Naturally Offshore Oil Seepage and Related Tarball Accumulation on the California Coastline - Santa Barbara Channel and the Southern Santa Maria Basin; Source Identification and Inventory; OCS Study 2009-030

This study is jointly funded by the Bureau, USGS Coastal and Marine Geology Program, and County of Santa Barbara Energy Division.

Oil seeps occur naturally all along the coast of California, notably in the Santa Barbara Channel near Coal Oil Point. The widespread nature of oil seeps in this area is well documented by early explorers and by coast-dwelling Chumash Indians.

The Bureau, USGS and the County of Santa Barbara initiated this study in 2001. In this study, naturally occurring oil seeps in the Western Channel and Santa Maria Basin were mapped, sampled on the ocean floor, and fingerprinted. Produced oil from offshore oil and gas platforms in the same area were sampled and fingerprinted, and beach surveys were conducted to estimate the relative amount of oil landing on the shore. Beached tarballs were also fingerprinted. The findings are provided in the Open File Report referred to below. Ongoing studies by the Bureau, USGS and the University of California at Santa Barbara continue to refine the results of this initial study.

Technical Summary and Report

• USGS Web page provides information about cruises, surveys, reports and data produced by this study
• County of Santa Barbara Beach Sampling Study