what happens immediately before a volcano erupts ?
a) magma collects in the mantle
b) lava hardens to form volcanic rock
c) expanding gases pushes magma through the pipe
d) the temperature in the magma chamber decreases
The answer is C. Im pretty sure.
I have no clue. I am not sure, it is a unit test, so... I AM IN DEEP DUDU!!!!
I think it is C or B
The correct answer is c) expanding gases push magma through the pipe.
To understand why this happens, we need to first look at the process leading up to a volcanic eruption.
Volcanic eruptions occur when there is a buildup of pressure beneath the Earth's surface caused by the accumulation of magma, which is molten rock beneath the Earth's crust. Magma is formed from the melting of rocks due to extreme heat within the Earth's mantle.
Before an eruption occurs, magma rises towards the surface through a vertical conduit called a volcanic pipe or vent. As the magma ascends, it encounters a variety of obstacles, including rock layers and pockets of trapped gases.
As the magma reaches higher and closer to the Earth's surface, the pressure decreases, causing dissolved gases within the magma to expand. These expanding gases exert an increasing force on the magma, eventually overcoming the weight and resistance of the surrounding rocks. This process is similar to shaking a carbonated beverage and then opening the cap, causing the release of built-up pressure.
When the pressure from the expanding gases becomes greater than the resistance from the rocks, the magma is forcefully pushed upwards through the volcanic pipe until it reaches the surface. The eruption occurs when the magma, now called lava, flows out onto the Earth's surface.
Therefore, the correct option is c) expanding gases push magma through the pipe, just before a volcano erupts.