Volcanoes
Volcanoes are the vents of the Earth, through which molten rock, gases and debris are emitted into the atmosphere.
80% of the surface of the Earth is of volcanic origin. eruptions are an example of the awesome power that exists within the Earth. Some eruptions are continuous and constant, like the picture of an Icelandic volcano to the left. Others are explosive and only happen once in a while.
80% of the surface of the Earth is of volcanic origin. eruptions are an example of the awesome power that exists within the Earth. Some eruptions are continuous and constant, like the picture of an Icelandic volcano to the left. Others are explosive and only happen once in a while.
It is rare that people live inside volcanoes, but there are some settlements within craters of inactive caldera volcanoes, like the island of aogashima in Japan (pictured below). Part of the island still has steam escaping from vents, which is used for power on the island. The extreme nature of these settlements is not that living in them is difficult- it is that there is a chance that they could be destroyed by unexpected eruptions!
Many people live near volcanoes, though. Some examples of areas that have been affected in recent years by volcanoes are Hawaii, Indonesia, Japan, Washington state, Colombia, the Congo and Italy. In 2010, a massive volcanic eruption in Iceland caused air traffic disruptions across the northern Atlantic for a week due to large amounts of dangerous ash in the sky.
A large eruption can be extremely dangerous for people living near a volcano. Flows of searing lava, which can reach 1,250 degrees Celsius or more, can be burn everything in its path, including whole towns. Boulders of hardening lava can rain down on villages. Mud flows from rapidly melting snow can strip mountains and valleys bare and bury towns. Ash and toxic gases can cause lung damage and other problems, especially for infants and the elderly. Scientists estimate that more than 260,000 people have died in the past 300 years from volcanic eruptions and their aftermath.
A large eruption can be extremely dangerous for people living near a volcano. Flows of searing lava, which can reach 1,250 degrees Celsius or more, can be burn everything in its path, including whole towns. Boulders of hardening lava can rain down on villages. Mud flows from rapidly melting snow can strip mountains and valleys bare and bury towns. Ash and toxic gases can cause lung damage and other problems, especially for infants and the elderly. Scientists estimate that more than 260,000 people have died in the past 300 years from volcanic eruptions and their aftermath.
Mt. Etna in Italy is one of Europe's most active volcanoes. This photograph, and the video on the right, were taken during the March 2013 eruption, which sent a lava fountain over a mile high.
Here are some words you should know:
magma: molten rock that has not reached the surface
lava: molten rock that has come to the surface
vent: opening where magma rises to surface; a volcano may have several vents - a main vent and secondary vents
magma chamber: a large underground pool of magma found beneath the surface of the Earth. The magma in such a chamber is under great pressure, and given enough time, that pressure can gradually break the rock around it creating outlets or vents for the magma.
Ring of Fire: a region around the Pacific tectonic plate boundary where most of the world's volcanoes and earthquakes occur (see below) The Ring of Fire has 75% of the Earth's volcanoes (over 450 volcanoes) and 90% of the Earth's earthquakes.
magma: molten rock that has not reached the surface
lava: molten rock that has come to the surface
vent: opening where magma rises to surface; a volcano may have several vents - a main vent and secondary vents
magma chamber: a large underground pool of magma found beneath the surface of the Earth. The magma in such a chamber is under great pressure, and given enough time, that pressure can gradually break the rock around it creating outlets or vents for the magma.
Ring of Fire: a region around the Pacific tectonic plate boundary where most of the world's volcanoes and earthquakes occur (see below) The Ring of Fire has 75% of the Earth's volcanoes (over 450 volcanoes) and 90% of the Earth's earthquakes.
1. Molten rock
a. Magma below surface
b. Lava above surface
2. Magma chamber: large underground pool of molten rock beneath Earth surface
3. Vent: pathway to surface from magma chamber
4. Ash/lava layers: cooled & solidified lava
5. Cone: cone-shaped hill or mountain produced from volcanic eruptions
a. Magma below surface
b. Lava above surface
2. Magma chamber: large underground pool of molten rock beneath Earth surface
3. Vent: pathway to surface from magma chamber
4. Ash/lava layers: cooled & solidified lava
5. Cone: cone-shaped hill or mountain produced from volcanic eruptions