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The city announced that regular bus service would resume the following day, and would be free of charge for the two days following the earthquake to help city residents get around on damaged roads. DOT&PF Maintenance and Construction crews are actively working the eight major damage sites . Earthquake aftershocks are continuing to contribute to settling and additional cracking. Hydrogeologic responses to earthquakes have been known for decades, and have occurred both close to, and thousands of miles away from earthquake epicenters. When earthquakes do occur, rapid reporting allows the public and emergency managers to assess the potential impacts.
We will minimize haul times by using the closest available asphalt plant as much as possible. We can add chemicals to the asphalt that will allow it to be compacted at lower temperatures than usual, which will give us more time to compact. Weather predictions are not favorable so please take extra precautions when traveling the roadways. Many times, in an emergency, we need to reach you during off-hours.
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Kodiak resident Ted Panamarioff survived the 1964 earthquake, which was magnitude 9.2. To him, Tuesday's quake felt far milder, although it did wake him up. The temblor reminded King of a deadly 1964 quake that generated tsunamis that killed 129 people and wreaked widespread devastation—events that remain vivid in the memories of many Alaskans. The Aleutian arc extends approximately 3,000 km from the Gulf of Alaska in the east to the Kamchatka Peninsula in the west. It marks the region where the Pacific plate subducts into the mantle beneath the North America plate. This subduction is responsible for the generation of the Aleutian Islands and the deep offshore Aleutian Trench.
As the EarthScope Transportable Array project added new seismic stations in previously unmonitored areas, we noticed an upward trend of detectable earthquakes from around the state. The westernmost Aleutians megathrust earthquake followed a year later on February 4, 1965. This M8.7 Rat Islands earthquake was characterized by roughly 600 km of rupture. Although this event is quite large, damage was low owing to the region's remote and sparsely inhabited location. A relatively small tsunami was recorded throughout the Pacific Ocean with run-up heights up to 10.7 m on Shemya Island and flooding on Amchitka Island.
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The hospital went to Hospital Incident Command System, or HICS, Level 1 right after the quake, and looked for possible damage. After the tsunami warning it went to HICS 2, said SPH Spokesperson Derotha Ferraro. “However, we don’t have any borough roads completely closed at this time.
The National Weather Service and Pacific Tsunami Warning Center initially issued a tsunami watch for Hawaii and the entire West Coast, but cancelled them after less than two hours. In the San Francisco Bay Area, residents within three blocks of the Pacific coast and five blocks of the San Francisco Bay were warned by the city's Department of Emergency Management to be ready for evacuation. Providence Alaska Medical Center kept its ER open and was evaluating damage and water leaks. “I’ve lived in earthquake country my whole life, and this was by far the worst,” he said. It was the first earthquake Anchorage resident Melissa Lohr has experienced. A security camera captured the reaction of a mother as she held her son during the first hit of the earthquake as the chandelier swings in the kitchen.
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The Pacific Plate subducts, or sinks, beneath the North American Plate at a deep-sea trench that defines the Alaska-Aleutian subduction zone on the seafloor, about 90 km to the northwest of the Jan. 23 earthquake epicenter. The easternmost megathrust earthquake was the March 28, 1964 M9.2 Prince William Sound earthquake, currently the second largest recorded earthquake in the world. The event had a rupture length of roughly 700 km extending from Prince William Sound in the northeast to the southern end of Kodiak Island in the southwest.
In addition, Matanuska Electric Association reported that 46,000 customers were left without electricity immediately after the earthquake. The earthquake had a magnitude of 7.1 on the moment magnitude scale using a centroid moment tensor inversion of the W-phase. The focal mechanism shows that the earthquake was a result of normal faulting.
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Back in Alaska, people reported on social media that the quake was felt hundreds of miles away, in Anchorage. Reports varied about how long the quake's shaking lasted, depending on location. In British Columbia, sirens blared and officials banged on doors to wake people from their sleep as a tsunami warning was issued along a large swath of the Canadian province's coastline. The magnitude 7.9 quake in the Gulf of Alaska triggered the jarring alert that roused people shortly after midnight Tuesday. Fleeing motorists clogged some highways in their rush to higher ground. There was also heavy damage in the Matanuska-Susitna Valley (Mat-Su), north of Anchorage.
The Matanuska-Susitna Borough School District reported that Houston Middle School, located in the town of Houston, was severely damaged, and students were forced to merge with their high school for the remainder of the year. Colony Middle School students were the last to return to learning. Severe damage to several buildings and a highway overpass near Ted Stevens Anchorage International Airport was reported. There were no fatalities, but at least 117 people were injured, mostly for minor injuries such as cuts, bruises or anxiety.
Most of these earthquakes—and all major earthquakes—can be traced to the movement of tectonic plates. The Alaska Department of Transportation and Public Facilities moved quickly to inspect bridges and begin road repairs. Despite not normally paving during winter, area asphalt plants were restarted and within days sufficient repairs were made to reopen several heavily damaged roads. The first major aftershocks occurred 20 minutes after the earthquake.
A fault dipping at 29° towards the east gives the best match to the observed seismic waveforms. The depth and mechanism are consistent with faulting within the down-going Pacific Plate. This implies that the earthquake was an intraslab earthquake within that plate, rather than at the plate boundary between the Pacific and North American Plates beneath the Anchorage area.
The Palmer exit at the Glenn/Parks interchange is now OPEN to one lane of traffic. We still advise you to avoid the area if possible and only travel if it is absolutely necessary. Every time a new bridge is constructed or an old one is worked on, the bridge is inspected by highly trained engineers, including experts in seismic design. In extreme cases, bridge inspectors can close a bridge to ensure your safety. Every single one of our bridges is inspected by bridge engineers at least every two years. They identify problems, if there are any, and repairs are prioritized and scheduled.
Large earthquakes can create many hazards such as liquefaction and landslides. The USGS has added near-real-time estimates of such ground failures for this earthquake event. This is the first major earthquake in the United States for which this product is available. The models indicate that liquefaction and landsliding have likely occurred and may be responsible for damage to infrastructure, with liquefaction potentially being the larger issue.
A tsunami warning was initially activated for the Cook Inlet area and Southern Kenai Peninsula, according to the National Oceanic and Atmospheric Administration, but it was lifted about 90 minutes after the initial shock. The Volcano Observatory combines these with other observations, including geology, satellite imagery, ground deformation and local observations to assess volcano hazards. The vigor of these faults, and our knowledge of them, generally decreases toward the north, although the impact of this compression can be traced all the way into the Arctic Ocean. Meanwhile, this northwest motion of the Pacific Plate exerts tremendous force on Alaska, compressing the land in a north-south direction and shearing or tugging southern Alaska to the west.
On Facebook, longtime resident Mike Lewis said it was the strongest quake he’s ever felt, too. Lewis posted a picture of his kitchen, strewn with items and debris after the earthquake. Dimond High School senior Anna Krsnak was in second period when the earthquake hit.
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