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

416 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 tsunami deposits, earthquakes, subduction, Guerrero seismic gap (1) Laboratorio de Tsunamis y Paleosismología, Instituto de Geografía, Universidad Nacional Autónoma de México, Ciudad de México, México. (2) COLMICH, Centro de Estudios de Geografía Humana, La Piedad, Michoacán, México (3) Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Freiberg, Germany. (4) Institute of Earth Sciences, University of Silesia, Katowice, Sosnowiec, Poland (5) International Research Institute of Disaster Science, Tohoku University, Tohoku, Japan (6) Department of Geosciences, Baylor University, Waco, Texas, USA (7) Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad de México, México. (8) Instituto de Geofísica, Unidad Morelia, Universidad Nacional Autónoma de México, Ciudad de México, México. *Email: tramirez@geografia.unam.mx M a Teresa Ramírez-Herrera (1) Nestor Corona (2) Jan Cerny (1,3) Krzysztof Gaidzik (4) Daisuke Sugawara (5) Steven L. Forman (6) M a Luisa Machain-Castillo (7) Avto Gogichaishvili (8) REVEALING THE POTENTIAL FOR HIGH-MAGNITUDE EARTHQUAKES : TSUNAMI DEPOSITS AS INDICATORS IN THE GUERRERO SEISMIC GAP, MEXICO A B S T R A C T Globally, the most powerful tsunamigenic earthquakes have occurred in subduction zones. Catastrophic events surpassing magnitude 9, like those witnessed in Chile, Sumatra, and Japan, occurred in areas lacking instrumental records of similar occurrences. Although the 1000-kilometer-long Mexican subduction zone has not experienced such events, historical and geological data hint at the likelihood of a magnitude 8.6 tsunamigenic earthquake (Ramirez-Herrera et al., 2020).However, the Guerrero seismic gap has remained devoid of high-magnitude earthquakes for over a century. This study presents findings from comprehensive analyses of sediment grain size, geochemistry, microfossils, magnetic properties, and dating methods along the Guerrero coast. These analyses reveal a 2000-year timeline marked by significant tsunamis triggered by potentially large earthquakes. Numerical simulations corroborate these findings, suggesting an earthquake exceeding magnitude 8 around 1300 in the Guerrero seismic gap. These results emphasize the necessity of evaluating earthquake and tsunami risks through historical data and instrumental observations across subduction zones worldwide.