Pacific Coastal & Marine Science Center
Natural Oil & Gas Seeps in California
There are many naturally-occurring oil and gas seeps in the state of California. Pictured below are some examples selected to portray the broad range in physical characteristics of seeps. The oil in some seeps is sticky and thick, like tar; in others it is dark and runny, like strong coffee; gas seeps are invisible but may be ignited with a match.
The asphaltum in this seep near Santa Barbara, California, is so viscous that it has a ropy texture like lava from a volcano.
Photo by I. Priestaf. From Onshore Oil and Gas Seeps in California.
This rock is streaked black by liquid crude oil that is trickling naturally out of the ground. This seep is located in Ventura County, California.
Photo by M. Dosch. From Onshore Oil and Gas Seeps in California.
This natural gas seep in Humboldt County is used by local inhabitants to roast marshmallows. It emits a mixture of flammable hydrocarbon gases, including methane, ethane, and propane.
Photo by L. Magoon.