FP Explainer

What Happens to the Oil After an Oil Spill?

Depends how fast you get to it.

A recovery effort is currently underway to clean up a massive oil slick caused by the explosion of the oil rig Deep Horizon in the Gulf of Mexico last week. The leaking well is gushing more than 1,000 barrels of oil a day into the gulf and has already created a slick covering about 28,600 square miles. The U.S. Coast Guard and oil giant BP -- which had the rig under contract -- are trying to contain the slick before it reaches the coast of Louisiana. But after the recovery workers remove the oil from the water, what do they do with it?

It's largely a matter of speed. As we all learn in science class, oil and water don't mix, and oil will float at the surface. After an oil spill at sea, recovery workers will attempt to contain the slick with booms and remove it with floating skimmers. Given how quickly oil can spread in rough seas, though, this is an extremely difficult process, and only 10 to 15 percent is typically recovered in major maritime spills.

Once oil waste is recovered, it is classified by type. The quality of the waste depends largely on how long the oil has been exposed to sediment and debris in the water. If it is recovered quickly, the oil can be separated from the water and reprocessed. Although it probably won't be sold on the open market, this oil can be burned to power oil refineries, power, stations, cement plants, or brick kilns.

Oil that's been in the water too long is typically rendered unusable by salt, sediment, and other materials. This includes oil that washes up on shore, which will usually settle into a tar-like substance on the beach. Such oil generally has to be disposed of in landfills, broken down with chemicals, or just incinerated.

While the collection of oil after a spill typically gets more attention, the disposal of the oil can be just as critical to mitigating environmental damage. Failure to probably segregate oil waste by type at the spill site can lead to thousands of gallons of reusable oil being wasted. Improper disposal or incineration can spread contamination further.

BP has not yet decided on a disposal method for the oil from the Deep Horizon spill, but with more than 35,000 gallons of crude recovered so far, it's a pretty big mess to clean up.

U.S. Coast Guard via Getty Images

FP Explainer

Why Have There Been So Many Geological Catastrophes Lately?

There haven't been.

These days, you don't have to be a conspiracy theorist or religious fanatic to wonder whether there's something strange going on with the Earth. Major earthquakes in Haiti, Chile, and China have killed thousands, and a cloud of volcanic ash has grounded flights across Europe. This past weekend also saw deadly quakes in Afghanistan, Papua New Guinea, and the Dominican Republic. So is the Earth going through a period of especially high geological activity?

No, we're just paying more attention. 2010 is actually shaping up to be a perfectly average year for quakes. According to the U.S. Geological Survey, since 1900 the Earth has experienced an average of 16 major quakes -- magnitude 7.0 or higher -- per year. In the first four months of 2010, there have been six. So though this will likely be a worse year than 1986, when there were only six major quakes total, it's unlikely to be as bad as 1943, when there were 32. And while major earthquakes like the ones in Haiti and Chile typically cause numerous aftershocks, scientists don't think that they are directly causing each other.

So why does it seem like this has been a particularly bad year? It likely has something to do with increased media coverage. This weekend's quake off the coast of the Dominican Republic is thought to have killed only three people and probably wouldn't have garnered much international attention if not for the catastrophic temblor that struck nearby Haiti in January.

But while earthquakes haven't become more frequent, they are getting more deadly. Earthquakes killed 650,000 people in the last decade, more than any other decade in history. Around 250,000 have already died this year. This is likely because of the expansion of urban areas in fault zones. China's Qinghai province has experienced 53 magnitude 5.0 or higher quakes since 2001, but it wasn't until one struck near the population center in Yushu that the casualty numbers exploded.

As for volcanoes, while the Eyjafjallajokull eruption may be causing chaos on the continent, it's not all that unusual for Iceland, which sits right on top of the Mid-Atlantic Ridge fault line and boasts 130 volcanoes of various levels of activity. This month's eruption is mild compared with the 1783 Laki eruption which caused a famine that wiped out a quarter of Iceland's population and altered climate patterns in Northern Europe for years. Obviously, there were no jets to worry about back then.

Eyjafjallajokull may be no Mount Pinatubo, whose powerful 1991 eruption had wide-ranging effects on the Earth's climate, but its ash has been especially disruptive because the height of its plume, about 20,000 to 30,000 feet, is high enough to get caught in prevailing winds and spread over a large area.

It's also been well known for some time that jets and volcanic ash are not a good combination. Since an eruption from Alaska's Mount Redoubt nearly took down a KLM 747 in 1989, the U.S. Geological Survey has kept close tabs on the volcanoes of the Aleutian Islands, which run across a popular route for jets crossing the Pacific. The Federal Aviation Administration imposed a no-fly zone around Mt. Redoubt during an eruption as recently as last year. Of course, unlike with the Aleutians, airlines can't exactly just go around continental Europe.

Thanks to geophysicist Don Blakeman of the U.S. Geological Survey and Frank Spera, professor of earth sciences at the University of California at Santa Barbara.