Eco Future Life

[youtube="http://www.youtube.com/watch?v=VwdOH9GayVw"]

Despite scientists have become much better at predicting volcano’s eruptions it continue to pose a terrifying threats. What is volcano, why?

About 550 volcanoes have erupted on Earth’s surface since recorded history; about 60 are active each year. Far more have erupted unobserved on the ocean floor. Most volcanoes exist at the boundaries of Earth’s crustal plates, such as the famous Ring of Fire that surrounds the Pacific Ocean plate. Fifty volcanoes have erupted in the United States since recorded history, and the United States ranks third, behind Indonesia and Japan, in the number of historically active volcanoes.

A volcano is active if it erupts lava, releases gas or shows seismic activity. It is dormant if it hasn’t erupted for a long time but could again one day. An extinct volcano will never erupt again.

The explosiveness of a volcanic eruption depends on how easily magma can flow and the amount of gas trapped in it. Large amounts of water and carbon dioxide are dissolved in magma. They behave like gas in fizzy drinks. After opening the bottle the gas expands, forming bubbles that escape. This also happens when magma rises quickly through the crust – gas bubbles form and expand up to 1000 times their original size.