Report on Mombacho (Nicaragua) — November 1994
Bulletin of the Global Volcanism Network, vol. 19, no. 11 (November 1994)
Managing Editor: Richard Wunderman.
Mombacho (Nicaragua) Venting continues from fumarole in south crater; two other fumarole areas located
Please cite this report as:
Global Volcanism Program, 1994. Report on Mombacho (Nicaragua) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 19:11. Smithsonian Institution.
11.826°N, 85.968°W; summit elev. 1344 m
All times are local (unless otherwise noted)
The fumarole that has been active since at least 1986 continued to vent vapor in November and December 1993. A strong sulfur odor was detected even when the wind was blowing towards the fumarole. This observation led to the discovery of two other previously unreported fumarole fields (figure 1). Vapor was seen rising from both, but they were not approached closely; neither appeared to be a new feature.
|Figure 1. Map of the Mombacho summit area, showing locations of reported and previously unreported fumarole areas. Courtesy of B. van Wyk de Vries and P. Hernandez.|
Geological Summary. Mombacho is an andesitic and basaltic stratovolcano on the shores of Lake Nicaragua south of the city of Granada that has undergone edifice collapse on several occasions. Two large horseshoe-shaped craters formed by edifice failure cut the summit on the NE and S flanks. The NE-flank scarp was the source of a large debris avalanche that produced an arcuate peninsula and a cluster of small islands (Las Isletas) in Lake Nicaragua. Two small, well-preserved cinder cones are located on the volcano's lower N flank. The only reported historical activity was in 1570, when a debris avalanche destroyed a village on the south side of the volcano. Although there were contemporary reports of an explosion, there is no direct evidence that the avalanche was accompanied by an eruption. Fumarolic fields and hot springs are found within the two collapse scarps and on the upper N flank.
Information Contacts: B. van Wyk de Vries, Open Univ; Pedro Hernandez, INETER.