How is the lava from a composite volcano different from a shield volcano?
Composite volcanoes have a low magma supply rate, resulting in infrequent eruptions. Shield volcanoes feature basaltic lava. This type of lava is hot, fluid and low in gas content. Shield volcanoes are characterized by a high magma supply rate, lending itself to frequent eruptions.
How does the composition and viscosity of lava flows differ between composite volcanoes and shield volcanoes quizlet?
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.
How does the composition of a typical lava dome differ from that of a typical fissure eruption quizlet?
How does the composition of a typical lava dome differ from that of a typical fissure eruption? a lava dome's flow is silica-rich and has a high viscosity, whereas a fissure eruption is basaltic and has a low viscosity.
How do the eruptions that created the Columbia Plateau differ from eruptions that create large composite volcanoes?
The Columbia Plateau was generated from fissure eruptions, or extrusion of basaltic magma from fissures in Earth's crust. These magmas spread far and wide. Large composite volcanoes are made from andesitic magmas and are generally the result of much more violent eruptive events.
How would you compare and contrast the three main types of volcanoes?
- Shield Volcanoes. -broad, slightly dome shaped. -not steep. -mild eruptions of large volumes of basaltic lava.
- Cinder Cones. -small size. -steep slope angle. -built from ejected lava fragments.
- Composite Volcanoes. -symmetrical cone. -many located in Pacific Ring of Fire.
What type of lava does a shield volcano have?
basaltic Shield volcanoes are usually constructed almost entirely of basaltic and/or andesitic lava flows which were very fluid when erupted.
What is viscosity and what is the relationship between viscosity and the way in which a volcano erupts?
You can measure lava in terms of viscosity as well. And the lava viscosity defines the size and shape of a volcano. Even though lava is 100,000 times more viscous than water, it can still flow great distances. When lava has low viscosity, it can flow very easily over long distances.
What is viscosity and what factors influence the viscosity of magma How does viscosity affect the explosiveness of a volcano?
How does magma viscosity influence the explosive potential? A more viscous (thick) magma will produce a more violent eruption This is controlled in part by the concentration of silica in the magma. A magma with low silica (<45%) will be runny and so the eruption will not be explosive. …
Why are shield volcanoes wider than composite volcanoes?
The magma that creates shield volcanoes is less viscous so it flows much more easily. For this reason the eruptions of shield volcanoes are non-explosive. In addition the less viscous lava spreads out more which makes shield volcanoes much larger and flatter than stratovolcanoes.
Which of the following factors influence the composition of a magma?
The composition of magma depends on the rock it was formed from (by melting), and the conditions of that melting. Magmas derived from the mantle have higher levels of iron, magnesium, and calcium, but they are still likely to be dominated by oxygen and silicon.
What causes a shield volcano to be shaped like a broad dome It is formed from?
It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form.
How are volcanoes different from each other?
When magma erupts at the surface as lava, it can form different types of volcano depending on: the viscosity, or stickiness, of the magma. the amount of gas in the magma. the composition of the magma.
What type of lava does a composite volcano have?
Magma Composition Composite volcanoes usually erupt a range of compositions from basalt to rhyolite, but intermediate (andesitic) and dacitic magmas are most common. Mount Rainier has less compositional diversity than many composite cones as it consists of mostly andesitic lava flows and lahar deposits.
Why do shield volcanoes have thin lava?
It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form.
Do composite volcanoes have high viscosity?
There are two types of volcanoes. Composite volcanoes have steep slopes consisting of layers of lava and ash, and often have very explosive eruptions. This type of volcano is found along convergent boundaries and has a very high viscosity. The gas content is high, but the temperature is low.
How does composition affect the viscosity of magma?
Viscosity of Magmas Viscosity depends on primarily on the composition of the magma, and temperature. Higher SiO2 (silica) content magmas have higher viscosity than lower SiO2 content magmas (viscosity increases with increasing SiO2 concentration in the magma).
Do shield volcanoes have high or low viscosity?
Most commonly, they are comprised of basaltic lavas, but some shield lavas of the high silica 'peralkaline' family have very low viscosity – equivalent to or sometimes even lower than basalt (Figure 20). Figure 20. Shield volcanoes form over great spans of time with the effusion of low-viscosity lava.
What type of lava erupts from shield volcanoes?
basalt Shield volcanoes are usually basalt but can be constructed of mostly andesitic lava flows. Mauna Loa and Kīlauea erupt almost exclusively basaltic lavas.
What is the difference between the composition of lava and magma?
Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth's surface.
What is the difference between the composition of lava and magma Brainly?
Earth Science FAQs – Volcanoes Magma is composed of molten rock and is stored in the Earth's crust. Lava is magma that reaches the surface of our planet through a volcano vent.
What is the difference between composite cone volcanoes and shield cone volcanoes?
Composite cone volcanoes are cone-shaped volcanoes composed of layers of lava, ash and rock debris. Composite cone volcanoes can grow to heights of 8,000 feet or more and have explosive eruptions. Shield volcanoes are broad, domed-shaped volcanoes with long, gently sloped sides.
How will you compare the different types of volcanic eruption?
Hawaiian eruptions have fire fountains and lava flows, whereas Strombolian eruptions have explosions causing a shower of lava fragments. Vulcanian eruptions are small to moderate explosive eruptions, lasting seconds to minutes.
Do shield volcanoes have high viscosity?
Shield volcanoes Where a volcano produces low viscosity, runny lava, it spreads far from the source and forms a volcano with gentle slopes: a shield volcano. Most shield volcanoes are formed from fluid, basaltic lava flows.
How does composition affect viscosity?
The viscosity of a liquid is related to the ease with which the molecules can move with respect to one another. Thus the viscosity of a liquid depends on the: strength of attractive forces between molecules, which depend on their composition, size, and shape.
How magma composition affects the eruption of a volcano?
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 kind of lava does a shield volcano have?
basaltic Shield volcanoes are usually constructed almost entirely of basaltic and/or andesitic lava flows which were very fluid when erupted.
Why are composite volcanoes more explosive than shield volcanoes?
Lavas and pyroclastics are usually andesitic to rhyolitic in composition. Due to the higher viscosity of magmas erupted from these volcanoes, they are usually more explosive than shield volcanoes.
What is the difference between magma and lava quizlet?
Magma and lava both refer to molten rock from which igneous rocks form. However, magma refers to molten rock below Earth's surface, and lava refers to molten rock at the surface.
What is magma How does magma differ from lava quizlet?
How does magma differ from lava? Magma is molten rock below the Earth's surface, lava is molten rock that has erupted onto the surface.
What is the difference between the composition of lava and magma answer?
Earth Science FAQs – Volcanoes Magma is composed of molten rock and is stored in the Earth's crust. Lava is magma that reaches the surface of our planet through a volcano vent.