At a destructive plate boundaries the heavy oceanic crust moves under the continental crust and sinks to the mantel. There is pressure on the magma in the asthenosphere.
Where the crust is weak, the magma rises to the earth surface. The place where the magma climbs out of the earth is a volcano. Before the volcano erupts you hear grumbling and ash comes out through the crater. During the eruption the magma shoots out of the volcano. The magma is now called lava and runs down the sides of the volcano. Sometimes there are explosions that shoot the lava out of the crater and send ash far into the atmosphere.
Now this was something about the eruption maybe there is coming more soon <3
