GEOLOGY

Detailed explanation-1: -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.

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: -Mt. St. Helens typically generates explosive pyroclastic eruptions, in contrast to many other Cascade volcanoes, such as Mt. Rainier which typically generates relatively non-explosive eruptions of lava.

Detailed explanation-4: -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-5: -The answer lies in the chemical compositions of the magmas produced by the two volcanoes. The basalt magma erupted by Kīlauea contains about 52% silica and about 0.5 % water while the dacite lava erupted by Mount St. Helens in 1980 contained more of both: about 64% silica and about 4% water.