How do convection currents create underground reservoirs of hot water and steam?

Underground reservoirs of hot water and steam are created through a process involving volcanism and convection.

The process begins when magma moves upward from deep within the Earth to depths of only a few kilometers. This magma transfers intense heat—often near 1,200 °C (2,200 °F)—to surrounding groundwater through conduction.1

Once heated, the water becomes less dense and rises due to buoyancy, while cooler, denser water sinks to replace it. This continuous cycle of movement, known as convection, circulates the water through porous rock formations, effectively concentrating the Earth's heat into large underground reservoirs of hot water and steam. These reservoirs are essential for geothermal power generation, as they allow for the extraction of thermal energy that can be funneled to the surface to drive turbines.12