![]() You know those squiggly and jumpy lines on a seismogram? When a big event occurred last year east of Juneau, Ruppert noticed it didn’t resemble a typical earthquake. So how do scientists know the difference between an earthquake and an ice quake when they’re looking at the data? Because the data look and even sound different. ![]() In Antarctica, scientists detected seismic activity which revealed how a giant river of ice called the Whillans Ice Stream lurches ahead into the ocean every 12 hours, as the tide rises and falls. In Greenland and Antarctica, giant icebergs slowly breaking away from tidewater glaciers create vibrations that can be detected around the world. Ice quakes actually may be caused by many different things, like a glacier scraping against the bedrock or a crevasse opening up. “And our seismic sensors are able to record that energy.” And every time it moves, deforms or cracks, it creates some energy that propagates in the form of seismic waves,” Ruppert said. That’s the same instrument they use to measure and locate earthquakes. Scientists can’t see or feel the quakes themselves, so they use seismometers. (Screen capture from Alaska Earthquake Center website)įor those who might be new to ice quakes or glaciology, let’s get a few things out of the way. Ogden is on the northeast side of the glacier just north of the blue dot. Far right cluster of yellow dots are located at the start of Wright Glacier. “To produce an earthquake like that, that could be detected regionally, you would need to have a pretty big event.” Dots show location of ice quakes, largely of magnitude 2.9 or lower, that were detected in two weeks preceding July 8, 2021. “The glaciers in that area are pretty small,” Amundson said. Last year, glaciologist Jason Amundson of the University of Alaska Southeast actually flew out to investigate one of the bigger ice quakes near Wright Glacier and Mount Ogden on the United States-Canada border. Ruppert said there have already been a hundred ice quakes recorded so far in 2021. This year the ice quakes started in May, with a big spike in activity starting four days before late June’s heatwave in Southeast Alaska. And magnitude three is a quite significant signal, that some of those ice quakes were reported to be felt in Juneau,” Ruppert said. Seismologist Natalia Ruppert of the Alaska Earthquake Center said there were 360 ice quakes in the area last year, including some significant shakers. Boulder, Colorado USA: National Snow and Ice Data) Wright Glacier: From the Glacier Photograph Collection. Ogden on the U.S.-Canada border are likely out of view on the left side of the picture. Photo taken 1905 of Wright Glacier, looking southeast. But they aren’t anything new - scientists have been studying them for a long time. Southeast Alaska made headlines in some blogs and online news sites recently, with people connecting them to the area’s recent heat wave. ![]() It’s one of many types, and it’s probably quite similar to what has been happening almost every day for the last few weeks in the mountains and glaciers near Mount Ogden, about 40 miles directly east of Juneau. This is a big iceberg in Antarctica either scraping against the ocean bottom or another iceberg. This groaning or rumble sound is sped up about three times. ![]() They’re not as widely understood as earthquakes, but researchers are monitoring them closely. Within a set of glaciers and mountains near Juneau, there’s seismic activity almost every day in the summer. Ogden, while investigating the source of ice quakes in 2020. Jason Amundson took this picture of Speel Glacier, located approximately 6 miles south of Wright Glacier and Mt.
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