Monitoring and Analyzing Collapse of KLSK-37 Glacier Tongue in Recent 40 Years with Multi-source Remote Sensing

  Objectives  With a background of global warming, alpine glacier-related geological disasters pose a severe threat to engineering facilities and the safety of human life and property in mountainous areas. Characterizing the spatiotemporal evolutions of the dynamics of glaciers is essential for hazard assessment and mitigation. The KLSK-37 valley glacier, located in the East Kunlun Mountain in Tibetan Plateau, exhibits a steep tongue and extensive crevasses on the glacier surface. These features raise the concerns of whether the glacier would collapse in the future and threaten the safety of the Qinghai-Tibet railway and Qinghai-Tibet highway, which are only about 3 km away the glacier terminus.

  Methods  We collected Hexagon KH-9 historical satellite images, multi-source digital elevation model (DEM), and the high-resolution satellite images from the Google Earth (GE) to characterize the evolutions of the glacier terminus and surface elevation in recent 40 years for the first time.

  Results  The multi-source remote sensing observations show that the KLSK-37 glacier tongue's ice-debris leads a slow-surge pattern in recent 40 years. Satellite GE images show a lateral glacier lake is formed when the glacier tongue moves forward and blocks the meltwater channel. Paraglacial ponds with exposed ice cliffs can also be observed in the middle and lower part of the glacier tongue. The KLSK-37 glacier tongue advanced at a velocity of (5±1.8) m/a between 1979 and 2010, and the flow speed accelerated to (30±4.2) m/a between 2015 and 2018. The increased volume of materials in the tongue region from DEM differencing for the three periods 1979―2000, 2000―2011, and 2011―2018 are (2.87±1.78)×10⁵, (5.03±1.22)×10⁵, and (2.74±1.25)×10⁵ m³, respectively, with a total increased volume of (10.64±2.50)×10⁵ m³.

  Conclusions  From a combined analysis of the topographic and climate data, we found that the step-like terrain in the front of the glacier and supraglacial lake development may play an important role in keeping the glacier tongue significantly active. The tendency of warmer and more humid of climate in the East Kunlun region in recent decades is likely the driving factor for the progressive collapse of the KLSK-37 glacier tongue. We highlight that further continuous monitoring of the KLSK-37 glacier, coupled with numerical modeling, is required to assessment its hazardous influence and ensure the operation safeties of Qinghai-Tibet Railway and Qinghai-Tibet Highway.