Report on Masaya (Nicaragua) — February 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 2 (February 1980)
Managing Editor: David Squires.
Masaya (Nicaragua) Active lava lake several times larger than in 1977
Please cite this report as:
Global Volcanism Program, 1980. Report on Masaya (Nicaragua) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 5:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198002-344100.
11.985°N, 86.165°W; summit elev. 594 m
All times are local (unless otherwise noted)
In early February, the plume appeared larger than any observed between 1968 and 1977. The diameter of the active lava lake in the pit crater was several times larger than in 1977 and the level of lava has dropped since then.
Geologic Background. Masaya is one of Nicaragua's most unusual and most active volcanoes. It lies within the massive Pleistocene Las Sierras caldera and is itself a broad, 6 x 11 km basaltic caldera with steep-sided walls up to 300 m high. The caldera is filled on its NW end by more than a dozen vents that erupted along a circular, 4-km-diameter fracture system. The Nindirí and Masaya cones, the source of historical eruptions, were constructed at the southern end of the fracture system and contain multiple summit craters, including the currently active Santiago crater. A major basaltic Plinian tephra erupted from Masaya about 6,500 years ago. Historical lava flows cover much of the caldera floor and there is a lake at the far eastern end. A lava flow from the 1670 eruption overtopped the north caldera rim. Masaya has been frequently active since the time of the Spanish Conquistadors, when an active lava lake prompted attempts to extract the volcano's molten "gold." Periods of long-term vigorous gas emission at roughly quarter-century intervals have caused health hazards and crop damage.
Information Contacts: R. Stoiber, S. Williams, and M. Bruzga, Dartmouth College.