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.

冰震，即由冰川形变与运动引起的微震，为研究冰川动力学及其对环境变化在不同时空尺度上的响应提供了关键信息。本研究中，我们采用多维自回归最大似然算法，在乌鲁木齐一号冰川上获取了12个冰震模板，并通过模板匹配检测到65,363次冰震。12个模板的重心位置表明，大多数冰震是由冰川内部的表面裂缝引起的，这些裂缝以表面波为主导。冰震表现出季节性变化，夏季由于高温和降水导致冰流速度加快，事件数量较多。然而，在冬季，冰震事件，与夏季相当，表明在寒冷天气条件下冰川有显著增长。由于低潮导致的冰流速度增加，冰震数量呈现两个每日峰值，这似乎与半日潮的固体潮呈负相关。