What is a hotspot and how do they affect volcanoes?
A hotspot is an isolated region of the earth that produces molten silicate rock, called lava. At temperatures in excess of 1000°C (1800°F), lava can periodically erupt from the ground. Before it erupts onto the earth's surface, this material is called magma. Magma contains many types of other chemicals, including large amounts of gases like carbon dioxide. Many of these gases are toxic.
Hotspots are sometimes associated with "mantle plumes", theoretical upwellings of unusually hot rock in the earth's mantle. The source of these hotspots is somewhat controversial. Most scientists think that their source lies deep within the earth, possibly even at the boundary between the outer core and the mantle. That boundary is at a depth of about 2900 km (1800 mi.) beneath the earth's surface. A few scientists think their origin may be shallower, caused by the gradual opening of a large crack. A mantle plume may have created the Hawaiian islands.
Hotspots are associated with volcanic activity at the mid-ocean ridges, underwater boundaries between the tectonic plates of the earth's crust. These are where "strike-slip" (horizontal motion) earthquakes occur. Examples of hotspots at mid ocean ridges include Iceland, the Canary Islands, and the Galapagos Islands.
Other hotspots occur at subduction zones, where one plate plunges into the earth beneath another. These are locations at which great "thrust" (vertical motion) earthquakes occur, such as the Great Tohoku, Japan, earthquake of March 11, 2011. Hotspots and volcanic activity at subduction zones include Mount Fuji in Japan, and Pinatubo volcano in the Philippines.
Hotspots are also found to exist beneath the continents. Continental hotspots include Yellowstone Park in Wyoming (home of the "Old Faithful" geyser), and Long Valley in California.
- OH Community
- Web Apps
- About Us