Asphalt Volcanism

Combining my last two posts about the Eyjafjallajökull volcano and petroleum, let's talk about petrolem volcanism. Little asphalt volcanoes, the same sort of structure as mud volcanoes, were photographed in 1907, as shown here. More recently, we've found a rare type of undersea volcano in which tar takes the place of magma. Tar volcanoes were first discovered in 2003 in the Gulf of Mexico, but in 2007 huge mounds of asphalt were reported off Santa Barbara, California. These "extinct asphalt volcanoes" are as high as 30 meters. When Nature Geoscience published a paper on the discovery in the May 2010 issue, National Geographic did a good job covering the story.
_{Tar volcanoes — US Geological Survey photo}