The effect of subsurface freezing-thawing in the SW Svalbard on the newly deglaciated areas

Abstract

<p>The rapid climatic changes and their impact in the regions where unique environmental balance is not polluted by human existence are strongly visible. One of those places, exposed to Arctic amplification, is the newly deglaciated areas of Southern Spitsbergen. One of the most important scientific aspects is understanding their response to climate and environmental changes. To do that, an extensive geophysical approach is required integrating results from multiple imaging techniques. To derive spatial information from complex geomorphological terrain, joint interpretation of three non-intrusive geophysical methods were applied: Electrical Resistivity Tomography, Ground Penetrating Radar, and time-lapse Seismic Tomography. These were used to identify subsurface structures in the forefield of the retreating Hansbreen glacier in SW Spitsbergen, Svalbard. As a result, the authors distinguish three main zones, with different responses to the freezing-thawing effect: outwash plain, terminal moraine at the last glacial maximum, and glacial forefield proximal to the glacier front. The obtained data allowed for differentiation between geological and periglacial structures, and seasonally changing effects. The estimation of the impact of the freezing-thawing effect based on the VP velocity change reveals, that changes are deeper than previously believed reaching down to 30 metres of flat terrain and even deeper to 40 metres at the slope area with the strong subsurface flow. The study provides a unique snapshot of the current situation on the forefield of retreating Hansbreen concerning the current climate state.</p><p>This research was funded by National Science Centre, Poland (NCN) Grant UMO-2016/21/B/ST10/02509 and, Poland (NCN) Grant 2020/37/N/ST10/01486.</p>