Large earthquake in Japan

TBH tsuanamis are kind of tame compared to half the side of a country lifting 4-5 meters in a few minutes
.

1855

https://www.nzgeo.com/stories/the-day-the-earth-shifted/



UPLIFT-Converted-600x557.jpg
 
cullennz said:
Trust me. 7.1 is "Large" when you are sitting on top of it.

Lucky it was quite deep though.

[qimg]http://i.imgur.com/pnUZM.gif[/qimg]
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Technically the Richter scale is no longer in use. These days we use Moment Magnitude, though the technical details of how they are different are beyond my knowledge.
 
One day after a major earthquake in Northern Japan:

Nikkei ends above 30,000 mark for 1st time in over 30 years

Upbeat corporate earnings, hopes for a U.S. recovery and robust growth data for Japan's pandemic-hit economy injected fresh vigor into the Tokyo stock market Monday, pushing the Nikkei index to close above the 30,000 mark for the first time in more than 30 years.

The 225-issue Nikkei Stock Average ended up 564.08 points, or 1.91 percent, from Friday at 30,084.15, its highest close since Aug. 2, 1990, when the Japanese economy was experiencing an asset bubble.
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Keep in mind that this particular index still has not recovered its all-time high (which was likely grossly overvalued at the time, as it assumed rapid economic growth would continue indefinitely in Japan; back in the 1980s Japan appeared to be an unstoppable economic juggernaut).

https://en.wikipedia.org/wiki/Nikkei_225

The Nikkei average has deviated sharply from the textbook model of stock averages, which grow at a steady exponential rate. The average hit its all-time high on 29 December 1989, during the peak of the Japanese asset price bubble, when it reached an intra-day high of 38,957.44, before closing at 38,915.87, having grown sixfold during the decade. Subsequently, it lost nearly all these gains, closing at 7,054.98 on 10 March 2009 — 81.9% below its peak twenty years earlier.
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The market may be reacting to positive news about the pandemic. Japan is beginning to vaccinate people this week, and the current wave of coronavirus also seems to be coming down to more manageable levels (new infections and current infections are about a third or a quarter of where they were a month ago).
 
cullennz said:
TBH tsuanamis are kind of tame compared to half the side of a country lifting 4-5 meters in a few minutes
.
1855

https://www.nzgeo.com/stories/the-day-the-earth-shifted/
Click to expand...

Isn't this the reason NZ exists at all, because of he collision point of 2 plates and all the land formed by the resulting volcanoes and uplift? Or was it there above sea level before and then got bumped into?

eta: I am thinking just in the last few million years...go back too far and it's all a big fireball.
 
Skeptic Ginger said:
Well that will teach me to go looking for the tsunami prediction map for the Juan de Fuca Straight to see if 200 feet was safe from a Cascadia Fault Slip. Probably because it only says > 10 feet the wave will whisk by you and I think if it was much greater they'd have had some more colors in the simulation.

But then I stumbled onto this site: Strange Sounds Blog

OK lets see, we've known about the periodic slow slip under the Olympic Peninsula for years. It starts in Southern OR and slowly works its way up to Vancouver Is. It recurs every ~14 months. I liken it to breathing because the affected area actually rides up and down, or at least that's how I remember it.

It's not directly connected to the Cascadia Fault. Then I see this on the blog: "Another intense slow slip earthquake event is starting much too early along the Pacific Northwest, prompting fears of the next Cascadia rupture"The answer, no one knows.:eek:

And more on the blog: Mt St Helens is stirring, not a big deal. If it erupts it won't be like the massive 1980 eruption.

And I delve further: Cumbre Vieja is going to erupt shortly: Second earthquake swarm within a month hits beneath the volcano on the Canary Islands prompting fears of a cataclysmic tsunami

There was a special on the mega-tsunami that was caused by this volcano before after the slope breaks free and slips into the Atlantic Ocean. It's in the geologic record. There is already a huge crack where the next break will occur.The volcano has erupted twice before in the last 70 years without causing a massive landslide.
In past eruptions the huge slab fell 13 feet and stopped. You can walk in the crack it's so big.

The current quake swarm signifying magma movement and an eruption would affect the slide risk area.

You have to watch the video to get all that detail.


I don't want to hijack the thread into volcanos and tsunamis so I just leave that link for people to peruse. Looks like you're safe at 200 feet Treb if your parch of the cliff doesn't break off in the shaking. :p
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According to geologist Nick Zentner, the working theory right now is that the big event will happen DURING one of the more common slow slip events.

Central Washington University Downtown Geology Series: "Slow Earthquakes"
 
portlandatheist said:
According to geologist Nick Zentner, the working theory right now is that the big event will happen DURING one of the more common slow slip events.

Central Washington University Downtown Geology Series: "Slow Earthquakes"
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I went here so I could full screen it. I need a good science lecture to make me happy again. :D

Thanks.
 
Darn, it's really hard to watch. The prof walks back and forth and back and forth and back and forth and back and forth..... It's maddening. If one was in the room I'm sure it would look different from the camera view. Bet the camera person was annoyed too. You think the Prof's going to write on the other board then he doesn't.

But I know the stuff he's going over, including the GPS measurements showing the uplift with the slow quakes so I'm going to skip ahead.
 
OK, here's what I got out of that: I didn't know the slow eq release was 2 weeks long. I didn't know the time frame of the release. I knew the buildup was 14 month.

He explained how the slow slip events are indeed connected to the Cascadia Fault. The plates are stuck where the big slip occurs, not as stuck where the slow slip is occurring, and fluid (not stuck) where magma surfaces (a separate but interesting issue).

But while he mentioned it, I don't think he explained why the Cascadia slip would occur during one of the slow slip events (I believe he meant during the 2 week pressure release).

In Japan and all along that side of the Pacific Plate the plates are taking a much deeper dive BTW. That's why the Mariana Trench is so deep.

There are other slow slips on the west coast, some further inland not related to this land mass movement.

There must be more current stuff since that lecture was 10+ years old. I'll do some looking.
 
For people that don't want an hour-long lecture with a professor making you dizzy ;) here's a 3 minute version that makes the SSE more clear. The discussion is about SSEs in New Zealand and notes that it's not really known if SLEs trigger sudden fault slips.



I'm off to see what's available re SSEs in Japan.
 
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Found an excellent discussion of these slow quakes that includes Japan. Essentially we have only been collecting the data on slow quakes over the last decade. The US and Japan have the most slow EQ monitors in place. He has a lot more to say. It's a bit techy but I thought it was good.

I'm impatient so I forwarded to ~min 25 and listened to the rest. I'm adding a link in case anyone wants to expand it to the full screen. His maps and graphs have a lot of tiny data/fonts so I had to watch it in full screen.


https://www.youtube.com/watch?v=AOjbY9wwpn0
 
Sherkeu said:
Isn't this the reason NZ exists at all, because of he collision point of 2 plates and all the land formed by the resulting volcanoes and uplift? Or was it there above sea level before and then got bumped into?

eta: I am thinking just in the last few million years...go back too far and it's all a big fireball.
Click to expand...
The glow worms in NZ and Australia have the same DNA.
No one understands how.
 
Since Nick Zentner's old public lectures from 10 years ago were already brought up a while back, I do want to interject here to direct people to his own YouTube channel which is like if Nirvana was real and it was geology knowledge. I also promise there's a lot less dizziness.

He does these great livestream series - presently he's doing one on the Missoula floods. But I'd especially encourage you to look through his playlists and find his Geology 101 and 351 courses from 2021. These were livestreams of his actual class lectures from that year, made during the pandemic for the benefit of remote-learning and social-distancing students, which he opened up to the public; in each case you're essentially sitting in on his class for the entire semester, it's fantastic.

The livestreams start a few minutes before the class begins and sometimes have extended substantially past the end of the actual lecture with a Q&A for online visitors, but each video is chapterized so you can focus on the lectures and skip the chat if you like.
 
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