Dacite, a volcanic rock with about 65% silica. This amount of silica in dacite is a lot higher than the basalts of Hawaii which have less than 50% silica. The high silica content makes the magma "sticky" and can cause more pressure to build up. With so much pressure, eruptions from Mount St. Helens can be very violent like the famous 1980 eruption.
The material produced by the eruptions of Mount St. Helens have varied over time, but the eruptions of recent decades, including the 1980 eruption, have involved dacite magma, whish is of intermediate-felsic composition. The famous 1980 eruption produced ash and pumice rather than lava.
As Mount St. Helens is a volcano the slopes would be covered in layers of volcanic dust and lava.
Mount St. Helens is predominantly composed of andesite, which is an intermediate volcanic rock that forms from the partial melting of the Earth's crust. This type of rock gives Mount St. Helens its characteristic gray color and is related to the volcanic activity in the area.
As with many stratovolcanoes, the type of activity at Mount St Helens varies. In its famous 1980 eruption it produce massive clouds of ash and pumice and later built a lava dome. The rock formed was dacite. However, other material has erupted in the volcano's past, including basaltic lava flows.
Mt St Helen's eruption of 1980 was a pyrocastic flow diverse lava, ranging from olivine basalt to andesite and dacite). The magma is believed to come from another area laterally located to the east. Magma and rock under the volcano are cool.
a pyroclastic flow
The material produced by the eruptions of Mount St. Helens have varied over time, but the eruptions of recent decades, including the 1980 eruption, have involved dacite magma, whish is of intermediate-felsic composition. The famous 1980 eruption produced ash and pumice rather than lava.
As Mount St. Helens is a volcano the slopes would be covered in layers of volcanic dust and lava.
it has pyroclastic flow and has small eruptions of ash.
Hot lava
The 1980 eruption of Mount St. Helens did not produce lava flows. It was a plinian eruption that produced aolumn of ash and pyroclastic flows. Pyroclastic flows are avalanche-like masses of hot ash, rock, and gas that rase away from an erupting volcano at speeds that can reachinto the hundreds of miles per hour.
Mount St. Helens is predominantly composed of andesite, which is an intermediate volcanic rock that forms from the partial melting of the Earth's crust. This type of rock gives Mount St. Helens its characteristic gray color and is related to the volcanic activity in the area.
Mount St. Helens has produced lava flows in the past. However, the famous eruption in 1980 produced something much more dangerous: pyroclastic flows. These are avalanche-like currents of hot ash, rock, and gas that race out of a volcano. The initial pyroclastic flow from the lateral blast may have briefly been supersonic.
As with many stratovolcanoes, the type of activity at Mount St Helens varies. In its famous 1980 eruption it produce massive clouds of ash and pumice and later built a lava dome. The rock formed was dacite. However, other material has erupted in the volcano's past, including basaltic lava flows.
Mt St Helen's eruption of 1980 was a pyrocastic flow diverse lava, ranging from olivine basalt to andesite and dacite). The magma is believed to come from another area laterally located to the east. Magma and rock under the volcano are cool.
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is part of the Cascade Range. The mountain is well known for its catastrophic eruption in 1980 which dramatically changed its landscape.
Mount St. Helens is a stratovolcano, also known as a composite volcano. This type of volcano is characterized by its steep slopes and explosive eruptions due to a mixture of lava flows and pyroclastic material.