Volcanoes: 5 Things You Didn't Know
Yet Another Icelandic Volcano Risks Erupting, But It's These Volcano Facts That Will Blow Your Mind
1- Volcanoes Accelerate EvolutionThe first thing you didn't know about volcanoes is their impact on the genome.
According to the bottleneck phenomenon postulated by anthropologist Stanley Ambrose, some eruptions — those on a massive scale — can throw the planet into a volcanic winter. The effect is devastating on species populations, reducing them to numbers low enough to accelerate evolutionary changes and encourage differentiation. Ambrose thinks our own species bottlenecked following the Toba supervolcano eruption 70,000 years ago, that nearly wiped out Homo Sapiens. Toba spewed 670 cubic miles of magma into the air, depositing a layer of ash 20 feet thick thousands of miles away. Compare that to Mount Saint Helens, which couldn't even sputter a single cubic mile of ash.
More recently, the eruption of Indonesia's Mount Tambora in 1815 caused snow to blanket New England in the summer.
2- Worldwide, There Are 1,500 Potentially Active VolcanoesThis figure comes from the U.S. Geological Survey, part of the Department of the Interior, the go-to guys for volcanic information worldwide but especially within the U.S. This number does not include the "continuous belt" of volcanoes on the ocean floor, but it does include the approximately 500 volcanoes that have erupted in so-called "historical time." In the U.S. there are only about 65 active volcanoes, and they're almost all found in Alaska and Hawaii. They include Kilauea, a volcano that's been erupting pretty much nonstop since the early 1980s
3- Volcanoes Don’t Have To Erupt To Be DangerousAnother thing you didn't know about volcanoes is sleeping giants aren't always as sleepy as they seem.
Dormant volcanoes appear to present no dangers to people living nearby, and seismic activity could alert scientists if things changed. But when landslides and mudflows suddenly break from the mountainside, there is no warning. Over time, hydrothermal activity in the form of hot water acid turns the surrounding solid rock into much softer material, and eventually it has to come down.
A good example is the stratovolcano Mount Rainier in Washington. Several thousand years ago, an avalanche of mud and ice known today as the Osceola Mudflow came tumbling down, removing a good 1,600 feet off the mountain's elevation.