UPDATED: Alaska quake prompts tsunami alert

[BumRushDaShow]

Last edited Tue Jan 23, 2018, 08:54 AM - Edit history (2)

Source: BBC

A tsunami alert has been issued after a 7.9-magnitude earthquake was recorded off the coast of Alaska in the US.

It hit 280km (173 miles) south-east of Kodiak, 25km deep, at 00:31 (09:31 GMT), the US Geological Survey said.

The US National Weather Service says a warning is in effect for the coasts of British Columbia and Alaska, while the US west coast is on tsunami watch.

Officials in Anchorage warned coastal areas, saying there was "extraordinary threat to life or property". The alert told people to seek refuge on higher ground in affected areas.

Read more: http://www.bbc.com/news/world-us-canada-42786107

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EDIT to add video of evacuation -

Local news clip said a buoy near the earthquake registered a near 40-ft wave. Watches/alerts mostly cancelled down into BC, WA, and CA.

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This happened within the past 45 minutes from original post time. USGS is showing it as an initial 8.2 and their details page has it as a 7.9.

https://earthquake.usgs.gov/earthquakes/eventpage/us2000cmy3#executive

ETA - multiple aftershocks happening - at least 7 as of 1st edit time, the largest being 5.0 so far.

ORIGINAL ARTICLE -

A tsunami alert has been issued after an 8.0-strength earthquake was recorded off the southern Alaskan coast in the US.

The quake struck some 300km south-east of Kodiak at a depth of 10km at 09:31 GMT, the US Geological Survey said.

The US National Weather Service said the alert was in effect for areas including California and the coasts of British Columbia and Alaska. The alert told people to seek refuge on higher grounds in affected areas.

The NWS Pacific Tsunami Warning Center said that, based on the preliminary earthquake parameters, "widespread hazardous tsunami waves were possible"

[applegrove]

1. Hoping people get to safety. That is huge.

[icymist]

2. Due to the government shutdown we have no idea if a tsunami is generated!

I finally got through to the site and there is a tsunami warning.
http://www.tsunami.gov/

Warning is throughout the Aleutian Islands, along the western Canadian coast, and the extreme western coast of Washington State from La Push through the Strait of Juan de Fuca. Tsunami alert is the entire West Coast of the USA.

[BumRushDaShow]

3. The "shutdown" was over yesterday afternoon

I don't think the delay you had was related to the shutdown. It's just that over the years, the NOAA/NWS pages have ALWAYS been slow to load!

[icymist]

4. It actually flashed that message. nt

http://www.tsunami.gov/

[BumRushDaShow]

9. Agencies were required to include the messages

just as furloughed employees were required to add a message on their phones & emails for "out of office" (been there done that as a former, now-retired fed). But that doesn't impact access to the website. I.e., the site might not be updated during a furlough but it doesn't just drop offline.

[icymist]

5. More information:

Link to tweet

[icymist]

6. Tsunami Warning Alaska and Canada

Link to tweet

[icymist]

7. From NOAA

...THE TSUNAMI WATCH REMAINS IN EFFECT FOR THE COASTAL
AREAS OF CALIFORNIA, OREGON AND WASHINGTON FROM THE
CAL./MEXICO BORDER TO THE WASH./BC BORDER ...

If you are located in this coastal area, stay alert
for further updates.

Tsunami watches are an advance notice to areas that could be
impacted by a tsunami at a later time. Watch areas may be
upgraded to a warning or advisory status, or canceled,
based on new information.

At 1232 AM Alaska Standard Time on January 23 an earthquake with
preliminary magnitude 8.2 occurred 175 miles southeast of
Kodiak City Alaska.

Estimated tsunami start times for selected sites are;

Neah Bay Washington 450 AM. PST. January 23.
Long Beach Washington 455 AM. PST. January 23.
Moclips Washington 500 AM. PST. January 23.
Port Orford Oregon 505 AM. PST. January 23.
Seaside Oregon 505 AM. PST. January 23.
Westport Washington 505 AM. PST. January 23.
Newport Oregon 510 AM. PST. January 23.
Charleston Oregon 510 AM. PST. January 23.
Brookings Oregon 515 AM. PST. January 23.
Crescent City California 520 AM. PST. January 23.
Fort Bragg California 525 AM. PST. January 23.
Horse Mountain California 525 AM. PST. January 23.
Port Angeles Washington 530 AM. PST. January 23.
Monterey California 555 AM. PST. January 23.
Port Townsend Washington 555 AM. PST. January 23.
San Francisco California 620 AM. PST. January 23.
Port San Luis California 620 AM. PST. January 23.
Santa Barbara California 635 AM. PST. January 23.
Los Angeles Harbor California 650 AM. PST. January 23.
Newport Beach California 700 AM. PST. January 23.
Oceanside California 705 AM. PST. January 23.
La Jolla California 705 AM. PST. January 23.

The tsunami watch will remain in effect until further notice.
Refer to the internet site tsunami.gov for more information.
https://inws.ncep.noaa.gov/a/a.php?i=18657090

[icymist]

8. Tsunami Warning Kodiak - 100 feet or higher

Link to tweet

[icymist]

10. The Latest: Police: No wave reported amid tsunami warning

ANCHORAGE, Alaska (AP) — The Latest on an Alaska earthquake that prompted a tsunami warning for coastal Alaska, Canada’s British Columbia and the West Coast of the U.S. (all times local):

2:30 a.m.

The city of Kodiak, Alaska, was projected to see the first wave at about 1:45 a.m., about an hour after an earthquake with a preliminary magnitude of 8.2 prompted a tsunami warning.

About a half hour later, Lt. Tim Putney of the Kodiak Police Department said there had been no reports of a wave and nothing had been seen, yet.

However, officials were telling people to hold fast at evacuation centers until further notice. He said the town has several shelters above the 100-foot mark, and they were still encouraging people below that level to evacuate.

The earthquake woke Putney up out of a dead sleep, and he estimates it shook for at least 30 seconds.

The police had not received any reports of damage.

The Alaska Earthquake Information Center said the quake was felt widely in several communities on the Kenai Peninsula and throughout southern Alaska, but it also had no immediate reports of damage.

https://apnews.com/b8128a04d8dc477fad6016e062dbf111/The-Latest:-Official:-No-early-damage-amid-tsunami-warning?utm_campaign=SocialFlow&utm_source=Twitter&utm_medium=AP

[BigmanPigman]

12. They just announced it on the local news

in San Diego (4:15 AM). I am inland a few miles and my family on the coast is up high on steep hills so we are OK.

The water is receeding in areas on the Alaskan Coast now. That is the first sign and the locals know to start moving fast while tourists go close to check it out and they are the ones who end up getting nailed first.

[Silver Gaia]

13. Water receding from harbor in Kodiak, AK

Link to tweet

Link to tweet

[icymist]

14. Tsunami Watches for BC, Washington, Oregon, and California have been cancelled.

Link to tweet

[Silver Gaia]

15. To corroborate the above post:

Link to tweet

[BigmanPigman]

16. It was just downgraded on the

local news in San Diego.

[watoos]

17. I wonder

what a tsunami would do to an oil rig?

[BumRushDaShow]

18. It could damage it depending on the strength of the underwater wave.

However as I understand, the "wave" under the ocean is not that evident at the surface and only builds as it gets to shallow water near a shore, where you'd see the characteristic huge wave above the surface.

[Bayard]

19. I was wondering

What kind of drilling may be going on in that area that may cause an earthquake.

[raven mad]

20. As I actually live here, and can verify.........

no biggy wave. No biggy shake or wiggle.

[BumRushDaShow]

21. Were you in an evacuation area?

Kinda rough for that to happen late at night there.

[raven mad]

23. No, about 800 miles from one.

But Kodiak, et al, are fairly used to it. Ours is usually any shaker over 8 that hits the interior or a flood - ain't no time to run!

[Baclava]

22. A powerful earthquake in Alaska didnt trigger a big tsunami heres why

Tsunami warnings cancelled, less than 1 ft wave

Last night, a magnitude 7.9 earthquake struck southeast of Kodiak Island in the Gulf of Alaska, prompting a tsunami warning that forced people to flee to higher grounds in the middle of the night. Fortunately, the tsunami waves were less than a foot high, and the advisories were canceled a little after 4AM local time. So why was Alaska so lucky?

“Alaska is no stranger to these kinds of quakes,” says Don Blakeman, a geophysicist with the US Geological Survey (USGS).

Last night’s earthquake generated because of all the strain building up on the subduction zone, but it did not occur exactly on a fault where the Pacific Ocean seafloor is sliding under the North American plate, Blakeman says. Instead, the quake occurred a little farther out, in a place where the fault is moving horizontally. This type of quake, called a strike-slip earthquake, is less likely to trigger large tsunamis, and this is probably why Alaska only saw waves of less than a foot, according to Blakeman.

When earthquakes happen on the subduction zone itself, where one plate is pushing down while the other is going up, then high waves form. “To get a tsunami, you have to have substantial vertical movement on the seabed,” Blakeman says. Those types of earthquakes were responsible for the massive tsunamis in Japan and Indonesia.

https://www.theverge.com/2018/1/23/16922914/alaska-earthquake-tsunami-pacific-north-america-plate-boundary