Reprocessing of ERT data from Åknes, Stranda Municipality, Møre and Romsdal County

Abstract

NGU performed consecutive geophysical investigations in the Åknes area from 2004 until 2007 in connection with the Åknes\/Tafjord project. These investigations consisted of 10 km of ERT profiling distributed in 10 profiles, 8 km of georadar profiling distributed in 10 profiles and 1.8 km refraction seismic profiling distributed in 4 profiles. All results were presented in NGU reports (Rønning et al. 2006; Rønning et al. 2007), interpretations were made on these results and conclusions were drawn regarding the extent of unstable bedrock in the area. Processing of resistivity data took place with the Res2DInv software version available at the time (versions 3.54j and 3.55.48) whereas traditional Hagedoorn's plus-minus method was applied on refraction seismic. In this report we focus on the ERT profiling since this method helped determining the dimensions of the unstable masses to 500 x 1200 meters spread and 40-60 meters thickness and gave indications on possible vertical or inclined fracture zones.