Earthquakes in Switzerland and surrounding regions during 2017 and 2018

A system of sub-parallel strike-slip faults, likely within the uppermost crystalline basement of the eastern Aar Massif, was identified through analysis of the 2017 M L 4.6 Urnerboden earthquake and its aftershocks in Switzerland's Swiss Tectonic Arena Sardona region. The study, published in the Swiss Journal of Geosciences, detected and located 1227 earthquakes in 2017 and 955 in 2018, with the Urnerboden event being the strongest since the M L 5.0 Vaz earthquake of 1991. Focal mechanisms and hypocentre relocations revealed a NNW–SSE striking sinistral strike-slip fault system. Additionally, the research highlighted NE–SW oriented extensional to transtensional deformation along the Alpine Front between Lake Geneva and the Fribourg Fault, as well as rare shallow thrust faulting in the Jura fold-and-thrust belt, indicating contraction in Switzerland's northwestern Alpine foreland.

Diehl, T., Clinton, J., Cauzzi, C., Kraft, T., Kästli, P., Deichmann, N., Massin, F., Grigoli, F., Molinari, I., Bӧse, M., Hobiger, M., Haslinger, F., Fäh, D., & Wiemer, S. (2021). Earthquakes in Switzerland and surrounding regions during 2017 and 2018. Swiss Journal of Geosciences, 114(1). https://doi.org/10.1186/s00015-020-00382-2