Developing conceptual models for the recognition of coseismic landslides hazard for shallow crustal and megathrust earthquakes in different mountain environments – an example from the Chilean Andes

Abstract

Landslides represent the most frequent geological hazard in mountainous environments. Most notably, landslides are a major source of fatalities and damage related to strong earthquakes. The main aim of this research is to show through three-dimensional engineer-friendly computer drawings, different mountain environments where coseismic landslides could be generated during shallow crustal and megathrust earthquakes in the Andes of central Chile. We have determined topographic, geomorphological, geological and seismic controlling factors in the occurrence of earthquake-triggered landslides from: (1) a comparison of local earthquake-induced landslide inventories in Chile (the M w 6.2, shallow crustal Aysén earthquake in 2007 (45.3° S) and the M w 8.8, megathrust Maule earthquake in 2010 (32.5°S–38.5°S)) with others from abroad; and (2) analysis of large, prehistoric landslide inventories proposed as likely induced by seismic activity. With these results, we have built four representative geomodels of coseismic landslide geomorphological environments in the Andes of central Chile. Each one represents the possible landslide types that could be generated by a shallow crustal earthquake v. those likely to be generated by a megathrust earthquake. Additionally, the associated hazards and suggested mitigation measures are expressed in each scenario. These geomodels are a powerful tool for earthquake-induced landslide hazard assessment. Thematic collection: This article is part of the Ground models in engineering geology and hydrogeology collection available at: https://www.lyellcollection.org/cc/Ground-models-in-engineering-geology-and-hydrogeology