what is a volcano
A volcano is a vent or chimney which transfers molten rock known as magma from depth to the Earth's surface.Magma erupting from a volcano is called lava and is the material which builds up the cone surrounding the vent. A volcano is active if it is erupting lava, releasing gas or generates seismic activity.A volcano is dormant if it has not erupted for a long time but could erupt again in the future. Once a volcano has been dormant for more than 10 000 years, it is termed extinct. volcano is active if it is erupting lava, releasing gas or generates seismic activity. A volcano is dormant if it has not erupted for a long time but could erupt again in the future. Once a volcano has been dormant for more than 10 000 years, it is termed extinct.