Can we discuss predicted 8.0 quake in Japan?

[ChibaResident]

I read it is likely the aftershock magnitude 8.0 will occur sometime relatively soon in Japan (along with 10 magnitude 7.0's, which Japan has already experienced 4 (I think??)).

My biggest concern, naturally, is a huge aftershock of this magnitude hitting near Fukushima. But my secondary concern is near Tokyo or Tokyo Bay where a tsunami or mega-tsunami may result.

Is my secondary concern unlikely? I've tried to research, but I haven't learned much except that historically tsunami has never affected Tokyo Bay (but a tsunami did affect Osaka Bay long ago).

To the earthquake and seismic experts, or intelligent amateurs, I'd like to hear thoughts on this (naturally we all hope any big shocks will happen way out to sea and away from Tokyo, Sendai, and Fukushima!

[MineralMan]

1. Where did you read that?

It's an important question. Lots of people predict lots of things.

[ChibaResident]

2. I read it from a geological website. If I'm wrong, please correct my error...

I read that in a large earthquake such as the Japanese Tohoku 9.0, the rule of thumb is the largest aftershock will be one magnitude lower (thus, 8.0 or so), and around 10 aftershocks of 7.0 or greater can be expected (again, rule of thumb).

As I mentioned, there have already been I think 4 magnitude 7.0 or greater. So there might be more.

Obviously, this is just a rule of thumb of geology, and perhaps I read the information wrong.

[MineralMan]

4. Without a link, I can't do that.

Without being able to read what you read, I can't correct or confirm anything. So, if you have the link, please post it, and I'll have a look.

[ChibaResident]

3. I've read it many places, but here's one.

http://www.earthfiles.com/news.php?ID=1825&category=Environment

"With such a huge earthquake, a magnitude 9.0, according to common seismological principles and observed laws we would expect to see Japan aftershocks now include one magnitude 8.0 quake and roughly ten magnitude 7.0 earthquakes and roughly 100 magnitude 6.0 earthquakes. So far the largest aftershock magnitude has been a 6.8.

Furthermore, in Japanese history in 1854, there were two earthquakes of magnitude 8.4 separated in time by only 31 hours, basically occurring right next to each other. In 1944 and 1946, again two earthquakes occurred right next to each other magnitude 8.1 and separated by two years"

(I'm well aware that the assumption the largest was an 6.8 is FALSE, even on March 11th there were at least a couple of 7.0+ magnitude aftershocks I'm aware of, plus at least one afterwards a couple of weeks ago)

[MineralMan]

5. OK. That's a reasonably reliable site. Yes, there is a chance of

an 8.0 aftershock. There have been many aftershocks above 7.0 since the 9.0 quake. But it's impossible to predict whether an 8.0 or larger one will occur. We won't know until one occurs, and there's really nothing that can be done to prepare for it that has not already been done.

When it comes to 9.0 earthquakes, we don't have a lot of information to work with, frankly. So, what happens will add to that information. The area where this quake occurred is very, very active, since it is the junction of three plates. Almost anything could happen there. Our records are young, in geological terms, so we just don't know.

[ChibaResident]

6. Does anyone know exactly how many 7.0+ magnitude quakes have occurred?

I think 4, but I can't recall.

I also know there was a 7.2 magnitude "foreshock" on March 9th, but I don't know if seismologists count such foreshocks in their "totals".

Thank you for your comments MineralMan. You are right, this is definitely uncharted territory to say the least (or, "relatively uncharted" anyway). The prospect of an 8.0 somewhere near Fukushima or Tokyo is certainly worrisome though (as is the prospect of more 7.0 quakes to come!).

Things seemed to settle down for a few days, but then we had a few aftershocks one after the other a couple of days ago. And again now it's quiet (eerily quiet).

Hopefully it's calmed down now, but historically speaking that's not too comforting. Feels ominous to me.

[MineralMan]

7. Japan is not a very safe place to be, frankly.

Especially along the eastern coast. It was poor judgment that allowed nuclear plants to be built in such a geologically active zone. I wouldn't live there, certainly. I lived in California for 60 years of my life, but never in places where serious active faults were present. I can remember dozens of earthquakes from my time there. Now, I live in Minnesota, one of the least earthquake-prone states in this country.

[ChibaResident]

8. Wow, 60 years in Cali and now Minnesota?

What, are you trying to die of boredom? :p

j/k

[MineralMan]

11. Nothing boring about Minnesota. Nothing at all.

From the cosmopolitan variety offered by the Twin Cities Metro Area to the fantastic fishing and other outdoor possibilities, It's a great place to live. I live in Saint Paul, and am loving every minute. Even the winter. We also have Al Franken as one of our Senators and my congressional representative is a real progressive.

What's not to like about all that?

[ChibaResident]

13. I wouldn't know, I fly over it. :p

Besides, for my "home" Congressman (my very district, in fact) I've got none other than Barney Frank, so I've got ya beat there too.

But I do like the outdoors. But not the winter.

I'd dig visiting Minnesota in the summertime that's for sure (but this summer, I've got to visit old Barney and old Bean Town (if I survive that long!).

[ChibaResident]

10. I do agree with you wholeheartedly about the nuke plants

Not only in an unstable region but On the Coast where TSUNAMI are historically recorded!!??

WTF!?

Truly corporate insanity and hubris in spades. And now Japan pays the price.

[ChibaResident]

12. "I can remember dozens of earthquakes from my time there"

I can remember dozens of earthquakes from March 11, 2011.

Got ya beat on that front buddy. (sorry, gallows humor and all that)

[ChibaResident]

9. But seriously, folks. Does anyone know accurately how many 7+ have occurred?

I'd really be interested in keeping tabs on this and I've tried to research it but somehow it's not easy to find.

I'm sure SOME people have kept up with the actual earthquake situations in Japan, no?

[SidDithers]

14. Check the usgs...

www.usgs.gov

Sid

[ChibaResident]

15. Thank you. Very useful link. nt

[SheilaT]

16. Keep in mind that any and all earthquake

predictions are just educated guesses. This one does seem based on historical earthquake precedent.

It's always correct to say that eventually "The Big One" will occur in California. Exactly where, exactly when, exactly how big is not possible to know this far out.

Plus, there are fault lines in LOTS of places, and a lot of places that aren't considered terribly earthquake prone could still be surprised. But I'm willing to bet that Minnesota is as close to guaranteed not to have an earthquake as any place on earth can be.

[MineralMan]

17. Ya sure, you betcha. Minnesota's ground doesn't move.

Of course, it's frozen solid for half the year, but we'll ignore that. :rofl:

[Logical]

18. Source please? A source with a post like this is very helpful. n-t

[ChibaResident]

19. It is included in the topic, further downthread (also, I've seen multiple sources).

I don't think such a prediction is any secret, nor too uncommon. Naturally it is a prediction. Japan could get many more aftershocks or surprising size from now, or none at all. I just started this topic to discuss the possibility and hear from people "in the know".

Thank you for your interest.

[SoCalDem]

20. Japan is "Earthquake Central"

always has been and always will be. The people there know it and accept it. All they can do is to try & build to mitigate any damage:(

What I always think about is this.. how many times can those buildings
"take it", before they reach their "limit"? :scared:

[ChibaResident]

21. Buildings are inspected regularly and damaged ones are repaired.

Japan is VERY careful about earthquake safety.

Watching some videos from Sendai is amazing, the shaking is so violent but I didn't even see a smashed window in any of the videos (lots of smashed store shelves and interiors though!). Really amazing.

Sadly though, nothing can stop a tsunami. I think warnings are the best prevention in that case.