The world has thousands of volcanoes, many of them active, and any attempt at a list requires classification. Volcanoes can be grouped according to their type: stratovolcanoes and shield volcanoes, as is done by Oregon State University.
Stratovolcanoes are sometimes known as composite cones, as they are built up by many layers of ash, pumice and other ejecta that has fallen near the base. These volcanoes tend to rise steeply, according to Wikipedia, and are characterized by their sudden, violently explosive eruptions that can sometimes blow the entire summit off the cone. Some active stratovolcanoes are Mt. Fuji in Japan and Tavurvur in Indonesia. Mt. Etna in Italy, is also a stratovolcano, but it is considered dormant.
Shield volcanoes tend to have lower profiles than stratovolcanoes as a result of having been built up almost entirely of liquid lava flows over the years. These flows can continue for a long time and gradually build up a low, massive mountain that resembles a shield resting against the ground. Notable shield volcanoes are Mauna Kea and Mauna Loa, both on the island of Hawaii, and Skjaldbriedour in Iceland. These volcanoes are active, as are 13 of the 21 known shield volcanoes of the Galapagos Island chain.
