What does magma become when it reaches the surface of the earth?

What's another word for a "sleeping" volcano that someday may erupt again?

The islands of Hawaii are made up of a series of Shield Volcanoes?

CInder Cone volcanoes are more explosive than Shield Volcanoes?

Mount St. Helens is an example of a Stratovolcano because of the violent eruptions?

Who is a person that studies volcanoes?

Worldwide, how many potentially active volcanoes are there?

The Ring of Fire, the path of potential volcanoes is located on the rim of which ocean?

Under which U.S. National Park lies enormous amounts of molten magma?