What kinds of lava are most closely associated with composite cones?
What kind of lava is most closely associated with composite cones? Andesite magma the most common but not the only magma type tends to form composite cones.
What kind of volcano or volcanic feature is most closely associated with pyroclastic flows?
Stratovolcanoes show inter-layering of lava flows and pyroclastic material, which is why they are sometimes called composite volcanoes. Pyroclastic material can make up over 50% of the volume of a stratovolcano.
When contrasting lava from a composite volcano to lava from a shield volcano?
When contrasting lava from composite volcanoes to lava from shield volcanoes, composite volcanoes most often produce silica-rich lavas with high viscosities, whereas shield volcanoes produce basaltic lavas with low viscosities.
What materials make up composite volcanoes quizlet?
Composite volcanoes are made up of alternating layers of lava and ash (other volcanoes just consist of lava).
Which type of volcano releases thick or viscous lava that can reach great heights?
In fact, Mount Vesuvius is a composite volcano that is most famous for burying the ancient Roman city of Pompeii in up to 20 feet of volcanic ash in 79 AD. The explosiveness of their eruptions is due to the thick, highly viscous lava that is produced by composite cone volcanoes.
What are composite volcanoes also known as?
Composite volcanoes are also called stratovolcanoes. Some geologists avoid the use of the term “stratovolcano” because these volcanoes typically are not stratified and do not consist of orderly layers of lava flows and pyroclastic deposits.
Which of the following type of eruption was formed from lava and pyroclastic materials?
Stratovolcanoes 5. Composite or Stratovolcanoes (Fig. 5.14) erupt both lava and pyroclastic deposits. The slopes of stratovolcanoes are therefore composed of lava flows alternating with layers of pyroclastic deposits.
Which of the following contributes to explosive volcanic eruptions from a composite volcano?
The amount of dissolved gas in the magma provides the driving force for explosive eruptions. The viscosity of the magma, however, is also an important factor in determining whether an eruption will be explosive or nonexplosive.
How does the composition and viscosity of lava flows differ between composite volcanoes and shield volcanoes?
How does the composition and viscosity of lava flows differ between composite volcanoes and shield volcanoes? Composite volcanoes are mostly formed from thick, viscous, andesitic composition lava whereas shield volcanoes are formed from runny, less viscous, basaltic composition lava.
Which statement describes the composition and viscosity of the lava associated with shield volcanoes?
Which statement describes the composition and viscosity of the lava associated with shield volcanoes? Lava from shield volcanoes is mafic and has a low viscosity.
Which of the following types of lava flows is typically associated with silica rich lavas?
a lava dome's flow is silica-rich and has a high viscosity, whereas a fissure eruption is basaltic and has a low viscosity.
What material make up composite volcanoes?
Composition. Composite volcanoes—also called stratovolcanoes—are named for their composition. These volcanoes are built from layers, or strata, of pyroclastic material, including lava, pumice, volcanic ash, and tephra. The layers stack on each other with each eruption.
Which type of volcano releases thick viscous lava?
In fact, Mount Vesuvius is a composite volcano that is most famous for burying the ancient Roman city of Pompeii in up to 20 feet of volcanic ash in 79 AD. The explosiveness of their eruptions is due to the thick, highly viscous lava that is produced by composite cone volcanoes.
What type of eruption is composite volcano?
Composite volcanoes are built up by successive eruptions of domes, lava flows and pyroclastic flows, but also can experience large blasts that destroy large areas of their summits, such as the May 1980 explosion and landslide at Mount St. Helens. Landslides may occur during eruptions or at other times.
What materials make up composite volcanoes?
Composite volcanoes—also called stratovolcanoes—are named for their composition. These volcanoes are built from layers, or strata, of pyroclastic material, including lava, pumice, volcanic ash, and tephra. The layers stack on each other with each eruption.
What type of volcanoes are formed from viscous and sticky lava that does not flow easily?
Stratovolcano. Stratovolcanoes have relatively steep sides and are more cone-shaped than shield volcanoes. They are formed from viscous, sticky lava that does not flow easily.
Which type of volcano is composed of interbedded lavas and pyroclastic deposits?
Volcanoes built up of alternating eruptions of pyroclastic material and lavas are termed stratovolcanoes. They are one of the most common types of volcanoes, especially in the volcanic arcs above subduction zones. They consist of interbedded layers of tephra, both fallout and pyroclastic flow deposits, and lava flows.
How is magma composition related to viscosity?
Magmas differ in composition, which affects viscosity. Magma composition has a large effect on how a volcano erupts. Felsic lavas are more viscous and erupt explosively or do not erupt. Mafic lavas are less viscous and erupt effusively.
What makes lava viscous?
Temperature, composition, and volatile (gas) content largely determine the viscosity of lava. Temperature: The hotter the lava, the lower the viscosity (the thinner it is). The cooler the lava, the higher the viscosity (the thicker it is).
How do the eruptions that created the Columbia Plateau differ from eruptions that create large composite volcanoes?
How do the eruptions that created the Columbia Plateau differ from eruptions that create large composite volcanoes? Eruptions that created the Columbia Plateau ejected basaltic magma from fissures; eruptions that create large composite volcanoes eject silica-rich magma from vents.
What happens when a composite volcano erupts?
Because they are built of layers of viscous material, rather than fluid lava, composite volcanoes tend to form tall peaks rather than rounded cones. Sometimes the summit crater collapses to form a caldera. Composite volcanoes are responsible for the most catastrophic eruptions in history.
What type of eruption does a composite volcano have?
Composite volcanoes are built up by successive eruptions of domes, lava flows and pyroclastic flows, but also can experience large blasts that destroy large areas of their summits, such as the May 1980 explosion and landslide at Mount St. Helens. Landslides may occur during eruptions or at other times.
Is mafic lava viscous?
Because mafic lava is low viscosity, when it erupts from a volcano it flows downslope away from the vent, gradually cooling and crystallizing.
What makes a stratovolcano erupt?
Explosive eruptions occur at stratovolcanoes due to the high gas concentration in the magma. As the magma rises, the gases release, causing the pressure beneath the volcano to increase. Once this pressure becomes large enough, an explosive eruption occurs.
What are composite cones?
Composite cones are large volcanoes (many thousands of feet or meters tall) generally composed of lava flows, pyroclastic deposits, and mudflow (lahar) deposits, as well as lava domes. Composite volcanoes are active over long periods (tens to hundreds of thousands of years), and erupt periodically.
What is the type of eruption of composite volcano?
Cone volcanoes (also called composite cone or stratovolcanoes) such as Ruapehu, Taranaki / Egmont and Ngauruhoe, are characterised by a succession of small-moderate eruptions from one location. The products from the successive eruptions over thousands of years build the cones.
How do composite cone volcanoes erupt?
Composite volcanoes are built up by successive eruptions of domes, lava flows and pyroclastic flows, but also can experience large blasts that destroy large areas of their summits, such as the May 1980 explosion and landslide at Mount St. Helens. Landslides may occur during eruptions or at other times.
What is a composite cone volcano?
Composite cone volcanoes are also called stratovolcanoes. They form when different types of eruptions deposit different materials around the sides of a volcano. Alternating eruptions of volcanic ash and lava cause layers to form. Over time these layers build up.
What type of eruption does composite volcanoes have?
Composite volcanoes are built up by successive eruptions of domes, lava flows and pyroclastic flows, but also can experience large blasts that destroy large areas of their summits, such as the May 1980 explosion and landslide at Mount St. Helens. Landslides may occur during eruptions or at other times.
What type of volcanoes are formed from viscous?
Stratovolcano. Stratovolcanoes have relatively steep sides and are more cone-shaped than shield volcanoes. They are formed from viscous, sticky lava that does not flow easily. The lava therefore builds up around the vent forming a volcano with steep sides.