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How does gas pressure affect the rising of magma in volcanic eruptions?

How does gas pressure affect the rising of magma in volcanic eruptions?

At depth in the Earth nearly all magmas contain gas dissolved in the liquid, but the gas forms a separate vapor phase when pressure is decreased as magma rises toward the surface of the Earth. Gas gives magmas their explosive character, because volume of gas expands as pressure is reduced.

How do dissolved gases cause explosive eruptions?

The standard explanation for explosive volcanism is that as liquid magma rises from a magma chamber at a depth of several miles, dissolved gases – mostly water – form bubbles. As bubbles grow, the overall magma volume increases, causing it to rise even faster.

Why is it dangerous to live near an active volcano?

In addition, the thermal energy from some volcanoes can be used to generate electric power. But if you live too close to a volcano—and it erupts—it can be lethal. If you live with a volcano like Merapi, it’;s wise to watch it closely. Volcanoes provide fertile soil–as well as deadly hot hurricanes of lava and ash.

How does the gas content of a volcano affect the eruption?

This is true for volcanoes as well. As the bubbles escape, they push the magma out, causing a spewing eruption. This content is not compatible on this device. The nature of this eruption depends mainly on the gas content and the viscosity of the magma material.

How is the severity of a magma eruption determined?

The severity of the eruption depends mostly on the composition of the magma. The first question to address is: why does the magma erupt at all? The erupting force generally comes from internal gas pressure. The material that forms magma contains a lot of dissolved gases — gases that have been suspended in the magma solution.

As the bubbles escape, they push the magma out, causing a spewing eruption. The nature of this eruption depends mainly on the gas content and the viscosity of the magma material. Viscosity is just the ability to resist flow — essentially, it is the opposite of fluidity.

Why does the vapor pressure of magma increase?

The vapor pressure increases because the magma cools, initiating a crystallization process that enriches the gas content of the magma. In either case, what you get is magma filled with tiny gas bubbles, which have a much lower density than the surrounding magma, and so push out to escape.