I felt it here in Anchorage when I was on my way to bed. It felt like a shallow, rolling earthquake. It reminded me of a quake I experienced in 2001 in Washington state. The shaking went on for what I thought was 30 seconds. My wife woke up but my kids did not.
We are in no danger from a tsunami here in Anchorage.
The alert shows potential tsunami waves arriving at coastal towns over the next couple of hours, with the first potential wave arriving in Kodiak in a few minutes. I have no idea how likely these waves are, but 7.9 is big. I am sure a lot of people are scrambling for high ground now.
What's really wild about this is that it's actually a strike-slip earthquake, based on the focal mechanism (e.g. https://earthquake.usgs.gov/earthquakes/eventpage/us2000cmy3...) Given how big it is, I'm extremely surprised that it's stike slip. Furthermore, given the area (shallow and very near a subduction zone), anyone would immediately guess that it was a megathrust earthquake, and therefore likely to produce a tsunami. Interestingly, it's not at all.
That's likely a big part of why the tsunami watch was canceled so quickly. In addition to there being no direct detection of tsunami waves, strike slip earthquakes don't produce significant vertical movement of the seafloor (barring triggering a landslide, anyway), and therefore don't typically produce tsunamis.
However, Mw 7.9 is huge for a strike-slip earthquake. They're usually not that large. Furthermore, it's out in the oceanic crust of the incoming plate, so it's not a subduction zone earthquake at all. Instead, it's related to internal deformation of the incoming plate (albeit very near the plate boundary, so it's not exactly an intraplate earthquake either).
Large strike slip earthquakes in oceanic crust aren't unheard of, but they're quite rare. This earthquake appears similar to the large strike-slip earthquakes near Sumatra in 2012 (e.g. http://www.earthobservatory.sg/news/exceptionally-large-stri...). Definitely interesting!
A 7.9 is quite large. That is about the maximum magnitude that the San Andreas fault produces and similar in size to the 1906 San Francisco earthquake.
Since the danger seems to be receding -- I hope NWS & related agencies can use this as a good drill to fix their web properties.
Tsunami.gov couldn't handle the load, and many other official links (like mobile.weather.gov) just dump you into a government shutdown notice. Cell.weather.gov isn't even resolving.
I'm sure someone thought the critical products would still be easily available even with a government shutdown, it sure didn't work out that way.
Most of the labor contracts (not to mention ADA litigation) for the government require a certain level of service if the property is in use. With the government shut down that's not the case. It's the same reason for the infamous "this website is only available from ~9am to ~5pm" nonsense you can find on certain Social Security/IRS pages.
Those are probably not essential as far as the shutdown is concerned. Even NTSB investigations aren’t—there was a train crash or something during the 2013 shutdown that wasn’t investigated.
Are you sure about that? Is that the Chicago crash your talking about? The reports I was able to find indicate that the investigation did proceed but there was limited communication to the public about it because the office was closed.
San Francisco Department of Emergency Management has tweeted that people within three blocks of the coast or five blocks of the San Francisco Bay should be prepared to evacuate.
Tsunami Watch for #SF. If you are w/in SF & 3 blocks of the Pacific Coast or w/in 5 blocks of SF Bay, PREPARE TO EVACUATE SO YOU ARE READY IF EVACUATION IS NEEDED. Check on neighbors who may need help. Visit http://sf72.org/hazard/tsunamis to see if you are in the evacuation zone.
We like to laugh about the Tuesday siren tests, but times like this are why we do them. If a tsunami really does hit WA and OR expect the waterfront sirens to make a pre-dawn announcement.
I'm a recent newcomer to the Bay area. What is the Tsunami situation for places like Mountain View? Places like the GooglePlex are pretty close to the Bay. Is there even any real high ground in the area?? If something happens for real, do sirens sound?
Excluding the coast and the east bay, it is not really a concern. A tsunami would have to come through the golden gate channel and make a quick turn to get to Mountain View with any strength.
Most bay area residents do not fear tsunami. The risk is low since local faults slip side to side which do not cause tsunami. A subduction fault can cause a tsunami, such as in Alaska, Japan or Chile. We would get hours of warning in such a case.
There are multiple notification systems available, I find that the twitter account tends to have a lot more info about hyperlocal and situational events vs the text-based system. I've just never straight up heard the outdoor one go off except for tests.
The national and state emergency alert systems have a cellphone program. You should get cellphone alerts in an emergency (I get them for flooding, AMBER alerts, etc.).
How would they know cell phone numbers? Where I live they call landlines for emergency alerts but there's no other way to specifically target residents.
If it was a big deal, beyond the opt-in SF text alerts, there's a thing called Wireless Emergency Alerts. It's geographically targeted. It's basically like Amber Alerts going to your phone except for imminent emergencies.
There has been some controversy about the timing and use of WEAs for evacuations for the big wildfires in California recently, but I imagine it's hard to balance alarm fatigue with the need to warn people.
How do amber alerts work? When I lived in SF I got SF-related alerts. I don't know enough about how they work - but it sounds like tech that could be re-used for major emergency alerts.
As I should have realized, they're sent to all wireless phones in the area. On an iPhone at least both Amber and Emergency alerts are on by default but you can turn either of them off.
I'd be _really_ suspicious of data showing a 10M tsunami in the open ocean. In deep water, they're super long wavelength low amplitude waves, it's only when they interact with the bottom that the wave piles up and gets to large amplitude.
What I don't get is that nearly all the buoys that have that moving icon "Tsunami alert" show some excitation at the ~9:45GMT mark.
But I would of course expect the buoys that are farther away
to only show some kind of peak when the wave actually reaches them. And it looks like they are thousands of km away, so some of them should not even have been reached yet.
Some what is going on there? Is the data time actually shifted and not in GMT but 'earthquake propagation time'? Am I reading the plots wrong?
The time skew of the events is small, but does exist. They're all within minutes of the 9:31am gmt earthquake, getting longer as you get away from the epicenter. i.e, way faster than a tsunami travels, but about how fast an earthquake travels. (Earthquakes spread in x miles per second, tsunamis in x miles per minute)
I _think_ what you're seeing is the pressure sensor picking up the earthquake and converting it to a water column height.
I'm probably completely wrong, but am wondering and trying to deduce the same thing. My assumption, guess really, is that they were remotely activated into "Tsunami Mode" -- a more rapid-pulse reporting mode or similar, which just is a bit noisier perhaps?
Total layman's guess though -- would love to know more if anyone knows the answer.
> My assumption, guess really, is that they were remotely activated into "Tsunami Mode" -- a more rapid-pulse reporting mode or similar, which just is a bit noisier perhaps?
That sounds like a very good guess. But then, the spikes that are purported to be the Tsunami in the media is just the ADC having a couple bad samples from being switched into a different mode or so :-)
If any USGS person is reading this thread here: Take it as a issue report that your page should be readable and understandable by lay persons, at least lay persons with a non-geophysics STEM background :D
Not an oceanic scientist but sound speed in water is ~1500m/s. This is the speed at which a pressure perturbation propagates. The speed at which the actual tsunami wave would propagate is much more slower than this. So I believe that the excitation marked in the plot is the pressure wave caused by the earthquake, which travels orders of magnitude faster than an actual water wave caused by the earth displacement.
But that doesn't fit the data, either. The buoys all report something around the 9:45ish GMT mark. And 1500m/s would mean you reach Mendocino bay in California only about now or so. But have a look at the plot:
> The system has two data reporting modes, standard and event. The system operates routinely in standard mode, in which four spot values (of the 15-s data) at 15-minute intervals of the estimated sea surface height are reported at scheduled transmission times. When the internal detection software (Mofjeld) identifies an event, the system ceases standard mode reporting and begins event mode transmissions. In event mode, 15-second values are transmitted during the initial few minutes, followed by 1-minute averages. Event mode messages also contain the time of the initial occurrence of the event. The system returns to standard transmission after 4 hours of 1-minute real-time transmissions if no further events are detected.
I see, thanks. But that rather sounds like the buoy itself is switching modes?
From the look of all the plots, even the far-away ones, it rather looks to me like they have been remotely switched into event mode (with that 15s stuff being plotted at about the same time)?
I guess I am really confused about the time stamps.
I think it's a combo of noise when that was activated (see the page above, describes exactly what it reports when it goes into that mode, etc) -- and then for the one that shows a substantial sea level rise, it's likely just the pressure since it's all pressure-based sea-level measurement "estimates". Guess I kind of thought it measured actual rise/fall of the buoy, or maybe used GPS or something, but makes a bit more sense that it's solely based on sea-floor pressure.
The spike corresponds to about 15min delay between the quake at 9:31 UTC. But some kind of spike visible in all stations at that time, even very far away ones, like Mendocino bay.
Honestly, this looks to me rather like some bad data due to the buoys switching mode because of radio commanding 15min after the quake rather than any wave arriving. (Like the other poster suggested)
Even if the shock would travel through an Earth made out of steel, it wouldn't have reached Mendocino bay that fast.
EDIT: There is actually a time shift and it seems to be enough, as wiredfool pointed out. Thanks!
>
Due to the Federal Government shutdown, NOAA.gov and most associated websites are unavailable. This site will remain accessible during the federal government shutdown; however, information on the site may not be up to date and we may not be able to respond to inquiries until appropriations are enacted
That's a big quake! Thank God didn't cause a tsunami, although data from buoys showed VERY early on that probability was VERY low for such an occurrence.
Watch for sustained wave height for serious tsunami warnings, issues coming onshore. Should you see a quick rise, sustained or increasing height offshore, then a drop... Don't wait for it! Get off the beach, away from waterways & to higher ground.
I suppode those of us in California need to be on watch for the next few weeks!
DutchSinse on YouTube has been working on earthquake prediction for years, and although not 100% accurate, he's been a LOT more accurate than anyone else, and has nailed the bigger quakes.
I haven't taken the time to learn his methods insideout, but I've seen him call accurately numerous earthquakes.
I believe with more funding, and a staff, this guy could save many, many more lives.
Having worked with these buoys, and on other NOAA projects, this DutchSince guy has a method to call earthquakes early. PLEASE support him! He is the best bet to predict quakes, to tell the difference between quakes and drilling, quakes set off by drilling, etc.
He's self-taught, and is more of a scientist than many I've met that went through years of "training" of methods that simply don't work. He breathes & lives this stuff, and he is onto something, far more than ANYONE else!
He gets resistance from oil companies, which is sad, as he can save them money and lives!
So get your batteries, your earthquake kits, Ham radios & be ready!
Stay safe, always be prepared & ready for any type of disaster!
Stay safe!
In case you're wondering whether an Alaskan earthquake could cause damage in California, the answer is yes. The tsunami from the 1964 Good Friday earthquake in Alaska obliterated the port of Crescent City:
I hope everything is okay - but I’m finding this a fascinating real-time case study of the chaotic nature of breaking information during a (potential) disaster. Conflicting reports, false alarms, difficult-to-parse data...
There was a study done a while back basically demonstrating that following breaking news too closely actually resulted in a less accurate recollection of the facts. Turns out it’s difficult to forget compelling information even if it ultimately proves to be false (and you’re aware that it’s false).
Do you know why these reports mention Hawaii, rather than (say) Vancouver and other coastal cities nearer to the epicenter, where I would imagine a tsunami would reach first?
The page is specific to Hawaii, but you can go to http://www.weather.gov/ and in the map, click your region and then "tsunami warning" or "tsunami watch" to see estimated times for other states. This is the tsunami watch notice for coastal areas of Oregon, Washington & California: http://forecast.weather.gov/wwamap/wwatxtget.php?cwa=sew&wwa...
You can also quickly access this info at http://www.tsunami.gov. Or at least normally it's quick; page is taking a good 10 seconds to load for me right now—under a bit of load, presumably.
It includes Canada as well. (In fact, the BC Emergency site quotes from it and links back to it!)
I wonder what their infrastructure looks like. This is the poster case for a scalable cloud setup. 99%+ of the time their traffic is probably nearly zero, and when there will be a significant spike it's generally going to be predictable!
I know but since tsunami.gov it's getting is getting hammered I figured out it's better to leave their bandwidth for people in risk rather than hit them with the HN frontpage effect.
This British Columbia government webpage includes the tsunami watch locations and time estimates for Canadian locations PLUS information from the same source as the USGS webpage.
Cut-n-paste to reduce their server load (but check directly later for updates. Stated update frequency is 30 minutes):
UPDATE: Tsunami Warning: coastal areas of BC following 7.9M earthquake in Gulf of Alaska. Jan. 23, 2018 at 02:08AM
January 23, 2018 at 2:57 am
This information is preliminary and may change rapidly. Listen to local officials and visit National Tsunami Warning Center for more information.
Update: revised magnitude
Tsunami Warning REMAINS in Effect for;
* BRITISH COLUMBIA, The Juan de Fuca Strait coast, the outer
west coast of Vancouver Island, the central coast and
northeast Vancouver Island, and the north coast and Haida
Gwaii
* SOUTHEAST ALASKA, The inner and outer coast from The
BC/Alaska Border to Cape Fairweather, Alaska (80 miles SE
of Yakutat)
* SOUTH ALASKA AND THE ALASKA PENINSULA, Pacific coasts from
Cape Fairweather, Alaska (80 miles SE of Yakutat) to Unimak
Pass, Alaska (80 miles NE of Unalaska)
* ALEUTIAN ISLANDS, Unimak Pass, Alaska (80 miles NE of
Unalaska) to Attu, Alaska including the Pribilof Islands
Tsunami Watch REMAINS in Effect for;
* CALIFORNIA, The coast from The Cal./Mexico Border to The
Oregon/Cal. Border including San Francisco Bay
* OREGON, The coast from The Oregon/Cal. Border to The
Oregon/Wash. Border including the Columbia River estuary
coast
* WASHINGTON, Outer coast from the Oregon/Washington border
to Slip Point, Columbia River estuary coast, and the Juan
de Fuca Strait coast
PPRELIMINARY EARTHQUAKE PARAMETERS – UPDATED
——————————————-
* The following parameters are based on a rapid preliminary
assessment and changes may occur.
* Magnitude 7.9
* Origin Time 0032 AKST Jan 23 2018
0132 PST Jan 23 2018
0932 UTC Jan 23 2018
* Coordinates 56.0 North 149.1 West
* Depth 12 miles
* Location 175 miles SE of Kodiak City, Alaska
360 miles S of Anchorage, Alaska
FORECASTS OF TSUNAMI ACTIVITY
—————————–
* Tsunami activity is forecasted to start at the following
locations at the specified times.
FORECAST
START
SITE OF TSUNAMI
—- ———-
* Alaska
Kodiak 0145 AKST Jan 23
Seward 0155 AKST Jan 23
Elfin Cove 0155 AKST Jan 23
Sitka 0200 AKST Jan 23
Yakutat 0205 AKST Jan 23
Valdez 0215 AKST Jan 23
Sand Point 0220 AKST Jan 23
Cordova 0225 AKST Jan 23
Unalaska 0240 AKST Jan 23
Homer 0255 AKST Jan 23
Craig 0300 AKST Jan 23
Cold Bay 0300 AKST Jan 23
Adak 0305 AKST Jan 23
Shemya 0350 AKST Jan 23
Saint Paul 0400 AKST Jan 23
* British Columbia
Langara 0210 AKST Jan 23
Tofino 0340 AKST Jan 23
* Washington
Neah Bay 0455 PST Jan 23
Long Beach 0500 PST Jan 23
Moclips 0500 PST Jan 23
Westport 0510 PST Jan 23
Port Angeles 0530 PST Jan 23
Port Townsend 0555 PST Jan 23
* Oregon
Port Orford 0505 PST Jan 23
Charleston 0510 PST Jan 23
Seaside 0510 PST Jan 23
Newport 0515 PST Jan 23
Brookings 0515 PST Jan 23
* California
Crescent City 0520 PST Jan 23
Horse Mountain 0525 PST Jan 23
Fort Bragg 0525 PST Jan 23
Monterey 0555 PST Jan 23
San Francisco 0620 PST Jan 23
Port San Luis 0620 PST Jan 23
Santa Barbara 0635 PST Jan 23
Los Angeles Harb 0650 PST Jan 23
Newport Beach 0700 PST Jan 23
La Jolla 0705 PST Jan 23
Oceanside 0705 PST Jan 23
OBSERVATIONS OF TSUNAMI ACTIVITY
——————————–
* No tsunami observations are available to report.
Vancouver is well protected from tsunamis caused by earthquakes in most spots (including this one) by Vancouver Island. The Greater Vancouver tsunami zone is the only one in BC not covered by the tsunami warning issued for this quake.
> Tsunami warning ends for B.C. after large earthquake strikes off Alaska
I first interpreted this as “There was going to be a Tsunami, but then an earthquake struck which nullified it.”
Wow, that is surprising. I should have thought about it further. The radius of earth is 6371Km and 10Km works out to be 0.15% of it. So 20Km is reasonable.
Will this wave affect boats? Imagine being on a yacht in the middle of the Pacific (not Atlantic Doh!) when a 10m wave moving at 20m/s hits (figures not accurate just guesses)
Picture a 1m high wave with a crest to crest wavelength of 100km. That is pretty much what an open water tsunami looks like.
This is why when there's a tsunami warning, boats are supposed to leave the harbor, where it's dangerous, and get to sea where they won't notice the wave.
There probably won't be 10m waves in the middle of the ocean. The waves will only be a few inches tall, but moving FAST. Then they get dramatically taller as they are forced to slow down in shallow water.
Within a couple of minutes, I saw the reported magnitude, depth, and location on the USGS earthquake site, https://earthquake.usgs.gov/earthquakes/map/.
About the same time, Google started showing a tsunami alert: https://www.google.org/publicalerts/alert?aid=43774f005241ac...
We are in no danger from a tsunami here in Anchorage.
The alert shows potential tsunami waves arriving at coastal towns over the next couple of hours, with the first potential wave arriving in Kodiak in a few minutes. I have no idea how likely these waves are, but 7.9 is big. I am sure a lot of people are scrambling for high ground now.
God speed and be safe.