GEO-STATE Tyrol: Groundbreaking Evidence of Postglacial Seismotectonic Activity in the Achen Valley, Tyrol?

Funded by the Tiroler Wissenschaftsförderung (TWF) ( 2020 - 2022)

PI:  Patrick Oswald

Collaborators: Dr. Jasper Moernaut;  Univ.-Prof. Dr. Michael Strasser 

Large earthquakes in intra-plate regions such as Central Tyrol typically have recurrence intervals which are much longer than the period of seismological or historical observations. Lacustrine paleoseismology uses the imprint of strong earthquake shaking in lacustrine sedimentary sequences to drastically extend our observational record of earthquake recurrence from a few centuries to thousands of years. Preliminary interpretation of new extensive geophysical data form Lake Achensee allows formulating the hypothesis that the sedimentary infill records both primary direct evidence for earthquake surface rupture produced by an active seismotectonic fault and secondary off-fault lacustrine paleoseismic evidences. This study aims to conduct a multidisciplinary amphibious investigation to examine the potential on-fault and off-fault paleoseismic evidences to test the hypothesis of recently active seismotectonic faulting in the Achensee Valley (Tyrol). The objectives are to systematically map occurrence, geometry, orientation and stratigraphic position of mass-movement and off-set stratigraphy features in terrestrial and lacustrine geophysical data and groundthruth them by structural field mapping and long coring, respectively. This is expected to allows testing above mentioned hypothesis and, furthermore, will conduct the first detailed geophysical and geological investigation (including retrieval and dating of longcore taken for the first time in Achensee) revealing unprecedented insights into the past geological and environmental development of the Achensee area.