Geothermal Energy Sources - Hot Creek Flows Through The Long Valley Caldera In A Volcanically Active Region Of East-central California. This Stretch Of The Creek, Looking Upstream To The Southwest, Has Long Been A Popular Recreation Area Because Of The Warm Waters From Its Thermal Springs. These Springs, However, Are Unpredictable And Can Suddenly Erupt With Violence And At Boiling Temperature. Because Of This Danger, The U.S. Forest Service Has Had To Close Parts Of The Hot Creek Geologic Site To Visitors. The Same Geothermal Reservoir That Feeds Hot Creek Provides Heat For Geothermal Electric Power Production At Nearby Casa Diablo. Read More About Hot Creek And It's Geothermal Properties At Pubs.usgs.gov/fs/2007/3045/fs2007-3045.pdf Photo Credit: Chris Farrar, USGS​. Photo