Report on Momotombo (Nicaragua) — May 1986

Scientific Event Alert Network Bulletin, vol. 11, no. 5 (May 1986)
Managing Editor: Lindsay McClelland

Momotombo (Nicaragua) Fumarole temperatures decline after heavy rains

Please cite this report as:

Global Volcanism Program, 1986. Report on Momotombo (Nicaragua). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 11:5. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198605-344090.

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Momotombo

Nicaragua

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

All times are local (unless otherwise noted)


Heavy rains fell along the entire Pacific coast of Nicaragua from 30 October to 3 November 1985. Of the three highest-temperature fumaroles, the temperature of one (#9) dropped 33°C around the time of the heavy rains (figure 3), while temperatures of the other two continued to increase slightly. The temperature of fumarole ##9 had recovered by late December and continued to increase gradually through early April (table 3).

Figure (see Caption) Figure 3. Temperature and precipitation data at three of Momotombo's fumaroles, January-December 1985. Rainfall data are from Nagarote Station, the nearest to Momotombo. Courtesy of INETER.

Table 3. Temperatures (°C) at Momotombo's fumarole #9, October 1985-April 1986. Courtesy of INETER.

Date Temperature (°C)
29 Oct 1985 875
11 Nov 1985 842
14 Nov 1985 843
20 Nov 1985 861
04 Dec 1985 869
11 Dec 1985 871
27 Dec 1985 875
15 Jan 1986 875
27 Jan 1986 880
20 Feb 1986 880
27 Feb 1986 876
06 Mar 1986 875
15 Mar 1986 880
23 Mar 1986 882
04 Apr 1986 885
10 Apr 1986 885

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: Douglas Fajardo B. INETER.