Seismic Analysis of a Pingo, Svalbard Islands, Arctic

Climate warming and permafrost thawing would allow the release into the atmosphere of any greenhouse gasses trapped beneath. Knowledge of the fluids (water or gases) present within and beneath the permafrost allows evaluation of the impact of atmospheric release upon thawing. The Italian National Polar Research Program (PNRA) project IMPERVIA - Integrated Methods to study PERmafrost characteristics and Variations In an Arctic natural laboratory (Svalbard) wants to combine exploration geophysical tools (2D and 3D) to image and characterize the ice-bound permafrost and the aquifer architecture. Such information can be of use to state ice-bound permafrost capability of acting as additional cap-rock to future injected CO2. The project is led by OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Italy), in collaboration with CIPR (Centre for Petroleum Research Bergen University, Norway), UNIS (University Centre in Svalbard, Norway), and the Department of Geosciences, University of Padua, Italy.The seismic test allowed to state that while fire-crackers have a better penetration in respect to sledge hammer and Seisgun, at shorter offsets the Seisgun can be a faster option while providing a broader frequency band. The preliminary results of surface data analysis confirm the suitability of the weight drop in providing enough low frequencies. The tomographic approach revealed successful in imaging the velocity field in depth, overcoming the difficulties of high lateral velocity variations and inversions, thanks to the joint inversion of both reflected and refracted (if any) arrivals. The preliminary results are in agreement with the presence of a high velocity body below the pingo’s apex and extending in depth in NW-direction, possibly bound to the presence of massive ice.