Answer;
Magma
-Hot springs are heated geothermally by underlying magma.
Explanation;
-Hot springs form the same way a regular spring does, however, the aquifer is heated geothermally on the bottom by underlying magma, which causes the spring to be a higher temperature than the surrounding area.
-Molten rock beneath the crust called magma can reach temperatures over 1,000 degrees Celsius.
-Water is heated geothermally in areas where magma rises close to the surface of the crust.