Do composite volcanoes have high or low viscosity?

The volcanoes form steep cones, rather than rounded shapes, because the magma is viscous. Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.

Do composite volcanoes have high viscosity?

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.

Are composite volcanoes low viscosity?

The magma rising into a composite volcano has a higher viscosity than average because it is felsic, which means it contains silicate rich minerals.

What viscosity are composite volcanoes?

They tend to be made of felsic to intermediate rock and the viscosity of the lava means that eruptions tend to be explosive. The viscous lava cannot travel far down the sides of the volcano before it solidifies, which creates the steep slopes of a composite volcano.

What type of volcanoes have high viscosity?

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.

Why do composite volcanoes have high viscosity?

Magmas that are more rhyolitic have a higher gas content. This gas content and relative viscosity leads to the more explosive and violent eruptions that occur at composite volcanoes.

Do lava dome volcanoes have high or low viscosity?

Lava Domes or Volcanic Domes – result from the extrusion of highly viscous, gas poor andesitic and rhyolitic lava. Since the viscosity is so high, the lava does not flow away from the vent, but instead piles up over the vent.

What type of lava is in a composite volcano?

felsic

Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.

What are the characteristics of composite volcano?

Composite volcanoes have the following characteristics:

• Acidic lava, which is very viscous (sticky).
• Steep sides as the lava doesn’t flow very far before it solidifies.
• Alternate layers of ash and lava. For this reason, they’re also known as stratovolcanoes . …
• Violent eruptions.
• Longer periods between eruptions.

Which type of lava has the lowest viscosity?

The least viscous of the silicate lavas is basaltic lava which has the highest temperature, around 1,000-1,200 degrees Celsius and is therefore also the most liquid as lava becomes more viscous as it cools.

What magma has the highest viscosity?

The magma that has the highest viscosity is rhyolitic magma.

Why do lava domes and composite volcanoes differ in morphology?

Unlike composite and shield volcanoes, lava domes are of significantly smaller stature. They are formed when the lava is too viscous to flow to a great distance. As the lava dome slowly grows, the outer surface cools and hardens as the lava continues to pile within.

Does lava have high viscosity?

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. This creates the classic rivers of lava, with channels, puddles and fountains.

Do composite volcanoes have high silica content?

Composite volcanoes mostly extrude lava of intermediate silica content and medium to high viscosity known as andesite.

What does viscosity mean in volcanoes?

When it comes to liquids, viscosity is a measurement of how thick or syrupy it is. … 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 high viscosity?

High viscosity means that the thickness of the material is very thick compared to low viscosity which is rather thin. Liquids like water have a much lower viscosity compared to liquids such as honey.

How does viscosity of lava determine the shape of volcanoes?

The low viscosity of the magma allows the lava to travel down slope on a gentle slope, but as it cools and its viscosity increases, its thickness builds up on the lower slopes giving a somewhat steeper lower slope. Most shield volcanoes have a roughly circular or oval shape in map view.

What is the difference between viscous and non viscous lava?

Answer and Explanation: Lava varies in viscosity based on its temperature and mineral composition. Non-viscous magma is magma with a low viscosity that can flow for great distances. This type of magma tends to create gently sloping shield volcanoes as a result.

What is the difference between high and low viscosity magma?

High viscosity lavas flow slowly and typically cover small areas. In contrast, low viscosity magmas flow more rapidly and form lava flows that cover thousands of square kilometers.

What volcano has lava type is highly viscous?

Composite Cones – Stratovolcanoes

Intermediate lavas are more viscous than the mafic lava which forms shield volcanoes (see above) and normally contain more volatiles. Sometimes the lava flows out as a thick, slowly-flowing fluid which is not able to flow too far before crystallizing.

What is low viscosity?

Viscosity is a measure of a fluid’s resistance to flow.

A fluid with low viscosity flows easily because its molecular makeup results in very little friction when it is in motion.

What is low and high viscosity?

Fluids with low viscosity have a low resistance and shear easily and the molecules flow quickly; high viscosity fluids move sluggishly and resist deformation. Some liquids, like pitch, glass and peanut butter, have such high viscosity they behave like solids.

Is high viscosity thick or thin?

The higher the viscosity of a liquid, the thicker it is and the greater the resistance to flow.

What is an example of high viscosity?

Liquids which flow very slowly, like glycerin or honey, have high viscosities. Those like ether or gasoline which flow very readily have low viscosities.

What has the highest viscosity?

Honey is between 2,000 and 10,000 times more viscous than water. Some fluids are so viscous they appear to be solid and yet, over time, slowly flow. One of the most viscous liquids known is pitch, also known as bitumen, asphalt, or tar.

Does air have low viscosity?

The viscosity of air depends mostly on the temperature. At 15 °C, the viscosity of air is 1.81 × 10^–5 kg/(m·s) , 18.1 μPa·s or 1.81 × 10^–5 Pa·s . The kinematic viscosity of air at 15 °C is 1.48 × 10^–5 m² /s or 14.8 cSt. At 25 °C, the viscosity is 18.6 μPa·s and the kinematic viscosity 15.7 cSt.