图  1  1950～2019年冰川地震学的论文数量增长情况（修改自Podolskiy and Walter, 2016）

Figure  1.  Cumulative number of papers on passive glacier seismology, 1950～2019 (modified from Podolskiy and Walter, 2016)

图  2  典型冰震的位置和发生机理示意图（修改自Larose et al., 2015）

Figure  2.  Schematic diagram of the location and mechanism of typical icequakes (modified from Larose et al., 2015)

图  3  （a）含P波的浅表冰裂隙冰震及瑞利波频谱；（b）深部冰震及更高频的P波频谱（修改自Roosli et al., 2014）

Figure  3.  (a) Surface crevasse icequake with P-arrival and dominant Rayleigh wave; (b) Deep icequake with dominant P-arrival, higher frequencies (modified from Roosli et al., 2014)

图  4  格陵兰岛冰崩的波形特征。（a）冰震时间序列的水平南北分量（红色）和附近测量的海洋水位（青色），清楚显示了冰山崩解事件引发长达1小时的水位振荡；（b）冰崩事件的开始时的频谱（红色）和前期噪声谱（黑色）（修改自Walter et al., 2013）

Figure  4.  Seismic signature of a calving event at Kangerdlugssup Sermerssua (Greenland), recorded on the station NUUG of the Greenland Ice Sheet Monitoring Network. (a) Horizontal north-south component of seismic time series (red) and nearby measured ocean water level (cyan). Both time series clearly show the hour-long water level oscillation triggered by the iceberg calving event. (b) Spectrum of the calving event's onset (red) and prevent noise (black) (modified from Walter et al., 2013)

图  5  冰腔水流震颤与水位有关（修改自Roeoesli et al., 2016）

Figure  5.  The tremor caused by subglacial water flow is related to rising water levels (modified from Roeoesli et al., 2016)

图  6  冰层基底黏滑的相似波形（修改自Allstadt and Malone, 2014）

Figure  6.  The similar waveforms of stick-slip motion (modified from Allstadt and Malone, 2014)

图  7  观测气温、气温梯度与高频冰震的时间分布（陈宇乔，2018）

Figure  7.  The temporal distribution of air temperature, air temperature gradient and number of detected short-period icequakes ( Chen, 2018)

图  8  阿汝冰川的冰震观测台站分布（五角星为震中）

Figure  8.  Distribution of icequake observation stations in Aru glacier (star is epicenter)

图  9  主频为20 Hz的典型冰震波形（震中标注于图8）

Figure  9.  Typical icequake waveforms with a dominant frequency of 20 Hz (The epicenter is marked in Fig.8)