/p>\n Interestingly of course, if the population had been able to understand the precursory signs of failure that they were observing then loss of life might have been prevented.\u00a0 Building capacity of remote communities to understand these signals continues to be one of the great challenges in landslide work.<\/p>\n .<\/p>\n EurekAlert has a good article<\/a> about new research to improve the modelling of landslide tsunami, being undertaken in Russia.<\/p>\n .<\/p>\n![\"Hanyuan](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2020\/10\/20_10-Hanyuan-1.jpg\")
Quickslide 1: Improved models of landslide tsunami<\/h4>\n
Quickslide 2: Learning lessons from the hazards faced by mountain railways<\/h4>\n