Powerful 7.3-magnitude quake rocks Alaska and sparks tsunami warning

Daily Mail​

3 days ago

Thousands of Americans along Alaska's coastline raced to higher ground on Wednesday, abandoning their homes after a major earthquake triggered a tsunami warning.
The US Geological Survey (USGS) detected a 7.3 magnitude at approximately 12:38pm local time (4:30pm ET), centered in the Pacific Ocean just south of the Alaska Peninsula near the Shumagin Islands, southeast of Sand Point.
Sirens wailed and emergency alerts lit up phones across the region, warning residents across a vast stretch of southwestern Alaska, from Kennedy Entrance near Homer to Unimak Pass near Unalaska, to evacuate immediately.
Rachel Lord, the mayor of Homer, said: 'We've been hearing [that] initially there was a lot of bumper-to-bumper traffic and people just trying to get you know to get off the spit.'
Officials also warned of potential tsunami impacts on Kodiak Island, the Alaska Peninsula, and parts of the eastern Aleutian Islands, with some areas expected to be hit first.
Dramatic images showed an eerily bare shoreline, the ocean having suddenly vanished, a chilling sign that a tsunami could be moments away.
David Snider, a tsunami warning coordinator at the National Oceanic and Atmospheric Administration, told KTUU that a tsunami had been confirmed, saying the tsunami generated small waves that rose sea levels about three inches.
The Tsunami Warning Center said: 'A tsunami was generated by this event, but no longer poses a threat. Some areas may continue to see small sea level changes.'
The initial alert issued a full tsunami warning shortly after the 7.3 magnitude quake struck but was downgraded to a tsunami advisory roughly 90 minutes later and then canceled at 12:45pm local (6:45pm ET).
Locals have been warned that unusual waves will continue for about 24 hours, and to stay cautious into Thursday.
As panic spread across coastal communities, officials confirmed that Kodiak High School and North Star Elementary School had been opened to the public as emergency shelters.
In Seward, a southern Alaska port town, one resident shared a video to X, revealing she had just returned to Alaska after 25 years, only to find herself fleeing from a tsunami threat.
The clip shows her and several others walking briskly away from the coast and heading for higher ground.
'Just pray we don't get waved,' she says nervously, before ending the recording.
The Alaska Earthquake Center has recorded more than 20 aftershocks following Wednesday's powerful quake, with the strongest so far measuring magnitude 5.2.
Michael West, seismologist with the Alaska Earthquake Center, told Fox Weather: 'The entire southern coast of Alaska is a gigantic earthquake zone. Four out of five earthquakes in the United States happen in Alaska.'
West noted that earthquakes are common in the region, though many are too small to be felt and rarely reach this magnitude.
He said: 'Early signs suggest we're on the lucky side today.'
The National Weather Service (NWS) issued a statement moments after the monster quake struck, confirming there was no tsunami threat to Oregon, Washington or other US states outside Alaska.
The NTWC said the advisory covered an area stretching approximately 700 miles, from about 40 miles southwest of Homer to Unimak Pass, near the eastern Aleutian Islands.
Although the shaking was felt most intensely in southern Alaska, where it struck near the Aleutian subduction zone, the energy released by the quake did not stay local.
Seismic waves, vibrations that travel through the Earth, activated seismic sensors as far east as the East Coast of the US and reaching across the ocean to Europe and parts of Asia and Africa.
While the vibrations were not strong enough to be felt by people thousands of miles away, sensitive instruments captured every pulse of the Earth's movement in real time.
Using a global network of sensors and cutting-edge computer simulations, scientists converted the raw data into animations showing how the seismic energy rippled out from the epicenter like waves from a stone thrown into water.
A yellow star marked ground zero on the map in Alaska, while red and blue dots representing seismic stations lit up one by one as the waves swept past.
In less than a minute, the tremors had reached monitoring stations across the world.
Large earthquakes are known to redistribute stress along fault lines, sometimes increasing the strain on already vulnerable zones.
If those areas are near their breaking point, the added pressure could trigger aftershocks or even fresh quakes, not just locally, but potentially in distant regions connected by geological stress transfer.
In rare cases, shifting stress can also activate entirely separate fault systems, making this kind of global disturbance more than a geological curiosity.
The vibrations were captured using real-time computer simulations that convert raw seismic data into animations of Earth's movement, showing how ground motion travels outward from the epicenter.
An animation of the traveling shockwaves depicted blue and red seismic stations scattered across the map, lighting up as each recorded the powerful geological event.
The visual sequence, starting at 0.00 seconds, showed the epicenter marked with a yellow star, with a red line tracing the expanding wavefronts as they moved away from Alaska.
As time progressed from 1.97 to 64.94 seconds, the seismic waves continued their relentless expansion.
In the early stages, between 1.97 and 15.74 seconds, the waves primarily impacted the western coast of North America.
The primary waves reached seismic stations in Alaska and the Pacific Northwest, with the red line on the map illustrating their rapid advance.
This phase highlighted the immediate regional impact, where the energy of the quake was most intensely concentrated.
During the mid-stages, from 17.71 to 37.39 seconds, the seismic waves pushed further inland across the US.
The wavefronts began to reach stations in Canada and the central US, demonstrating the broadening scope of the earthquake's influence.
The red line on the map continued to extend, tracking the waves' progression as they traversed the continent.
In the later stages of the event, between 39.36 and 64.94 seconds, the seismic waves reached the East Coast and began influencing stations in Europe and Asia.
Adding to the mystery, a massive magnetic pulse was detected at the exact moment the earthquake occurred. The very second the rupture began, Earth's magnetic field showed a sharp spike.
Within hours, a G1-class geomagnetic storm developed, disrupting the planet's magnetic environment.
Strangely, this occurred despite otherwise nominal solar wind conditions, prompting researchers to question whether the quake may have played a role in triggering the storm.
While the link between earthquakes and geomagnetic activity remains poorly understood, the coincidence is striking.