![]() Triggered seismicity rate increases may therefore be most likely to occur in areas where loading rates are highest and elevated pore pressures, perhaps facilitated by high-temperature fluids, reduce frictional stresses and promote failure. The permanent and dynamic (transient) stress changes inferred to trigger earthquakes are usually orders of magnitude smaller than the stresses relaxed by the earthquakes themselves, implying that triggering occurs on critically stressed faults. Other major faults in the region experienced much smaller static Coulomb stress changes.Įarthquake nucleation by transient deformations caused by the M = 7.9 Denali, Alaska, earthquake We also find that the two main earthquakes together transferred more than 400 kPa of Coulomb stress to the Cross Creek segment of the Totschunda fault system and to the Denali fault southeast of the mainshock rupture, and up to 80 kPa to the Denali fault west of the Nenana Mountain rupture. We find that the Nenana Mountain foreshock transferred 30-50 kPa of Coulomb stress to the hypocentral region of the Denali Fault mainshock, encouraging its occurrence. We have modeled static Coulomb stress transfer effects during this sequence. It was followed on 3 November 2002 by the Mw 7.9 Denali Fault mainshock, the largest strike-slip earthquake to occur in North America during the past 150 years. On 23 October 2002, the Mw 6.7 Nenana Mountain earthquake occurred in central Alaska. In 1964, southern Alaska experienced the most powerful earthquake known to hit North America - a 9.2 magnitude quake, with an epicenter about 75 miles east of Anchorage.Static stress transfer during the 2002 Nenana Mountain- Denali Fault, Alaska, earthquake sequence And counting the smallest quakes, the state experiences more than 1,000 earthquakes per month. Since 1900, the state has experienced one magnitude 7 to 8 quake every year, and six magnitude 6 to 7 quakes annually, according to the Alaska Seismic Hazards Safety Commission. The Trans Alaska Pipeline System has been shut down in the aftermath of the quake, and crews are assessing possible damage.Īlaska is the most seismically active region of the United States. However, the Federal Aviation Administration says it has issued a ground stop, and it is not clear when flights into Anchorage will resume. While some ramps to the airport are closed, the terminal is open, and flights are arriving and departing, the airport announced on Twitter. dqHGPCv6XO- Heather Hintze November 30, 2018 Evacuated the building after the shaking stopped. This is what happened on the 6th floor of the Nesbett Courthouse during the Anchorage #earthquake. "We continue to feel aftershocks but are lucky to have power." "It seemed like it lasted well over a minute (even accounting for the misperception of time in nightmares)," she tells NPR. Kari Tai, who is visiting Anchorage, was in her brother's house when the earthquake began. It felt like for a minute we might watch that ground open up," Bartley said. "That's the quickest I've ever seen one come on and the hardest I've ever seen it shake. "I've been here 11 years and I've felt movers before, but that scared me s***less," Anchorage resident Kevin Bartley told reporter Nat Herz of Alaska Public Media. The original earthquake powerfully shook Anchorage, the most populous city in Alaska. "People went back inside after the first earthquake struck, but the 5.8 aftershock about five minutes later sent them running back into the streets," The Associated Press reports. It was followed by a series of aftershocks, including one particularly powerful one. #anchorage #alaska #earthquake #weather /d1SaxriGw9- Cassie Schirm November 30, 2018 KTVA’s newsroom felt the blow of the earthquake this morning. ![]() ![]() The epicenter was about 8 miles north of Anchorage, at a depth of some 25 miles. The earthquake struck just before 8:30 a.m. "Many roads and bridges are closed."Ī tsunami warning was temporarily issued for coastal regions of Cook Inlet and the Southern Kenai Peninsula, but it has since been canceled. Anchorage police report "major infrastructure damage." "Many homes and buildings are damaged," the police department says. Bill Walker has issued a declaration of disaster. Schools were evacuated and parents told to pick up their children - a challenge, in some cases, given the traffic jams that quickly formed across the city.Īlaska Gov. Some roads, bridges and buildings have been damaged, and some businesses shuttered for the day. In Anchorage, Alaska, people took refuge under tables and fled outdoors on Friday morning, as a magnitude 7.0 earthquake struck just north of the city. After an earthquake on Friday, a car is trapped in a crumbled section of an off-ramp from Minnesota Drive, a major road in Anchorage, Alaska. ![]()
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