| Popis: |
Summary Temperatures are rapidly increasing in the Arctic, but the actual impact of surface warming on the degree of freezing of permafrost is uncertain. We conducted active and passive seismic experiments on permafrost in Adventdalen, Svalbard, several times in 2019. Active seismic data can be generated at any given time and have strong signals, but the drawback is the generation of noise during acquisition. Passive seismic acquisition makes little noise and makes it feasible to acquire data over a longer period, but the signal may be weak and vary in strength throughout the year. The resulting seismic data show strong surface waves. High-quality dispersion images can be generated from the active data at any time, and from the passive data whenever frost quakes occur. The dispersion curves from active experiments can be followed to higher frequencies than those from passive experiments, whereas the latter type of data can easier distinguish between different modes. A seasonal time-lapse effect suggests that surface seismic data may be useful for monitoring permafrost degradation, both on a seasonal scale and on a longer-term scale due to climate change. |
