The Salton Buttes lie within the Salton Sea Geothermal Field located about 145 km (90 mi) southeast of Palm Springs in Imperial Valley, California. The geothermal system is fueled by heat emanating from zones of partially molten rock (magma) deep below the Earth’s surface. Eruptions occurring about 400,000 years ago were followed by a long lull in volcanic activity until about 18,000 years ago.
The most recent eruptions, which took place about 9,000 years ago, started explosively, then progressed to relatively gentle effusion of dense, glassy-looking (obsidian) lava domes. The Salton Sea Geothermal Field, which currently produces enough power to supply about 325,000 homes, has persistent small to moderate earthquakes related to the geothermal system and to movement along regional faults.
Monitoring of earthquake activity began in the 1930s, and the dense seismic network installed in the 1970s is operated by the USGS and the California Institute of Technology (Caltech). The available data are insufficient to establish a pattern of volcanic activity to determine the likelihood of eruption. The high heat flow from the area and relatively young age of Salton Buttes, however, attest to the potential for future eruptions.