A volcano erupts by the magma (lava) pushing or finding a way out of the slate under ground and it sprays out.
WHO CAN YOU INTERVEIW ON THIS SUBJECT?
You can interview people who have seen a volcano, volcanologists, and geologists.
GENERAL   DESCRIPTION
WHAT IS A VOLCANO?
   A volcano is an opening in the earth that explodes or gives off lava, hot molten rock, ashes, or smoke. Some volcanoes are just craters in the earth that give off gas. Others are mountains that explode, and still others throw lava and hot rock.

Volcano Home Page
Volcano "Where and When"
Volcano "Personal Safety"
Volcano Resources
Volcano Photo Gallery
Volcano Activities

HOW CAN YOU PREDICT A VOLCANO? You can listen to the volcanologists and geologists. You can also predict by minor earthquakes. It is very important to obey any warnings or instructions given by public safety officials.