All volcanoes share a common fundamental process: the movement of magma from the Earth's interior to the surface. This process can be broken down into several key stages:
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Magma Generation: Magma forms in the Earth's mantle due to the melting of rock, which can occur due to temperature increases, pressure decreases, or the addition of volatiles (like water).
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Magma Ascent: Once formed, magma tends to rise toward the surface because it is less dense than the surrounding solid rock. This ascent can create fractures and pathways through which the magma can travel.
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Magma Storage: The magma can accumulate in chambers beneath the surface, where it may undergo changes in composition, temperature, and pressure.
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Eruption: When the pressure in these magma chambers builds sufficiently, or when the composition of the magma changes (often due to gas accumulation), an eruption occurs, releasing magma, ash, and gases into the atmosphere.
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Formation of Volcanic Features: Over time, the erupted materials can build up around the vent to form various volcanic structures, such as cones, shields, or calderas, depending on the eruption style and the properties of the erupted material.
Regardless of the specific tectonic setting or the type of volcano (stratovolcano, shield volcano, fissure eruption, etc.), the underlying process of magma generation, ascent, storage, and eventual eruption is common to all volcanoes.