Mount Cleveland Introduction
Mount Cleveland, also known as Cleveland Volcano and Chuginadak, is one of the most active volcanoes in the central part of the Aleutian
island arc. It is a stratovolcano that comprises the entire western half of Chuginadak Island.
The portion of the volcano that is above sea level is about 8.5 kilometers in diameter (5.3 miles) and rises to an elevation of 1,730 meters (5,675 feet).
The volcano has been the site of recurrent eruptions throughout the recorded history of this area. It has produced many eruptions since 2000. Ash plumes from these eruptions are a threat to air traffic between North America and Asia. Volcanic ash can damage the
exterior of an aircraft. It can also be pulled into jet engines where it melts, accumulates and can cause engine failure.
|Map: Where is Mount Cleveland?|
|Map showing the location of Mount Cleveland in the Aleutian islands of Alaska. The boundary between the North American plate and the Pacific plate is shown by the gray toothed line. The North American plate is to the north of this boundary and the Pacific plate is to the south of the boundary. The A-B line shows the location of the cross section below.
Mount Cleveland: Plate Tectonic Setting
The Aleutian Islands were formed by interactions between the North American and Pacific plates.
They are located on the southern edge of the North American plate where it collides with the Pacific plate (see map above) to form a convergent plate boundary.
In this area, the location of the plate boundary is marked on the ocean floor by the Aleutian Trench.
Map of Earth's Tectonic Plates
At the plate boundary, the Pacific plate is moving to the northwest and in collision with the North American plate,
which is moving in a southerly direction. At the boundary the Pacific plate descends steeply into the mantle to form a
subduction zone (see image below).
As the plate descends into the mantle its temperature rises and some of the rock begins to melt. Water contained within sea floor sediments carried down with the plate facilitates melting. Magma bodies produced from
this melting are lighter than the surrounding rock and will rise towards the surface. The magma bodies can cool within the
crust before reaching the surface or contribute to a volcanic eruption.
|Simplified plate tectonics cross section (A to B)|
|Simplified plate tectonics cross-section showing how Mount Cleveland is located on an island above a subduction zone formed where the Pacific plate descends beneath the North American plate. Magma produced from the melting Pacific plate rises to the surface and erupts to form the volcanic islands of the Aleutian island chain.
Mount Cleveland: Eruptive History
The earliest history of Mount Cleveland is the oral record of the Aleut people. They realized that
the mountain was a volcano and named it "Chuginadak", after their Goddess of Fire, who was thought to
live within the mountain. The Aleut people also knew that Mount Cleveland and the other half of
today's Chuginadak Island were once separate islands. The isthmus connecting the islands was formed
from volcanic debris produced during one of Cleveland's eruptions.
The written record for volcanic eruptions in the Aleutian Islands area begins in the early 1700's.
At that time very few people travelled near the island so eruptions there could go unnoticed and unrecorded.
Today the closest settlement is at Nikolski, about 50 miles (75 kilometers) away. Small eruptions at
Mount Cleveland could go unnoticed. If an eruption was noticed it could be very difficult to attribute it
to Cleveland or another nearby volcano without visiting the area for close observations.
For the above reasons, the eruptive history of Mount Cleveland is incomplete and contains uncertainty.
The eruption chart below shows just one eruption for the 1700s - and the attribution of that eruption
to Mount Cleveland is questionable. There could have been many more eruptions but they went unnoticed
or unrecorded. The island was more regularly seen by ships in the 1800s, by aircraft in the 1900s and
by continuous satellite monitoring in the 2000s. This increased observation probably explains why the recent record shows a
greater number of eruptions.
|Chart of the eruptive history of Cleveland Volcano by century. The greater
frequency of eruptions over the last century can most likely be attributed to closer observation and greater
interest. Data from the Alaska Volcano Observatory.
Activity at Mount Cleveland typically produces ash plumes, lava flows, pyroclastic flows and lahars. It has produced
VEI 3 eruptions several times. These occurred on: February 6, 2006; February 2 (?), 2001; May 25, 1994; June 19, 1987; and
June 10, 1944. The Smithsonian Institution has brief descriptions of historic eruptions and more detailed descriptions
of recent eruptions.
Today the incentive to monitor volcanoes in the Aleutian Islands is very high because of the risk that they
present to air traffic. Ash clouds can damage aircraft and cause jet engine failure. The Alaska Volcano Observatory
is operated as a joint program of the United States Geological Survey, the Geophysical Institute of the University of
Alaska Fairbanks, and the State of Alaska Division of Geological and Geophysical Surveys. AVO was formed in 1988 to monitor
Alaska's hazardous volcanoes, predict and record eruptive activity, and mitigate volcanic hazards.
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| A photo of Mount Cleveland taken on July 24, 1994. This image shows Cleveland's steep stratovolcano geometry. USGS image.|
|Facts About Mount Cleveland
||Chuginadak Island, Aleutian Islands, Alaska
||52° 49′ 20" N 169° 56′ 42" W
||1,730 meters (5,675 feet)
|Topographic Map - Chuginadak Island|
| A topographic map of Chuginadak Island. Mount Cleveland forms the western half of the island. According to the oral history of the Aleut people this was once two islands. Debris from a Cleveland eruption formed the isthmus between the two halves of the island. Enlarge for a view of this map that shows adjacent Kagamil Island, Carlisle Island and Herbert Island.
Mount Cleveland Geology and Hazards
An important danger posed by an eruption at Mount Cleveland is an ash plume that rises high into the atmosphere.
In May, 2001, eruptions at Mount Cleveland sent ash plumes to an elevation of about 30,000 feet (about 9 kilometers).
Airborne ash can damage the instruments and engines of overflying planes. When an ash eruption occurs, air traffic
must be rerouted. This disrupts schedules and significantly increases fuel costs.
|Mount Cleveland Ash Plume|
|GOES satellite image of an ash plume released by an eruption at Mount Cleveland on February 19, 2001. This ash cloud rose to an altitude of 30,000 feet (about 9 kilometers). The Alaska Volcano Observatory relies on satellite observations to detect eruptions of Aleutian volcanoes that are otherwise difficult to monitor. The red and yellow plume is ash being distributed by winds. NASA image.
|Mount Cleveland Spreading Ash Plume|
| GOES satellite image of an ash plume from Mount Cleveland being spread by the wind. This image shows how a single ash event can spread to disrupt an air space that is hundreds of miles in width. NASA image.
Mount Cleveland is an uninhabited island in a remote part of the Aleutian Island arc. The nearest settlement is
at Nikolski, about 50 miles (75 kilometers) away. Because this area has historically been poorly monitored, minor
eruptions may have gone unnoticed. Because several volcanoes are located close together, there has
been difficulty assigning eruptive activity to a specific volcano.
Today eruptions in this area are monitored by the Alaska Volcano Observatory. AVO has daily
access to remote-sensing data from a number of satellites. They use this data to monitor for ash in the atmosphere and
thermal anomalies on the ground. This data can detect heat produced by lava flows, ash eruptions and very shallow magma.
This type of information was used to detect the eruption on February 19, 2001, which sent plumes of ash to an elevation of
30,000 feet (about 9 kilometers), disrupting air traffic.
Did You Know? AVO has a webcam pointed at Mount Cleveland. It is located on
High Hill, near the village of Nikolski, on Umnak Island. Mount Cleveland is about 45 miles (72 kilometers)
from the camera and can be seen on days with excellent visibility.
A small network of seismographs is needed to detect and map the earthquake activity produced by magma moving beneath a
volcano. AVO does not have this type of monitoring on Chuginadak Island. It does have access to earthquake information
from the United States Geological Survey's Earthquake Hazards Program which would detect a very large eruption but not
detect minor activity that would produce an ash plume.
|More Mount Cleveland Information