Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation
Glacially induced intraplate faults are conspicuous in Fennoscandia where they reach trace lengths of up to 155 km with estimated magnitudes up to 8 for the associated earthquakes. While they are typically found in northern parts of Fennoscandia, there are a number of published accounts claiming the...
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ftdoajarticles:oai:doaj.org/article:abadab3b042a4110b8d32d8fdd751b91 2023-05-15T16:11:53+02:00 Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation A. Malehmir M. Andersson S. Mehta B. Brodic R. Munier J. Place G. Maries C. Smith J. Kamm M. Bastani H. Mikko B. Lund 2016-04-01T00:00:00Z https://doi.org/10.5194/se-7-509-2016 https://doaj.org/article/abadab3b042a4110b8d32d8fdd751b91 EN eng Copernicus Publications http://www.solid-earth.net/7/509/2016/se-7-509-2016.pdf https://doaj.org/toc/1869-9510 https://doaj.org/toc/1869-9529 1869-9510 1869-9529 doi:10.5194/se-7-509-2016 https://doaj.org/article/abadab3b042a4110b8d32d8fdd751b91 Solid Earth, Vol 7, Iss 2, Pp 509-527 (2016) Geology QE1-996.5 Stratigraphy QE640-699 article 2016 ftdoajarticles https://doi.org/10.5194/se-7-509-2016 2022-12-31T06:09:57Z Glacially induced intraplate faults are conspicuous in Fennoscandia where they reach trace lengths of up to 155 km with estimated magnitudes up to 8 for the associated earthquakes. While they are typically found in northern parts of Fennoscandia, there are a number of published accounts claiming their existence further south and even in northern central Europe. This study focuses on a prominent scarp discovered recently in lidar (light detection and ranging) imagery hypothesized to be from a post-glacial fault and located about 250 km north of Stockholm near the town of Bollnäs. The Bollnäs scarp strikes approximately north–south for about 12 km. The maximum vertical offset in the sediments across the scarp is 4–5 m with the western block being elevated relative to the eastern block. To investigate potential displacement in the bedrock and identify structures in it that are related to the scarp, we conducted a multidisciplinary geophysical investigation that included gravity and magnetic measurements, high-resolution seismics, radio-magnetotellurics (RMT), electrical resistivity tomography (ERT) and ground-penetrating radar (GPR). Results of the investigations suggest a zone of low-velocity and high-conductivity in the bedrock associated with a magnetic lineament that is offset horizontally about 50 m to the west of the scarp. The top of the bedrock is found ∼ 10 m below the surface on the eastern side of the scarp and about ∼ 20 m below on its western side. This difference is due to the different thicknesses of the overlying sediments accounting for the surface topography, while the bedrock surface is likely to be more or less at the same topographic level on both sides of the scarp; else the difference is not resolvable by the methods used. To explain the difference in the sediment covers, we suggest that the Bollnäs scarp is associated with an earlier deformation zone, within a wide (> 150 m), highly fractured, water-bearing zone that became active as a reverse fault after the latest Weichselian ... Article in Journal/Newspaper Fennoscandia Directory of Open Access Journals: DOAJ Articles Solid Earth 7 2 509 527 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Geology QE1-996.5 Stratigraphy QE640-699 |
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Geology QE1-996.5 Stratigraphy QE640-699 A. Malehmir M. Andersson S. Mehta B. Brodic R. Munier J. Place G. Maries C. Smith J. Kamm M. Bastani H. Mikko B. Lund Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation |
topic_facet |
Geology QE1-996.5 Stratigraphy QE640-699 |
description |
Glacially induced intraplate faults are conspicuous in Fennoscandia where they reach trace lengths of up to 155 km with estimated magnitudes up to 8 for the associated earthquakes. While they are typically found in northern parts of Fennoscandia, there are a number of published accounts claiming their existence further south and even in northern central Europe. This study focuses on a prominent scarp discovered recently in lidar (light detection and ranging) imagery hypothesized to be from a post-glacial fault and located about 250 km north of Stockholm near the town of Bollnäs. The Bollnäs scarp strikes approximately north–south for about 12 km. The maximum vertical offset in the sediments across the scarp is 4–5 m with the western block being elevated relative to the eastern block. To investigate potential displacement in the bedrock and identify structures in it that are related to the scarp, we conducted a multidisciplinary geophysical investigation that included gravity and magnetic measurements, high-resolution seismics, radio-magnetotellurics (RMT), electrical resistivity tomography (ERT) and ground-penetrating radar (GPR). Results of the investigations suggest a zone of low-velocity and high-conductivity in the bedrock associated with a magnetic lineament that is offset horizontally about 50 m to the west of the scarp. The top of the bedrock is found ∼ 10 m below the surface on the eastern side of the scarp and about ∼ 20 m below on its western side. This difference is due to the different thicknesses of the overlying sediments accounting for the surface topography, while the bedrock surface is likely to be more or less at the same topographic level on both sides of the scarp; else the difference is not resolvable by the methods used. To explain the difference in the sediment covers, we suggest that the Bollnäs scarp is associated with an earlier deformation zone, within a wide (> 150 m), highly fractured, water-bearing zone that became active as a reverse fault after the latest Weichselian ... |
format |
Article in Journal/Newspaper |
author |
A. Malehmir M. Andersson S. Mehta B. Brodic R. Munier J. Place G. Maries C. Smith J. Kamm M. Bastani H. Mikko B. Lund |
author_facet |
A. Malehmir M. Andersson S. Mehta B. Brodic R. Munier J. Place G. Maries C. Smith J. Kamm M. Bastani H. Mikko B. Lund |
author_sort |
A. Malehmir |
title |
Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation |
title_short |
Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation |
title_full |
Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation |
title_fullStr |
Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation |
title_full_unstemmed |
Post-glacial reactivation of the Bollnäs fault, central Sweden – a multidisciplinary geophysical investigation |
title_sort |
post-glacial reactivation of the bollnäs fault, central sweden – a multidisciplinary geophysical investigation |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/se-7-509-2016 https://doaj.org/article/abadab3b042a4110b8d32d8fdd751b91 |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_source |
Solid Earth, Vol 7, Iss 2, Pp 509-527 (2016) |
op_relation |
http://www.solid-earth.net/7/509/2016/se-7-509-2016.pdf https://doaj.org/toc/1869-9510 https://doaj.org/toc/1869-9529 1869-9510 1869-9529 doi:10.5194/se-7-509-2016 https://doaj.org/article/abadab3b042a4110b8d32d8fdd751b91 |
op_doi |
https://doi.org/10.5194/se-7-509-2016 |
container_title |
Solid Earth |
container_volume |
7 |
container_issue |
2 |
container_start_page |
509 |
op_container_end_page |
527 |
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1765997079910416384 |