Health & Science

How fracking causes mini-earthquakes

Ramped-up oil and gas production is triggering small earthquakes in the central U.S., a report by the U.S. Geological Survey says. Scientists first noticed that earthquakes were increasing in the middle of the country a decade ago, but “what really caught our attention” was a recent spike in activity, USGS seismologist Bill Ellsworth tells NPR.org. In 2009, 50 minor quakes rattled the center of the continent; last year, 134 did. Ellsworth and others believe that increase is due to more oil and gas drilling, especially by a method called hydrofracking, which blasts billions of gallons of water and chemicals into underground rock formations to crack them and release natural gas. Surprisingly, it doesn’t appear that it’s the fracturing of rock itself that causes quakes, but rather the injection of wastewater deep underground, where it can cause bedrock to shift more easily. The removal of vast quantities of oil and gas may also unsettle local geology. In one major oil and gas production area near Dallas, scientists recorded 183 slight temblors in 2008 and 2009. “We doubt that it’s a natural process,” says USGS researcher Arthur McGarr. All the fracking-related quakes have been minor so far, and have caused no significant damage.

A blood test for depression

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More than 10 percent of teenagers suffer from major depression during adolescence, but some two thirds of them go untreated—often because doctors and parents can’t distinguish between depression and typical adolescent moodiness. Now researchers at Northwestern University say they’ve developed a first-ever blood test that can identify teens with serious early-onset depression. While the exact causes of the disease are still impossible to pinpoint, researchers studying rats identified 26 genetic markers that could be linked to depression and anxiety in people. They then tested blood samples from severely depressed teens and from teens without depression for the presence of those markers, and found that 11 of them turned up only in the depressed teens. Being able to diagnose depression by blood test rather than with an array of often subjective questions might help dispel the stigma attached to the disorder, particularly among teens, “the age group that needs the most help,’’ study author Eva Redei tells WebMD.com. Adolescents with depression are more likely to abuse drugs and alcohol and have trouble connecting with their peers, and are predisposed to struggle with the condition later in life.

The perils of seeing yourself

People chagrined by their own images on video chats may be driving a skyrocketing demand for chin implants, says the American Society of Plastic Surgeons. Surgeons performed 71 percent more “chinplants” last year than they did the year before—and men are getting slightly more of them than women are. The biggest jump was in people over the age of 40, many of whom get “loose skin under the jawline” as they approach middle age, Columbia University surgery professor Darrick Antell tells MSNBC.com. But a surprising number of younger people who simply “don’t like the shape of their face’’ are asking for chinplants too, says Tony Youn, a plastic surgeon in Michigan. He and other experts suspect that the surge in chinplant requests is linked to the prevalence of video-chat technologies like Skype and FaceTime. Those applications allow users to view themselves and the people they’re talking to onscreen, causing them “to see cosmetic imperfections they may not have noticed before,” Youn says. The other fastest-growing cosmetic procedures last year were also for the face: Lip augmentations and cheek implants both increased by nearly 50 percent.

How guns intimidate

Simply carrying a weapon makes you appear taller and stronger than you actually are, a new study says. Researchers showed subjects hundreds of photographs of hands holding objects, some of them guns and others hand tools such as power drills and caulking guns. When the subjects were asked how big and powerful they thought the person holding an object was, they tended to see the handgun wielders as the most imposing—rating them an average of 2 inches taller and 17 percent stronger than those holding a caulking gun. That intuitive assessment may help explain how we decide whether to flee, attack, or negotiate when facing a dangerous encounter, UCLA anthropologist Daniel Fessler tells Discovery News. Instead of separately weighing all the variables that could determine a fight’s outcome—such as the weapons our opponent carries—Fessler says our brain summarizes our odds of winning in an “easy-to-think form”: The worse our chances are, the larger our opponent seems to loom. That mental shortcut likely evolved from our early ancestors’ understanding, he says, that “all things being equal, the bigger, stronger individual wins the conflict.”