Geothermal activity is the heat emanating from the earth’s interior. It is a natural phenomenon and has been going on since the earth was formed. The word “geothermal” comes from the Greek words meaning “earth” and “heat.”
The earth’s interior is very hot, about 4,000 degrees Fahrenheit (2,200 degrees Celsius) at its core. This heat is continually released into the atmosphere through a process called convection. Convection is caused by the slow movement of hot molten rock (magma) toward the surface of the earth. As magma rises, it pushes cooler rock out of its way, causing it to move downward. This continual circulation of hot and cool rock creates a convection current that drives plate tectonics and powers volcanic eruptions.
Geothermal energy can be harnessed for electricity generation or for direct use in heating applications. Geothermal power plants use steam produced by geothermal activity to drive turbines that generate electricity. Direct-use applications include space heating, domestic hot water production, greenhouse cultivation, aquaculture, industrial processes, and spas and recreation facilities.
Geothermal resources are found in areas where there is evidence of past or present geothermal activity. These areas are typically located near plate boundaries or along hot spots (areas where mantle plumes rise close to the Earth’s surface). Countries with high levels of geothermal activity include Italy, Iceland, New Zealand, Japan, Philippines, El Salvador , Costa Rica , Guatemala , Kenya , Ethiopia , Tanzania . The United States also has significant geothermal resources; California alone has over 700 identified geothermal systems!