Linking Andean paleo-landslides to the probable triggering seismic source (31°–33°S).

MOREIRAS, S.M.; JUNQUERA TORRADO, S.; RODRGUEZ PECES, M.; SEPULVEDA, S.A.

Congreso; INQUA; 2023

Landslides are maybe the most striking seismic environmental effect which impact scales with earthquake magnitude. However, the determination of the seismic source of paleolandslides is not fully understood, being a matter of discussion. In seismically active mountain regions, large-volume landslides clustered along active faults are assumed to be coseismic. Thus, shallow crustal earthquakes from nearby active faults assumed as the most likely source of slope collapses. To investigate this hypothesis, several prehistoric landslides in the Arid Central Andes were geomorphological, geological, and geotechnical studies. Newmark-type, limit equilibrium, and numerical modeling back-analyses methodology were also conducted. This methodology allowed us to identify the potential sources of earthquakes that may have induced the studied gravitational process. Moreover, the chronology obtained for some of these landslides disallows a probable climate forcing on slope instability in this arid region and our finding extends the regional neotectonics until the Late Pleistocene.