[3] In hydrothermal systems, the circulation of ground water is driven by a combination of topography and geothermal heat sources.

The meltwater infiltrates to depths of a few kilometers (or miles), where some is heated to at least 430 °F (220 °C) by hot rock near the Inyo craters.

It then flows eastward through rock layers to hydrothermal vent discharge points at the surface along Hot Creek and around Crowley Lake.

This water flow represents nearly 70 percent of the total heat discharged by all thermal springs in Long Valley Caldera.

Rock fracturing happens because the thermal area lies within a region of frequent earthquakes and active uplift of the ground.

Since May 2006, springs in and near the most popular swimming areas have been geysering or intermittently spurting very hot, sediment-laden water as high as 6 feet (2 m) above the stream surface.

The unpredictability of this hazardous spring activity led the U.S. Forest Service to close parts of the Hot Creek Gorge in June 2006,[6] and the closure has remained in effect as of February 2016.