[1] Table on https://www.tsunami.gov/
(Update: It was just revised upward to 8.8.)
https://earthquake.usgs.gov/earthquakes/eventpage/us6000qw60...
Not sure what that means for the tsunami - but so far it seems less intense than the 8.8 would imply.
[0]: https://en.wikipedia.org/wiki/Japan_Meteorological_Agency_se...
Intensity: 7
Category: Brutal
Description: Standing or moving is only possible by crawling. People may be thrown through the air.
If anyone gets on, please post a screenshot.
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).
Does anyone know of a map app that works offline and can save overlays like this?
They have had quite a swarm of quakes there over the last couple of weeks, including one that was M7+ around the 20th.
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.
That port right next to the water has probably disappeared.
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.
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
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.
The news mentioned a previous similar event where the largest wave was 4 hours later.
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.
E.g. the 2011 tsunami may have had a height of 1.2m or so in open ocean, but when concentrated by shallower water and a bay inlet reached 40m.
https://m.youtube.com/watch?v=-VcWF8dIDj4
Japan, Tsunami. Coast Guard ship rides over the tsunami waves. 日本 - 津波 4.1M views · 14 years ago
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.
From a helicopter Japanese KATU news https://www.youtube.com/live/mBQHNV7cqrM?si=lwqB5YHknA7KUTY_
Webcams https://www.youtube.com/live/5pTPKHJxQ4g?si=xWe5MkLKIZ3N5I8D
Hawaii news https://m.youtube.com/watch?v=lVy5nLWruu0&pp=ygUSSmFwYW4gdHN...
The average actual height in eastern Japan (Tohoku) was 4-6m, but there were peaks up to 20m in places like Ofunato where the local geography funneled all the water upwards.
https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an...
At the start, there's just a white line at the horizon. Then the fishing boats in the harbor start rocking and jangling. Then water starts pouring over some walkways and sea walls.
Eventually the cameraman backs away and starts climbing a concrete tower; water starts to flood over the area where they had been standing. I think they climb a couple stories and are safe up there.
I haven't been able to find the video in years, but I remember being fascinated by it and I'd love to watch it again.
Edit: I never expected to find that video again, but here it is. A little more terrifying than I remember.
I seriously wonder if people brains are being cooked these days. One of the blessing of HN used to be it was full of fairly well educated, and most importantly, curious people. Sometimes with a bit too much of a focus of the technical side of things, but at least on most technical topics the comments where a great place to get a richer understanding of a whatever was being discussed.
Even worse is tsunamis are also often preceded by a 'disappearing coast' effect where the water will recede back into the ocean for hundreds of meters. This often drives tourists or locals who don't know better to go check out the sea bed and the weird behavior of the ocean, then the tsunami comes in and they're right in the middle of it.
If you're ever at a beach where the water starts rapidly disappearing, yell tsunami and get away as fast as you can. Ignore the normalcy bias, because most people, even locals, will be just standing around taking videos or even walking out into it. And don't stop running even when you're well away from the beach. It's nature's warning sign.
If that is the one of December 2004, it affected not just Thailand, but also many other countries around the Indian Ocean:
https://en.m.wikipedia.org/wiki/2004_Indian_Ocean_earthquake...
Excerpts:
2004 Indian Ocean earthquake and tsunami
On 26 December 2004, at 07:58:53 local time (UTC+7), a major earthquake with a magnitude of 9.2–9.3 Mw struck with an epicentre off the west coast of Aceh in northern Sumatra, Indonesia. The undersea megathrust earthquake, known in the scientific community as the Sumatra–Andaman earthquake,[8][9] was caused by a rupture along the fault between the Burma plate and the Indian plate, and reached a Mercalli intensity of IX in some areas.
A massive tsunami with waves up to 30 m (100 ft) high, known as the Boxing Day Tsunami after the Boxing Day holiday, or as the Asian Tsunami,[10] devastated communities along the surrounding coasts of the Indian Ocean, killing an estimated 227,898 people in 14 countries, violently in Aceh (Indonesia), and severely in Sri Lanka, Tamil Nadu (India), and Khao Lak (Thailand). The direct result was major disruption to living conditions and commerce in coastal provinces of surrounding countries. It is the deadliest natural disaster of the 21st century,[11] one of the deadliest natural disasters in recorded history, and the worst tsunami disaster in history.[12] It is also the worst natural disaster in the history of Indonesia, Maldives, Sri Lanka and Thailand.[13]
It is the most powerful earthquake ever recorded in Asia, the most powerful earthquake in the 21st century, and the third or second most powerful earthquake ever recorded in the world since modern seismography began in 1900.[14][a] It had the longest fault rupture ever observed, between 1,200 km and 1,300 km (720 mi and 780 mi), and had the longest duration of faulting ever observed, at least ten minutes.[18] It caused the planet to vibrate as much as 10 mm (0.4 in),[19] and also remotely triggered earthquakes as far away as Alaska.[20] Its epicentre was between Simeulue and mainland Sumatra.[21] The plight of the affected people and countries prompted a worldwide humanitarian response, with donations totalling more than US$14 billion[22] (equivalent to US$23 billion in 2024 currency).
I was around (in India) at the time, but not near the coast, much further inland and to the north, so was not affected.
It’s a wave, but it is often not at all like a regular ocean wave. I’ve been at sea when a 3m tsunami passed, we barely felt it. If it had been a 3m wind wave in that otherwise calm sea, it would have knocked dinner off the table.
It’s a wave, but it is often not at all like a regular ocean wave. I’ve been at sea when a 3m tsunami passed, we barely felt it. If it had been a 3m wind wave in that otherwise calm sea, it would have knocked dinner off the table.
and it IS a wave. I don't understand the resistance here. It BOTH is a wave and looks like a wave.
But because it does not stop, it is not a "wave". Let's just stop with the strange pedantism.
Regular waves that are a little higher than your seawall might cause some water damage to the buildings right next to it. A tsunami that is a little higher than your seawall will flood your entire town and drown people who are caught in basements.
So saying it's not waves is dangerous, and saying it's not a sea level rise is dangerous. It's not useful to try and delineate between a tsunami being one of the two when it's in reality an event that consists of both.
(Ignoring that a sea level rise and a long-wavelength wave are the same thing)
I have heard description of a tsunami being "a temporary rise in sea level", which describes its behavior much more intuitively. A tsunami that tops a sea wall will flood the entire lower-lying area behind it. A usual wave, even a tall one, will only deposit some splashes of water behind the wall and go away immediately.
What you get is not a "wave" but a wall of water.
“I’m Surprised so many people don’t know what ‘X’ is/are isn’t a very nice thing to say. Your comment could have done without that, the rest of it would have been fine.
Saying that tsunamis are waves is easy to equivocate into tsunamis are waves, like other waves. This is an equivocation that is very misleading and can get people killed.
Insofar as the goal of communication is to communicate meaningful information, it is less accurate to say “tsunamis are waves” than it is to say “tsunamis are nothing like normal waves”, or to say “tsunamis are like a wall of water, not like a wave” or “tsunamis are more like tides than waves”.
So yes, tsunamis are waves, but insisting that tsunamis are waves without qualification that their effective characteristics are fundamentally much different and more dangerous than a regular wave is misleading through omission in a way that could directly put people’s lives in jeopardy.
Being pedantic about definitions and being accurate in conveying meaning are not the same thing, and communicating in good faith normally is about conveying meaning in an accurate manner, not just using words in an accurate manner.
FWIW I also believe that meanings are important, but there is a point where pedantry falls into bad-faith territory.
You’re like coming up to me and saying hurricane is not wind because it’s dangerous to think of a hurricane as only wind.
Dude. Nobody is thinking hurricanes are just chill just because hurricanes are wind. This is a fucking non-issue.
I think what you’re trying to say is that the wave length of a tsunami is much longer than the amplitude even though the amplitude is still epically high. But don’t try to conflate this with a safety issue of people dying because somebody called it a “wave” that’s just garbage.
Everyone knows hurricanes are wind. So they look for the wind speed to understand the threat. And it’s effective at characterizing the threat. A 100mph wind is going to be similarly destructive as any other 100mph wind. It works and is semantically and linguistically accurate.
Everyone knows a tsunami is a wave, and it is a strong intuition to believe that a wave is defined by its height. , and the height of the tsunami is actually one of the most widely reported metrics. But intuition about the effects of a tsunami by wave height is dangerously wrong. A tsunami is not at all similar to the vast, vast majority of waves in character and effect. Its speed and length at way, way out of band, and are seldom reported.
1. the storm surge, the potential wall of water brought by the continuous winds and waves near the shore, followed by 2. the flooding from heavy rains, then 3. followed by the wind.
So your example might also be hitting the same issue you're trying to avoid.
Note, the worst storm surge is from the eye towards the side where the winds are blowing in the direction of the shore. That's only part of the area with the peak winds.
That said, in context the original statement was so extremely misrepresentative of the reality that I felt it left the realm of "inaccurate but effective for communication". I certainly didn't see the objections as pedantic.
Perhaps it wasn’t intentionally pedantic, but the way that it was doubled down on later makes me suspect an argument in bad faith, or at least an epic case of missing the opportunity to usefully inform.
I value this site for the general character of people trying to educate more than just troll, and I think it’s important to try to educate trolls as well to understand a more constructive and respectful way to interact here. Ostensibly, we take off our clown shoes and leave them at the door.
OTOH I may have read multiple comments in similar tone that were not all attributed to one poster , giving me a mistaken impression of the intent. In that case, I owe an apology for perhaps overreacting.
The most obvious (but relatively rare) are tsunamis amplified by submarine canyons and other coastal bathymetry like the Nazare submarine canyon famous for the biggest waves on the planet (50+ footers are common in season). If an earthquake directs a tsunami at that canyon, the resulting waves will be spectacular and probably drown everything north of the cliffs. Unfortunately we don’t have any historical records about what happened at Nazare after the 1755 Lisbon earthquake so we don’t know just how big those waves can get.
Then there’s landslides like the one that caused the 1958 tsunami in Lituya Bay, Alaska which creates a much more sudden displacement than an earthquake. Based on the surrounding mountainsides the wave created from that landslide might have peaked at ~500 meters without the 100+ mile wavelength you’d see in a normal tsunami wave.
The most common however are tidal bores, which can send a 30+ foot vertical wave down rivers and narrow channels. This phenomenon shows up relatively frequently in earthquake youtube videos near rivers, though the wall is usually only 5-10 ft tall.
Imagine you have a fault line. There is a left side and a right side to the fault line. If the left side lowers with a shift then that shift MUST be localized to the area around the fault. Because if it wasn't then that means there's an elevation change across the board for everything to the left of the fault. You see how that doesn't make sense? So if the entire country of japan was on the left side of the fault then the entire country of japan shifts in elevation which is unrealistic.
So that means, if what you say is semi-true then the shift in elevation is localized to the area left along the fault but the elevation further left remains the same. It's like a slight dip or bump along the fault line. It must be like this because the alternative is just unrealistic. This MUST be what happens when tectonic plates "shift". You won't see the ENTIRE plate shifting in elevation.
With naive logic, one would think that the water simply fills the localized gap but given how deep the ocean is relative to the actual shift way down in the abyss I'm betting if you were on a boat on top of the fault you wouldn't notice anything. But the movement does create a slight imperceptible "filling" that you don't notice. This is a "wave" but it's invisible.
The wave will translate leftward if the movement of the "shift" was sort of in that direction, but you don't see it. BUT as the sea floor gets nearer and nearer to the surface of the ocean the energy of the wave gets squuezed into less and less ocean water mass (i'm remembering how tsunamis work now) and THEN it becomes visible. Right? Just imagine a sideways cross section. As the tiny wave travels from big ocean with huge depth to coastline with no depth the energy of the wave gets concentrated into a thinner and thinner layer of water.
My intuition just sort of converged with my obscure memory of how tsunamis work so I'm pretty sure this is what's going on.
So it is indeed a "wave" that is acting on wave like phenomena beyond simply "filling a gap". In fact say there's an elevation lowering on the left side of the fault by 1 meter. The resulting wave on the coast line hundreds of miles away will be a wave that extends upward by MORE then 1 meter above sea level which is the opposite of water "filling up a gap." That's totally a wave.
Additionally water from tsunamis always recede. This wouldn't happen if the "wall of water" was simply equalizing. If that's the case the water would never recede.
Any expert who says otherwise, let me know.
edit: Actually why the fuck am I using my intuition to explain it? Just cite a source:
https://www.noaa.gov/explainers/science-behind-tsunamis
tsunamis are 100% waves as explained in the link. Anyone who says otherwise clearly doesn't know what they are talking about, that includes the person I'm responding to. End of story.
Here's a video of what it looks like from the 2011 event, from the POV of the coast guard approaching it. Waves don't typically look like a sheet has been flapped across one front of the entire horizon of what is visible on the ocean
That's a huge ass wave as it's a pulse traveling on top of the ocean, above sea level.
Yo heard of fluid dynamics? Good luck localizing this;) maybe you can build a wall or something real quick
Obviously it is all technically waves. Even if EVERYTHING to the left lowered we would be talking about waves caused by it. But it don't need to be all lowered because waves propagate. And point is these particular waves, tsunami are not the waves you think about because you saw some on the beach. It's an ocean rising for a while. Watch some vids to get a vibe for it.
It’s a wave, but it is often not at all like a regular ocean wave. I’ve been at sea when a 3m tsunami passed, we barely felt it. If it had been a 3m wind wave in that otherwise calm sea, it would have knocked dinner off the table.
How far out at sea were you? And how did you know at the time?
I saw the wave on radar first, since it lifted ships that were below our horizon up to where they could be seen again for a few sweeps. But it just felt like A gentle lifting. I didn’t even feel the subsidence of the wave. Interestingly, ships 20 miles away from us but near the edge of the shelf reported isolated severe and chaotic waves.
In fact, I'm not sure I should have quotes around that. Isn't your interlocutor saying a tsunami is literally a direct current of water flowing toward the shore?
Waves can get bigger due to earthquakes not being instantaneous or necessarily a single movement, due to amplification by geography, by reflections, by aftershocks, and many other things. The news is suggesting waves lasted about a day for a previous event in a similar area.
Its a wave (or series of waves) with a large wavelength and speed in deep ocean, that becomes a shorter wavelength and very large amplitude by shoaling as it hits shallow water.
Its different from typical wind-driven ocean waves for a lot of reasons; but a big indicator is wavelength -- wind-driven ocean waves have wavelengths up to hundreds of meters, tsunamis have wavelengths (in deep ocean) of hundreds of kilometers.
More like tides than waves, as has been stated elsewhere in the thread, is both technically wrong but substantively (with the caveat that "waves" really means "typical wind-drive waves") correct, in that tides are also manifested through waves, but waves which have wavelengths of thousands of kilometers, and so tsunamis are waves more similar to those making up tides (hence the old colloquial use of "tidal waves", which properly refers to the waves manifesting tides, to refer to tsunamis) than to wind-driven waves.
The seawall was 5.7m.
The screen is filled with data and blinking like a Bloomberg Terminal.
But then again, take a stroll around a shop-laden street in Japan and you'll see the exact same thing. They just like it that way.
Funny thing is how for interior design they do a full 180 and typically go very minimalistic.
Only if they are well to do. Most family houses in Japan are crammed full of stuff with very little "design".
My God. Everything , everywhre, no design ( haha ), no exceptions. People were actually living there.
Had a cultural shock.
But the cities themselves are like that. There is zero urban planning, just buildings thrown around in impossible non-Euclidean patterns.
( btw, has anyone noticed in anime there are always frames of street cabling? Like those cylindrical transformes and thick cables. Almost cyberpunk! )
Then the cameraman zooms at the ocean, which is blurry and shaky because they're in the designated evacuation zone Z km away from the coast.
But yeah, the handheld telephoto zoom from a safe location is definitely on the Japanese Disaster TV bingo card. That said, I appreciate that they just keep repeating the same warnings and data, rather than the ridiculous speculation that the US news media engages in when they get bored.
“We’re here inside the hurricane, let me go outside so you can see that the wind will push me over. Can’t hear anything because my microphone is getting blasted by the wind. Over there you can see the emergency responders, they appear to be fleeing. Tell my wife I love her, but I’ve got to die for some b-roll.”
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.
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.
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....)
Nothing yet from japan
[1] https://www.ndbc.noaa.gov/station_page.php?station=21416&typ...
[1] https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an...
[2] https://www.ngdc.noaa.gov/hazard/data/DART/20110311_honshu/j...
[3] https://www.ngdc.noaa.gov/hazard/dart/2011honshu_dart.html
[4] https://www.ngdc.noaa.gov/hazard/data/DART/20110311_honshu/j...
<https://www3.nhk.or.jp/news/html/20250730/k10014878741000.ht...>
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.
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.
(Woo is surely possible but all those who can pull it off were gifted abilities that are deactivated by non-monetary incentives)
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.
Is it wrong? Did the book actually just call the time and month, not day?
No it isn't
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.
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.
Nearby quakes, faults, movement visualization, etc.
https://earthquakes.builtbyvibes.com/quake/m8.8-119-km-ese-o...
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.
Each incremental increase in magnitude is 10^1.5 in power. The difference between 1994 Northridge and this one is 2.1, so roughly 10^3 difference in power.
The Richter Scale is a logarithmic scale, based on shaking measurements (think of the old pencil-based seismograph!). Power. (10^1).
The Moment Magnitude Scale (the more modern/replacement of Richter Scale) is based on energy. Geological organisations reporting on an earthquake will usually show this as "M <number>" or "Mw <number>".
Richter works well for small-to-medium earthquakes, and it's not accurate for really large or distant earthquakes.
The energy released in an earthquake increases exponentially, not just linearly.
EDIT: The Moment Magnitude Scale is where the "10^1.5" figure is coming from. https://en.wikipedia.org/wiki/Moment_magnitude_scale
AFAIK, it was done that way to maintain rough congruence with historical seismic magnitude scales, which were more qualitative in nature. Modern seismic scale systems are significantly more scientific and quantitative but you can kind of retcon the historical systems if you set the exponential strength scale to 10^1.5 in the modern systems.
https://earthquake.usgs.gov/earthquakes/eventpage/ci3144585/...
And today's earthquake for comparison:
https://earthquake.usgs.gov/earthquakes/eventpage/us6000qw60...
And some information of Magnitude types: https://www.usgs.gov/programs/earthquake-hazards/magnitude-t...
I think it's probably safe to assume, that today's earthquake is much more energetic at least.
That's the thing with standards, there's so many to choose from.
I am afraid Waikiki will see flooding. I know Duke's and some other restaurants were closing early.
My kids are at camp right now on the North Shore and are being evacuated by bus to Mililani.
Unclear if its related to the tsunami that is about to hit or the typhoon it is currently experiencing. Wild. Stay safe everyone!
I guess I will have to sleep with a big wooden log.
>Important Context: In the Japanese audio, a TV announcer says they don't know if this incident is related to the earthquake/tsunami: "We have no information indicating a connection with the recent tsunami".
>Also, stranded whales in Tateyama have been observed since yesterday
I'd expect they are safe from a bit of shaking. Are there shock waves involved?
..I'll show myself out :)
Wow!
https://old.reddit.com/r/interestingasfuck/comments/1mcwvpw/...
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.
https://www.newsweek.com/russia-klyuchevskoy-volcano-erupts-... ("Russia's Klyuchevskoy Volcano Starts Erupting after Earthquake")
andsoitis•19h ago
Just “watch” level for US west coast, but warning level for Hawaii and Alaska.
_fs•19h ago
nytesky•19h ago
supportengineer•16h ago
Taniwha•14h ago
seb1204•12h ago
benzible•17h ago
dragonwriter•16h ago