LOS GRANDES DESLIZAMIENTOS (VOLCÁNICOS Y NO VOLCÁNICOS) DE TIPO <i>DEBRIS AVALANCHE</i> EN COSTA RICA

Abstract

A series of large and complex landslides of the debris avalanche type (1.5-23.5 km long, 3-127km2, 0.1-8.2 km3), have been identified in Costa Rica. They are associated inland, with large volcanoes (Cacao,Rincón de la Vieja, Miravalles, Tenorio and Turrialba), or smaller in old volcanic and sedimentary ranges (i.e.,Costeña Range), as well as colossal ones in the bottom of the Pacific Ocean (22 km long, 1100 km2, >500 km3).At volcanoes, these deposits have ages ranging between 0.2 Ma and 9000 years. The Arancibia landslide in 2000was an event of this type, in an inactive volcanic zone (Tilarán Range). It is speculated that an event of this kindcould happen every 500-2000 years. The unstable slopes offshore in front of the Pacific coast are prone areasfor the generation of tsunamis triggered by large submarine slides.