[A-HW17] Near Surface Investigation and Modeling for Groundwater Resources Assessment and Conservation

[AHW17-P03] Imaging the Changes of the Active Zone in Arctic Permafrost in Kaffiorya Area of Svalbard, with Borehole Measurements and Electrical Resistivity Methods

*CHANG PINGYU^1,2,3、Ying-Long Chen¹、Ding-Jiun Lin¹、Chuen-Fa Ni^2,5、Slawomir Jacek Giletycz¹、 Ireneusz Sobota⁴、Jordi Mahardika Puntu¹ (1.Department of Earth Sciences, National Central University , Jhong-li, Taiwan.、2.Earthquake Disaster & Risk Evaluation and Management Center (E-DREaM), National Central University, Jhong-li, Taiwan.、3.Center for Astronautical Physics and Engineering(CAPE), National Central University, Jhong-li, Taiwan.、4.Department of Hydrology and Water Management, Nicolaus Copernicus University, Poland.、5.Graduate Institute of Applied Geology, National Central University, Jhong-li, Taiwan.)

キーワード：Electrical Resistivity Imaging, Permafrost, Acive Zone, Global warming

This study, conducted near NCU’s Kaffiorya Polar Research Station on Spitsbergen Island in the Svalbard archipelago, utilized electrical resistivity imaging (ERI) to investigate subsurface characteristics. Surveys along two lines, LN (148 meters) collected in 2022 and 2023 and ST (40 meters) collected in 2023, were employed to assess resistivity and its correlation with temperatures. The LN line revealed a 1 to 2 meters thick resistive unsaturated outwash sediment layer, possibly indicative of permafrost. The difference between LN resistivity profiles in 2022 and 2023 showed a 600 Ohm-m decrease in the unsaturated active layer in 2023, attributed to a 5.8℃ temperature increase, suggesting a link to global warming. The ERI image along the ST line showed resistivity reaching its minimum at approximately 1.6 meters, rising to over 200 Ohm-m at 4 meters, and slightly decreasing to around 150 Ohm-m at 7 meters. Temperature measurements from the ST line's monitoring well confirmed permafrost at a depth of 1.6 to 2 meters. We also attempted to estimate water content distribution in the ST line after temperature correction. The results revealed a groundwater table depth of approximately 1.06 meters, consistent with measurements from the S4 borehole on the ST line. This study provides valuable insights into Arctic subsurface dynamics, highlighting the sensitivity of resistivity patterns to climate change and offering a comprehensive understanding of permafrost behavior in the region.