Is Felsic Lava Viscous?

What makes Lava viscous?

The cooler the lava, the higher the viscosity (the thicker it is).

Composition: he more felsic the lava (the more silica in the lava), the higher the viscosity because silica forms chains in the cooling lava even before it crystallizes.

The more mafic the lava (the less silica in it), the lower the viscosity..

Why is felsic lava so much more viscous than mafic lava?

Felsic magma has more silica and alumina content, which makes magma more viscous. Mafic magma has less silica content and more iron and magnesium in it. The amount of gas in the magma helps determine how explosive the eruption will be. … Viscous lava flows tend not to flow far and therefore build up steep slopes.

Is lava hotter than fire?

In fact, as it spills out onto Earth’s surface as lava, the runny rock’s temperature is only a little lower than the hottest part of a candle flame: about 1200 °C. On the other hand, a big blob of lava contains many more bouncing particles than a small candle flame, so it has a lot more heat energy.

Why is lava so dangerous?

Deaths attributed to lava flows are often due to related causes, such as explosions when lava interacts with water, the collapse of an active lava delta that forms where lava enters a body of water, asphyxiation due to accompanying toxic gases, pyroclastic flows from a collapsing dome, and lahars from meltwater.

Is felsic magma more viscous?

Felsic magma is viscous and does not flow easily. Most felsic magma will stay deeper in the crust and will cool to form igneous intrusive rocks such as granite and granodiorite. If felsic magma rises into a magma chamber, it may be too viscous to move and so it gets stuck.

What type of lava is viscous?

An example of a low viscosity (fast flowing) lava is basaltic lava. This flows quickly out of a volcano at a temperature of about 950 degrees Celsius. This flows out for great distances creating shield volcanoes or flood basalt fields. An example of high viscosity lava is felsic lava, like rhyolite or dacite.

Can lava kill you?

Lava won’t kill you if it briefly touches you. You would get a nasty burn, but unless you fell in and couldn’t get out, you wouldn’t die. … People have been killed by very fast moving lava flows. A recent example was the 1977 eruption at Nyiragongo.

Which lava has the highest viscosity?

rhyoliticThe magma that has the highest viscosity is rhyolitic magma.

What are the 3 types of volcano?

Volcanoes are classified by the eruption type and by the volcanic cone shape. There are three basic cone shapes and six eruption types. The three cone shapes are cinder cones, shield cones, and composite cones or stratovolcanoes.

What are the 3 major types of magma?

There are three basic types of magma: basaltic, andesitic, and rhyolitic, each of which has a different mineral composition. All types of magma have a significant percentage of silicon dioxide. Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium.

Is Lava viscous?

Although lava can be up to 100,000 times more viscous than water, lava can flow great distances before cooling and solidifying because of its thixotropic and shear thinning properties.

Which volcanoes are more likely to explode thick lava or thin lava?

The lava that flows from both types of eruptions is very hot, thin, and runny which allows for fast flowing lava flows. The main difference lies in the fact that most Hawaiian eruptions have the greatest quantity of lava pouring out of the main vent at the volcano’s summit, not along side fissures.

Why does silica increase viscosity?

In other words, as magma cools, its viscosity increases. This property is increased by crystallization of magma while temperature decreases. Finally, the composition of a magma highly affects its viscosity. A higher concentration in silica leads to a more acid/more viscous magma.

Why do some volcanoes erupt violently while others erupt quietly?

The two main factors that influence how a volcano will erupt are viscosity and gas content. … The magma is very sticky and resists the expansion of the gas bubbles. Ultimately, enough bubbles grow and expand to blow the magma into ash size fragments and eject them violently into the atmosphere.

Which type of volcano has the most violent eruptions?

StratovolcanoesStratovolcanoes are considered the most violent. Mount St. Helens, in Washington state, is a stratovolcano that erupted on May 18, 1980.