M8.7 earthquake in Western Pacific, tsunami warning issued

4 days ago (earthquake.usgs.gov)

Japan forecasting tsunamis up to 3m across basically the entire eastern coast. First waves will hit within 10 minutes.

https://www.nhk.or.jp/kishou-saigai/tsunami/

https://www3.nhk.or.jp/news/live/ (live, Japanese)

https://www3.nhk.or.jp/nhkworld/en/live/ (live, English)

The east coast is also where the vast majority of Japan's population lives, and was previously hit by the 2011 tsunami (Fukushima and all that). We're about to find out the hard way what lessons they have learned.

Update: First detected wave in Nemuro, Hokkaido (northernmost Japan) was only 30cm. There may be more. Waves of 3-4m have apparently already hit Kamchatka in Russia.

Update 2: We're almost an hour in and highest waves to actually hit Japan remain only 40 cm. It looks unlikely that this will cause major damage.

  • Japanese news reporting during disaster scenarios is something to behold.

    The screen is filled with data and blinking like a Bloomberg Terminal.

    • To be fair, most of Japanese TV is like that. I always joke that the primary reason they developed HD TV was to be able to cram more text in every corner xD

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    • My favorite is the NHK reporters standing in the middle of absolutely nowhere with their NHK helmets. No matter what the event, there is a reporter wearing a helmet.

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    • Also when you visit most japanese websites you can see this phenomenon.

      I've read an explanation once that this is because culturally, japanese people perceive a wealth of information and choice as being re-assuring and trustworthy, while most westerners feel more re-assured by seeing less content and choice presented in a more minimalist kind of way.

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    • Yes, but it does make sense.

      Eg. old people without smartphones or someone just turning their TV on, seeing big letter "Tsunami evacuate" with map and other information. You instantly know the most important information and you can act on it.

  • A̶F̶A̶I̶C̶T̶,̶ ̶N̶T̶V̶ ̶i̶s̶ ̶r̶e̶p̶o̶r̶t̶i̶n̶g̶ ̶t̶h̶a̶t̶ ̶3̶m̶ ̶w̶a̶v̶e̶s̶ ̶h̶a̶v̶e̶ ̶j̶u̶s̶t̶ ̶s̶t̶a̶r̶t̶e̶d̶ ̶t̶o̶ ̶h̶i̶t̶ ̶J̶a̶p̶a̶n̶.̶

    EDIT: Apologies, I misunderstood—a reply to this comment said they were just predictions. (I saw in this video[0] that the first waves had arrived, and assumed the heights would've therefore corresponded to actual measurements. But it's still in the "predictions" section, and I should've noticed that before posting....)

    [0] https://www.youtube.com/watch?v=YbRCvDZO5Zk

    • No. That's the predictions. Biggest wave so far has been 60cm (EDIT: as of 6am UTC it's 1m30cm, but that's still relatively small. It came up almost exactly to the top of the pier in Kuji.)

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  • My guess is that the wide area simply reflects the uncertainty, and not some apocalyptic scenario. Hopefully this broad warning and plenty of time gets everyone out of danger effectively

  • Question: Could you cancel out a tsunami with a underwater explosion, similar to active noise canceling ?

    • Yes, but it would have to be equal and opposite the incoming tsunami, and the amount of energy involved is mind boggling. The recoil would have its own repercussions. Your neighbors on the receiving end of the resulting double tsunami would want to have a word with you.

My wife decided to not travel to Japan due to an impending warning from a manga for July 2025. I have been making fun of her all month only to get this tsunami warning now!

https://en.wikipedia.org/wiki/July_2025_Japan_megaquake_prop....

> The 2021 reprint capitalizing off this revived popularity warned of a "real disaster" in July 2025, causing a minor case of mass hysteria in 2025 when summer trips to Japan from East Asia decreased markedly and several airlines even cancelled flights.

  • Sadly we won’t hear from the partners of everyone whose manga didn’t successfully predict a real disaster in a month.

    • That's because the other mangas forgot to adjust by +/- some 1000 km for location, 25 days, 365 days, 1825 days, or some other arbitrary but possibly nicely divisible number, for when and where it strikes.

      You also have to conveniently forget the things that don't sell mangas such as annual typhoons, heatwaves, and of course thousands of premature deaths from man-made causes such as pollution and poor lifestyle.

      Otherwise, if predicting disasters was easy, everybody would be doing it. No, it takes special, paper-based skills such as mangas , tarot cards, weekly horoscopes, etc.

      3 replies →

  • Well, you can continue to make fun of her because, fortunately, this has turned out to be basically nothing (for Japan, anyway).

  • > The statement was revised later to specify the date "July 5, 2025" as that of an asteroid impact,[8] or even the end of the world.[9]

    • Ryo Tatsuki clarified it wasn't her that said July 5th was when the big one will hit but that it was her publisher that pushed that date for marketing and sales.

      She along with the Thai clairvoyant and Brandon Biggs all say July is the month when the earthquakes and tsunamis begin.

      It is unwise to simply write this off, Ryo Tatsuki said she saw 4:18am in July 2025 which can only mean 14 hours from now we will know if that is it.

      It is July 30th 2:14pm, in 14 hours it will be July 31st 4:18am. After that a 20 hour period until the deadline.

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  • Is your wife generally fearful like that or this was a rare occurrence and she can actually have some introspection on that and has a fighting chance of coming on top of that?

    I know few folks like that, for them it comes from general lack of understanding of reality, society and human nature, a lot of superstition in various directions and similar traits. Suffice to say its very hard to live up to one's potential in life with such mindset, but such things could be conquered if there is enough resolve.

That is _really_ big. It will likely crack the top 8 ever recorded. https://en.wikipedia.org/wiki/Lists_of_earthquakes

  • From videos online so far, it seems the strength of the quake didn't translate to massive lateral movement. There seemed to be lots of intense P-wave wiggling and bumping rather than large S-wave swings back and forth. The big Japan quake was one of those, where you saw offices being slid back and forth and everything flying off shelves.

    Not sure what that means for the tsunami - but so far it seems less intense than the 8.8 would imply.

  • The 1960 Valdivia quake released about 1.5e23 J, or about 1000 hurricanes, or about 25% of the total energy of all earthquakes in the past 100 years.

  • By magnitude it would be the second largest on that list

    • The first list on that page is specifically for the deadliest earthquakes, and so it only includes earthquakes with 100,000+ fatalities. The ranking by magnitude is farther down (and according to that list, a magnitude of 8.8 would make it tied for sixth place).

    • Multiple lists. On the list of strongest by magnitude, it would be in a three-way tie for 7th if there's no further revision to the magnitude estimate (which there usually is). It would be second by magnitude on the list of deadliest earthquakes, but thankfully due to location will not likely make that list.

~1.3m water column height variation observed by the closest DART buoy at 48°7'34" N 163°22'35" E (5787m nominal water depth).[1]

[1] https://www.ndbc.noaa.gov/station_page.php?station=21416&typ...

Quick link to the tsunami view: https://www.tsunami.gov/

Just “watch” level for US west coast, but warning level for Hawaii and Alaska.

  • Air alarms are going off in Hawaii. Still a few hours away, but they are not joking around. Saying it can wrap around all the islands and hit anywhere

  • Watch has been upgraded to Warning (Aleutian Islands and California from Cape Mendocino to the Oregon border) or Advisory (California from Cape Mendocino south, and pretty much everything from the California/Oregon border to Alaska until you reach the Aleutian Islands, it looks like.)

Has anyone heard how bad it was in Petropovlosk? USGS estimates "severe" shaking with the possibility of moderate to heavy damage and a chance of fatalities.

They have had quite a swarm of quakes there over the last couple of weeks, including one that was M7+ around the 20th.

  • From what I see in Russian-language news, only relatively minor damage. I've lived in Petropavlovsk, it's an ugly city in various states of disrepair, but they do take seismic reinforcements seriously, like mag 7 should cause zero damage according to plan.

    It's basically immune to tsunamis as it's protected by a bay with narrow entrance that extinguishes the waves, also most of the city is raised at least 10m above the sea.

    • it's not That ugly :)

      but yeah I totally get what you mean, better watch volcanoes and nature than the urban scape around

      indeed thankfully not that much damage there

  • Severo-Kurilsk, an island town destroyed by a similar tsunami in 1956, lost its port again: https://en.wikipedia.org/wiki/Severo-Kurilsk — the rest of the settlement was rebuilt on higher ground, leaving only the port vulnerable.

    The settlement is notable as having belonged to the Japanese in late 19th and early 20th centuries, who once relocated islanders there. Russian Wikipedia says they were Ainu.

  • So far the news here has only shown damage to a school (which apparently was empty due to repair work), and some bad flooding in one part. Let’s hope for the best.

  • Current official news:

    Around 3k were evacuated in the region to safe areas as a precaution: aftershocks are expected for a month.

    Some buildings (including hospitals) have cracks due to an earthquake.

    Some minor damage to power lines, some near-shore flooding at some businesses.

    All in all, it’s ok.

  • On Twitter, a search for Russia brings up some videos of pretty severe shaking

  • Officials report M5-6 in the area, minor damage, several injuries, tell locals not to go to the beach in the next few weeks. They are used to it…

People tripping over eachother arguing whether a tsunami is a "wave" on a disaster warning submission... If HN was a village everyone would drown in the process.

That area of Russia has seen quite a bit of massive seismic activity over the last couple of weeks. I keep getting earthquake alerts about each one.

  • What do you use for alerts?

    • I use MyShake which will let me get alerts based on specific magnitude cutoffs. I actually just ratcheted up my "global" alert from 7.5 to 8 because of all the alerts from the last couple weeks in the pacific.

Waves at Midway Atoll and Guam are reported to be 3ft (1m) amplitude by Hawaii Governor Josh Green as of 6:24pm Hawaii Time

I have family members who were in Hawaii (Haleiwa) today and they are wondering if they should try to beat the tsunami and get back to their hotel in Waikiki.

I am afraid Waikiki will see flooding. I know Duke's and some other restaurants were closing early.

  • Do not stay in Haleiwa or go to Waikiki. Consult a map, and find some uphill areas above 100ft to drive to. Drive towards Mililani and wait it out in the upland areas.

    My kids are at camp right now on the North Shore and are being evacuated by bus to Mililani.

    • I'm sorry you're going through that, it sounds like they will be safe in Mililani.

AIS map of vessels in the area: https://www.marinetraffic.com/en/ais/home/centerx:166.7/cent...

A fairly small US fishing vessel is in relative proximity... https://www.marinetraffic.com/en/ais/details/ships/shipid:43...

Talked to the AI which said: MMI 4.5 in the context of an M8.7 quake, for your vessel: Danger level from shaking alone: Very low in open water. Danger from tsunami in the open ocean: Very low (unless extremely close to epicenter). Prime danger: If near shore, from tsunami run-up, NOT the shaking. Actionable advice: Remain in deep water until tsunami warnings have cleared; proceed to port only when officially safe. Monitor official maritime and tsunami alerts closely after any major earthquake.

That's interesting. Mental note, if piloting a vessel in a tsunami, head to deep water.

https://www.conservation.ca.gov/cgs/tsunami/maps is getting a hug of death :(

If anyone gets on, please post a screenshot.

  • The USA also has a site that seems to be up at the moment. Without seeing the CA version I'm not sure how it differs, but I suspect it's possible for Canadians to get some useful local information from it: https://www.tsunami.gov/

    • ca.gov is California, not Canada.

      But our funny-accented cousins can access useful information on the .gov as well (the entire west coast of Canada is under tsunami watch at the moment).

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  • This also happened during the tsunami last year.

    Does anyone know of a map app that works offline and can save overlays like this?

    • No, but an archive.org for US govt webpages like tsunami.gov (including dynamic content) seems like something that is currently needed.

I was parked at Selzer beach in Seaside, Oregon when the earthquake/tsunami news hit around 7:30pm. Within 30 minutes it was impossible to buy gas without queueing and now there is a pretty steady stream of cars heading out of town. As of 9pm it’s been upgraded to a warning up and down the coast. I was just thinking of tsunamis the two days ago in the Del Rey beach parking lot, where I noticed the locals seemed to park at the exit end of the lot, facing out. I moved my car to match because that just makes sense.

  • I’ve never thought about a tsunami when visiting the beach in my life. Are they much more common in the Pacific? We go to the Gulf and Atlantic and it’s never something I think about. We usually go in June/July, so we don’t worry much about hurricanes either.

    • There is no Atlantic ring of fire, is there. What little places like Iceland show is nothing compared to what pacific has to offer in much larger area.

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Reading the news, it seems there was no significant impact in the neighbouring societies, except the death of sea life (whales in Chiba), is that right?

  • I wonder how they died.

    I'd expect they are safe from a bit of shaking. Are there shock waves involved?

I’m in Costa Rica on vacation, hotel said the beach is closed but they didn’t know why (lol yeah right). Per tsunami alerts it should be hitting right now at 1-3M above tide, I don’t see any evidence on various beach livecams like Taramindo. I’m in puerto Jimenez which is on the inland side of a small peninsula in southern CR so not expecting much.

What happens to the US West coast?

  • All the tectonics and volcanos that are underground are linked, these seismic events aren't just isolated on islands.

    I hate to say this but we can expect a major event in August. All I can tell people is to prepare but I see people just with blank expression, there is almost no concern at all which reminds me very much of November 2019.

I happened to be visiting Miyagi just before the tsunami struck, and I was really panicked. When I got out of the car, everyone's smartphones nearby suddenly started beeping. A message in Japanese, saying something like "TSUNAMI EVACUATE NOW," sounded throughout the area. At the time, my phone displayed a warning that a three-meter tsunami would hit the area within an hour. I waited on slightly higher area for about two hours, but the locals kept going about their usual business, and there were no announcements from the nearby police.

Fortunately, nothing happened, but it's difficult to know which information to trust. Still, it's good that there's a system in place for evacuation alerts.

Just when I am about to depart on vacation to Sulawesi in Indonesia, mostly for diving and some culture and adventure... well at least Togian islands are not directly exposed to part of pacific ocean that generated this.

I guess I will have to sleep with a big wooden log.

Can the wave be seen and tracked from planes above? I know they can travel at upwards of 300+mph but given the distance from Russia to the west coast seems like it should be able to be tracked.

  • No. When they travel at that speed they are not visible. Only when they hit shallow water (a necessary , but not sufficient, condition) do they slow down and become a threat.

  • You can see bouys displaced by the seismic event, some up to one foot close by. Pretty crazy

  • There are planes, buoys and other things being mentioned on the news here in Japan as ways things are being tracked. Maybe not what you meant, but tracking the wave isn't necessarily correct. There are many waves, and the initial wave is often (in this case also) not the largest.

    The news mentioned a previous similar event where the largest wave was 4 hours later.

Why are the predictions of the tsunami experts so poor? What can be done to get higher accuracy?

  • I don’t think there’s a high false positive rate on these. They do happen pretty rarely, and a false negative is far worse than a false positive. Due to the tsunami wave propagation, it can sometimes take hours for significant waves to reach the coastline.

    • We just had another one in the SF Bay Area a few months ago where they were wildly off.

to put this in perspective, and please, if you work for USGS or whatever, correct me if i am wrong: this is roughly the same magnitude of the 1994 Northridge earthquake in California.

i think i got the scale the wrong way around, the magnitudes reported now are only larger (than Richter) with smaller quakes compared to the Richter; it looks like 8.8ML ~= M8.8. Sorry, i looked at the chart the wrong way around.