Report on Momotombo (Nicaragua) — December 1980

Scientific Event Alert Network Bulletin, vol. 5, no. 12 (December 1980)
Managing Editor: David Squires

Momotombo (Nicaragua) Summit crater fumaroles remain hot; night glow from crater

Please cite this report as:

Global Volcanism Program, 1980. Report on Momotombo (Nicaragua). In: Squires, D (ed.), Scientific Event Alert Network Bulletin, 5:12. Smithsonian Institution.

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12.422°N, 86.54°W; summit elev. 1297 m

All times are local (unless otherwise noted)

The summit crater fumaroles remained very hot in late 1980 with temperatures measured up to 735°C and reported to > 900°C. A small vapor plume continued and remote sensing revealed very low rates of SO2 emission. Portions of the crater were seen to glow red and orange when observed at night, with the highest temperatures on the steep S wall of the crater. No seismic activity has occurred recently at Momotombo.

Geologic Background. Momotombo is a young, 1297-m-high stratovolcano that rises prominently above the NW shore of Lake Managua, forming one of Nicaragua's most familiar landmarks. Momotombo began growing about 4500 years ago at the SE end of the Marrabios Range and consists of a somma from an older edifice that is surmounted by a symmetrical younger cone with a 150 x 250 m wide summit crater. Young lava flows from Momotombo have flowed down the NW flank into the 4-km-wide Monte Galán caldera. The youthful cone of Momotombito forms a 391-m-high island offshore in Lake Managua. Momotombo has a long record of strombolian eruptions, punctuated by occasional larger explosive activity. The latest eruption, in 1905, produced a lava flow that traveled from the summit to the lower NE base. A small black plume was seen above the crater after an April 10, 1996 earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the southern flank of the volcano.

Information Contacts: R. Stoiber, S. Williams, H.R. Naslund, L. Malinconico, and M. Conrad, Dartmouth College; A. Aburto Q. and D. Fajardo B., Instituto de Investigaciones Sísmicas.