0
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.
Landen Heaney
Wiki User
∙ 6y agoDacite, 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.
Wiki User
∙ 11y agoThe eruption of 1980 was Plinian in nature, however, the collapse of the Northern flank removed the confining pressure rapidly, causing volatiles to exsolve explosively and leading to a lateral debris avalanche (pyroclastic flow), more typical of the Pelean eruption style (and Nuee Ardentes). The eruption was also accompanied by a hydrothermal blast.
Sources: Own knowledge. Use link for reference: http://www.geology.sdsu.edu/how_volcanoes_work/Sthelens.html
Wiki User
∙ 9y agoThe 1980 eruption of Mount St. Helens did not produce lava flows. It was a highly explosive Plinian eruption that produced a massive plume of ash and pyrolastic flows. These are not lava flows but rather avalanche-like masses of hot ash, rock, and gas. Some time after that eruption Mount St. Helens produced a lava dome, which consists of lava so viscous that it piles up at the vent rather than flowing away.
Add your answer:
Earn +20 pts
What kind mountain is mount st Helens?
Mount St. Helens consists of lava rock interlayered with ash, pumice and deposits, together with layers of basalt and andesite.
What type of rock layer does mount st helens have?
As Mount St. Helens is a volcano the slopes would be covered in layers of volcanic dust and lava.
Mount St Helens has layers of this type of rock as well as Andesite through which several domes of Dacite lava have erupted?
The rock type you're looking for is basalt -- St. Helens contains basalt, andesite, and dacite in the form of lava flows and pyroclastic deposits.
What rock type is mount st Helens?
the type of material it is, is a composite which has high eruptive forces, has high silica content, and has high gas content. which makes it an eruption product of gas and ash.
What type of volcano rock fragment or lava comes out of mt st helens?
Mount St Helens erupts dacitic lava, which forms dacite when it cools. Because of the high gas content and high viscosity much of the material gets erupted as ash and pumice rather than lava.
What type of eruption does mount saint helens have?
a pyroclastic flow
What kind mountain is mount st Helens?
Mount St. Helens consists of lava rock interlayered with ash, pumice and deposits, together with layers of basalt and andesite.
What type of lava flow does mount meakan have?
it has pyroclastic flow and has small eruptions of ash.
What type of rock layer does mount st helens have?
As Mount St. Helens is a volcano the slopes would be covered in layers of volcanic dust and lava.
What type of lava forms mt.st helens?
Hot lava
Mount St Helens has layers of this type of rock as well as Andesite through which several domes of Dacite lava have erupted?
The rock type you're looking for is basalt -- St. Helens contains basalt, andesite, and dacite in the form of lava flows and pyroclastic deposits.
What rock type is mount st Helens?
the type of material it is, is a composite which has high eruptive forces, has high silica content, and has high gas content. which makes it an eruption product of gas and ash.
What type of lava flow did mt st helens have?
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.
What type of volcano rock fragment or lava comes out of mt st helens?
Mount St Helens erupts dacitic lava, which forms dacite when it cools. Because of the high gas content and high viscosity much of the material gets erupted as ash and pumice rather than lava.
What type of flow does mt st helens have?
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.
Is dike a type of lava flow?
No, a dike is not a type of Lava flow.
What type of volcanic rock or lava fragments come out of mt Saint Helens?
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.
