Las Pilas-El Hoyo Complex

Geography & Climate

Las Pilas-El Hoyo Complex is located in Nicaragua, within the Central America Volcanic Arc of the broader Middle America-Caribbean Volcanic Regions. Situated at 12.49° N, 86.68° W in the Northern Hemisphere, the volcano lies within a tropical climate zone. With a summit elevation of 1,088 meters above sea level, Las Pilas-El Hoyo Complex is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Las Pilas-El Hoyo Complex sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in Nicaragua near Las Pilas-El Hoyo Complex, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is andesite / basaltic andesite, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

Las Pilas-El Hoyo Complex has 3 recorded eruptions in the geological database, spanning from 1528 CE to 1954 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1954 CE, reaching VEI 2 on the Volcanic Explosivity Index. These eruptions span roughly 426 years of volcanic history. The most recent eruption in 1954 CE places this volcano within the modern era of volcanological observation.

GVP Reference Summary

Las Pilas-El Hoyo volcanic complex, overlooking Cerro Negro volcano to the NW, includes a diverse cluster of cones within about a 3-km-diameter area. A N-S-trending fracture system cutting across the edifice is marked by numerous 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 and possible distinct magmatic system. 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, eruptions of Las Pilas took place in the 1950s from a fissure that cuts the eastern side of the 700-m-wide crater and extends down the N flank.

— Smithsonian Institution, Global Volcanism Program