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

500 1 2 T H I N T E R N AT I O N A L I N Q U A M E E T I N G O N PA L E O S E I S M O L O G Y , A C T I V E T E C T O N I C S A N D A R C H A E O S E I S M O L O G Y ( PATA ) , O C T O B E R 6 T H - 1 1 T H , 2 0 2 4 , L O S A N D E S , C H I L E PATA Days 2024 K E Y W O R D S sedimentology, lake, paleoseismology, megathrust, Chile Katleen Wils (1,2) Markus Niederstätter (1) Valentina Moreno Allende (1) Maarten Van Daele (2) Jürgen Konzett (3) Ariana Molenaar (1) Jean Nicolas Haas (4) Olivier Evrard (5) Karen Fontijn (3) Daniel Melnick (7) Roberto Urrutia (8) Mario Pino (7) Marc De Batist (2) Jasper Moernaut (1) (1) Institute of Geology, University of Innsbruck, Innsbruck, Austria. (2) Renard Centre of Marine Geology, Department of Geology, Ghent University, Ghent, Belgium. (3) Institute of Mineralogy and Petrography, University of Innsbruck, Innsbruck, Austria. (4) Department of Botany, University of Innsbruck, Innsbruck, Austria. (5) Laboratoire des Sciences du Climat et de l’Environnement (LSCE-IPSL), Université Paris-Saclay, Gif-sur-Yvette, France (6) Laboratoire G-TIME, Department of Geosciences, Environment and Society Université Libre de Bruxelles, Brussels, Belgium. (7) Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, Chile. (8) Faculty of Environmental Sciences, University of Concepción, Concepción, Chile. *Email: Katleen.Wils@UGent.be A LONG LACUSTRINE SEDIMENTARY RECORD OF 1960-LIKE EARTHQUAKES IN SOUTH-CENTRAL CHILE A B S T R A C T In 1960, the Valdivia segment of the Chilean subduction zone hosted the largest earthquake that has ever been instrumentally recorded (Mw 9.5). Paleoseismic studies have revealed that such a 1,000 km long full-segment rupture was not unique in the region and occurs on average once every ~300 years. This recurrence rate is, however, only validated for the last two millennia, mostly due to a lack of sufficient longer earthquake records. In this study, we accommodate this knowledge gap by presenting preliminary results from a newly obtained long lacustrine sedimentary shaking record from Lago Rupanco, likely covering the last ~6-8,000 years. In this way, we aim to extend the timeframe of existing inferences on the recurrence of 1960-like events, thus allowing for more statistically valid hazard assessments. I N T R O D U C T I O N Giant earthquakes are not uncommon along the Chilean subduction, with the 2010 Maule (Mw 8.8) and 1960 Valdivia (Mw 9.5) as the most notorious recent examples. It is therefore not unsurprising that many research efforts have been made to understand the recurrence times of these high-magnitude events, ultimately aiming at mitigating the risk of future earthquakes in the