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This map is preliminary and has not been reviewed for conformity with U.S.Geological Survey editorial standards or with the North AmericanStratigraphic Code. Any use of trade, product, or firm names is fordescriptive purposes only and does not imply endorsement by the U.S.Government.

2001

Base maps from Nicaragua 1:50,000 scale series; Masaya quadrangle, 1972(2951 I); Nandaime quadrangle, 1972 (2951 II); Isla Zapatera quadrangle,1972 (3051 III); Granada quadrangle, 1972 (3051 IV);from best available source;Digital Bases Maps from Titan Averstar, Inc. Universal Transverse Mercatorprojection, Zone 16, Horizontal Datum North American 1927, Vertical Datum MeanSea Level, Spheroid Clarke 1866.

Location Map

Nicaragua

Lahar Hazards for Mombacho Volcano, Nicaragua

J.W. Vallance, S.P. Schilling, and G. Devoli

NOTE: Although the map shows sharp boundaries for hazard zones, thedegree of hazard does not change abruptly at these boundaries. Rather,the hazard decreases gradually as distance from the volcano increases(small volume events are more common than large volume events). Thehazard decreases rapidly as elevation above the valley floor increases.Areas immediately beyond outer hazard zones should not be regarded ashazard-free, because the boundaries of hazard zones can be located onlyapproximately, especially in areas of low relief. Many uncertaintiesabout the source, size, and mobility of future events preclude locatingthe boundaries of zero-hazard zones precisely.

Numerals in brackets refer to end notes in the report.

Area that could be inundated by a lahar having a volume of 1 millioncubic meters. Highest probability.

Area that could be inundated by a lahar having a volume of 2 millioncubic meters.

Area that could be inundated by a lahar having a volume of 4 millioncubic meters.

Area that could be inundated by a lahar having a volume of 8 millioncubic meters. Lowest probability.

Channels that head on Mombacho volcano are subject to lahars generatedby landslides, debris avalanches, torrential rains, and earthquakes.Distal hazard zones are subdivided into four zones on the basis of arange of hypothetical lahar volumes [3].

Areas now underlain by deposits of debris avalanches.

Nandaime

Diriomo

Diria

Granada

El Diamante

El Encunto

La Calera

LasDelicias

Mecatepe

Santa Rosa

LasPlazuelas

Heroes De Pancasan

PedroAranz Palacio

Santa Isabel

San Jose Del Mombacho

Pancasan

Las Colinas