Fig. 1. Large rockslides^19,35–38, historical severe earthquakes and the investigated lakes in the Eastern Alps.

a Study area comprises large rockslides (>25 × 106 m³) clustering in space and time affecting different geological units (Austroalpine basement, Northern Calcareous Alps), historical earthquakes M_L 4.6–5.3 and location of the investigated lakes Piburgersee and Plansee. Major reverse and strike-slip faults⁵³ subdivide tectonic units or unit-internal nappes. Dashed line shows location of the Piburgersee-Plansee transect of Fig. 4. b Lake Piburgersee bathymetry and coring site of Fig. 2. Blue lines indicate the in- and outflow. c Lake Plansee bathymetry including seismic profile and coring location of Fig. 3 in the central basin. Contour distance is 20 m. Blue lines with arrows indicate main in- and outflows. Onshore digital elevation models are derived from Copernicus Land Monitoring Services and Land Tirol—data.tirol.gv.at.