Volcanoes General

There are a few historic examples of simultaneous eruptions from volcanoes or vents located within about 10 km of each other, but it's very difficult to determine whether one eruption might have caused the other.
Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers.
There are about 1,500 potentially active volcanoes worldwide, aside from the continuous belt of volcanoes on the ocean floor. About 500 of these have erupted in historical time.
More than 80 percent of the Earth's surface -- above and below sea level -- is of volcanic origin.
Over geologic time, volcanic eruptions and related processes have directly and indirectly benefited mankind.Volcanic materials ultimately break down and weather to form some of the most fertile soils on Earth, cultivat
Volcanoes that have produced exceedingly voluminous pyroclastic eruptions and formed large calderas in the past 2 million years include Yellowstone, Long Valley in eastern California, Toba in Indonesia, and Taupo in New Zealand.
Volcanoes are not randomly distributed over the Earth's surface. Most are concentrated on the edges of continents, along island chains, or beneath the sea forming long mountain ranges.
Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth's
There are many paths to becoming a volcanologist. Most share a college or graduate school education in a scientific or technical field, but the range of specialties is very large.