Magnetotelluric investigation on Björkö impact structure, west of Stockholm, Sweden
2016 (English)In: Arabian Journal of Geosciences, ISSN 1866-7511, E-ISSN 1866-7538, Vol. 9, no 13, 618Article in journal (Refereed) Published
This paper describes the application of magnetotelluric (MT) method to investigate Bjorko impact structure located at west of Stockholm, Sweden. This structure has formed in crystalline rocks ca. 1.2 Ga ago and located relatively close to the district heating infrastructure of the Stockholm region, as the largest district heating system in Europe. Since impact structures mostly contain fractured rock volumes in the form of breccia formations, the occurred brecciation zones in this region are more favorable potential targets for geothermal investigations. The main objective is evaluating the capability of the study area to have potential for geothermal resources by mapping the subsurface structure. To image electrical characteristic of underground layers, 1D and 2D bimodal inversions of TE and TM modes of MT data are performed. The results are also compared with the outputs of the inversion of the determinant data (yielding a direction independent average of the subsurface conductivity) along the same profiles, proving good accordance of the outputs. The processed resistivity sections at depth along with measuring various rock physical properties across two drilled boreholes at Bjorko and Midsommar islands localized two conductors at depths of 1 km and from 2.5 to 4.5 km, which may be attributed to be a potential zone for geothermal energy retrieval.
Place, publisher, year, edition, pages
2016. Vol. 9, no 13, 618
Geothermal field, Magnetotelluric, 1D and 2D inversion, Resistivity, Bjorko impact structure
IdentifiersURN: urn:nbn:se:uu:diva-307754DOI: 10.1007/s12517-016-2653-xISI: 000384319000009OAI: oai:DiVA.org:uu-307754DiVA: diva2:1048348