GEOLOGY

Detailed explanation-1: -Which describes pressure during a volcanic eruption?-Pressure increases as magma rises.

Detailed explanation-2: -The magma rises and collects in chambers within the crust. As magma fills the chamber, pressure grows. If the pressure gets high enough, the magma can break through the crust and spew out in a volcanic eruption. Most explosive volcanoes occur above subduction zones.

Detailed explanation-3: -Near the surface, the pressure decreases and they can exsolve from the melt, ultimately forming gas bubbles in a process called vesiculation. This exsolution of magmatic gases as a magma ascends towards the surface is one of the forces that propels volcanic eruptions.

Detailed explanation-4: -Deep beneath the surface, gasses are dissolved in magma, but as magma rises toward the surface the pressure decreases and gases separate from the liquid. Because gas is less dense than magma, it may rise more quickly and be detected at the surface of the earth.

Detailed explanation-5: -Magma can rise when pieces of Earth’s crust called tectonic plates slowly move away from each other. The magma rises up to fill in the space. When this happens underwater volcanoes can form. Magma also rises when these tectonic plates move toward each other.