Report on Momotombo (Nicaragua) — February 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 2 (February 1989)
Managing Editor: Lindsay McClelland
Momotombo (Nicaragua) Numerous incandescent fumaroles seen at night; large areas of hot ground
Please cite this report as:
Global Volcanism Program, 1989. Report on Momotombo (Nicaragua). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 14:2. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198902-344090.
12.422°N, 86.54°W; summit elev. 1297 m
All times are local (unless otherwise noted)
During a 4-5 March visit, incandescence from numerous fumaroles was visible at night. A maximum gas temperature of 873°C was measured by thermocouple. Surface temperatures measured by both infrared thermometers - Minolta Cyclops 33 (bandpass 8-14 µm, 1° field of view) and Cyclops 52 (bandpass 0.8-1.1 µm, 0.33° field of view) - dropped considerably beyond vent edges, but large areas of ground were hotter than 100°C. Temperatures are not corrected for emissivity and atmospheric absorption effects.
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: C. Oppenheimer and D. Rothery, Open Univ; B. van Vyk de Vries, O. Castellon, and L. Urbina, INETER.