Landslide classification

Loess

Rockfall

Geomorphology

Landslide

Rockslide

Geology

Seismology

Oceanography

Debris

Debris flow

Engineering Geology

Earthquake-triggered landslides are a major geological hazard in Central Asia. In July 1949, the M7.4 Khait earthquake triggered many hundreds of landslides in a mountainous region near the southern limit of the Tien Shan Mountains, central Tajikistan. These landslides involved widespread rock-slope failure as well as large numbers of flowslides in loess that mantles the steep slopes of the region. In the Yasman valley hundreds of loess landslides coalesced to form a massive loess flow (est. vol. 245 Mm3) that travelled up to 20 km on a slope of only 2°. In an adjacent valley, the Khait landslide involved transformation of an earthquake-triggered rockslide into a very rapid flow by the entrainment of saturated loess into its movement. It travelled 7.41 km over a vertical distance of 1421 m with an estimated average velocity of ~30 m/s. We estimate its volume as 75 Mm3, an order of magnitude less that previously published estimates. The Khait landslide was simulated using DAN. The number of casualties due to e...

Landslides triggered by the 1949 Khait earthquake, Tajikistan, and associated loss of life