![]() When that much ice scrapes, the earth itself shakes. ![]() The quakes he recorded, he believes, are the vibrations set up by all that ice-in one case, six cubic miles of it-skidding as much as forty-two feet in under a minute. Those warmer months melt lots of glacial ice.Įkström suspects that liquid water is pooling underneath the glacial ice to the point where the thin veneer of water at the base of the glacier allows the whole mass to slip a little, the way your foot can skid on a slick road. He also found that they mostly occurred during July, August, and September. Just because it takes centuries to rearrange things, though, doesn't mean a glacier isn't enormously powerful at any given moment.īy carefully measuring seismic signals, Ekström was able to spot numerous low-frequency quakes in Greenland that hadn't been identified. It's made of solid ice, but over long periods of time it can flow gradually over the land, sometimes carving deep trenches and bulldozing up rock and soil. What are they near instead? Ice.Ī glacier can be thought of as a very slow-moving stream. Recent earthquakes were felt in the area in April 2008 and December 2010. He found over a hundred quakes have happened in the last decade that aren't along any fault line. INDIANAPOLIS (WISH) Several WISH-TV viewers reached out over the weekend over concerns of what they called loud pops or booms Saturday night and early Sunday morning. Although rare, earthquakes do impact Central Indiana. ![]() Just recently, though, a geophysicist at Harvard University named Göran Ekström studied low-frequency vibrations instead, and discovered something interesting. Those destructive energy bursts are high frequency ground vibrations, and that's the range of vibrations seismologists most actively study. They're dramatic events: a good-sized earthquake can bring buildings and bridges toppling down. It’s more typical to hear of booms once every few years in rural areas of states such as Wisconsin and Massachusetts.We're used to thinking of earthquakes as tremors that happen along fault lines when tectonic plates shift. Leung suggested that in addition to social media reports, frost quakes have garnered extra attention becuase they have occurred in a major city, Toronto. As recently as Sunday, 911 operators in Illinois and Missouri took reports from callers who said they heard booms. A study on ice faulting and icequake activity in the Lake Suwa. King’s map shows frost quake markers in states such as Maine, New York, Ohio, and Wisconsin. Frost quake events and changing wintertime air mass frequencies in southeastern Canada. “Soon enough, it appeared to everyone that these noises were not random due to the sheer volume of reports,” Leung said. “It amazed me how gracious people were to have a Web page where they could see that other people were hearing and feeling the same strange events as them,” King said. She assembled a Google Map to allow users to pinpoint and describe their own frost quake experience. While visiting Texas during Christmas, King heard news reports of “booms” in her hometown and turned to Twitter to see what people were saying. Since the beginning of the year, Leung has tracked numerous frost quakes in freeze-gripped parts of the Midwest. Witnesses have described the sounds as being similar to gunshots, exploding bombs and falling trees. When temperatures suddenly reach near 0 degrees, the water table expands and starts cracking the soil and smashing nearby rock formations. They might crack roadways and building foundations, but that kind of result is rare.įrost quakes can strike after a pounding of rain or when the rapid melting of snow saturates underground streams. “Since frost quakes are rare, localized, cannot be monitored and tend to cause only minimal damage, the scientific community has very limited amount of information,” said University of Toronto Scarborough Climate Laboratory researcher Andrew Leung. “But typically they will not be felt very far away.”Īnd social media have given researchers a new way to study the little-discussed temblors. “Even though their source sizes are small, the shaking they cause at the surface can be large because they occur so close to the surface,” Thurber said in an email to the Los Angeles Times. The most intense frost quake he’s seen was a magnitude 1.5. ![]() ![]() A cryoseism, also known as an ice quake or a frost quake, is a seismic event potentially. He guesses that the frozen water tables are tens of meters long. The last frost dates in northern Indiana are May 1 to 15. The term also includes the cracking and slipping of glacial ice and the fracturing of frozen lake ice, said Clifford Thurber, a geophysics professor at the University of Wisconsin Madison. “I went on Twitter and found several tweets from people who were awoken by the same thing, at the same time, around the same area as my apartment building,” she said.įrost quakes have a scientific name: cryoseism. ![]()
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