Any movement of magma on or inside the earth is called volcanoism. Sometimes magma flows between rock layers of the crust and hardens. A sill forms. If magma cuts across rock layers and hardens, a dike is forms. Magma foorms dome mountains. This happens when magma pushes up the crust of the earth. The magma flows onto the surface of the earth. Magma on the earth's surface is called lava.
Would you like a mountain to form in your residential area? In 1943, a farmer in Mexico did just that! He watched a mountain form! First the ground started shaking. A few weeks later, the farmer found large craks, of fissures, on his farmland. Hot gases came out of the fissures. The fissures widened. Lava began to come out. The opening from which lava flow is called a vent. Dust, ash, and rock particles were thrown out of the vent. A volcano was fored. A volcano is the vent and the volcanic cone. The volcanic cone. The volcanic cone is the pile of lava, dust, ash, and rock particles around the vent. After several months, a volcanic cone built up that was 450 m high. It had a base 5 km wide. The volcano was called Paricutin.