Geomorphological evidence of paleoseismicity: Surficial and underground structures of Pasmajärvi postglacial fault

Abstract The cyclic nature of glaciations and related postglacial faulting represents a risk for the deep geological disposal of spent nuclear fuel in areas likely to be affected by future glaciations. Seismic history was therefore studied by means of detecting geomorphological structures on airborn...

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Published in:Earth Surface Processes and Landforms
Main Authors: Markovaara‐Koivisto, Mira, Ojala, Antti E.K., Mattila, Jussi, Kukkonen, Ilmo, Aro, Ilkka, Pullinen, Arto, Hänninen, Pekka, Middleton, Maarit, Sutinen, Aleksi, Majaniemi, Juha, Ruskeeniemi, Timo, Sutinen, Raimo
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2020
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Online Access:http://dx.doi.org/10.1002/esp.4948
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Summary:Abstract The cyclic nature of glaciations and related postglacial faulting represents a risk for the deep geological disposal of spent nuclear fuel in areas likely to be affected by future glaciations. Seismic history was therefore studied by means of detecting geomorphological structures on airborne laser scanning digital elevation models and underground by excavating in an esker and trenching across a postglacial fault located in northern Fennoscandia. OLS dating and assessing the geomorphological structures was used for timing of the seismic history. The results suggest that the faulting of different segments in the Pasmajärvi complex is due to at least two late Weichselian events, which probably occurred both subglacially and postglacially. The most reliable input for the moment magnitude estimates was vertical slip profiles, and therefore these estimates (M W ≈ 6.4–6.9) are suggested. © 2020 John Wiley & Sons, Ltd.