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M8.7 earthquake in Western Pacific, tsunami warning issued

earthquake.usgs.gov

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Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#201

Post by javcasas »

hsbauauvhabzb wrote: post #54
decimalenough wrote: post #38

Earlier quoted context omitted.

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...

Is height the only thing that matters? Presumably 1x 2m wave is less impactful than 10 x 1m waves spread 20 seconds apart?

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.

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#203

Post by hsbauauvhabzb »

dgfitz wrote: post #113
crystal_revenge wrote: post #98

Earlier quoted context omitted.

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.

> 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.

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.

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#204

Post by fc417fc802 »

K0balt wrote: post #150
ninetyninenine wrote: post #124

Earlier quoted context omitted.

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.

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 bot…

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.

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#205

Post by bulatb »

misiek08 wrote: post #200
xav0989 wrote: post #43

Earlier quoted context omitted.

Anything that ends in .gov is related to a government entity in the US. Other countries don’t get access to that TLD.

I'm not sure if understood correctly, but https://www.tsunami.gov/ works without any problems even from Europe, Poland.

The US government controls who gets .gov domain names, but the websites are available to anyone.

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#206

Post by inglor_cz »

TylerE wrote: post #79
hsbauauvhabzb wrote: post #54

Earlier quoted context omitted.

Is height the only thing that matters? Presumably 1x 2m wave is less impactful than 10 x 1m waves spread 20 seconds apart?

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.

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.

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#208

Post by RugnirViking »

ninetyninenine wrote: post #167
K0balt wrote: post #150

Earlier quoted context omitted.

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 bot…

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 becau…

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

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#209

Post by Amadiro »

sugarpimpdorsey wrote: post #45
decimalenough wrote: post #17

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'…

Japanese news reporting during disaster scenarios is something to behold. The screen is filled with data and blinking like a Bloomberg Terminal.

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.

Re: M8.7 earthquake in Western Pacific, tsunami warning issued

#210

Post by pezezin »

ccozan wrote: post #195
socalgal2 wrote: post #186

Earlier quoted context omitted.

> 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".

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.

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.

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