More frequent glacier-rock avalanches in Sedongpu gully are blocking the Yarlung Zangbo River in eastern Tibet
Abstract
Increasingly frequent glacier-rock avalanches (GRAs) - events triggered by the detachment of both glacier and rock materials - have occurred in recent years in the Sedongpu gully in the eastern Himalayan syntaxis, blocking the course of the Yarlung Zangbo River repeatedly. To identify spatio-temporal patterns and influencing factors of these GRAs, we analyzed remote sensing images and produced high-resolution digital surface models.
At least eight GRAs, originating from the same source areas, have occurred in the past decades: one in 1974, one in 2014, and six between 2017 and 2018. The GRAs that occurred since 2014 were responsible for the loss of > 70 Mm(3) of glacier and rock and > 150 Mm(3) of moraine deposits and increased the elevation of the basin outlet by 60-120 m.
Climate change-induced glacier retreat, steep topography, and a recent strong earthquake were found to be related to the occurrence of the recent GRAs, which resulted in the formation of a knickpoint in the Yarlung Zangbo River.