Lake Ilopango

Lake Ilopango

Lake Ilopango seen from the east, San Salvador city and San Salvador Volcano can be seen just behind the lake looming in the haze
Highest point
Elevation 450 m (1,480 ft)
Coordinates 13°40′N 89°03′W / 13.67°N 89.05°W / 13.67; -89.05 
Geography
Location El Salvador
Geology
Mountain type Caldera
Last eruption 1879 to 1880
Lake Ilopango
Location Central El Salvador
Coordinates 13°40′N 89°03′W / 13.67°N 89.05°W / 13.67; -89.05Coordinates: 13°40′N 89°03′W / 13.67°N 89.05°W / 13.67; -89.05
Type crater lake
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)
Islands Islas Quemadas

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.[1] 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.[2] Any surplus drains via the Jiboa River to the Pacific Ocean. The lake is known for being 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.

Eruptive history

Engraving the eruption of the Ilopango volcano, 1891.
U.S. Soldiers with the 7th Special Forces Group and Salvadoran service members maneuver after jumping from the ramp of a U.S. Army CH-47 Chinook helicopter during a joint airborne operations training exercise over Lake Ilopango, El Salvador, Jan. 21, 2014. The training allowed service members from both nations to maintain currency while strengthening the relationship between the forces. (DoD photo by Capt. Zach Anderson, U.S. Air Force/Released)

Four major dacitic - rhyolitic eruptions occurred during the late Pleistocene and Holocene, producing pyroclastic flows and tephra that blanketed much of the country.[2]

The caldera collapsed most recently[2] sometime between 410 and 535 AD (based on radiocarbon dating of plant life directly related to the eruption),[3] 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 kilometres waist-deep in pumice and ash", which would have stopped all agricultural endeavor in the area for decades.[4] 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.[2] The lava dome reached the surface of the lake, forming the islets known as Islas Quemadas.[5][6]

See also

References

  1. ↑ "Lake Ilopango". Encyclopædia Britannica. Retrieved 13 July 2012.
  2. 1 2 3 4 "Ilopango: Eruptive History". Global Volcanism Program. Smithsonian Institution.
  3. ↑ 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. JSTOR 971755. doi:10.2307/971755., esp. p.27.
  4. ↑ Clive Oppenheimer (2011). Eruptions that shook the world. Cambridge University Press. ISBN 978-0-521-64112-8.
  5. ↑ 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.
  6. ↑ "Historia y cultura de Ilopango". Elsalvadorenelmundo.com. Retrieved 2014-02-02.
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