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

186 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 archaeoseismology, historical earthquake, co-seismic damage, Colca, Andes (1) Institute of Earth Sciences, University of Silesia in Katowice, Sosnowiec, Poland. (2) Information Technology Office, National University of Saint Augustine, Arequipa, Peru. (3) Instituto Geológico Minero y Metalúrgico (INGEMMET), Lima, Peru. (4) Eötvös Loránd University, Budapest, Hungary. *Email: krzysztof.gaidzik@us.edu.pl, andrzej.tyc@us.edu.pl, justyna.ciesielczuk@us.edu.pl / mel@unsa.edu.pe / cbenavente@ingemmet.gob.pe / mkazmer@gmail.com Krzysztof Gaidzik (1) Andrzej Tyc (1) Justyna Ciesielczuk (1) Melvin Benavente (2) Carlos Benavente (3) Miklós Kázmér (4) UNRAVELING REPEATED ABANDONMENT AND NEW SETTLEMENTS IN THE UPPER COLCA REGION (PERU) – ARCHAEOSEISMOLOGICAL STUDY A B S T R A C T The Colca Region in southern Peru, situated above the Nazca subduction, showcases a mosaic of settlement with histories spanning pre-Inca times, Inca rule, and the 16th-century Spanish conquest. Archaeoseismological evidence reveals that some settlements might have been abandoned due to local shallow earthquakes, rather than wars or Spanish interventions. Notably, the Upper Colca Region witnessed three relocations of communities over three centuries, with structures exhibiting seismic-induced deformations. Malata, a Pre-Inca settlement, shows no seismic evidence, while the Spanish constructions in Laiqa Laiqa and Mawchu Llacta display tilted and torn walls, exaggerated buttresses, U-shaped collapses, and extensional fractures. The rapid abandonment of Laiqa Laiqa suggests earthquake-induced destruction, and the "bad conditions" in Mawchu Llacta may result from repeated seismic events amplified by the site conditions. This aligns with current seismic activity, evident in earthquake instrumental catalogs and deformations observed in churches, supporting the hypothesis that earthquakes influenced historical relocations and abandonment. I N T R O D U C T I O N The Colca Region in southern Peru is characterized by high seismic activity related to both (1) repeated large and great megathrust earthquakes related to the subduction of the Nazca