Once the magma reaches the surface it is called lava. The shape of the three main types of volcanoes depends on the type of eruption. The way a volcano erupts depends on the type of magma, the length of the vent, and the amount of pressure present in the vent. Volcanoes that erupt regularly are called active . Volcanoes that no longer erupt are extinct , or dead.
Dormant volcanoes lie peacefully for centuries and then erupt suddenly.
Next, you will read the information on the three different kinds of volcanoes. The sides of a Shield volcano gently slope, like an ancient warrior's shield. The magma is of thin consistency that spreads over a wide area. The eruption is gentle. It may continue over a long period of time as magma bubbles from the vents.