Volcanoes are one of nature's most destructive forces. Sometimes they can happen without notice and sometimes they give many warning before they finally erupt, spewing hot molten lava. Volcanoes can lie dormant for years before erupting again. Scientists have worked for years to learn how to predict them. Volcanoes are found in all climate areas in most areas of the world. They are found more so in the "Ring of Fire". Below, this webpage will explain how volcanoes form and erupt, what types of volcanoes there are, famous volcanoes that have happened before, and the aftermath of a volcano.
About Types of Volcanoes Famous Volcanoes Aftermath Links
When hot, molten rock under the earth's surface rises up between plate boundaries volcanoes are formed. The hot material is stored in a chamber beneath other weaker chambers. Which enables pressure to build up inside causing an eruption to occur on the surface. Most volcanoes will stay dormant for many years and not show any signs of eruption. When they do erupt, they erupt very violently.
Most of the active volcanoes of the world are located on the Ring of Fire, a circle on the earth's surface where plates are undergoing subduction. Another cause of volcanoes includes hot spots, which have nothing to do with surrounding plates, just weak spots in the earth's crust where magma is released.
Types of Volcanoes
There are four types of volcanoes:
Shield volcanoes form by layers of lava flows. The Hawaiian Islands are shield volcanoes.
Composite volcanoes form by alternating layers of ash and lava. Mount St. Helens in Washington State is a composite volcano.
Cinder volcanoes are composed of small lava fragments and form slopes of 30 to 40 degrees. Sunset Crater in Arizona is a cinder volcano.
|Recent volcanoes||Location||Year of last activity|
|Africa and the Indian Ocean|
|Lengai Ol Doinyo||Tanzania||1993|
|Piton de la Fournaise||Zaire||1992|
|Mount Erebus||Ross Island||1990|
|Big Ben||Heard Island||1986|
|Deception Island||South Shetland Island||1970|
|Central America and the Caribbean|
|Santiaguito (Santa Maria) Dome||Guatemala||1993|
|Rincon de la Vieja||Costa Rica||1992|
|Europe and the Atlantic Ocean|
|Mt. St. Helens||Washington||1991|
|Australia, New Zealand, and the Pacific Islands|
|Langila||Papua New Guinea||1993|
|Ulawun||Papua New Guinea||1993|
|Manam||Papua New Guinea||1992|
|White Island||New Zealand||1992|
|Copahue||Aregentina and Chile||1992|
The aftermath of a modern volcano
When Mount Pinatubo erupted, it created a stratospheric cloud that held sulfur dioxide. It circled the earth in three weeks. All the sulfur released by Mount Pinatubo created brilliant sunsets in parts of the world. Scientists believe that the sulfur released caused the Pacific ocean to heat up which in turn caused El Nino. Scientists say that Mount Pinatubo's eruption assisted in the blizzard of '93 on the eastern seaboard.
- United States Geological Survey
- Volcano World
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(All images on this page provided by United States Geological Survey)