Icequakes on the Urumqi Glacier No. 1, China and their relations with solid tide and environmental changes
Icequakes, micro-seismicity caused by glacier deformation and motion, provide important information to study glacier dynamics and its responses to environmental changes at various temporal and spatial scales. In this study, we apply a multi-dimensional autoregressive maximum-likelihood algorithm to obtain 12 icequake templates on the Urumqi Glacier No. 1, China, and detect 65,363 icequakes through template matching. Centroid location of the 12 templates indicate that most icequakes are caused by surface crevasses inside the glacier, which are characterized by dominant surface waves. The icequakes show seasonal variation with more events in summer because of faster ice flow due to high temperature and precipitation. In winter, however, the icequakes, on par with those in summer, suggest considerable glacier growth in cold weather. Because of higher ice flow velocity due to low tide, the number of icequakes has two daily peaks which seems to negatively correlate with semi-diurnal solid tide.