GEOLOGY

Detailed explanation-1: -Mount St. Helens is an example of a composite or stratovolcano. These are explosive volcanoes that are generally steep-sided, symmetrical cones built up by the accumulation of debris from previous eruptions and consist of alternating layers of lava flows, volcanic ash and cinder.

Detailed explanation-2: -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.

Detailed explanation-3: -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.

Detailed explanation-4: -Composite volcanoes are tall, symetrically shaped, with steep sides, sometimes rising 10, 000 feet high. They are built of alternating layers of lava flows, volcanic ash, and cinders. Famous composite volcanoes include Mount Fuji in Japan, Mount Shasta and Mount Lassen in California, Mount St.

Detailed explanation-5: -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.