[HN Gopher] M8.7 earthquake in Western Pacific, tsunami warning ...
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M8.7 earthquake in Western Pacific, tsunami warning issued
Author : jandrewrogers
Score : 842 points
Date : 2025-07-30 00:38 UTC (22 hours ago)
(HTM) web link (earthquake.usgs.gov)
(TXT) w3m dump (earthquake.usgs.gov)
| andsoitis wrote:
| Quick link to the tsunami view: https://www.tsunami.gov/
|
| Just "watch" level for US west coast, but warning level for
| Hawaii and Alaska.
| _fs wrote:
| 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
| nytesky wrote:
| It will arrive in California in the middle of the night. Hope
| they don't materialize.
| supportengineer wrote:
| I have family staying in Waikiki
| Taniwha wrote:
| Phone just went off screaming with a warning here in NZ -
| more a "stay away from the water" warning than a "head for
| the hills" one
| seb1204 wrote:
| Impressive, glad the alarm chain works. And from what you
| say the warning message is also clear and understandable.
| Not tech or geology jargon that people don't understand and
| then take no or the wrong actions.
| benzible wrote:
| Upgraded to an "advisory" for the California coast.
| dragonwriter wrote:
| 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.)
| bicx wrote:
| 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.
| grigri907 wrote:
| What do you use for alerts?
| mayneack wrote:
| 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.
| yinser wrote:
| That is _really_ big. It will likely crack the top 8 ever
| recorded. https://en.wikipedia.org/wiki/Lists_of_earthquakes
| ac29 wrote:
| By magnitude it would be the second largest on that list
| addaon wrote:
| 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.
| BalinKing wrote:
| 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).
| swader999 wrote:
| I think it has been revised to 8. Earth is going off today.
| Edit my mistake, 8.8 now!
| nsingh2 wrote:
| The other way around it seems, on `07-29-2025 23:24:56 UTC`
| went from 8 to 8.7 [1]
|
| [1] Table on https://www.tsunami.gov/
| adzm wrote:
| Looks like it was just updated to 8.8?
| tjohns wrote:
| USGS still has it listed as magnitude 8.7.
|
| (Update: It was just revised upward to 8.8.)
|
| https://earthquake.usgs.gov/earthquakes/eventpage/us6000qw60.
| ..
| russellbeattie wrote:
| 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.
| rtpg wrote:
| Japan uses a scale that measures the movement[0]. Of course
| depending on where you are the result changes, but it's a lot
| more usable for the practical "how much shaking will be
| involved here/was involved here".
|
| [0]: https://en.wikipedia.org/wiki/Japan_Meteorological_Agenc
| y_se...
| russellbeattie wrote:
| Holy crap. That scale definitely makes it pretty clear what
| the effect of a quake is! Here's the highest level:
|
| Intensity: 7
|
| Category: Brutal
|
| Description: Standing or moving is only possible by
| crawling. _People may be thrown through the air._
| SubiculumCode wrote:
| Wow. The same region had a 9.0 in 1952
| burnt-resistor wrote:
| 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.
| lordswork wrote:
| https://www.conservation.ca.gov/cgs/tsunami/maps is getting a hug
| of death :(
|
| If anyone gets on, please post a screenshot.
| wging wrote:
| 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/
| sugarpimpdorsey wrote:
| 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).
| Waterluvian wrote:
| Yeah but for how much longer? It's a fire sale on anything
| intellectual down there.
| TrnsltLife wrote:
| I can't wait for Wexit to secede/succeed so we can
| welcome our beloved new territories with open arms.
| xav0989 wrote:
| Anything that ends in .gov is related to a government entity
| in the US. Other countries don't get access to that TLD.
| wging wrote:
| ah, you're right. I knew that, think I must've looked at it
| too fast and assumed it was .gov.ca. (which isn't even the
| TLD that the Canadian government uses, but never mind...)
| misiek08 wrote:
| I'm not sure if understood correctly, but
| https://www.tsunami.gov/ works without any problems even
| from Europe, Poland.
| bulatb wrote:
| The US government controls who gets .gov domain names,
| but the websites are available to anyone.
| dehrmann wrote:
| This also happened during the tsunami last year.
|
| Does anyone know of a map app that works offline and can save
| overlays like this?
| smcin wrote:
| No, but an archive.org for US govt webpages like tsunami.gov
| (including dynamic content) seems like something that is
| currently needed.
| mordechai9000 wrote:
| 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.
| czhu12 wrote:
| On Twitter, a search for Russia brings up some videos of pretty
| severe shaking
| shusaku wrote:
| 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.
| decimalenough wrote:
| It's a very remote, very thinly populated area. The entire
| Kamchatka peninsula has under 300,000 people, who
| (statistically) have 1 km2 each.
| cozzyd wrote:
| Sure but a bunch of those people live in Petropavlovsk and
| surroundings
| rhet0rica wrote:
| 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.
| jychang wrote:
| https://www.google.com/maps/place/50deg40'00.0"N+156deg07'00.
| 0"E...
|
| That port right next to the water has probably disappeared.
| ivan_gammel wrote:
| 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...
| ansgri wrote:
| 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.
| realaaa wrote:
| 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
| piskov wrote:
| 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.
| discordance wrote:
| Interactive map:
| https://earthquake.usgs.gov/earthquakes/eventpage/us6000qw60...
| nodesocket wrote:
| 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.
| swader999 wrote:
| You can see bouys displaced by the seismic event, some up to
| one foot close by. Pretty crazy
| gosub100 wrote:
| 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.
| dboreham wrote:
| Space-based assets.
| nessex wrote:
| 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.
| swader999 wrote:
| Dutchsinse coverage.
| https://youtu.be/58ab1phrFF0?si=gb_gpEld8uLTDu8M
| contingencies wrote:
| 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.
| temp0826 wrote:
| Makes sense. More cushion for the pushin.
| mlyle wrote:
| > 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_.
| x______________ wrote:
| Here's a visual of your thoughts from the Fukushima event:
|
| https://m.youtube.com/watch?v=-VcWF8dIDj4
|
| Japan, Tsunami. Coast Guard ship rides over the tsunami
| waves. Ri Ben - Jin Bo 4.1M views * 14 years ago
| mlyle wrote:
| Neat video. It seems to capture the middle between "super
| high coastal wave" and "shallow but long duration wave in
| deep water". That's what you'd get with coastal waters
| several tens of meters deep.
| decimalenough wrote:
| 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.
| fblp wrote:
| Here are some live streams.. No action yet. Fingers crossed!
|
| 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...
| ls-a wrote:
| Now that things have calmed i can say that the webcam chats
| were very entertaining
| Brystephor wrote:
| How big was the 2011 tsunami? Is 3m bigger or smaller?
| decimalenough wrote:
| It's complicated. Tsunami forecasting is a very inexact
| science and "3m" means "very large".
|
| 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.
| ..
| hsbauauvhabzb wrote:
| Is height the only thing that matters? Presumably 1x 2m
| wave is less impactful than 10 x 1m waves spread 20 seconds
| apart?
| edoceo wrote:
| Velocity of wave as well.
| brewdad wrote:
| Depends on topography and protections in place. 10 1m
| waves against a sound 1.5m seawall is no big deal. 1 2m
| wave against the same seawall could be a problem.
| idontwantthis wrote:
| A tsunami is a gigantically long wave. I don't think what
| you're describing describes a tsunami.
| leptons wrote:
| That is not really a good description of a tsunami.
| Tsunamis can occur in very narrow areas too, like when
| landslides happen in fjords.
| idontwantthis wrote:
| I mean long as in wavelength. You wouldn't have a series
| of tsunami waves.
| TylerE wrote:
| Despite the common vernacular calling them "waves"
| they're really more like really really high tides. You're
| talking about something that happens over, say, 10-90
| minutes, not seconds.
| bgwalter wrote:
| Again the only correct comment is downvoted. Watch
| Tsunamis on Youtube. The water just keeps coming and
| coming. They are like high tides.
| foobarian wrote:
| Ah, and here I was wondering if it would be possible to
| surf one of these for miles in if the timing were right.
| The grandparent answers that question.
| VintageCool wrote:
| I remember in 2015 watching this great tsunami video at a
| harbor. It was about 11 minutes long.
|
| 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.
|
| https://youtu.be/PvJs2iWQuFs
| andoando wrote:
| It never got above the boats, cant be more than a few
| feet tall
| bonzini wrote:
| The port's wall slow down the entry of the water and the
| boats can float. The "tide" caused by the tsunami was
| several meters.
| MPSimmons wrote:
| I feel like you're making a bad joke. Did you drop your
| /s?
| crystal_revenge wrote:
| > Again the only correct comment is downvoted.
|
| 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.
| somenameforme wrote:
| This is also in many ways what makes them so deadly in
| places that aren't used to tsunamis. It often just looks
| like a regular wave or a tide that will imminently break
| or recede, but they never do. Here [1] is a video of one
| of the later waves of Thailand's 2004 tsunami.
|
| 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.
|
| [1] - https://www.youtube.com/watch?v=WO7TZFBAlaE
| fuzztester wrote:
| >Here [1] is a video of one of the later waves of
| Thailand's 2004 tsunami
|
| 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_earthqu
| ake...
|
| 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.
| tracerbulletx wrote:
| They are very literally long wavelength waves though.
| K0balt wrote:
| Yes, they are waves, but they are often very long waves.
| A typical 1m wave might be 20m long. A tsunami wave might
| be a kilometer long or longer. That is why people say
| they are like a tide. The wave arrives, then does not
| recede for several minutes. So, while a 4m wind driven
| wave might break over a seawall and even wash a car off
| the road, a 4m tsunami washes ships over that same
| seawall and floods the city.
|
| 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.
| Thrymr wrote:
| So are tides.
| tracerbulletx wrote:
| Perhaps we can just go back to calling them tidal waves.
| Which is also ambiguous. I guess if I had any point it's
| just that it's not colloquial to call tsunami waves, its
| technical. If anything distinguishing based on how they
| feel compared to regular wind waves is more colloquial.
| ninetyninenine wrote:
| These things are 100% waves. It's not a misnomer. It fits
| the scientific definition of waves and it fits our
| intuition of what waves are. These are NOT tides.
|
| https://www.noaa.gov/explainers/science-behind-tsunamis
| K0balt wrote:
| Yes, they are waves, but they are often very long waves.
| A typical 1m wave might be 20m long. A tsunami wave might
| be a kilometer long or longer. That is why people say
| they are like a tide. The wave arrives, then does not
| recede for several minutes. So, while a 4m wind driven
| wave might break over a seawall and even wash a car off
| the road, a 4m tsunami washes ships over that same
| seawall and floods the city.
|
| 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.
| Tor3 wrote:
| A tsunami absolutely does not fit our intuition of what
| waves are. It looks like a wave. But it does not stop. It
| just continues. That little wave goes on an on, farther
| and farther inland. After an hour it may still go on.
| It's a nightmare wave, _because_ it doesn 't not fit
| one's intuition of what waves are.
| ninetyninenine wrote:
| >It looks like a wave.
|
| 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.
| nessex wrote:
| It's a distinction without value I think. There are
| waves, and many of them. There is a rise in the sea
| level. For anywhere affected, both certainly matter. Like
| you mentioned, tsunami isn't a brief event. And here in
| Japan, they are talking about tsunami waves, not a
| singular tsunami. And talking about sea level rise and
| checking the local power poles for sea level indicators
| from previous tsunami events and floods.
| brazzy wrote:
| I is absolutely a VERY valuable distinction because the
| behavior as it affects humans (up to and including
| killing them) is VERY different.
|
| 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.
| nessex wrote:
| Sure, but if you insist it's like a tide you downplay the
| risk of the initial hit of the wavefronts and the
| potential for it to slam up the coast or a seawall
| becoming a larger local wave. And if you insist it's like
| a wave, you downplay the persistent risk of both follow-
| up waves and ongoing flooding that won't subside quickly.
|
| 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)
| inglor_cz wrote:
| They are waves, but they don't _behave_ like the sort of
| waves we are used to. This is the source of all the
| confusion.
|
| 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.
| crystal_revenge wrote:
| I'm surprised so many people don't understand what
| tsunamis are. It's a "wave" created by a sudden shift in
| the Earth's crust. Imagine, suddenly, water on each of
| side of that split is now at different heights and has to
| equalize. It's much closer to just removing a dam that is
| holding back water equal in height to the new difference
| between the sea floors.
|
| What you get is not a "wave" but a _wall_ of water.
| dgfitz wrote:
| > I'm surprised so many people don't understand what
| tsunamis are.
|
| "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.
| nathos wrote:
| Obligatory https://xkcd.com/1053/
| ninetyninenine wrote:
| I don't think he's even right. Like what he is saying is
| in actuality wrong. He's surprised because he's ignorant.
| I'm all for people saying stuff the way he says it. He
| believes it's true, then he should stand behind. But then
| the consequence is that he needs to be accepting of when
| people call him out for being utterly wrong.
| K0balt wrote:
| The difference is that people know what 2m (wind driven)
| waves look like at their cities seawall. A 2m tsunami is
| a -completely- different phenomenon, because of its
| length. Depending upon the underwater geography, a 2m
| tsunami might flood right over their 3m seawall, and wipe
| out entire parts of the city, sweeping hundreds of people
| out to sea. A 2m wind wave will get saltwater spray on
| cars driving by. They are both waves, but they share very
| little in characteristics other than their fundamental
| physics. It's like saying that a slingshot fires a 12mm
| projectile, and so does a 50 caliber anti material rifle.
| The fact that they are both projectiles, of the same
| size, is much, much less informative than other facts
| about their nature.
|
| 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.
| ninetyninenine wrote:
| I think you're out of touch. A tsunami is a wave both
| from a pedantic perspective and an intuitive one and most
| people aren't deceived into thinking that tsunamis aren't
| dangerous at all because it's a wave. That's just made up
| garbage.
|
| 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.
| RugnirViking wrote:
| Idk. I don't live anywhere where tsunamis are an issue
| but seeing measurements like a 1m wave does make me
| wonder about waves I see at the beach that are that high
| regularly. I find myself going "oh not so bad then" only
| to read about thousands of people being evacuated and
| major damage
| K0balt wrote:
| So, I'm sorry that I evidently didn't manage to convey my
| point effectively. The problem is that wave is
| accompanied by a measurement that deceptively buries the
| lede.
|
| 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.
| lief79 wrote:
| My understanding is the most deadly/destructive parts of
| hurricanes are usually:
|
| 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.
| K0balt wrote:
| Good points. Where I am at it's mostly the wind because I
| am a well drained higher elevation, so I'm sure that
| coloured my perception. But you are right, the storm
| surge and flooding also do a great deal of damage.
| fc417fc802 wrote:
| I appreciate your effort to provide an understandable
| explanation.
|
| 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.
| K0balt wrote:
| A clarification was appropriate because it really did
| miss the physics, but doubling down on the definition of
| wave without talking about speed, length, and volume
| (which is what had confused OP in the first place) was
| not only suboptimal in teaching useful knowledge to OP,
| it was also misleading in a way that could (and did, in
| at least one case of a commenter in this thread) lead to
| a dangerous misconception about characterising tsunamis.
|
| 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.
| throwup238 wrote:
| Nitpick: while what you say is generally true, there are
| several scenarios that can create true dramatic "wall of
| water" tsunami waves that have leading slopes of 45-90
| degrees and heights in the tens of meters.
|
| 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.
| K0balt wrote:
| Oh yes! It's absolutely true that underwater geography
| can steepen the wave front and amplify the height,
| sometimes by orders of magnitude. The deep water height
| of a tsunami wave is often a lot different from what you
| will see at the coastline.
|
| An entertaining anecdote from the pre- smartphone era:
|
| I sailed to the site near Chenega bay where the
| earthquake wiped out the village in 1958. We got
| permission from the elders at the Chenega bay village to
| land at the island, and it was extremely humbling to see
| the high water mark from the coastline, and to see the
| wreckage of boats far, far up on mountainsides.
|
| I'm not a big believer in supernatural stuff, and there
| are plenty of alternative explanations, but it still
| freaks me out a bit that the photos we took (aside from
| the digital ones) did not develop any images of the
| village site. It was white as if it had been overexposed,
| even in the case of 1/2 frames. On both disposable
| cameras. Other photos from the same day, taken in other
| directions, turned out fine. The digital camera fell
| overboard in 500 fathoms, so we lost those photos the
| next day.
|
| As for how exactly this could happen in any reasonable
| version of events, I've got nothing. I guess sometimes
| chance events line up just right to make for a good
| story.
|
| Interestingly, there are big tidal bores frequently in
| Turnagain arm, with 1-3m being common. I've seen people
| surfing it with wetsuits in the ice cold water, getting a
| run of several miles lol.
| hsbauauvhabzb wrote:
| I don't take offence. I'm not the most educated, and I
| don't live in or near a tsunami prone area, I know about
| other natural disasters that are relevant to where I live
| though, maybe more than the parent poster.
| ninetyninenine wrote:
| This doesn't make sense to me intuitively. It must be a
| wave.
|
| 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.
| jamal-kumar wrote:
| https://www.youtube.com/watch?v=wAFYVpX45xs
|
| 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
| ninetyninenine wrote:
| Yeah that's a wave bro. Notice how the ocean rises above
| it's own typical sea level? That's not water "filling in
| a gap" the way tides do it as sea level changes.
|
| That's a huge ass wave as it's a pulse traveling on top
| of the ocean, above sea level.
| AshleyGrant wrote:
| That's what it is like out at sea. There's a reason
| tsunamis are referred to as "tidal waves." For example,
| watch this video of a tsunami hitting a port today:
| https://www.youtube.com/watch?v=M1B1J6sgFxk
| bee_rider wrote:
| Yeah, they are waves I think. Just, really incredibly big
| waves with lots of mass behind them. I think people want
| to say "not a wave" to emphasize the fact that they are
| much bigger than the waves that the local environment is
| used to, so they can be really surprising.
| throwaway290 wrote:
| > 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
|
| 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.
| K0balt wrote:
| Yes, they are waves, but they are often very long waves.
| A typical 1m wave might be 20m long. A tsunami wave might
| be a kilometer long or longer. That is why people say
| they are like a tide. The wave arrives, then does not
| recede for several minutes. So, while a 4m wind driven
| wave might break over a seawall and even wash a car off
| the road, a 4m tsunami washes ships over that same
| seawall and floods the city.
|
| 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.
| chimeracoder wrote:
| > I've been at sea when a 3m tsunami passed, we barely
| felt it.
|
| How far out at sea were you? And how did you know at the
| time?
| K0balt wrote:
| We were about 50 miles offshore, off the continental
| shelf (in very deep water) we got the information of the
| wave from our regular meteorological diligence, since it
| was my job to get our satellite weather and any notices
| to mariners on a 6 hour rotation.
|
| 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.
| yantzr3j wrote:
| Sure it's a wave, but tides, swells and waves all
| oscillate just on different frequencies and amplitudes.
| When they all align you get rogue waves and to the casual
| observer of a tsunami, a wall of water coming your way.
| jancsika wrote:
| Since we're intuiting, I'm just imagining something like
| quickly adding a "D.C. offset" of some given height to
| the crests and troughs you'd measure by sampling ocean
| 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?
| bee_rider wrote:
| I guess it is like a step function, or at least a step
| function on one side and a really long decay on the
| other. Is a step function a wave? I'm not sure, my signal
| processing class was too early in the morning. Maybe it
| depends on who you ask, mathematicians vs engineers. I'll
| go along with the ones that might make a taser or
| something.
| k7sune wrote:
| Tsunamis are waves the same way a step function is the
| sum of a series of waves.
| golem14 wrote:
| Maybe the easiest way is explain it by volume of water
| coming at you. A 'normal' wave comes at you for maybe 2-5
| seconds, then recedes. A tsunami wave might come at you
| for what, a few minutes? So moves more than 20x-50x the
| water than an equivalent 'normal' wave, which has no
| other way to go?
| nessex wrote:
| Not true. As the news reporters here in Japan are
| repeating every few minutes, there will be many waves and
| they can get bigger over time. They already have, 20-30cm
| initial waves had 40-60cm later waves.
|
| 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.
| dragonwriter wrote:
| > What you get is not a "wave" but a wall of water.
|
| 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.
| javcasas wrote:
| A tsunami is not a "bigger" wave like the ones that crash
| on the beach every minute. A tsunami is a single wave
| that crashes and crashes and adds more and more and more
| water for several minutes non stop, not pausing or
| pulling back for a single second. It is a sudden flood
| coming from the sea.
| timr wrote:
| For perspective, the tsunami that topped the seawall at
| Fukushima Dai-ichi had a peak height of ~14m.
|
| The seawall was 5.7m.
| shusaku wrote:
| 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
| deadbabe wrote:
| Don't worry, if there's one nation we can trust to have done
| the right thing, it's Japan.
| mulmen wrote:
| I honestly can't tell if this is satire.
| decimalenough wrote:
| Same. Japan's earthquake/tsunami preparedness is genuinely
| unmatched, but earthquakes/tsunamis have the annoying habit
| of happening in the "wrong" place and the country's overall
| record of "doing the right thing" can charitably be
| described as spotty.
| sugarpimpdorsey wrote:
| Japanese news reporting during disaster scenarios is something
| to behold.
|
| The screen is filled with data and blinking like a Bloomberg
| Terminal.
| pezezin wrote:
| 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
| gibagger wrote:
| haha, makes a lot of sense!.
|
| 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.
| socalgal2 wrote:
| > 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".
| ccozan wrote:
| I was wondered that. Like from movies or documentaries,
| etc. Very nice, clear, order, minimalistic. Then I was
| looking to buy a house and I found a site with "almost"
| abandoned house for sale.
|
| My God. Everything , everywhre, no design ( haha ), no
| exceptions. People were actually living there.
|
| Had a cultural shock.
| pezezin wrote:
| I do live in Japan and good god, I have never seen such
| messy people anywhere else in the world. The offices of
| all my Japanese colleagues are piles upon piles of
| documents and boxes without any kind of order.
|
| But the cities themselves are like that. There is zero
| urban planning, just buildings thrown around in
| impossible non-Euclidean patterns.
| msephton wrote:
| They're a book from the early 1990s called "Tokyo Style"
| that is packed with photos of real living conditions from
| back then. Chaos of every variety. Plus some Super
| Famicom and PC-Engines laying around. A very cool book,
| most recently reprinted in 2024 with Japanese/English
| captions.
| ccozan wrote:
| and the cables, the cables hanging from everywhere!
|
| ( btw, has anyone noticed in anime there are always
| frames of street cabling? Like those cylindrical
| transformes and thick cables. Almost cyberpunk! )
| Symbiote wrote:
| The transformers are a result of a the lower voltage
| (also used in America), for efficiency and to keep the
| required voltage the transformer needs to be nearer to
| the house.
| pezezin wrote:
| I know, I live in Japan, shopping streets are seizure-
| inducing here xD
| jazzyjackson wrote:
| "content is beautiful"
| Ma8ee wrote:
| And most Japanese websites.
| pezezin wrote:
| Yeah, shopping in Rakuten or Yahoo Auctions is quite an
| experience...
| timr wrote:
| 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.
| decimalenough wrote:
| Also, the very first thing they say when the camera cuts to
| them is that they are standing in designated evacuation
| zone X that's Y meters above sea level.
|
| 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.
| timr wrote:
| That makes sense, though. To do otherwise would be pretty
| dumb for a tsunami situation.
|
| 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.
| derefr wrote:
| I mean, they could at least fly some drones over to the
| beach for some B-roll.
| sugarpimpdorsey wrote:
| It would take too long to fax back the Ultra HD footage
| taken with optics we can't even comprehend exist.
| bee_rider wrote:
| That's probably the responsible thing to do. It is always
| odd to see American weather disaster reporters, like:
|
| "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."
| danneezhao wrote:
| Self-satisfaction or more professional?
| username135 wrote:
| Pachinko!
| Fokamul wrote:
| 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.
| Amadiro wrote:
| 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.
| nottorp wrote:
| Can you point to some japanese websites that have an
| english version and are a good example of this?
| akg_67 wrote:
| I actually prefer content style of Japanese websites. I get
| all the relevant info on one screen instead of having to
| scroll/click thru tens. The western style websites are very
| inefficient and hide info (feels scammy with lack of info).
| eboynyc32 wrote:
| Yike!!
| BalinKing wrote:
| AFAICT, NTV is reporting that 3m waves have just started to hit
| Japan.
|
| 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
| timr wrote:
| 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.)
| BalinKing wrote:
| I've updated my comment, I indeed misunderstood what I
| read.... Unfortunately it's too late for me to delete the
| comment, so everyone please feel free to flag/downvote it
| (both to push it down for the sake of clutter, and also to
| punish my carelessness :-P).
| timr wrote:
| No worries -- the way they present it is confusing,
| particularly if you're watching the NHK World stream,
| which layers poorly translated English versions on top of
| the Japanese.
| carabiner wrote:
| I've been monitoring the situation, but it appears nothing ever
| happens.
| ashoeafoot wrote:
| Question: Could you cancel out a tsunami with a underwater
| explosion, similar to active noise canceling ?
| kstrauser wrote:
| 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.
| ajsnigrutin wrote:
| Russian media has some videos of the earthquake (RT, etc.),
| telegram channels have some tsunami videos, eg:
| https://t.me/Slavyangrad/136436
|
| Nothing yet from japan
| dhx wrote:
| ~1.3m water column height variation observed by the closest DART
| buoy at 48deg7'34" N 163deg22'35" E (5787m nominal water
| depth).[1]
|
| [1]
| https://www.ndbc.noaa.gov/station_page.php?station=21416&typ...
| hn_go_brrrrr wrote:
| Is that a lot?
| dhx wrote:
| Not that it's much use to compare, but the closest DART buoy
| 21418 to the M9-9.1 2011 Tohoku earthquake[1] (which had an
| epicentre just 72km East of Japan's east coast) recorded a
| water column height variation of ~3m.[2][3] The closest DART
| buoy to today's M8.7-8.8 earthquake is 21416 and this
| recorded a water column height variation of ~0.6m back in the
| M9-9.1 2011 Tohoku earthquake.[4]
|
| [1] https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake
| _an...
|
| [2] https://www.ngdc.noaa.gov/hazard/data/DART/20110311_honsh
| u/j...
|
| [3]
| https://www.ngdc.noaa.gov/hazard/dart/2011honshu_dart.html
|
| [4] https://www.ngdc.noaa.gov/hazard/data/DART/20110311_honsh
| u/j...
| willyd1 wrote:
| Map on USGS:
|
| https://earthquake.usgs.gov/earthquakes/eventpage/us6000qw60...
| indigodaddy wrote:
| Agenda-free TV channel on YouTube has pretty good live/current
| coverage right now
| smcin wrote:
| Which TV channel please? Link or name?
| barlog wrote:
| each Live cam.
|
| <https://www3.nhk.or.jp/news/html/20250730/k10014878741000.ht...>
| vasusen wrote:
| 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.
| Waterluvian wrote:
| Sadly we won't hear from the partners of everyone whose manga
| didn't successfully predict a real disaster in a month.
| refactor_master wrote:
| 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.
| jrflowers wrote:
| I'm pretty sure they sell mangas about deaths from man made
| causes. I'm not an expert but I am fairly certain about
| this
| Barbing wrote:
| Reminded of the available $1m award from James Randi's org
| that was never claimed b/c no one could ever do anything
| supernatural under reasonable testing conditions.
|
| (Woo is surely possible but all those who can pull it off
| were gifted abilities that are deactivated by non-monetary
| incentives)
| theogravity wrote:
| > 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]
| jjangkke wrote:
| 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.
| throwai wrote:
| This article states that that the book references the 5th
| day:
| https://www.newsweekjapan.jp/akane_t/2025/05/202575jaxa.php
|
| Is it wrong? Did the book actually just call the time and
| month, not day?
| philipwhiuk wrote:
| > It is unwise to simply write this off
|
| No it isn't
| physicles wrote:
| Well, you can continue to make fun of her because, fortunately,
| this has turned out to be basically nothing (for Japan,
| anyway).
| bamboozled wrote:
| the manga was about a mega quake in Japan, not a tsunami from
| Russia
| bravesoul2 wrote:
| Thats well within acceptable cleirvoyant margins of error.
| pryce wrote:
| a P value of 1.00?
| jajko wrote:
| 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.
| ddtaylor wrote:
| What happens to the US West coast?
| dylan604 wrote:
| It moves to Arizona? Or is that the other "big one"?
| jjangkke wrote:
| 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.
| mock-possum wrote:
| Okay Charlie Frost
| a-curious-crow wrote:
| Evidence?
| watkajtys wrote:
| There's some interesting visualizations of the quake here
|
| Nearby quakes, faults, movement visualization, etc.
|
| https://earthquakes.builtbyvibes.com/quake/m8.8-119-km-ese-o...
| genewitch wrote:
| 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.
| redwood wrote:
| What? No that was a 6.7 or less than one hundredth an 8.8 on a
| log10 scale
| jandrewrogers wrote:
| You are off by about a factor of 1,000.
|
| 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.
| rcthompson wrote:
| I thought that it was a log10 scale, so each increment of 1
| on the scale is a 10-fold power increase, not a 10^1.5-fold.
| Dylan16807 wrote:
| It's a log10 scale measuring amplitude.
| tim-- wrote:
| This is power vs. energy.
|
| 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
| jandrewrogers wrote:
| I agree that it is not intuitive.
|
| 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.
| Arelius wrote:
| I'm actually not sure the Northridge earthquake was cited in
| the Richter scale, most references I see have it as about a
| 6.7, which based on the USGS catalog, was it's moment magnitude
| 6.7 Mw
|
| 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.
| genewitch wrote:
| yeah i misread the charts, where like 3.5ML (richter) is
| ~5.0, and i missed that it was mb rather than ML, 8.8 ~=
| 6.7ish body wave magnitude.
|
| That's the thing with standards, there's so many to choose
| from.
| tonyhart7 wrote:
| hope everyone is safe
| supportengineer wrote:
| 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.
| Kozmik1 wrote:
| 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.
| ehnto wrote:
| I'm sorry you're going through that, it sounds like they will
| be safe in Mililani.
| Kozmik1 wrote:
| Waves at Midway Atoll and Guam are reported to be 3ft (1m)
| amplitude by Hawaii Governor Josh Green as of 6:24pm Hawaii Time
| Dazzler5648 wrote:
| 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.
| illusive4080 wrote:
| 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.
| jajko wrote:
| 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.
| pixl97 wrote:
| While the Atlantic doesn't really have many faults that
| will generate earthquakes causing tsunamis there is always
| a risk of landslides creating large tsunamis up to what
| we'd consider mega-tsunamis. This said this is something
| that may have thousands of years between incidents.
| thenthenthen wrote:
| Shanghai has relocated 280.000 people from its coast according to
| this article: https://mp.weixin.qq.com/s/HLf3PM29IqaWajMhflo_uA
|
| Unclear if its related to the tsunami that is about to hit or the
| typhoon it is currently experiencing. Wild. Stay safe everyone!
| thenthenthen wrote:
| Update: The yellow warning has been lifted
| N19PEDL2 wrote:
| It is the sixth strongest earthquake ever recorded on the planet.
| PicassoCTs wrote:
| Any supervolcanoes nearby? How is
| https://en.wikipedia.org/wiki/Paektu_Mountain holding up?
| nabla9 wrote:
| 6th largest in the measurement history.
| jajko wrote:
| 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.
| haunter wrote:
| Whales have been washed ashore in Chiba
| https://x.com/AZ_Intel_/status/1950395615944511821
| sunaookami wrote:
| Community Notes says:
|
| >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
| ranguna wrote:
| 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?
| KeplerBoy wrote:
| I wonder how they died.
|
| I'd expect they are safe from a bit of shaking. Are there shock
| waves involved?
| chrisgd wrote:
| Just downgraded to advisory in Hawaii (10:44pm HST)
| user____name wrote:
| 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.
| x______________ wrote:
| Didn't it take years to solve the debate about light being a
| particle or a wave?
|
| ..I'll show myself out :)
| LightBug1 wrote:
| The US still has a National Earthquake Information Centre?
|
| Wow!
| x______________ wrote:
| Here is a 2 minute compilation video from a helicopter and other
| vantage points showing the waves crashing into the shores of
| Japan.
|
| https://old.reddit.com/r/interestingasfuck/comments/1mcwvpw/...
| kozika wrote:
| 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.
| rufus_foreman wrote:
| The National Weather Service wants you to know that "There is no
| threat for tsunami impacts in North Dakota",
| https://x.com/NWSGrandForks/status/1950377134565785933.
| 1xer wrote:
| Wow! I hope they stay safe. As others have pointed out it will
| break records [1]
| https://en.wikipedia.org/wiki/List_of_earthquakes_in_Japan
| perihelions wrote:
| Also, a volcano,
|
| https://www.newsweek.com/russia-klyuchevskoy-volcano-erupts-... (
| _" Russia's Klyuchevskoy Volcano Starts Erupting after
| Earthquake"_)
| spullara wrote:
| Why are the predictions of the tsunami experts so poor? What can
| be done to get higher accuracy?
| Shank wrote:
| 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.
| spullara wrote:
| We just had another one in the SF Bay Area a few months ago
| where they were wildly off.
| chasd00 wrote:
| 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.
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(page generated 2025-07-30 23:01 UTC)