An active volcano may be defined as the one which is definitely known to have erupted periodically in historic times. Kilauea volcano on Hawaii is the world’s most active volcano, followed by Etna in Italy and Piton de la Fournaise on La Réunion island. Further ordering the value of the activity of volcanoes is very difficult. It is very hard for the geologists to decide which volcano is more active than the other, but still, the scientists classified Stromboli, Merapi, Erta Ale, Ol Doinyo Lengai, Unzen, Yasur, Ambrym, Arenal, Pacaya, Klyuchevsky, Sheveluch, and Erebus to be the most active volcanoes of the world.
The dormant volcanoes are that in which renewal of eruptive activity is possible. For example, verunuius had been dormant for a long time before its eruption in 79 AD. There are many other examples of volcanoes, which are considered to be dormant volcanoes. However, for the scientist is also difficult to assume, that how long will a volcano stay dormant. Volcanoes like Moana Kea in Hawaii, United States, Mount Edziza of Canada, Tanzanian Mount Kilimanjaro, Western Victorian Volcanic Plains of Australia, Mount Hood (Origon, United States), and Trou aux Cerfs in Mauritius are the good examples to understand the existance of the dormant volcanoes.
The extinct volcanoes are those which belong to long-past geological times. The power of extrusion of such volcanoes has long long ago been extincted. They seldom have power to extrude again. There are hundreds of examples of extinct volcanoes, among these following are the most famous extinct volcanoes.
- Ben Nevis, the tallest mountain in the United Kingdom.
- Hawaiian–Emperor seamount chain in the northern Pacific Ocean.
- Huascarán in Peru.
- Kyushu-Palau Ridge in the Philippine Sea.
- Mount Buninyong in Victoria Australia.
- The Nut in Tasmania Australia.