Are volcanoes distributed randomly or in a pattern?

Answer 1

There are several processes in Plate Tectonics that cause volcanism, but they result in two main types of volcanism.

Volcanism in subduction is caused by volitals, like H2O, CO2. These are carried down by the plate, mainly in the form of weak minerals. These minerals break down with pressure and temperature into stronger minerals that don't contain water and carbon dioxide. The leftover gases and liquids travel into the mantle (the mantle wedge) and hydrate the mantle, causing melting. The melt rises and then... volcano!

The other main cause is from rising mantle material, which forms decompression melting. Basically, hot mantle is kept from melting by the pressure of the earth at depth. When this material rises, the pressure drops much faster than the temperature, and thus it partially melts. This mainly occurs at divergent boundaries and hot spots, which are areas in plate tectonics that have rising materials or spreading.

Answer 2

Question: What is the "Ring of Fire"?
Answer:

Volcanoes are not randomly distributed over the Earth's surface. Most are concentrated on the edges of continents, along island chains, or beneath the sea forming long mountain ranges. More than half of the world's active volcanoes above sea level encircle the Pacific Ocean to form the circum-Pacific "Ring of Fire". -- From: Brantley, 1994, Volcanoes of the United States: USGS General Interest Publication.



Source of this FAQ:
http://vulcan.wr.usgs.gov/LivingWith/VolcanicFacts/misc_volcanic_facts.html

Answer 3

Volcanoes are found only at two places:

Where two or more tectonic plates meet and/or overlap, scuh as the Phillipines, Central America, Alaska, and Japan

where there is a hot spot in the middel of a plate, such as Hawaii or Iceland

Check out the USGS Real time earthquake site. Where you see the most earthquake activity also gives you an idea where volcanoes can be found. ou can also link to a volcano map, and note how they run in chains or lines.

Answer 4

Most volcanoes are located on fault lines; areas where the plates that make up the solid portion of the earth's surface meet. Magma can creep up through the cracks of the fault line, and build a volcano.

Answer 5

They distributed manly where the plates meet. And sometime randomly.

Answer 6

there is a pattern of volcanos called the ring of fire in the pacific

Answer 7

Don't they mainly occur where the techtonic plates meet?