La lluvia y los deslizamientos de tierra en Antioquia: análisis de su ocurrencia en las escalas interanual, intraanual y diaria

Abstract

Relationship between rain and reported landslides in the department of Antioquia for the period of 1929 to 1999 is studied. The georeference of 405 landslides possibly produced by rain is made, on the region of study. The analysis of the occurrence of landslides during the warm and cold phases of ENSO phenomenon (El Niño Southern Oscillation) and the behavior of the intra-annual cycle are described. La Niña, on interannual scale, and the two rainiest periods in Andean zone, on intra-annual scale, contribute to increase the number of landslides per year. Analysis of precipitation data associated with historical landslide events in Antioquia has resulted in the identification of precipitation thresholds for the initiation of landslides and the possible combinations of preceding accumulated rain are described. The data indicated that the cumulative precipitation (15 days or more) influences the amount of subsequent 3-day precipitation that is needed to initiate ground movement. This study constitutes a first intend toward rain modeling and its influence on landslides occurrence which can help authorities on disasters prevention to declare states of emergency by conditions of threshold exceed. The analysis must be complemented having into account geotechnical, morphological, hydraulics, and anthropogenic conditions own to each place to have an integral view of the landslide phenomenon.