Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

502 PATA Days 2024 M E T H O D S During a first fieldwork campaign, high-resolution subbottom profiles (Geopulse pinger; 3.5 kHz) and short sediment cores (~1-2 m long) were collected in Lago Rupanco (Fig. 2). Detailed analysis of these data allowed identifying the most suitable target locations to obtain a long paleoseismic shaking record. For this purpose, long sediment cores were retrieved in November 2023 from the lake’s southern subbasin using a UWITEC coring platform (Fig. 2). The first site comprises an 8 m record (with a 20 cm stratigraphic gap at a depth of 6 m), while the second site completely covers the upper 12 m of sedimentation. Seismic profiles are analysed using the S&P Global Kingdom software version 2022. All sediment cores were CT scanned at the Ghent University Hospital (Siemens; SOMATOM Definition Flash; Siemens AG) and subsequently split and scanned at the Austrian Core Facility to determine the magnetic susceptibility, P-wave velocity and gamma density (Geotek MSCL), as well as the geochemical composition (Itrax-XRF, CS- 45). To establish an age-depth model for each core, organic macroremains, supplemented by bulk material, are prepared for 14C analysis at the ETH Zürich radiocarbon lab (Switzerland). Additionally, short-lived radionuclides (210Pb and 137Cs) are analysed at the Laboratoire Souterrain de Modane (France) to determine sedimentation rates in the upper part of the cores and identify the 1960 turbidite with certainty. Selected tephra samples are analysed for their major element composition using a JEOL JXA-iSP100 Electron Probe Microanalyzer at the University of Innsbruck (Austria). This allows linking them to known volcanic eruptions in the area (Fontijn et al., 2016), thus providing additional age constraints. Moreover, these tephra deposits also serve as regional markers that can help improving inter-record correlations and thus providing an opportunity to attribute earthquake deposits in different locations to the same event with higher confidence levels. Fig. 2: Map of Lago Rupanco, showing the location of all the subbottom profiles and short sediment cores that have been acquired, as well as those of the long cores retrieved in November 2023 in the southern subbasin. Bathymetric map (contour lines every 50 m) results from gridding of lake-bottom horizon picks on the seismic profiles. The sediment cores (1004-1, 1004-16 and long core site 2) and seismic profile (rup02_6) shown in Fig. 3 are highlighted.