Red Island (or Red Hill) is a

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

volcano in the

Salton Trough The Salton Trough is an active tectonic pull-apart basin, or graben. It lies within the Imperial, Riverside, and San Diego counties of southeastern California and extends south of the Mexico–United States border into the state of Baja Califo ...

, and part of the

Salton Buttes The Salton Buttes are a group of volcanoes in Southern California, on the Salton Sea. They consist of a row of five lava domes, named Mullet Island, North Red Hill, Obsidian Butte, Rock Hill, and South Red Hill. They are closely associated wi ...

, the only active volcanoes in Southern California. It is located in

Imperial County, California Imperial County is a county located on the southeast border of the U.S. state of California. As of the 2020 census, the population was 179,702, ranking as the least populous county in Southern California. The county seat and largest city is ...

. It contains two lava domes, Prospect Dome and Alamo Dome.USGS Topographic Map 7.5 Minute - Niland The domes have been dormant for 2,000 to 8,000 years. The saddle between the domes, about below the summit of each dome, is a parking lot for county park visitors. In around 2006-2007 the island became connected to the mainland due to the drying up of the salton sea and being close to the

Alamo River The Alamo River () flows west and north from the Mexicali Valley (Baja California) across the Imperial Valley (California). The river drains into the Salton Sea. The New River, Alamo River, and the Salton Sea of the 21st century started in aut ...

only served to accelerate this process and by 2022 the island was surrounded on three sides by land.

References

External links

Imperial County PDS website for park
Volcanoes of California Lava domes of the United States Volcanoes of Imperial County, California {{Volcano-stub