What causes a volcano to erupt?

Answer

A volcano erupts when the pressure of a subterranean pool of magma becomes great enough to crack the earth's crust. Whether the eruption results in a violent explosion or a slow seepage depends on several different factors, according to How Stuff Works.

Molten rock, called magma, forms underground when Earth's tectonic plates collide or move apart, or when activity within the mantle, a very hot layer beneath the earth's crust, causes the crust to melt. Magma contains dissolved gases that remain dissolved as long as the pressure of the gas is not greater than the confining pressure of the solid rock around it. If the vapor pressure becomes great enough, the gas forms small bubbles within the magma. These bubbles are less dense than the surrounding magma, so they push upward to escape it, and an eruption occurs. The composition of the magma is an important factor in determining the force of this eruption. If it contains larger amounts of gas, it erupts more violently. Another factor is the viscosity of the magma. Magma with a high viscosity resists flowing, and the gas bubbles must forcefully push out more material to escape. On the other hand, magma with a low gas content and low viscosity is likely to result in a slow, non-explosive eruption.

Q&A Related to "What causes a volcano to erupt?"
Volcano eruptions are caused mainly be the shifting of underground plates at a speed greater than our control. When the plates shift, gases are released and the heat of the underground
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A volcano can best be described as a fissure in the earth's crust. This fissure is filled with gases and molten lava (rock) The volcano is the opening through which these gases and
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Volcanoes causes to errupt when the inner core of the earth holds more pressure or heat temperature inside it. Volcanoes are the outside source of releasing the lava and magmas that
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Volcanology is a branch of geology, the study of the earth. Volcanology emphasizes studies of the processes, products, hazards, and environmental impacts of volcanic eruptions. Volcanologists
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1 Additional Answer
Ask.com Answer for: what causes a volcano to erupt
Several factors trigger volcanic eruptions, including the buoyancy of magma, a build-up of pressure from the gases in the magma and an injection of new magma into a full magma chamber.
When a part of the earth's upper mantle or lower crust melts, magma forms. A volcano is essentially an opening or a vent through which this magma and the dissolved gases it contains are discharged.
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