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What are magma bubbles?
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. These bubbles grow in size, because the pressure in the surrounding magma decreases as it rises toward the surface.
How does the formation of bubbles in a magma impact the magma density?
As the bubbles degas, they lose pressure and collapse, increasing the density of the magma and causing it to sink, perhaps at the margins of the conduit (q). Viscous magmas may degas in this manner, as long as mass flow is sustained from depth.
What do the gas bubbles create in the magma?
When this magma reaches the surface, the gas bubbles will have a high pressure inside, which will cause them to burst explosively on reaching atmospheric pressure. This will cause an explosive volcanic eruption.
What makes some magma explosive?
A volcano’s explosiveness depends on the composition of the magma (molten rock) and how readily gas can escape from it. As magma rises and pressure is released, gas bubbles (mainly of water vapor and carbon dioxide) form and expand rapidly, causing explosions.
What do gas bubbles in lava form?
Gas bubbles formed and rose to the surface of lava which flowed freely on the surface of a young Earth. As the lava gradually solidified to form rock, these bubbles were trapped inside, forming spaces inside the rock called vesicles.
Is magma hotter than lava?
Magma is hotter than lava, depending on how recently the lava reached the surface and if the magma and lava are from the same magma chamber below the…
What are the three factors that may affect the formation of magma?
The factors that mainly affect in the formation of magma can be summarized into three: Temperature, Pressure and composition.
- Temperature plays a role in the formation of the melts in the magma.
- Pressure can affect the shape and formation of melts.
What happens to bubbles in a magma when the pressure drops?
As pressure decreases higher in the conduit, bubbles grow. The bubbles lower the density of the ascending magma.
What is the most explosive type of magma?
Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas). The explosive bursting of bubbles fragments the magma into clots of liquid that cool as they fall through the air.
What eruption is driven by the bursting gas bubbles?
There are two types of eruptions in terms of activity, explosive eruptions and effusive eruptions. Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra. Effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption.