Lake Ilopango is a crater lake which fills a scenic 8 by 11 km (72 km2 or 28 sq mi) volcanic caldera in central El Salvador, on the borders of the San Salvador, La Paz, and Cuscatlán departments. The caldera, which contains the second largest lake in the country and is immediately east of the capital city, San Salvador, has a scalloped 100 m (330 ft) to 500 m (1,600 ft) high rim. Any surplus drains via the Jiboa River to the Pacific Ocean. An eruption of the Ilopango volcano is considered a possible source for the extreme weather events of 535–536. The local military airbase, Ilopango International Airport, has annual airshows where international pilots from all over the world fly over San Salvador City and Ilopango lake.
|Elevation||450 m (1,480 ft)|
|Last eruption||1879 to 1880|
|Location||Central El Salvador|
|Basin countries||El Salvador|
|Max. length||11 km (6.8 mi)|
|Max. width||8 km (5.0 mi)|
|Surface area||72 km2 (28 sq mi)|
|Max. depth||230 m (750 ft)|
|Surface elevation||440 m (1,440 ft)|
The caldera collapsed most recently sometime between 410 and 535 AD (based on radiocarbon dating of plant life directly related to the eruption), which produced widespread pyroclastic flows and devastated Mayan cities. The eruption produced about 25 km3 (6.0 cu mi) of tephra (20 times as much as the 1980 eruption of Mount St. Helens), thus rating a 6 on the (VEI) Volcanic Explosivity Index. The "ash-cloud fallout [..] blanketed an area of at least 10,000 square kilometers waist-deep in pumice and ash", which would have stopped all agricultural endeavor in the area for decades. It is also theorized that the eruption and subsequent weather events and agricultural failures directly led to the abandonment of Teotihuacan by the original inhabitants. There is an opinion that this eruption caused the extreme weather events of 535–536 in Europe.
Later eruptions formed several lava domes within the lake and near its shore. The only historical eruption, which occurred from December 31, 1879, up to March 26, 1880, produced a lava dome and had a VEI of 3. The lava dome reached the surface of the lake, forming the islets known as Islas Quemadas.
- "Lake Ilopango". Encyclopædia Britannica. Retrieved 13 July 2012.
- "Ilopango: Eruptive History". Global Volcanism Program. Smithsonian Institution.
- Dull, Robert A.; Southon, John R.; Sheets, Payson (2001). "Volcanism, Ecology and Culture: A Reassessment of the Volcan Ilopango Tbj eruption in the Southern Maya Realm". Latin American Antiquity. Latin American Antiquity, Vol. 12, No. 1. 12 (1): 25–44. doi:10.2307/971755. JSTOR 971755., esp. p.27.
- Clive Oppenheimer (2011). Eruptions that shook the world. Cambridge University Press. ISBN 978-0-521-64112-8.
- Golombek, Matthew P.; Carr, Michael J. (1978). "Tidal triggering of seismic and volcanic phenomena during the 1879–1880 eruption of Islas Quemadas volcano in El Salvador, Central America". Journal of Volcanology and Geothermal Research. 3 (3–4): 299–307. Bibcode:1978JVGR....3..299G. doi:10.1016/0377-0273(78)90040-9.
- "Historia y cultura de Ilopango". Elsalvadorenelmundo.com. Retrieved 2014-02-02.