Apoyeque is a pyroclastic shield

Pyroclastic shield

In volcanology, a pyroclastic shield or terrestrial ignimbrite shield is an uncommon type of shield volcano. Unlike most shield volcanoes, pyroclastic shields are formed mostly of pyroclastic and highly explosive eruptions rather than relatively fluid basaltic lava issuing from vents or fissures on...

, located in the Chiltepe Peninsula Natural Reserve

Chiltepe Peninsula Natural Reserve

Chiltepe Peninsula Natural Reserve is a nature reserve in Nicaragua. It is one of the 78 reserves which are officially under protection in the country....

 in Nicaragua

Nicaragua

Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

. It has a 2.8-km wide, 400-m-deep, lake-filled caldera

Caldera

A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

.

Geography

Apoyeque is a volcanic complex that formed and occuplies the Chiltepe Peninsula. It is part of the Chiltepe pyroclastic shield volcano, one of three ignimbrite shields on the Nicaraguan volcanic front.

The lake at its center, Apoyeque lake (Spanish:

Spanish language

Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

 Laguna de Apoyegue, also called Laguna de Apoyaque, Laguna Apoye, and Laguna Apoyo), its shore 100 meters below the peak of the caldera, at its bottom reaches down to sea level.

Apoyeque, as well as the entire Chiltepe peninsula are part of the Managua administrative region, in close proximity to city of Managua, Nicaragua's capital.

Immediately Southeast of Apoyeque peak is the 2.5 x 3 kilometer wide lake-filled Xiloá (Jiloá) maar

Maar

A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake. The name comes from the local Moselle...

, a part of the Apoyeque complex.

Volcanology

Apoyeque, with a volcanic explosivity index

Volcanic Explosivity Index

The Volcanic Explosivity Index was devised by Chris Newhall of the U.S. Geological Survey and Stephen Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions....

(VEI) of 6, the second highest, had one of the largest explosions known in history, last erupted in about 50 BC.

In addition to the Chiltepe dome (volcán Chiltepe), which is used synonymously with Apoyeque, the Apoyeque complex contains the Jiloa caldera (Laguna de Jiloa aka Xiloá), the Miraflores dome and the Cerro Talpetate dome.

An eruption of Laguna Xiloá 6100 years ago produced pumiceous pyroclastic flows that overlay similar deposits of similar age from Masaya.