Lake breakout

Lake breakout

Lake breakout is a geological term that refers to the collapse of a (usually high-altitude) lake. High-altitude lakes tend to form in volcanic craters – where they are called crater lakes – or in valleys dammed as the result of earthquakes or glacial or volcanic deposition. Lake breakouts are most common a few weeks or months after a volcanic eruption as a river becomes blocked by volcanic debris.

Process

The walls of such lakes can be unstable and may be breached after fresh earthquakes or because of erosion. As water rushes outwards, the initial channel is cut wider and deeper, further increasing the flow. This may cause the lake's rim to collapse abruptly. The usual result is for huge amounts of water to be displaced, incorporating a great deal of sediment which increases it in volume by as much as two or four times, or even more. This produces violent floods and lahars with devastating effects for any settlements in their path.

Historical events

The larger a temporary lake is, the more extreme the likely breakout will be. One of the largest known to have occurred in recent geological history was the collapse, around 15,000 years ago, of the ancient Lake Bonneville which was filled with meltwater from the last ice age and covered large areas of Utah, Idaho and Nevada. Erosion broke through the lake shore's lowest point, the Red Rock Pass in Idaho, releasing as much as 1,000 mile³ (4,000 km³) of water within a period estimated to have lasted only two weeks. The energies released by the outburst were capable not just of stripping surface features, but gouging out bedrock to a depth of many feet. It drastically reshaped the landscape downstream, carving out many of the features of the Snake River and its surrounding area.
Glacial Lake Missoula also had lake breakouts, due to breaking of ice dams, see Missoula Floods. These lake breakouts caused extensive erosion throughout eastern Washington.It has been suggested that gigantic breakouts from underground lakes may have been responsible for carving some of the canyons of Mars.

Mitigation

Although there is little that can be done about many lake breakouts, some have been prevented (or at least delayed) by human intervention. The 1980 eruption of Mount St. Helens blocked nearby Castle Creek, forming a lake which geologists feared would produce a sudden lahar. The United States Army Corps of Engineers excavated an outlet channel which prevented the lake from overtopping its new debris dam.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Lake Speed — Infobox NASCAR driver Name = Lake Chambers Speed Birthdate = birth date and age|1948|1|17 Birthplace = flagicon|USA Jackson, Mississippi Best Cup Pos = 10th 1985 (Winston Cup) Cup Wins = 1 Cup Top Tens = 75 First Cup Race = 1980 Winston Western… …   Wikipedia

  • Crater lake — This article is about the geological feature. For the lake of the same name in Oregon, see Crater Lake. For other uses, see Crater Lake (disambiguation). Landsat image of Lake Toba, the largest volcanic crater lake in the world …   Wikipedia

  • Lahar — A lahar is a type of mudflow / landslide composed of pyroclastic material and water that flows down from a volcano, typically along a river valley.cite web|url= http://volcanoes.usgs.gov/Products/Pglossary/lahar.html|title=Lahar|work=USGS Photo… …   Wikipedia

  • Tauposee — Lake Taupo (dt. Tauposee) Geographische Lage Taupo Distrikt, Waikato, Neuseeland Zuflüsse Wa …   Deutsch Wikipedia

  • Battle of Chosin Reservoir — Coordinates: 40°29′N 127°12′E / 40.483°N 127.2°E / 40.483; 127.2 (Chosin Reser …   Wikipedia

  • List of locations in Prehistoric Park — This is a list of locations in the fictional show Prehistoric Park Main complex The park appears to have a central base, not far from the entrance, on a grassy hill. The main road appears to lead to the Main complex and is surrounded by trees… …   Wikipedia

  • Wonder World Tour — Wonder World Tour …   Wikipedia

  • Cowra — New South Wales Main street of Cowra …   Wikipedia

  • Campaign — Pays  Royaume Uni Langue Anglais Genre Histoire militair …   Wikipédia en Français

  • River Torrens — Infobox River river name = River Torrens caption = View of Elder Park and Riverside Precinct from Torrens Lake. origin = Mount Pleasant, Mount Lofty Ranges mouth = Gulf Saint Vincent at Henley Beach South basin countries = length = 85 kilometres… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”