用英文简单介绍一下火山喷发的原因?

Volcanic eruption is how creates?Originally,the interior of the earth filled with hot magma.Under tremendous pressure,from weak magma will break through the earth's crust and,where spouted out,causing the volcano.
The volcano can be divided into active volcanoes,volcano and dormant volcano.Said before jotham boula volcanoes and the island of Hawaii volcanoes,now still in activity,this is active.Refers to the volcano in prehistoric had activity,but without eruption history records volcano.Within the territory of China,more than 600 volcano,mostly volcano.Some volcanoes in history have had activities of records,but later has not volcanic activities,which is called the dormant volcano.Dormant volcano may suddenly "wake up",becomes active.