HAZARDS MAP OF CONCEPCIÓN VOLCANO (NICARAGUA)

Disasters associated with volcanic eruptions can be mitigated by using hazards maps. Hazards maps are the basic tool to communicate and relatively forecast the possible future behavior of a volcano during an eruptive event. Even though several efforts have been made to construct this kind of maps, every country, institution or research group build maps in different ways and, at present, no single criteria exists for construction of these maps. Experience obtained during construction of hazards maps in Mexico allowed to establish a methodology applicable at any case around the world. This methodology assumes that a hazards map is not a modified geological map, nor an isopach or isopleth map, nor a geomorphological map, but a map that shows the likelihood for the occurrence, distribution and/or range of certain volcanic processes and their related products in a series of possible scenarios tailored for every case volcano. Our methodology implies, compilation of available geological, cartographic, meteorological information and mapping, eruptive records and basic cartography. Basic geological fieldwork is desirable in order to recognize the features found in the geological literature and establish the representative range and distribution for every eruptive magnitude or scenario. Besides, computer simulation is an important part of the process, in order to reproduce past events, establish software parameters and then, create new simulations around the volcanic edifice using the calibrated parameters, according to established scenarios. Following this methodology, the resulting map should be an understandable map by authorities and general public, not only by experts. The logical consequence is a translation of the hazards map into a risk map. We have developed a hazards map for Concepción volcano depicting 6 processes (ballistic projectiles, lava flows, ash falls, pyroclastic flows, laharic processes and sector collapse) with 3 different scenarios. For every process, we use a red color to distinguish the most likely scenario (large hazard, low eruptive magnitude), orange color for intermediate level of hazard and eruptive magnitude, and yellow for the less likely scenario but contradictorily the largest eruptive magnitude.