Does magma sometimes forces its way out of the side of a volcano through a vent?
The magma pushes its way through small cracks in the crust and finally reaches the surface. This causes a dike to be produced. When the magma reaches the surface of the Earth it is then called lava. The lava leaving the side vent causes the volcano to add a layer of lava and usually a layer of ash with each eruption.
What happens to gasses dissolved in magma as it ascends toward the surface and pressure decreases?
Magma contains dissolved gases, which provide the driving force that causes most volcanic eruptions. As magma rises towards the surface and pressure decreases, gases are released from the liquid portion of the magma (melt) and continue to travel upward and are eventually released into the atmosphere.
Why is the amount of gas in magma important in relation to volcanic eruptions?
Gases in Magmas Gas gives magmas their explosive character, because volume of gas expands as pressure is reduced. The composition of the gases in magma are: Mostly H2O (water vapor) & some CO2 (carbon dioxide)
Which structure allows magma to escape through the side of a volcano?
main vent – this is the channel through which magma travels to reach the Earth’s surface. secondary vent – some magma may escape through the side of the volcano, particularly if the main vent becomes blocked.
What do the volatile gases in magma provide in an eruption?
Volatiles in a magma with a high viscosity, generally felsic with a higher silica (SiO2) content, tend to produce eruptions that are explosive. Volatiles in a magma with a low viscosity, generally mafic with a lower silica content, tend to vent and can give rise to a lava fountain.
What provides the force that causes magma to erupt to the surface?
Ch. 15 Review Volcanoes
| Question | Answer |
|---|---|
| What provides the force that causes magma to erupt to the surface? | dissolved gases trapped in the magma |
| When magma hardens in a volcano’s pipe, the result will eventually be a landform called a | volcanic neck |
| Magma that forces across rock layer hardens into a | dike |
What would be the possible effect of volcanic eruption?
Major health threats from a volcanic eruption Health concerns after a volcanic eruption include infectious disease, respiratory illness, burns, injuries from falls, and vehicle accidents related to the slippery, hazy conditions caused by ash.
What forces the magma beneath to move?
Cause of volcano tectonic earthquakes The compression of plates at these subduction zones forces the magma beneath them to move. Magma can not move through the newly compressed crust in as easily a manner. This means it tends to pool in magma chambers beneath the surface and between the converging tectonic plates.