Geologists call Mount St. Helens a composite volcano (or stratovolcano), a term for steep-sided, often symmetrical cones constructed of alternating layers of lava flows, ash, and other volcanic debris.
What type of volcano is Mount St Helens?
Mount St. Helens is a stratovolcano, a steep-sided volcano located in the Pacific Northwest region of the United States in the state of Washington. Sitting about 97 miles south of Seattle and 52 miles northeast of Portland, Oregon, Mt.
What type of volcano is Mt St Helens and why did it form?
Mount St. Helens is primarily an explosive dacite volcano with a complex magmatic system. The volcano was formed during four eruptive stages beginning about 275,000 years ago and has been the most active volcano in the Cascade Range during the Holocene.
What type of volcano was Mount Saint Helens pre eruption?
PHYSIOGRAPHY. Mt. St. Helen’s was known as one of the most picturesque stratovolcanoes in the Cascade Range before its violent eruption on May 18, 1980.
What type of volcanoes are Mt St Helens and Mt Rainier?
Mount Rainier as seen from the crater rim of Mount St. Helens, overlooking Spirit Lake. Mount Rainier is an episodically active composite volcano, also called a stratovolcano.
Is Mt St Helens divergent or convergent?
Mt. St. Helens is a volcano in Washington, near the Oregon border, in the Cascade Range. The Cascade Volcanoes, which stretch all from British Columbia through Northern California, are stratovolcanoes that have formed inland from a convergent plate boundary, where ocean crust is subducting below the continent.
Is Mt St Helens a shield volcano?
Mount St. The two volcanoes are also different shapes: Kilauea is a gently sloping shield volcano, unlike Mount St. Helens, which is a steep-sided stratovolcano, also known as a composite volcano. This allows for different types of eruptions, with shield volcanoes being much less violent.
What type of volcano is Mt St Helens shield or composite?
Geologists call Mount St. Helens a composite volcano (or stratovolcano), a term for steepsided, often symmetrical cones constructed of alternating layers of lava flows, ash, and other volcanic debris. Composite volcanoes tend to erupt explosively and pose considerable danger to nearby life and property.
What type of plate boundary is Mt St Helens?
2.1 Approximately how far is Mount St. Helens from the convergent plate boundary separating the Juan de Fuca and North American plates? Mount St. Helens, like the other volcanoes of the Cascades, is composed of andesitic and rhyolitic pyroclastic materials.
What type of volcano is Mt Etna?
This active stratovolcano on the east coast of Sicily is almost always venting steam into the atmosphere. Stratovolcanoes form as alternating layers of volcanic ash and lava flows come from their central vents and cool to form rock.
What type of volcano is Mount St. Helens and what caused the explosion quizlet?
What type of volcano is Mount St. Helens and what caused the explosion? It is a strato-volcano that exploded when trapped gasses were quickly released. The most violent volcanic eruptions occur when gasses cannot easily escape from the magma.
How did Mount Saint Helens form?
Mt St Helens is a major stratovolcano in the Cascades Range, all of which have formed as a result of the ongoing subduction of the Juan de Fuca tectonic plate beneath the western coast of North America. Prior to 1980, Mt St Helens was a classical cone-shaped volcano, and a well-visited site on the tourist trail.
Is Mt St Helens effusive or explosive?
Helens can be confidently classified as an explosive eruption. The common image of red hot lava flowing down Kilauea and covering roads and houses is an effusive eruption. However, predominantly explosive volcanoes such as Mount St.
What type of volcano is Kilauea?
Kīlauea Volcano is a shield volcano located on the eastern slope of Mauna Loa Volcano on the Island of Hawai’i. The volcano is considered to be in the shield-building stage of Hawaiian volcanism.
Are there active volcanoes in Washington State?
Washington State is home to five active volcanoes located in the Cascade Range, east of Seattle: Mt. Baker, Glacier Peak, Mt. Rainier, Mt. Washington and California are the only states in the lower 48 to experience a major volcanic eruption in the past 150 years.
What type of volcano is Newberry Volcano?
Newberry Volcano is a large active shield volcano located about 20 miles (32 km) south of Bend, Oregon, United States, 35 miles (56 km) east of the major crest of the Cascade Range, within the Newberry National Volcanic Monument. Its highest point is Paulina Peak.