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Strong earthquake hits northern Japan, tsunami warning issued

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Re: Strong earthquake hits northern Japan, tsunami warning issued

#151
post #134

I’m in Niseko (Hokkaido) and had just driven 2.5h through a snowstorm to my hotel, opened door, and put down bags and phone. Weird alarm from my phone (new phone; forgot to disable, which I usually do because where I live abuses the system for a bunch of stupid alerts for chronic issues), looked at it, realized in Japan it is probably real, so I stood in a doorway. Pretty decent sized storm. If a tsunami affects me o…

Do those alerts work for foreigners on data-only SIMs?

Unclear. I have a t-mobile e-sim in the phone I was using and that worked for me.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#152

Earlier quoted context omitted.

Why was the July megaquake, an 8.8 magnitude, a dumb prophecy, but this "strong quake" at a magnitude of 7.6 is a smart prophecy?

This isn’t something that I personally wish to debate, but I’ll leave link to the wikipedia page for the July 2025 prophecy [1] for anyone who may not know what we are talking about. And also point out that last night’s earthquake in Northern Japan was not a “prophecy”. Just a regular, large earthquake - which do occur pretty frequently in Japan. And I say "large" not just because of the magnitude, but because parts…

Source: it came to me in a manga.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#153
post #99

Was in a hotel in Sapporo, almost got thrown out of bed. Lot of people in the hotel lobby now. Considering leaving Hokkaido by air if a Hokkaido and Sanriku Subsequent Earthquake Advisory is issued, don't really want to be in a potential megaquake.

People were freaking about the July megaquake prophecy and nothing happened. Trying to time it is silly, just chill and enjoy your stay, you'll probably be fine.

That's a bit like comparing apples to oranges. One was published by social media, one was published by the Government of Japan.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#154
post #24
post #20

Earlier quoted context omitted.

No, estimated height has nothing to do with actual measurements

Can you elaborate?

Yes. The Japan Meteorological agency has a piss poor machine learning model that basically defaults to predicting 3 meters wave every time there is an earthquake in the sea and in the end it's usually a few dozens of centimeters. They lost all credibility by crying wolf every single time.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#155
USGS Tsunami warning circa. Dec. 2024

Seismic measurement, where weak or strong faults that are measured as seismometer, textual references to cartography, taking stock of tectonic plates.

[1]: https://news.ycombinator.com/item?id=42331326

[2]: https://web.archive.org/web/20250318161013/https://www.tsuna...

Re: Strong earthquake hits northern Japan, tsunami warning issued

#156
About 20 hours after the earthquake, the University of Tokyo sent out a follow-up advisory to faculty, students, and staff [1, scroll down for English]. This part hit home with me:

“The ‘follow-up earthquake advisory for the Hokkaido and Sanriku Coastal regions’ was established following the earthquake (M7.3) that occurred off the coast of Sanriku on March 9, 2011, two days prior to the Great East Japan Earthquake (Tōhoku Region Pacific Offshore Earthquake) that occurred on March 11, 2011.”

I was eating lunch in a fourth-floor restaurant in Nihonbashi, Tokyo, on March 9, 2011, when that preliminary tremor occurred. I had felt many earthquakes before, but that one seemed different: longer, slower, creepier. It didn’t cause any damage, but I often recalled it after the much bigger one struck two days later. (I missed the March 11 quake, as I happened to leave for Osaka just a few hours before it hit. My office back in Tokyo was damaged, though.)

[1] https://kankyoanzen.adm.u-tokyo.ac.jp/%e5%8c%97%e6%b5%b7%e9%...

Re: Strong earthquake hits northern Japan, tsunami warning issued

#157

Earlier quoted context omitted.

The Wikipedia redirect is apparently dead ( https://en.wikipedia.org/?title=Shadow_clone&redirect=no ) and the main page for Naruto doesn't show anything about shadow clones. Care to explain the reference? Do people dress up like a character from the TV show and help out people or what's going on?

The reference is that the anime character "Naruto"[0] wears the same colors and roughly the same uniform as a Japanese recovery worker[1]. During disaster work, you see swarms of recovery workers and the joke/reference being made is that this looks like Naruto doing a "shadow clone" technique. [0] https://i.redd.it/psseu93j62la1.jpg [1] https://sendai-resilience.jp/media/images/efforts/case31_ima...

It took a while, but finally someone managed to get us confused westerners an answer! Thank you :)

Re: Strong earthquake hits northern Japan, tsunami warning issued

#159

Earlier quoted context omitted.

This part is unquestionably true. But since we don't have a direct measurement of the stored energy at a given time, the occurrence of an earthquake acts as both an indicator of release of stored energy but also, potentially, evidence of increasing stored energy. Like how buying a Porsche costs money, and leaves you poorer than before you bought it, but when you see stranger buy a Porsche, you update towards believin…

Fair enough. I'm also not a geoscientist, and to clarify I didn't mean to imply any specific statistical effect there. It seems entirely reasonable to me that a series of EQs might tend to increase in intensity. In reality I think (layman's impression) that there's rough (post hoc) evidence for both things. Foreshocks followed by noticably larger EQs as well as trains of progressively smaller EQs.

Precisely, and the 'myth' is worded in such a way that the effect of stress relieving pre-quakes is set to a big fat zero and that seems to be a thing more related to the composition of what is underground than the fact that it does not happen at all, and if it happens at what magnitude you would expect the effect to show up.

To me a myth is something that isn't true at all, not something that we do not have data on to be able to rule it out completely or that may be an influence just not a capital one. I think the most generous reading of the 'myth' claim would be that the energy available in the smaller quakes is too low to have a meaningful effect on releasing energy from a larger quake and I'll buy that. But at the same time an absence of such fore-shocks in an area where earthquakes are known to happen indicates that stress may be been building up over a longer time and that stress would be released in the next bigger quake if and when it happens.

This too may not be a big enough difference due to the immense increase in energy present in larger events (the scale is logarithmic). But its effect is quite probably still non-zero and for it to be a myth it would have to be zero.

Myth = the sun rotates around the earth

Myth = unicorns exist

Myth = the earth is 6000 years old

Those are directly falsifiable, and we know all of these to be categorical falsehoods.

Smaller earthquakes can - depending on local crust composition and other environmental factors - affect the amount of energy released in a larger one following, is not necessarily a significant effect (though even this would be tricky to establish) but I find it hard to believe they are completely unrelated though the effect may not be large.

Insignificant effect != Myth

Re: Strong earthquake hits northern Japan, tsunami warning issued

#160
post #134

I’m in Niseko (Hokkaido) and had just driven 2.5h through a snowstorm to my hotel, opened door, and put down bags and phone. Weird alarm from my phone (new phone; forgot to disable, which I usually do because where I live abuses the system for a bunch of stupid alerts for chronic issues), looked at it, realized in Japan it is probably real, so I stood in a doorway. Pretty decent sized storm. If a tsunami affects me o…

Do those alerts work for foreigners on data-only SIMs?

Yes. My partner got one in Morioka about 6 weeks ago.

Edit: very, very quickly after the quake, which we felt, I might add. I got a notification via the 'Safety tips' app long after. I think I was on Airplane mode at the time.

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