Hope Ranch 'volcano' erupts, causes small brush fire
Jul. 29—A small fire was ignited Wednesday after the Hope Ranch "volcano" erupted along the hillside of a beach near Santa Barbara.
The fire was reported shortly after 11 a.m. at Hope Ranch, an unincorporated area near the city, and burned a small amount of brush before County Fire crews quickly extinguished it, according to spokesman Mike Eliason.
The Hope Ranch "volcano" is natural geologic formation, although technically no volcanoes exist in Santa Barbara County. The formation is called a solfatara, or a fire well, which is more like an opening in the Earth's crust that emits steam and gases. A similar formation is called a fumarole.
It's the second time the Hope Ranch "volcano" has erupted this month. The formation also erupted on July 10, causing a small vegetation fire along the hillside approximately one mile west of Arroyo Burro Beach, according to Eliason. Three County Fire engines responded to that incident.
Some of the first modern observations of the formation was made by Spanish explorers in the 18th and the 19th centuries. The formation was likely created by fault lines of the Transverse Mountain ranges, which transfer heat to the surface, according to volcanologist Erik Klemetti, who writes the Eruptions blog on bigthink.com.
"These faults are excellent places for heat from within the crust to move towards the surface — and, remember, even in non-tectonically active areas, the ground warms at almost 2-3C (per 100 meters), so it can get hot enough to boil water quite quickly," Klemetti wrote in 2011. "You see hot springs along faults in much of the western U.S., such as in the Oregon or New Mexico (amongst many others), so we know a lot of heat can be transferred along faults."
Additionally, the faults lie near hyrdocarbon fields off the coast of Santa Barbara. Combine the two and combustion occurs, Klemetti added.
A 2004 landslide that occurred near Santa Barbara and exposed subsurface pyrite (also known as fool's gold) to oxygen could have caused a similar event, according to a 2008 article published in Geology.
"No magma, no volcanism needed, just the right combination of events," Klemetti wrote. "Remember, Santa Barbara is nowhere near any of the active or potentially active volcanoes of California."
