According to improved knowledge of ocean floor, topography, and geology the entire Pacific Ocean floor constitutes a very large tectonic plate with smaller Cocos and Juan de Fuca Plates. Most of the global volcanic activity is concentrated at convergent plate boundaries. The majority of the world’s active volcanoes lie along the Pacific Ring of Fire.
However, these are certain exceptions such as the Hawaii Island which lies in an archipelago near middle of the Pacific Plate. In this region, lava erupted in a mountain in Kilauea during the 1970s and 1990s. Similarly, another active Mount Cameroon lies on the African plate. On the basis of the nature of the volcanoes, these can be divided into three categories viz., the active, dormant, and extinct volcanoes. An active volcano is one that has erupted in recorded history. A dormant volcano has been seen to erupt but it shows evidence of recent activity. Majority of famous mountains with volcanic peaks stand astride or near plate boundaries. For example, Mount Fuji (Japan), Mount Vesuvius (Italy), Mount Rainier (US), and Mount Egmont (New Zealand). A brief outline of the location of major volcanoes of the world is as under:
(1). Pacific Ring of Fire: Two-third of the world’s volcanoes are located in the Pacific Ring of Fire. One group occurs in the Cascade Mountains of western USA. the ring of fire also includes the Kurile Island of Japna, the Philippines, Indonesia, and New Zealand. Important mountains are Mount Fuji, Mount Rainier, Hood, Lassen, Shasta and Mt. Egmont.
(2). Another 3,200 km long chain lies in Southern Alaska and Aleutian Islands. There are 80 active volcanoes ith 227 major eruptions since 1760.
(3). South American also has many volcanoes such as Aconcagua (23,035 ft) and Cuayatiri (19,882 ft).
(4). Another line runs through the East Indies.
(5). The islands of Hawaii, Tonga, and Samoa have many volcanic cones.
(6). In Africa, volcanoes are found along the lines of East African rift valleys. These include Mount Kenya (17,058 ft) and Mount Kilimanjaro (19,340 ft).
(7). The Eurasian belt comprises of Italy and Eastern Mediterranean region which runs through Caucasia, Armenia, Persia, Baluchistan, and Burma.
(8). The Atlantic belt includes West Indies and the islands between Iceland and St. Helena.
(9). Asia Minor and to the South of Caspian have a few Soltataric cones.
(10). Some Atlantic islands along the Mid-Atlantic ridge have volcanoes such as peak on Tristan de Cunha and peaks in Azores and Canaries.