The Salton Buttes are a small but active chain of five rhyolitic lava domes on the southeastern shore of the Salton Sea, formed during the Holocene mostly between about 2,300 and 1,800 years ago. Rising modestly above the low desert but lying within the below-sea-level Salton Trough, they reflect active continental rifting tied to the San Andreas and San Jacinto fault systems. Their eruptions were mainly effusive, though some explosive activity produced pumice and ash. The buttes also anchor an intense geothermal field used for power generation. Obsidian Butte became a major prehistoric source of obsidian, helping archaeologists trace regional trade and settlement, while ongoing fumarolic activity and seismicity signal continued volcanic hazard.