Volcanoes
Introduction
A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface.
How is a volcano formed?
Most volcanoes are formed by the movement of tectonic plates on the surface of the earth. These plates are basically huge pieces of rock that ‘float’ on the mantle (a layer of the earth that is sort-of liquid rock). The tectonic plates are in constant motion, albeit very slow motion. They sometimes move toward each other, other times they’ll move apart, and still other times one will sink while the other rises above it.
When a tectonic plate sinks, it sinks down into the mantle and becomes very hot. So hot, in fact, that the rock melts. This molten rock will gradually make its way up to the surface of the earth through a series of cracks. When it reaches the surface of the earth, we refer to it as lava. As layer upon layer of lava builds up, a volcano is formed.
What affects the forming of volcanoes?
There are many factors that determine what kind of lava flow will occur and what type of volcano it will be. The amount of gas trapped in the lava, the kinds of minerals making up the lava, and how much pressure can be trapped in the area all affect the eruption and formation of the volcano.
Where are volcanoes mostly found?
There are more than 500 active volcanoes (those that have erupted at least once within recorded history) in the world--50 of which are in the United States (Hawaii, Alaska, Washington, Oregon, and California)--although many more are hidden under the seas. Most active volcanoes are strung like beads along, or near, the margins of the continents, and more than half en circle the Pacific Ocean as a "Ring of Fire."
Many volcanoes are in and around the Mediterranean Sea. Mount Etna in Sicily is the largest and hiqhest of these mountains. Italy's Vesuvius is the only active volcano on the European mainland. Near the island of Vulcano, the
A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface.
How is a volcano formed?
Most volcanoes are formed by the movement of tectonic plates on the surface of the earth. These plates are basically huge pieces of rock that ‘float’ on the mantle (a layer of the earth that is sort-of liquid rock). The tectonic plates are in constant motion, albeit very slow motion. They sometimes move toward each other, other times they’ll move apart, and still other times one will sink while the other rises above it.
When a tectonic plate sinks, it sinks down into the mantle and becomes very hot. So hot, in fact, that the rock melts. This molten rock will gradually make its way up to the surface of the earth through a series of cracks. When it reaches the surface of the earth, we refer to it as lava. As layer upon layer of lava builds up, a volcano is formed.
What affects the forming of volcanoes?
There are many factors that determine what kind of lava flow will occur and what type of volcano it will be. The amount of gas trapped in the lava, the kinds of minerals making up the lava, and how much pressure can be trapped in the area all affect the eruption and formation of the volcano.
Where are volcanoes mostly found?
There are more than 500 active volcanoes (those that have erupted at least once within recorded history) in the world--50 of which are in the United States (Hawaii, Alaska, Washington, Oregon, and California)--although many more are hidden under the seas. Most active volcanoes are strung like beads along, or near, the margins of the continents, and more than half en circle the Pacific Ocean as a "Ring of Fire."
Many volcanoes are in and around the Mediterranean Sea. Mount Etna in Sicily is the largest and hiqhest of these mountains. Italy's Vesuvius is the only active volcano on the European mainland. Near the island of Vulcano, the