Observations of Activation of the Blomstrand Glacier in the North of Western Spitsbergen according to Data from a Single Seismic Station

Abstract—At the end of 2019, the automated seismological monitoring system of the Kola Branch, Federal Research Center Geophysical Survey, Russian Academy of Sciences, recorded an increase in weak seismicity localized in the northwestern part of Spitsbergen. The intensity of the seismic process reached several dozen events per day. Preliminary analysis of seismic event records visually revealed a high degree of similarity in their waveforms. To obtain the most complete catalog and spatiotemporal representation of the development of this seismic process, the cross-correlation detection method was used. The resulting catalog contains over 9000 seismic events in the magnitude range (ML) from –0.4 to 0.6. The localization of the epicenters showed that they were confined to the ablation zone of the Blomstrand glacier. Analysis of the resulting catalog showed that the sequence began and ended abruptly, with variations in the amplitudes of seismic events and times between their occurrence happening synchronously. Comparison of the results of seismic monitoring with satellite images obtained by the Santinel-2 research apparatus in the radio frequency range showed a relationship between this seismic sequence and large-scale movement of the terminal part of the Blomstrand glacier, accompanied by massive releases of ice material into the bay. At the same time, during the period of the active seismic process, no significant movements of the glacier front were observed, and large-scale movement of the glacier coincided with the end of seismic activation. Satellite data, as well as the periodicity in the occurrence of seismic events and the high similarity of their waveforms, may indicate manifestation of stick-slip motion of the glacier along the bed in the preparation for large-scale movement.