Lake Ilopango
Encyclopedia
Lake Ilopango is a crater lake
which fills a scenic 8 x 11 km (72 km2 or 28 sq mi) volcanic caldera
in central El Salvador
. The caldera, which contains the second largest lake in the country and is located immediately east of the capital city, San Salvador
, has a scalloped 100 m (328.1 ft) to 500 m (1,640.4 ft) high rim.
- rhyolitic
eruptions occurred during the late Pleistocene
and Holocene
, producing pyroclastic flow
s and tephra
that blanketed much of the country.
The caldera collapsed most recently during a cataclysmic eruption in the 5th century AD. which produced widespread pyroclastic flow
s and devastated Mayan cities
This eruption produced about 25 km³ (6 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
. One of the most prominent tourist destinations is a town called Apulo, which was one of the towns affected by the 2009 floods and mudslides
caused by Hurricane Ida
.
Later eruptions formed several lava dome
s 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 islet
s known as Islas Quemadas.
Crater lake
A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...
which fills a scenic 8 x 11 km (72 km2 or 28 sq mi) volcanic 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...
in central El Salvador
El Salvador
El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
. The caldera, which contains the second largest lake in the country and is located immediately east of the capital city, San Salvador
San Salvador
The city of San Salvador the capital and largest city of El Salvador, which has been designated a Gamma World City. Its complete name is La Ciudad de Gran San Salvador...
, has a scalloped 100 m (328.1 ft) to 500 m (1,640.4 ft) high rim.
Eruptive History
Four major daciticDacite
Dacite is an igneous, volcanic rock. It has an aphanitic to porphyritic texture and is intermediate in composition between andesite and rhyolite. The relative proportions of feldspars and quartz in dacite, and in many other volcanic rocks, are illustrated in the QAPF diagram...
- rhyolitic
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
eruptions occurred during the late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
and Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
, producing pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
s and tephra
Tephra
200px|thumb|right|Tephra horizons in south-central [[Iceland]]. The thick and light coloured layer at center of the photo is [[rhyolitic]] tephra from [[Hekla]]....
that blanketed much of the country.
The caldera collapsed most recently during a cataclysmic eruption in the 5th century AD. which produced widespread pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
s and devastated Mayan cities
Maya civilization
The Maya is a Mesoamerican civilization, noted for the only known fully developed written language of the pre-Columbian Americas, as well as for its art, architecture, and mathematical and astronomical systems. Initially established during the Pre-Classic period The Maya is a Mesoamerican...
This eruption produced about 25 km³ (6 cu mi) of tephra
Tephra
200px|thumb|right|Tephra horizons in south-central [[Iceland]]. The thick and light coloured layer at center of the photo is [[rhyolitic]] tephra from [[Hekla]]....
(20 times as much as the 1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington state, in the United States, was a major volcanic eruption. The eruption was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California...
), thus rating a 6 on the (VEI) 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....
. One of the most prominent tourist destinations is a town called Apulo, which was one of the towns affected by the 2009 floods and mudslides
2009 El Salvador floods and mudslides
The 2009 El Salvador floods and mudslides were extreme weather events that killed 199 people with others 76 missing and left $239 million in damages in El Salvador, some unofficial sources have the death toll up to 275 people....
caused by Hurricane Ida
Hurricane Ida (2009)
Hurricane Ida was the strongest landfalling tropical cyclone during the 2009 Atlantic hurricane season, crossing the coastline of Nicaragua with winds of 80 mph . The remnants of the storm became a powerful nor'easter that caused widespread damage along coastal areas of the Mid-Atlantic States...
.
Later eruptions formed several lava dome
Lava dome
|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...
s 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
Lava dome
|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...
and had a VEI
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....
of 3. The lava dome reached the surface of the lake, forming the islet
Islet
An islet is a very small island.- Types :As suggested by its origin as islette, an Old French diminutive of "isle", use of the term implies small size, but little attention is given to drawing an upper limit on its applicability....
s known as Islas Quemadas.
External links
- Global Volcanism Program: Ilopango
- Lake Ilopango at NASA Earth ObservatoryNASA Earth ObservatoryNASA Earth Observatory is an online publishing outlet for NASA which was created in 1999. It is the principal source of satellite imagery and other scientific information pertaining to the climate and the environment which are being provided by NASA for consumption by the general public...
website