Earthquake-induced landslides in Central America

Central America is a region of high seismic activity and the impact of destructive earthquakes is often aggravated by the triggering of landslides. Data are presented for earthquake-triggered landslides in the region and their characteristics are compared with global relationships between the area of landsliding and earthquake magnitude. We find that the areas affected by landslides are similar to other parts of the world but in certain parts of Central America, the numbers of slides are disproportionate for the size of the earthquakes. We also find that there are important differences between the characteristics of landslides in different parts of the Central American isthmus, soil falls and slides in steep slopes in volcanic soils predominate in Guatemala and El Salvador, whereas extensive translational slides in lateritic soils on large slopes are the principal hazard in Costa Rica and Panama. Methods for assessing landslide hazards, considering both rainfall and earthquakes as triggering mechanisms, developed in Costa Rica appear not to be suitable for direct application in the northern countries of the isthmus, for which modified approaches are required.