A volcano is a hill or mountain that is usually dome shaped or an opening in the earth's crust. At the peak of a volcano, there is a depression called a crater, which is tens to hundreds of miles deep and nearly one mile in diameter. When a volcano erupts, you can see lava flowing down around it. Lava is magma that reaches the earth's surface. the magma pocket is about 30 miles down into the earth's crust and away from the volcano itself. A volcano conduit connects the magma pocket and the volcano. Also when a volcano erupts,or an earthquake might occur,or if an earthquake occurs, it might trigger a volcano and cause it to erupt. Many people die from volcanoes not beacuase the earthquakes or the lava flows, but the ash and rock particles that are blasted up in the air as the volcano erupts, clog up peoples lungs and suffocate them. Most gases from the eruption of a volcano are poisonous. Thus if humans breath in the gas they would most likely die. Many ialands were created by volcanoes .Yet many volcanoes created islands that were destroyed . Some volcanoes are so violent that when they erupt, they blow off their top.