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These "volcanoes" vent subterranean carbon dioxide, and are a geologic anomaly resulting from geothermal activity caused by the movement of the North American plate to the east and the Pacific Plate to the west. They are not hot and can be easily, though muddily approached. Nearby is one of the numerous geothermal energy facilities dotting the southern end of the sea. Take Schrimpf Road from Highway 111 rather than Wister Road unless you're not fond of your car.
It's at the southern end of the Salton Sea and 227 feet below sea level. This wild life refuge is also part of the Pacific Flyway host to heavy migrations of waterfowl, marsh and shorebirds during spring and fall, with the greatest number of species present from November to May. Over 400 species of birds have been recorded. The Refuge has two separate managed units, 18 miles apart. Each unit contains wetland habitats, farm fields, and tree rows.