Report on Las Pilas (Nicaragua) — April 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 4 (April 1990)
Managing Editor: Lindsay McClelland.
Las Pilas (Nicaragua) Fumarolic activity
Please cite this report as:
Global Volcanism Program, 1990. Report on Las Pilas (Nicaragua). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 15:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199004-344080.
12.495°N, 86.688°W; summit elev. 1088 m
All times are local (unless otherwise noted)
An 8-14 µm infrared thermometer was used on 23 April to measure temperatures of the inner wall of the prominent 20-m-deep chasm formed in the  eruption. Weak fumarolic activity was occurring there, and the maximum recorded temperature was 96°C, probably corresponding closely with the gas temperature.
Geologic Background. Las Pilas volcanic complex, overlooking Cerro Negro volcano to the NW, includes a diverse cluster of cones around the central vent, Las Pilas (El Hoyo). A N-S-trending fracture system cutting across the edifice is marked by numerous well-preserved flank vents, including maars, that are part of a 30-km-long volcanic massif. The Cerro Negro chain of cinder cones is listed separately in this compilation because of its extensive historical eruptions. The lake-filled Asososca maar is located adjacent to the Cerro Asososca cone on the southern side of the fissure system, south of the axis of the Marrabios Range. Two small maars west of Lake Managua are located at the southern end of the fissure. Aside from a possible eruption in the 16th century, the only historical eruptions of Las Pilas took place in the 1950s from a fissure that cuts the eastern side of the 700-m-wide summit crater and extends down the N flank.
Information Contacts: C. Oppenheimer, Open Univ; B. van Wyk de Vries, INETER.