Alaska quake depth8/30/2023 ![]() The July 2020 temblor broke part of the gap, surprising some scientists because they thought the plates in this region were slowly sliding past one another and not building up enough stress to trigger a big quake. This so-called seismic gap is an area along the subduction zone that hasn’t had a big earthquake in a relatively long time-the Shumagin Gap has largely laid quiet over the last century. These quakes both sit adjacent to a curious area known as the Shumagin Gap. Scientists are still analyzing the event, but it’s possible the zone where these two quakes tore through the subsurface may even overlap. The latest quake struck within 25 miles of another magnitude 8.2 that rattled the region in November 1938. "Every earthquake makes other earthquakes more likely," Bohon says. The position of these three large events is likely no coincidence: While an earthquake may release stress in one area, it can layer on stress in nearby zones, increasing their potential for future quakes. Bohon explains it using pasta: If one spaghetti noodle is the energy released by a magnitude 5 quake, then 900 noodles would represent a magnitude 7, and 25,000 noodles would be a magnitude 8. While the numerical differences sound small, they translate to huge amounts of energy. The latest event is particularly intriguing to scientists because it struck just a few dozen miles east of two large temblors that gripped the region in 2020: a magnitude 7.8 on July 22 and a magnitude 7.6 on October 19. This was just a year after a powerful magnitude 9.2 temblor rocked the region, the second-largest earthquake ever recorded anywhere in the world. The last time a larger earthquake struck in the United States was also in Alaska, when a magnitude 8.7 quake hit near the Aleutian's Rat Island in 1965. On average, a quake rumbles detectors of the Alaskan Earthquake Center every 15 minutes, which translates to tens of thousands of temblors each year. This tectonic battle means that earthquakes in Alaska come as no big surprise. Just such an event happened during last night's temblor, which scientists think fractured right at the subsurface juncture between the Pacific and North American plates. But the pair of tectonic plates don't smoothly slide by each other, and each slow shift builds stresses along the fault until it hits a breaking point and the land suddenly shifts in a ground-rattling quake. The process, known as subduction, can raise mountains and is responsible for the volcanoes that built the Aleutian Islands. The Pacific plate is slowly shoving its way beneath the overlying North American plate, shifting northward roughly 2.5 inches each year in the zone where the new quake struck. Find out the origins of our home planet and some of the key ingredients that help make this blue speck in space a unique global ecosystem. This sweep of land and the quake that recently rocked it both come from the same source: a subterranean battle between tectonic plates.Įarth is the only planet known to maintain life. Here, the land juts out from North America in a thin curving spit that peters out into a series of islands, like beads falling off a string. The powerful earthquake struck off the southern coast of Perryville, on the Alaskan Peninsula. "It's an excitement to see that data." A shaky history "Every earthquake we're recording is going to teach us something new," Aderhold says. Additionally, comparing this quake to past events can help scientists better understand the region's potential to produce future shakes. The event was so strong, it sent out seismic waves that lit up detectors around the world, even disturbing groundwater levels in Washington County, Maryland.īecause the waves move differently through rocks with different temperatures and compositions, scientists can use these seismic rattles and shakes like planetary x-rays to map out Earth's innards. The quake now serves as a powerful reminder of the restlessness of our planet's surface-and it presents an exciting opportunity to peer deeper at our planet’s inner workings. She looked up to see her hanging stained glass lamp-a remnant from the house's past owners-slowly swinging side to side "like a pendulum," she says. This intense shaking had dissipated to gentle rocking by the time it reached Aderhold, an earthquake seismologist also at IRIS. "The ‘big one’ that we talk about in Southern California, it's like that," says Wendy Bohon, an earthquake geologist at the Incorporated Research Institutions for Seismology (IRIS), an assemblage of research universities that collects, curates, and distributes U.S. A magnitude 8.2 earthquake is nearly as large as the biggest earthquake thought possible along the San Andreas fault. ![]() But such a large event would be devastating elsewhere. It struck far from dense population centers and only caused rough seas.
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