Evidencias ambientales de cambios de nivel de la costa del Pacífico de México: terremotos y tsunamis

Abstract

The study of prehistoric earthquakes and tsunamis using environmental evidence of coastal level changes, where sudden changes from terrestrial to marine environments, and vice versa, and where tsunami deposits are preserved, has provided valuable information in the earthquake and tsunami hazard assessment. The Pacific coast of Mexico is tectonically active and has experienced numerous large magnitude earthquakes (M > 7.5) in historical times, frequently accompanied by coastal-level changes and tsunamis (> 50 tsunamis recorded since 1732). Using the case study of tropical lagoons and marshes on the Guerrero coast, it is shown the feasibility of recording tectonically induced coastal level changes through the proxy method that integrates geomorphic, stratigraphic, geochemical, microfossil, and radiometric data. The applied method confirms evidence for environmental changes indicative of coastal subsidence and a potential great earthquake and tsunami by ca. 3400-3500 yr BP. In general, most of the Holocene relative sea-level changes observed obscure any climatic signal in this period on the Mexican Pacific coast