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

484 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 Paleoseismology, Liquiñe-Ofqui Fault System (LOFS), 2007 Aysén Earthquake Sequence (2007-AYSS), Seismic Profiling, Landslide Deposits. (1) Roy M. Huffington Department of Earth Sciences, Southern Methodist University. Dallas TX, USA. (2) Departamento de Geología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile (3) School of Engineering and Natural Sciences, University of Iceland *Email: avillalobosclaramunt@smu.edu / geaston@uchile.cl Angelo Villalobos (1,2) Gabriel Easton (2)* Gregory De Pascale (3) PALEOSEISMIC EVIDENCE OF ACTIVE FAULTING AND LANDSLIDE EVENTS IN LIQUIÑE-OFQUI FAULT SYSTEM: INSIGHTS FROM THE 2007 AYSÉN EARTHQUAKE SEQUENCE A B S T R A C T Research on the Aysén Fjord in southern Chile, near a trench- ridge-trench triple junction, highlights significant tectonic activity along the Liquiñe-Ofqui Fault System (LOFS). The 2007 Aysén Earthquake Sequence (2007-AYSS), culminating in an Mw 6.2 event, revealed seismic hazards in the region. Villalobos et al. (2020) utilized local seismic data and profiling to analyze fault behavior, focusing on the Punta Cola, Río Cuervo, and Quitralco faults. Findings indicate that seismic activity originated at approximately 8 km depth and migrated through various fault structures. Pre- 2007 landslide deposits linked to significant ground shaking were identified, with the Punta Cola Fault rupturing the seafloor, while the Río Cuervo and Quitralco faults exhibited earlier deformation. These results suggest stress transfer from the ductile lower crust to the brittle upper crust due to the nearby triple junction. The recurrence of strong ground motions emphasizes the need for ongoing seismic hazard assessment of the Río Cuervo and Quitralco faults. I N T R O D U C T I O N Identifying fault geometry and historical seismic events is crucial for understanding seismic cycles and hazards, especially in areas with limitedhistorical data (e.g.,Healyet al., 2004).While surface ruptures on land are easily recognized, marine faults present challenges due to the absence of visible geomorphology. Geophysical tools such as multibeam bathymetry and seismic profiling are vital for identifying active fault segments and slip rates (e.g., Barnes, 2009). Fjords, with rapid sedimentation and long depositional histories, serve as excellent sites to study submarine faulting through seismic records (Atwater et al., 2014; Wils et al., 2018).