Integration of InSAR and ground-based geophysical measurements to study an area prone to quick-clay landslide in Sweden

• Main Authors: Malehmir, Alireza, Darvishi, Mehdi, Nilfouroushan, Faramarz
• Format: Conference Object
• Language: English
• Published: Högskolan i Gävle, Samhällsbyggnad 2021
• Subjects: InSAR; Sweden; deformation; clay; Geosciences; Multidisciplinary; Multidisciplinär geovetenskap; Norway; Ice Sheet
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-35210

Landslides and floods are the two most important geohazards in Sweden. Due to the climate change effects, it is believed that the risk of occurring these geohazards will increase in Sweden causing for example the land to become more prone to landslides. Additionally, due to the isostatic uplift caused by the retreating of the ice sheet, approximately 10,000 years ago, marine sediments involving marine clays have become exposed above sea level in Scandinavia. Infiltration of fresh water has (and is) leached the salt from the pores within the marine clays leading to the formation a special kind of clay known as the quick clay in the northern countries. These glacial clays and postglacial silts cause more ground surface instability and slopes become more prone to trigger landslides, which is the case for concentration of the most landslides in the southwest of Sweden. Hence, quick-clay landslides are common geohazards in Nordic countries, which potentially could cause a considerable economical and live cost. The most recent Gjerdurm landslide in Norway was of this kind quick-clay related. In recent years, an area close to the Göta River of southeast of Sweden has been the subject of numerous surface and airborne geophysical surveys for detailed subsurface mapping and delineation of the quick-clay and sediments hosting them including the very undulating the crystalline bedrock. These existing studies including access to bore hole observations and geotechnical studies motivated us to study also long-term surface deformation in order to study climate effects, erosion, precipitation and underlying quick-clay presence in this area and neighboring regions. We employed radar data with Syntenic Aperture Radar (SAR) interferometry techniques. To this end, Sentinel-1 data from 2015 to 2019 were processed with the Small BAslineSubset (SBAS) technique to estimate time-series displacements and to generate deformation map for that region. The initial results show that the heterogenous deformation observed in the study area with ...