The ring of fire is an area where a numer of vocanoes in the basin of the Pacific Ocean. The reason we call this area as "The ring if fire" is beaucse it seems to be a circle which looks like a ring. ( It is sometimes called the circum cacific belt or the circum pacific sesismic belt.)

This ring is home to over 75% of the world's active and dormant volcanoes. In 1900s, a German scientist, Alfred Wegner, first declared the theory of land movement and it says [continents moved slightly similar to the way large things move while floating on water. - copyed]

Recently, scientists found that most of his ideas were right.So the scientists made a new thoery which is based on Alfred's and it is now knowned as plate tectonics. A new theory says the surface of the Earth was divided to  a numer of huge plates or sections of rock and it diffuses at speeds between one to ten cm/year. ( It's about the rate our fingernails grow.)

To make new plates, hot liquid rock called magma erupts from center of the Earth. For this reason, all the plates have to move for the new materails. By movement of these plates, plates hit each other and it sometimes causes earthquakes.  Also, magma can come out to surface of Earth  by this process becuase the plate on the bottom makes under of the top plate very hot.