What is Geothermal Energy?
   
    The Greek word "geo" means "earth," and "thermal" refers to "heat." Geothermal energy is a renewable and sustainable energy. It is a resource that is naturally replenished at a rate that exceeds what humans use of it. The thurmal energy is generated in side the erarth about 4,000 miles below the surface. There is a continuous flow of heat to the surface of Earth by conduction and convection through it's layers, but at the surface the cools rapidly.
  There are four main layers of the Earth, including the inner core, outer core, mantle, and crust. The earth's crust is broked into pieces called tectonic plates. On Earth there are seven major and many minor plates. The plates move and colide into one another frequently, causing much activity below and above surface.
    "Tectonics" from the Greek word "tektõn" meaning builder, is a theory of geology developed to explain the large scale movements of the earth's crust and outer most parts of the mantle. More extreme heat in the form of lava and magma comes to the earths surace near the edges of these plates, when they collide and diverge. Deep underground magma also heats water and rock. The deeper the ground is below the surface, the warmer it becomes.
    People around the world use geothermal energy to produce electricty by digging wells deep underground and pumping heated steam or water to the surface. It's thurmal energy comes from radioactive decay, which resulted from the gravitational collapse of the earth and was incorperated when the earth formed. Geothermal energy that reaches the surface in valcanoes can also be found in furmaroles (holes where volcanic gases are released) and in hotsprings and geyers.
    The most active geothermal resources are found along the major plate boundries where there is a concentration of earth quakes and valcanoes. The Ring of Fire is a major plate boundry that surrounds the pacific ocean, bording the coast of Alaska, North America, South America, the Philippines and Asia. In the 40,000 km long plate boundry there are 452 vacanoes, and over 75% of the world active and dormant valcanoes. Since the Ring of Fire is so active it has thurmal energy, it has many geothurmal resevoirs and potentail for producing a great amount of electricty and heat on many the Earths largest continents.