Obviously volcanoes will be found in those regions where the crust of the earth is weak because lava can easily be discharged from such places. These are found in areas of Fold mountains. 

There are three main belts of volcanoes : 

1. Circum-Pacific Belt : This belt runs round the Pacific Ocean in Asia and the America. It starts from Cape Horn goes along the Andes and the Rockies to Alaska. From their it turns westwards and passing through Aleutian Islands Japan and Formosa goes to the Philippine Island. Here one branch goes to East Indies that is Java Sumatra and Bameo and other branch goes to New-Zealand. Some of the well known Volcanoes are Karakatoa (on a hilly island between Sumatra and Java) Mayon (N. Philippines) Fujiyama (Japan) Chimborezo and Cotopaxi (Equador S. America). 

2. Mid World Mountain Belts : This belt starts from the West Indies and passing through the Canavy Islands. The Mediterranean sea Caucasus mountains and Turkey reaches the Himalayas. Mt. Vesuvius (Italy) Mt Stromboli (Sicily) Etna (the Mediterranean sea) and Mt. Pelee (West Indies) are the important Volcanoes of this belt. 

3. African Belts : This belt follows the Great African Rift Valley. This belt running through Red Sea extends upto Africa. Important Volcanoes are Kilimanjaro Kenya Canary Islands St. Helena (Atlantic ocean).