geothermal energy is formed by magma heating earth 's crust
geothermal_energy is not heat. volcanic_rock is igneous_rock. magma is rock. earths_core is not magma. geothermal_energy is not energy. heat is form_of_energy. heat is not form_of_energy. geothermal_energy is energy. earths_core is magma. geothermal_energy is heat.