Quake Lake
Encyclopedia
Quake Lake is a lake
in southwestern Montana
, United States
. It was created after a massive earthquake
struck on August 17, 1959, which killed 27 people. Today, Quake Lake is 190 feet (58 m) deep (150 feet as of July 2009) and six miles (10 km) long. US 287 follows the lake and offers glimpses of the effects of the earthquake and landslide and allows access to a visitor center. The lake is mostly within Gallatin National Forest
.
which formed a landslide dam
on the Madison River
. The landslide traveled down the south flank of Sheep Mountain, at an estimated 100 miles per hour (160 km/h), killing 27 people who were camping along the shores of Hebgen Lake and downstream along the Madison River. Upstream the faulting caused by the earthquake forced the waters of Hebgen Lake
to shift violently. A seiche
, a wave effect of both wind
and water
, crested over Hebgen Dam
, causing cracks and erosion. Besides being the largest known earthquake to have struck the state of Montana in recorded history, it is also the largest earthquake to occur in the Northern Rockies for centuries and is one of the largest earthquakes ever to hit the United States in recorded history.
The earthquake created fault scarps
up to 20 ft (6.1 m) high in the area near Hebgen Lake and the lake bottom itself dropped the same distance. 32000 acre (129.5 km²) of the area near Hebgen Lake subsided more than 10 ft (3 m). Several geysers in the northwestern sections in Yellowstone National Park
erupted and numerous hot springs became temporarily muddied.
, built in 1917, is a concrete
core and rock fill faced structure that sustained severe damage but continued to hold. Repairs were completed on the dam spillway in a few weeks. The landslide, which occurred downstream from the dam, blocked almost all the flow of the Madison River which began to fill in the void upstream from the slide. In less than a month, the waters had created what is now known as Quake Lake. The lack of a reliable water outlet for this new lake forced one of the largest mobilizations of the U.S. Army Corps of Engineers ever commenced in the western U.S. Before the new landslide was breached by the quickly rising waters, a spillway
was constructed to ensure erosion and potential failure of the natural dam would be minimized. Within the immediate vicinity of the earthquake and resultant landslide a few dozen cabins and homes were destroyed. Overall damages to buildings and roads were minor with damage costs placed at 11 million dollars
in 1959. Aftershock
s up to 6.5 on the Richter scale continued for several months.
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
in southwestern Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It was created after a massive earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
struck on August 17, 1959, which killed 27 people. Today, Quake Lake is 190 feet (58 m) deep (150 feet as of July 2009) and six miles (10 km) long. US 287 follows the lake and offers glimpses of the effects of the earthquake and landslide and allows access to a visitor center. The lake is mostly within Gallatin National Forest
Gallatin National Forest
Founded in 1899, Gallatin National Forest is located in south central Montana, United States. The forest comprises 2.1 million acres and has portions of both the Absaroka-Beartooth and Lee Metcalf Wilderness areas within its boundaries...
.
The earthquake
The earthquake measured 7.5 on the Richter scale (Revised by USGS to 7.6) and caused an 80 million ton landslideLandslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...
which formed a landslide dam
Landslide dam
A landslide dam, debris dam, or barrier lake is a natural damming of a river by some kind of mass wasting: landslide, debris flow, rock avalanche or volcano. If it is caused by earthquake, it may also be called a quake lake. Some landslide dams are as high as the largest existing artificial dam...
on the Madison River
Madison River
The Madison River is a headwater tributary of the Missouri River, approximately 183 miles long, in Wyoming and Montana. Its confluence with the Jefferson and Gallatin rivers near Three Forks, Montana form the Missouri River....
. The landslide traveled down the south flank of Sheep Mountain, at an estimated 100 miles per hour (160 km/h), killing 27 people who were camping along the shores of Hebgen Lake and downstream along the Madison River. Upstream the faulting caused by the earthquake forced the waters of Hebgen Lake
Hebgen Lake
Hebgen Lake is a lake located in Southwest Montana and is created by Hebgen Dam. It is well known for a magnitude 7.5 earthquake which occurred nearby on August 17, 1959, forming Quake Lake which is located immediately downstream.-Recreation:...
to shift violently. A seiche
Seiche
A seiche is a standing wave in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbors and seas...
, a wave effect of both wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
and water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, crested over Hebgen Dam
Hebgen Dam
The Hebgen Dam is a concrete-core earthen embankment dam on the Madison River in the U.S. state of Montana. The dam is 85 feet tall and 721 feet long. The dam is owned and operated by PPL Montana and its purpose is to store and regulate water for other downstream reservoirs and hydroelectric power...
, causing cracks and erosion. Besides being the largest known earthquake to have struck the state of Montana in recorded history, it is also the largest earthquake to occur in the Northern Rockies for centuries and is one of the largest earthquakes ever to hit the United States in recorded history.
The earthquake created fault scarps
Geologic fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement along the fractures as a result of earth movement. Large faults within the Earth's crust result from the action of tectonic forces...
up to 20 ft (6.1 m) high in the area near Hebgen Lake and the lake bottom itself dropped the same distance. 32000 acre (129.5 km²) of the area near Hebgen Lake subsided more than 10 ft (3 m). Several geysers in the northwestern sections in Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...
erupted and numerous hot springs became temporarily muddied.
Hebgen Dam and creation of the lake
Hebgen DamHebgen Dam
The Hebgen Dam is a concrete-core earthen embankment dam on the Madison River in the U.S. state of Montana. The dam is 85 feet tall and 721 feet long. The dam is owned and operated by PPL Montana and its purpose is to store and regulate water for other downstream reservoirs and hydroelectric power...
, built in 1917, is a concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
core and rock fill faced structure that sustained severe damage but continued to hold. Repairs were completed on the dam spillway in a few weeks. The landslide, which occurred downstream from the dam, blocked almost all the flow of the Madison River which began to fill in the void upstream from the slide. In less than a month, the waters had created what is now known as Quake Lake. The lack of a reliable water outlet for this new lake forced one of the largest mobilizations of the U.S. Army Corps of Engineers ever commenced in the western U.S. Before the new landslide was breached by the quickly rising waters, a spillway
Spillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...
was constructed to ensure erosion and potential failure of the natural dam would be minimized. Within the immediate vicinity of the earthquake and resultant landslide a few dozen cabins and homes were destroyed. Overall damages to buildings and roads were minor with damage costs placed at 11 million dollars
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
in 1959. Aftershock
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
s up to 6.5 on the Richter scale continued for several months.