Download Hot Spots Hundreds of hot spots exist around the world. These are

Hot Spots
Hundreds of hot spots exist around the world. These are areas in the lithosphere that are
underlain by unusually hot magma. This heat causes partial melting of the lithosphere,
eventually leading to volcanic activity. The Hawaiian Islands are a classic example of a
volcanic grouping formed over one hot spot.
Over thousands of years, as the Pacific Plate inched its way in a northwest direction, the stationary hot spot underneath the plate
successively created volcanoes above it. Several of these volcanoes reached the ocean’s surface, forming the Hawaiian Islands.
As the plate continued to move, volcanoes, embedded in the plate, travelled away from the source of magma and eventually
became extinct. This hot spot still continues to create new volcanoes. Thus, the islands are progressively younger from the
northwest to the southeast. Several volcanoes in the chain are still quite active, and new underwater volcanoes are forming to the
southeast of Hawaii as the Pacific Plate continues to move over the hot spot.
In many locations the hot molten magma from deep within the Earth rises up through the crust to reach the surface. This
sometimes happens in the middle of plates. When a hot spot forms in the middle of a plate, it remains constant, as the plate
continues to move over it. The result is that a trail of volcanoes is left behind, with older volcanoes moving away from the
hot spot, and newer ones forming over top of the hot spot.
http://pubs.usgs.gov/gip/dynamic/hotspots.html
The trace of a hot spot appears as a chain, such as an island chain. As the overlying plate moves one volcano off the hot spot, another is formed. The
Hawaiian Island Chain is an example. The island of Hawaii has been formed in the last 1 million years. The other Hawaiian islands to the Northwest are
progressively older. Kauai was over the hotspot approximately 5 million years ago. A new Hawaiian Island is being formed off the southeastern coast of
Hawaii.
Hot spots" are places where a chamber of magma has accumulated at depth beneath the surface. The volcanic islands of Hawaii are a
notable example of this. The Hawaiian Islands ride atop the Pacific plate as it moves in a northwesterly direction over the hot spot that
creates the volcanoes. Therefore, the oldest volcanic island is found at the northwest end of the chain and the youngest to the southeast.
Volcanic activity ceases as the older islands move off the hot spot.
Animation of Hotspots
http://www.wwnorton.com/college/geo/egeo2/content/animations/2_6.htm
Hot spot volcanoes occur somewhat randomly around the globe. Their relationship (or lack of one) to the plate tectonic cycle is still being debated. The map below shows
several hotspots, but not all of the ones that exist. In fact, there are over 100 hotspots that have been active sometime during the last 10 million years or so. Notice on the map
below that out of the 25 hotspots shown, about 10 occur on top of a mid-ocean ridge. Whether this a coincidence or not is a current topic of debate among scientists.
Hawaii