What are scientists that study volcanoes called?

This is a 1,700^o F avalanche of hot rock, ash, and gas. It can move at speeds of 450+ mph.

The ring of fire is a chain of volcanoes around the edge of the Pacific Plate. Approximately how many volcanoes are in this chain?

In what year was the Roman city of Pompeii buried by a pyroclastic flow?

Where on earth can you find blue lava?

What is the name of largest volcano ever discovered? (It is about the same size as Arizona and is now extinct)

This volcano produced the loudest sound ever recorded. It could be heard over 3,000 miles away and the sound waves it produced circled the earth 4 times.

This eruption in April 1815 resulted in "the year without a summer". In 1816 temperatures in the north eastern USA were cold enough that it snowed in June!

This "sleeping" supervolcano is thousands of times more powerful that regular volcanoes. At times it has erupted in excess of 600 cubic miles of material. Compare that to: Krakatoa (4.3 cu mi), Mt. St. Helens (.24 cu mi), Tamboa (36 cu mi)