Dynamic relief development and geological risks of the San Cristobal and Casita Volcanic Groups, Nicaragua

Abstract

The volcanic San Cristobal group represents above all two stratovolcanoes that formed in the La Pelona caldera and a number of minor volcanoes and volcanic centers. This Group lies on the SW margin of the Nicaraguan depression. The San Cristobal volcano has been active until present. The Casita volcano is not considered to be active, there is, nevertheless, an intensive hydrothermal alteration of lava flows and agglomerates that form it. The surface of the volcano is made up of up to several tens of meters thick polygenetic slope deposits, which become unstable on the clayey weathered underground. In 1998, as a consequence of hurricane Mitch, a catastrophic flash flood annihilated two villages. The area is known not only for its exodynamic hazard but also volcanic and seismic hazards. The development of the San Cristobal Volcanic group is polycyclic and its age is thought to be Plio Pleistocene up to recent.