Acceleration of Late Pleistocene activity of a Central European fault driven by ice loading

0559743 - ÚSMH 2023 RIV NL eng J - Článek v odborném periodiku
Štěpančíková, Petra - Rockwell, Thomas - Stemberk, Jakub - Rhodes, E.J. - Hartvich, Filip - Luttrell, K. - Myers, M. - Tábořík, Petr - Rood, D.H. - Wechsler, N. - Nývlt, D. - Ortuno, M. - Hók, J.
Acceleration of Late Pleistocene activity of a Central European fault driven by ice loading.
Earth and Planetary Science Letters. Roč. 591, AUG 1 (2022), č. článku 117596. ISSN 0012-821X. E-ISSN 1385-013X
Grant CEP: GA ČR GP205/08/P521; GA MŠMT LH12078; GA ČR GAP210/12/0573
Institucionální podpora: RVO:67985891
Klíčová slova: paleoseismology * intraplate earthquakes * ice-loading * glacially triggered fault * Sudetic Marginal fault * Central Europe
Obor OECD: Geology
Impakt faktor: 5.3, rok: 2022
Způsob publikování: Omezený přístup
https://www.sciencedirect.com/science/article/pii/S0012821X22002321

We studied the southern part of the NW-SE trending Sudetic Marginal fault (SMF), situated at the northeastern limit of the Bohemian Massif in central Europe, to assess its Quaternary activity. Eighteen trenches and thirty-four electric resistivity profiles were performed at Bila Voda to study the fault zone and 3-dimensional distribution of a beheaded alluvial fan on the NE side of the fault. We interpret a small drainage, located about 29-45 m to the SE of the fan apex, as the only plausible source channel implying a similar amount of left-lateral offset. The alluvial fan deposits' radiometric ages range between about 24 and 63 ka, but postglacial deposits younger than 11 ka are not displaced, indicating that all motion occurred in the late Pleistocene. The site lies similar to 150 km south of the late Pleistocene Weichselian maximum (similar to 20 ka) ice sheet front. We model the effects of the ice load on lithospheric flexure and resolved fault stresses, and show that slip on the SMF was promoted by the presence of the ice sheet, resulting in a late Pleistocene slip rate of similar to 1.1(+2.3)/(-0.6) mm/yr. As the most favorable time for glacial loading-induced slip would be during the glacial maximum between about 24 and 12 ka, it is doubtful that the slip rate remained constant during the entire period of activity, and if most slip occurred during this period, the short-term rate may have been even higher. Considering that the modern maximum principal stress (sigma(1)) is oriented nearly parallel to the Sudetic Marginal fault (NNW-SSE) and is thus unfavorable for fault motion, our observations suggest that the likelihood of continued motion and earthquake production is much lower in the absence of an ice sheet.
Trvalý link: https://hdl.handle.net/11104/0333464