Firefighters responded to Hope Ranch on Thursday after the area’s “volcano” caused a fire in an underground PVC drainage pipe, according to Santa Barbara County Fire Department spokesperson Karen Cruz-Orduña.

In that area is a unique geological phenomenon nicknamed the Hope Ranch Volcano.

It isn’t a “true volcano, but a natural solfatara — a vent in the coastal bluffs that releases heat, steam and sulfurous gases due to underlying rock formations,” Cruz-Orduña said.

That vent “periodically flares up and can ignite vegetation or nearby materials,” she added.

Emergency personnel first responded at around 10:26 a.m. Crews had stopped the fire from spreading as of 2 p.m.

Structures were not threatened.

“Residents may notice lingering smoke,” Cruz-Orduña said. “Please avoid the immediate vicinity while crews complete their work.”

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