Dynamic process of the massive Aru glacier collapse in Tibet
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Xiuqiang Bai I Siming He
Dynamic process of the massive Aru glacier collapse in Tibet
Abstract Due to global climatic warming, the possibility of collapse of polythermal glaciers is increasing. In the summer of 2016, two massive glaciers suddenly collapsed at Aru Village, Ali District, Xizang Autonomous Region, China, running out up to 7 km and killing nine herders. These events occurred suddenly in a remote area, and quantitative data about them was difficult to obtain quickly. Their seismic waves, however, could be quickly inverted to estimate the event motion parameters; the inversion results reflecting the average state. In order to have an initial judgment on the deposit range and the kinematic parameters at different positions after the collapse, seismic-wave inversions were used to estimate parameters (e.g., mass and friction coefficient) for numerical simulation to quickly simulate the motion processes that are important for the initial rescue, especially in the absence of topographic data. Numerical simulation showed that even though the shape and depth of the source area as assigned from such inversion were slightly different from the real situation, the effect on the final deposit morphology was not so great, which can be used as a reference for useful assessment after future disasters. Keywords Aru ice avalanches . Seismic wave inversion . Numerical analysis . Natural terrain Introduction With continuing global warming, the environment in which we live is experiencing great changes, especially in polar regions and the Qinghai-Tibet Plateau (Liu and Chen 2000; Wang et al. 2008; Duan and Xiao 2015) (Fig. 1). The most obvious features are melting ice sheets, ice-shelf collapses, and the occurrence of ice avalanches, which may cause sea level rise, casualties, and property loss. Compared with the large reserves of glaciers in the polar-regions, mountain glaciers are more sensitive to climate change. Large ice avalanches, rock avalanches, and mixed events are well documented for the glaciated regions in the world (McSaveney 2002; Kääb et al. 2005; Schneider 2004; Sosio et al. 2008; Tian et al. 2017). Most of them are located in high mountains or sparsely populated areas, and have such destructive power that field measurements relevant to their dynamics are scarce. Characterizing the dynamics of ice-rock avalanches is important for our understanding of the mechanical properties of the flowing material and for the prediction of the velocity and runout extent of rapid ice-rock avalanches(Favreau et al. 2010), which will help us to establish protective structures in their potential motion paths to reduce damage to people and property in future geological disasters. Important information about their motion process is recorded in the seismic signals generated by the gravitational mass flows during their emplacement. Using the seismic stations around them, these seismic signals can be used to estimate collapsed mass, dynamics, and mechanical behavior (friction coefficient, velocity, momentum,
etc.)(Brodsky et al.
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