A database of potential paleoseismic evidence in Switzerland

• DOI: 10.1007/s10950-020-09908-5
• Publication Date: 2020-03-02T13:03:08Z
• Authors: Katrina Kremer; Gabriela Gassner-...; Remo Grolimund; Stefanie B. Wirth; Michael Strasser; Donat Fäh
• Keywords: Paleoseismology; Paleoseismological database; Earthquakes; Sublacustrine mass movements; Rockfalls; Soft sediment deformation structures; Tsunami; Liquefaction; 01 natural sciences; 550 Earth sciences & geology; 0105 earth and related environmental sciences

Paleoseismological evidence is indispensable for the identification of large prehistoric earthquakes and the extension of the temporal coverage of historical and instrumental earthquake catalogues. In the geological record, diverse traces of past earthquakes are found. This study presents a database of potential primary and secondary evidence for seismic activity in the past 20,000 years in Switzerland. The database includes data from sedimentological, archaeological, speleological and geomorphological research. This unique dataset allows identifying periods during which the geologic record reveals enhanced occurrence of evidence that are further discussed as potentially earthquake-triggered. For the most recent 700 years, an increased occurrence of evidence features was found. This clustering is an effect of the historical earthquakes. Furthermore, periods with enhanced occurrence are identified at six phases during the past 20,000 years. Even though dating uncertainties for the geological record are large (e.g. 14C calibration range) and an unequivocal attribution of earthquakes as trigger mechanism for secondary evidence is not possible, the database reflects the natural-hazard potential of a region and represents valuable information for seismic hazard assessment. Furthermore, despite the uncertainty regarding the definition of the trigger mechanism, we propose that the database can be used to validate and improve earthquake-hazard models.