A petroleum seep is a place where liquid or gaseous hydrocarbons escape to the surface through fractures and fissures in the rock and between geological layers. Petroleum seeps are quite common: California has thousands of them. Much of the petroleum discovered in California during the 19th century was from observations of seeps.1
Petroleum seeps may be a significant source of pollution.
This seep also releases on the order of 100 to 150 barrels of liquid petroleum per day. The field produces about 9 cubic meters of natural gas per barrel of petroleum.2
Hornafius, J.S.Quigley, D.C., and Luyendyk, B.P. "The world's most spectacular marine hydrocarbon seeps (Coal Oil Point, Santa Barbara Channel, California): Quantification of Emissions", Journal of Geophysical Research, v.104, n. C9, pp. 20,703-20,711, September 15, 1999. [1]