What is the source of geothermal energy answer. com?

The earth contains a huge amount of liquid or hot rock at a relatively short distance from the surface. Some of it is welling up now at various points in the world. Hot springs are the result of water seeping into the heated rocks and coming back up hot. In a geothermal power plant water is piped down to the hot area and the returning boiling water is used to produce electricity. It is a fact that lava up welling in the mid-Atlantic is moving Europe and America apart. That is a large amount of geothermal energy at work.

True as the lakes are a marine body. also there's no difference in lake and ocean except for the size.