Volcano World

Coseguina is located in the northwest corner of Nicaragua. It is a basaltic shield volcano with a large central collapse crater that contains a lake. This crater is about 1.24 by 1.55 miles (2 by 2.5 km) in diameter and 1,640 ft (500 m) deep. It was formed during a huge eruption on January 22, 1835 that covered a large area of Central America and Mexico with ash and pumice .This mighty eruption deposited ash as far as Mexico City, some 1400 km to the north and Jamaica, which is 800 miles (1300 km) to the east. This eruption cloud blocked out the sun in a 93 mile (150 km) radius.

Coseguina erupted explosively again in 1852 producing lava flows. Its last eruption was in 1859. A lake began to form in the crater in 1938. The volcano hasn't been active since, only small emissions from fumaroles.

This 150 kilometer stretch of the Pacific coastal plain of Nicaragua extends from the Gulf of Fonseca to Lake Managua. The large crater on the peninsula on the left side of the above photo is Coseguina. A plume of steam can also be seen venting from the volcano San Cristobal located in the Marabios Range, the highest group mountains in Nicaragua.

Sources

Mooser, F., et al, "Catalogue of the Active Volcanoes of the World Including Solfatara Fields: Part 6 -- Central America," International Volcanology Association, pp. 109-111, 1958.

Simkin, Tom and Siebert, Lee, "Volcanoes of the World," Geoscience Press, Tuscon, AZ, 349 pp., 1994.

Weyl, Richard, "Geology of Central America," p. 212, 1980.