Volcanoes are found in many parts of the world.  There are about 600  active volcanoes on land, others are found in the sea.  Most volcanoes are found along plate boundaries at subduction zones. There is an area of stratovolcanoes which circles the Pacific Ocean called the Ring of Fire.  Nearly 75% of the world's active volcanoes are found here.  Volcanic activity is causing the formation of the Hawaiian Islands.  It is believed that these islands sit on top of a hot  spot under the Pacific Plate.