West Crater facts for kids
Quick facts for kids West Crater |
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| Highest point | |
| Elevation | 4,131 ft (1,259 m) |
| Geography | |
 West Crater
Location in Washington (state)
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| Location | Skamania County, Washington, U.S. |
| Parent range | Cascade Range |
| Topo map | Lookout Mountain |
| Geology | |
| Age of rock | Holocene |
| Mountain type | lava dome |
| Volcanic arc | Cascade Volcanic Arc |
| Last eruption | ~8,000 years BP |
West Crater is a small lava dome (a type of volcano) found in southern Washington, United States. It is located in Skamania County and stands about 4,131 feet (1,259 m) tall. West Crater is part of the Cascade Volcanic Arc, a chain of volcanoes in the western U.S.
It is also part of the Marble Mountain-Trout Creek Hill volcanic field. This area has many small volcanoes. You can visit West Crater by hiking, and it's easy to get to using roads in the Gifford Pinchot National Forest.
West Crater is one of 13 volcanoes in its area, which covers about 39 square miles (100 km2). These volcanoes range in age from 360,000 years old to 2,000 years old. West Crater has a crater at its top that is 660 feet (200 m) wide and 79 feet (24 m) deep. Its lava dome formed in a valley carved by a glacier. It's similar in size to the lava dome that appeared after the 1980 eruption of Mount St. Helens.
West Crater has erupted at least two large lava flows about 8,000 years ago. These flows stretched about 2 miles (3.2 km) from the volcano. They flowed into canyons and are slowly being worn away by streams. Scientists believe the lava dome formed before these lava flows erupted.
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Where is West Crater?
West Crater is located in Skamania County, in the state of Washington. It reaches a height of 4,131 feet (1,259 m) above sea level. The volcano was officially named in 1979.
You can reach West Crater and other volcanoes in the Marble Mountain-Trout Creek Hill area using roads in the Gifford Pinchot National Forest and Mount St. Helens National Volcanic Monument. Washington Route 503 and Forest Service Route 90 are about 31 miles (50 km) east of Woodland. To get to West Crater, you can travel north on the Wind River highway and then take Forest Service road 54.
How West Crater Formed
The Cascade Range is a long chain of mountains and volcanoes in western North America. It stretches for about 600 miles (970 km) from Canada down to northern California. The volcanoes in this range, including West Crater, were created because the Juan de Fuca tectonic plate is slowly sliding underneath the North American Plate. This process is called subduction.
The Cascade Mountains in Washington are made of volcanic rocks from different time periods. The older parts, called the Western Cascades, formed between 50 and 5 million years ago. The younger parts, called the High Cascades, formed in the last 5 million years. The High Cascades are mostly untouched by major ground movements, while the Western Cascades have more folds and cracks.
The area around West Crater sits on top of old lava flows and volcanic ash. The Cascade Arc, the main chain of volcanoes, began forming about 34 million years ago. Volcanic activity increased in Washington about 2.6 million years ago, with new volcanoes forming.
West Crater is part of the Marble Mountain-Trout Creek Hill volcanic field. This field is made up of small shield volcanoes and cinder cones. It covers an area of about 12 miles (20 km) and is located south of Mount St. Helens. This field has at least 22 small volcanoes. Many of these volcanoes are "monogenetic," meaning they erupted only once or a few times.
The West Crater-Soda Peaks area, which includes West Crater, is about 22 miles (35 km) southeast of Mount St. Helens. It has 13 volcanoes that are between 360,000 and 2,000 years old.
West Crater itself is a small lava dome. It is made of a type of lava called andesite. The dome is about 950 feet (290 m) tall and 3,166 feet (965 m) wide. It has a crater at its top that is 660 feet (200 m) wide and 79 feet (24 m) deep. There is still a small amount of hardened lava at the bottom of this crater. The lava dome formed in a bowl-shaped valley created by a glacier. It is similar in size to the lava dome that grew inside Mount St. Helens after its big eruption in 1980.
When West Crater Erupted
West Crater has erupted at least two large lava flows. Each of these flows extends about 2 miles (3.2 km) from the volcano. They flowed into canyons and are now slowly being worn away by local streams. These lava flows are gray and contain small crystals. The western flow has ridges up to 9.8 feet (3 m) high and two walls, called levees, up to 49 feet (15 m) high. The eastern flow has a rough surface and was thicker than the western flow.
Scientists believe West Crater erupted about 8,000 years ago. Its lava flows are mixed with ash from an eruption of Mount St. Helens and ash from the huge eruption of Mount Mazama (which formed Crater Lake) about 7,700 years ago.
In the Marble Mountain-Trout Creek Hill area, only two other volcanoes have erupted in the last 11,700 years (the Holocene epoch). These are a cone near Hackamore Creek and a steam explosion crater at Bare Mountain's top. It's possible these volcanoes erupted at the same time as West Crater. One of West Crater's lava flows is even mixed with a lava flow from the Hackamore Creek cone. Their similar ages and locations suggest they might have come from the same underground magma chamber.
Scientists think the lava dome of West Crater formed before the lava flows erupted. This is suggested by its steep western side and the fact that rock from the dome is found on the western lava flow. The 20 feet (6 m) deep dip on the dome's top might have formed when the top collapsed as lava flowed out during the eruptions.
Is West Crater Dangerous?
About 500 people live within 6.2 miles (10 km) of West Crater. More than 14,000 people live within 19 miles (30 km), and over 2 million live within 62 miles (100 km). However, the United States Geological Survey says that the chance of West Crater causing harm is "Low/Very Low."
Visiting West Crater
You can get to West Crater by driving northwest on Wind River Road to Stabler. From there, follow Forest Road 54 to Forest Road 34, and then go about a mile to the left. There is a trail called Trail #155 West Crater that runs through the area for about 0.39 miles (0.63 km). This trail is only for hiking; you cannot use bicycles or motorized vehicles on it.
