Report on Momotombo (Nicaragua) — March 1998

Bulletin of the Global Volcanism Network, vol. 23, no. 3 (March 1998)
Managing Editor: Richard Wunderman.

Momotombo (Nicaragua) Higher-than-normal fumarole temperatures

Please cite this report as:

Global Volcanism Program, 1998. Report on Momotombo (Nicaragua). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 23:3. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199803-344090.

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Momotombo

Nicaragua

12.423°N, 86.539°W; summit elev. 1270 m

All times are local (unless otherwise noted)


Measurements during a 28 February visit revealed higher-than-normal fumarolic temperatures in the summit area. The high temperatures were associated with a recent period of aridity, during which time fumarolic activity increased. Temperatures ranged from 318-748°C (figure 7).

Figure (see Caption) Figure 7. Sketch of Momotombo's active crater showing fumarole temperatures on 28 February. Areas of fumarolic activity are gray. View is towards the S; the crater is ~150 m wide. Courtesy of A. Creusot.

Geologic Background. Momotombo is a young 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 extend down the NW flank into the 4-km-wide Monte Galán caldera. The youthful cone of Momotombito forms an island offshore in Lake Managua. Momotombo has a long record of Strombolian eruptions, punctuated by occasional stronger 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 a 10 April 1996 earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the south flank.

Information Contacts: Alain Creusot, Instituto Nicaraguense de Energía, Managua, Nicaragua.