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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

#71

Post by theogravity »

vasusen wrote: post #50

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 E…

> 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]

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

#73

Post by edoceo »

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?

Velocity of wave as well.

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

#74

Post by brewdad »

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?

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.

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

#75

Post by dhx »

hn_go_brrrrr wrote: post #61
dhx wrote: post #37

~1.3m water column height variation observed by the closest DART buoy at 48°7'34" N 163°22'35" E (5787m nominal water depth).[1] [1] https://www.ndbc.noaa.gov/station_page.php?station=21416&typ...

Is that a lot?

Not that it's much use to compare, but the closest DART buoy 21418 to the M9-9.1 2011 Tōhoku 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 Tōhoku earthquake.[4]

[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...

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

#76

Post by idontwantthis »

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 a gigantically long wave. I don’t think what you’re describing describes a tsunami.

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

#77

Post by ivan_gammel »

mordechai9000 wrote: post #7

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.

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…

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

#78

Post by pezezin »

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.

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

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

#79

Post by TylerE »

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?

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.

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

#80

Post by mayneack »

grigri907 wrote: post #72
bicx wrote: post #3

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

What do you use for alerts?

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