Captive Geyser, Idaho

"The world's only captive geyser" in downtown Soda Springs spews jets of water 100 feet in the air every hour, or every half hour during the tourist season. Similar to the famed Old Faithful and other geysers, the Soda Springs geyser erupts due to pressure created by the combination of carbon dioxide gas mixing with water in an underground chamber. In most geysers, occasional venting through natural fissures in the overlying rock releases the pressure. In the case of the captive geyser, this release is controlled by an electric motor, activated by a timer, which opens and closes the valve at the top of the pipe. The geyser was created in 1937 when a drilling operation accidentally hit a deposit of pressurized gas and water, 300 feet underground. After a few months of uncontrolled spewing, when the town was close to being flooded, the well was finally capped by installing a valve on the casing pipe.