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Report on Masaya (Nicaragua) — June 1997


Masaya

Bulletin of the Global Volcanism Network, vol. 22, no. 6 (June 1997)
Managing Editor: Richard Wunderman.

Masaya (Nicaragua) Stable and non-eruptive during May-June

Please cite this report as:

Global Volcanism Program, 1997. Report on Masaya (Nicaragua) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 22:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199706-344100



Masaya

Nicaragua

11.9844°N, 86.1688°W; summit elev. 594 m

All times are local (unless otherwise noted)


Besides the strong degassing and high tremor, which are normal for this volcano, Masaya lacked signs of abnormal activity during May and June 1997.

Geological Summary. Masaya volcano in Nicaragua has erupted frequently since the time of the Spanish Conquistadors, when an active lava lake prompted attempts to extract the volcano's molten "gold" until it was found to be basalt rock upon cooling. 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 NindirĂ­ and Masaya cones, the source of observed 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. Recent 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. Periods of long-term vigorous gas emission at roughly quarter-century intervals have caused health hazards and crop damage.

Information Contacts: Wilfried Strauch, Department of Geophysics, and Marta Navarro C., Department of Volcanoes, Instituto Nicaragüense de Estudios Territoriales (INETER), P.O. Box 1761, Managua, Nicaragua.