Mount Mazama and Crater Lake

Where is it located?

Mount Mazama is located in the Cascade Mount Mazama is located in the Cascade Range in the United StatesRange in the United States

The coordinates areThe coordinates are

42° N 122° W It is located in the stateIt is located in the state

of Oregonof Oregon

Picture from: http://www.watersedgeranch.info/images/OregonMap.png

Plate Tectonics

Mount Mazama occurs along a convergent Mount Mazama occurs along a convergent boundary, where the North American and boundary, where the North American and Juan de Fuca plates meetJuan de Fuca plates meet

This boundary has createdThis boundary has created

the entire Cascade Range,the entire Cascade Range,

because the two plates arebecause the two plates are

pushing against each otherpushing against each other

Picture from: http://pubs.usgs.gov/gip/dynamic/slabs.html 

Plate Tectonics

The oceanic crust (the Juan de Fuca plate) The oceanic crust (the Juan de Fuca plate) is being subducted beneath the continental is being subducted beneath the continental crust (the North American plate)crust (the North American plate)

The North American plate is moving The North American plate is moving towards the west and the Juan de Fuca plate towards the west and the Juan de Fuca plate is moving eastwardis moving eastward

Picture from: http://pubs.usgs.gov/gip/dynamic/slabs.html 

Seismic Activity

In the area there is a multitude of In the area there is a multitude of earthquakes, some are shallow and others earthquakes, some are shallow and others are very strongare very strong

The current state of the plates is like the The current state of the plates is like the plate boundaries where some of the most plate boundaries where some of the most devastating earthquakes occurdevastating earthquakes occur

There hasn’t been any recorded much There hasn’t been any recorded much recorded activity in the recent pastrecorded activity in the recent past

Seismic Activity

Pictures from:http://www.geophys.washington.edu/SEIS/PNSN/CRATER/ Pictures from:http://www.geophys.washington.edu/SEIS/PNSN/CRATER/

What Occurs at Convergent Boundaries? Island arcs are common along convergent Island arcs are common along convergent

boundaries and are volcano chains that boundaries and are volcano chains that occur under the water and then reach the occur under the water and then reach the surface (i.e. the Aleutian islands off the surface (i.e. the Aleutian islands off the coast of Alaska)coast of Alaska)

What is Mount Mazama?

Mount Mazama used to be an active Mount Mazama used to be an active volcano, with an estimated maximum volcano, with an estimated maximum height of 3660 metersheight of 3660 meters

The last known eruption at the site was The last known eruption at the site was 4800 years ago4800 years ago

About 7700 years ago About 7700 years ago the top of the mountain the top of the mountain exploded offexploded off

Picture by Paul Rockwood and from: http://pubs.usgs.gov/fs/2002/fs092-02/

Pumice and Ash Accumulation

Photo by Ed Klimasauskas, USGS

This picture shows This picture shows some of the pumice some of the pumice and ash and ash accumulation from accumulation from the eruption of the eruption of Mount Mazama Mount Mazama 7700 years ago.7700 years ago.

What happened to it?

What remains of Mount Mazama is now a What remains of Mount Mazama is now a caldera with a diameter of 8 kilometers and caldera with a diameter of 8 kilometers and a depth of 1.6 kilometersa depth of 1.6 kilometers

The caldera filled with water and is now the The caldera filled with water and is now the deepest lake in the United States and the 7deepest lake in the United States and the 7 thth deepest lake in the world, with a depth of deepest lake in the world, with a depth of 592 meters592 meters

Images Showing Depth of Lake and Lake Bottom

From: http://pubs.usgs.gov/fs/2002/fs092-02/

Images Showing Depth of Lake and Lake Bottom The picture shows the depth of the lake (the The picture shows the depth of the lake (the

colors change from orange to blue as depth colors change from orange to blue as depth increases) along with the details of the increases) along with the details of the bottom of the lakebottom of the lake

There are depressions under the sediment There are depressions under the sediment due to steam explosionsdue to steam explosions

This image was created in 2000 with the This image was created in 2000 with the use of sonar and using specialized softwareuse of sonar and using specialized software

From: http://pubs.usgs.gov/fs/2002/fs092-02/

Crater Lake

Crater Lake is a National ParkCrater Lake is a National Park The lake is at its maximum depth because The lake is at its maximum depth because

of a natural drainage processof a natural drainage process 30 meters of sediment lie at the bottom of 30 meters of sediment lie at the bottom of

the lakethe lake

Picture from: http://pubs.usgs.gov/fs/2002/fs092-02/

Sequence of Events

This sequence starts with theThis sequence starts with the

top-blowing eruption, to thetop-blowing eruption, to the

lake todaylake today In summary, the eruptionIn summary, the eruption

occurred, led to the creationoccurred, led to the creation

of a new caldera that filledof a new caldera that filled

with water to form a lakewith water to form a lake

Picture from: http://pubs.usgs.gov/fs/2002/fs092-02/

What will happen?

It is predicted that eventually, the volcanic It is predicted that eventually, the volcanic area will be active again, but not to the area will be active again, but not to the same extent as the one that changed the same extent as the one that changed the scenery to its form todayscenery to its form today

However, it is possible for there to be However, it is possible for there to be pyroclastic surges in the more shallow areas pyroclastic surges in the more shallow areas of the lakeof the lake

Defining terms

A caldera is a volcanic depression in A caldera is a volcanic depression in Earth’s crust.Earth’s crust.

A pyroclastic surge is a quickly moving A pyroclastic surge is a quickly moving cloud of gas and ash that is at very high cloud of gas and ash that is at very high temperatures.temperatures.

A quote from a February 1901 edition of Pearson’s Magazine““Showing how some mountains commit Showing how some mountains commit

suicide by blowing off their heads, while suicide by blowing off their heads, while others behave like Mount Mazama, which others behave like Mount Mazama, which undermined its foundations with volcanic undermined its foundations with volcanic explosions, causing such extensive outflows explosions, causing such extensive outflows of lava that the entire structure collapsed, of lava that the entire structure collapsed, and only a hole in the earth was left to mark and only a hole in the earth was left to mark the place where the Mountain once stood. the place where the Mountain once stood. ~~By T.E. James.By T.E. James.””

From The Disappearance of Mount Mazama. http://gesswhoto.com/mt.mazama.html

Works Cited

Crater LakeCrater Lake. National Park Service, 2 Jan. 2010. Web. 5 . National Park Service, 2 Jan. 2010. Web. 5 Feb. 2010. <http://www.nps.gov/crla/ index.htm>. Feb. 2010. <http://www.nps.gov/crla/ index.htm>.

Crater Lake, Oregon/ Mount Mazama, OregonCrater Lake, Oregon/ Mount Mazama, Oregon. . USGS/Cascades Volcano Observatory, Vancouver, USGS/Cascades Volcano Observatory, Vancouver, Washington, 29 July 2008. Web. 6 Feb. 2010. Washington, 29 July 2008. Web. 6 Feb. 2010. <http://vulcan.wr.usgs.gov/Volcanoes/CraterLake/ <http://vulcan.wr.usgs.gov/Volcanoes/CraterLake/ framework.html>. framework.html>.

Klimasauskas, Ed, Charles Bacon, and Jim Alexander. Klimasauskas, Ed, Charles Bacon, and Jim Alexander. Mount Mazama and Crater Lake: Growth and Mount Mazama and Crater Lake: Growth and Destruction of a Cascade VolcanoDestruction of a Cascade Volcano. U.S. Geological . U.S. Geological Survey, 17 May 2005. Web. 6 Feb. 2010. Survey, 17 May 2005. Web. 6 Feb. 2010. <http://pubs.usgs.gov/fs/2002/fs092-02/>. <http://pubs.usgs.gov/fs/2002/fs092-02/>.

Lewis, C. Lewis, C. The Disappearance of Mount MazamaThe Disappearance of Mount Mazama. . Pearson's Magazine, 1901. Web. 8 Feb. 2010. Pearson's Magazine, 1901. Web. 8 Feb. 2010. <http://gesswhoto.com/mt.mazama.html><http://gesswhoto.com/mt.mazama.html>