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9.0 Earthquake strikes Japan


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as already noted, they are 2 different systems of measurement. it's still 8.9.

also, please stop posting full articles per the board rules.

They're not two different systems of measurement. The only scale relevant for quakes of this magnitude is Moment.

USGS is likely avoiding the constant changing they had in 2004; etc, and waiting to update.

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NHK news channel is available on a lot of satellite and cable services. I'm watching it on Verizon FIOS now and they have been streaming live video from helicopter now that the sun is up. It's a good watch without having to listen to talking heads. Unreal devastation and fires, as noted.

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I think that there are going to be some interesting studies about the possibility that the earlier MM7.3 shock in the same general area may have been the trigger that sent the mega thrust rupture zone over the edge. The reported size of the rupture and the associated crustal deformation of 7500 sq miles compares poorly with the rupture and crustal deformation in AK in 1964 which was 20X larger. One now has to be concerned as to where the stress in the tectonic system has been relocated in the subduction zone-to the south towards the more populated centers of Japan or to the north up towards Russia. Remember that the 2004 Indonesian shock was followed by a high 8 down zone from where the 2004 rupture began not long after and that seismic gaps remain in that zone. I'm sure that this is of concern in Japan-their version of the "Big One" is a repeat of the horrific Kanto Plain earthquake of 1923. One other thing, I heard on a report last night that the authorities in Taiwan had advised fishermen to bring their boats back into harbor to ride out the tsunami there-I hope that was untrue because that's the last thing one wants to do.

Steve

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I think that there are going to be some interesting studies about the possibility that the earlier MM7.3 shock in the same general area may have been the trigger that sent the mega thrust rupture zone over the edge.

Steve

I think it's pretty clearly a foreshock; the 1960 Chile Quake had 4 fairly substantial foreshocks, I think. Only about 50% of big subduction quakes have foreshocks, IIRC.

There's also a phenomenon of dual subduction earthquakes in faults with certain geometries.

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Some horrific numbers are going to start coming out later.

Yeah, I remember how when the 2004 tsunami happened, the initial death estimates were extremely small compared to the final, terrible tally. The areas effected by the tsunami this time are much smaller, but still a high number of people, plus the damaging earthquake this time.

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I think it's pretty clearly a foreshock; the 1960 Chile Quake had 4 fairly substantial foreshocks, I think. Only about 50% of big subduction quakes have foreshocks, IIRC.

There's also a phenomenon of dual subduction earthquakes in faults with certain geometries.

I'm thinking that way as well. There was a foreshock before the 1906 in SFO but only a minute before. The San Andreas Fault around SFO is much more complex than being a simple strike-slip but that's something for a general discussion on CA earthquakes.

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NHK news channel is available on a lot of satellite and cable services. I'm watching it on Verizon FIOS now and they have been streaming live video from helicopter now that the sun is up. It's a good watch without having to listen to talking heads. Unreal devastation and fires, as noted.

CNN has the NHK feed on its Live Video page. (or on the cnn.com page, currently marked as LIVE: Daylight arrives in Japan)

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The Weather channel just said the death toll could top 1000 when all is set and done!...... Are the aftershocks above 6.0 causing extra damage??

I'm worried they may be off by a 0....or 2.

I don't think it's aftershocks so much as an inability to get reports from the most heavily damaged areas.

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I think that there are going to be some interesting studies about the possibility that the earlier MM7.3 shock in the same general area may have been the trigger that sent the mega thrust rupture zone over the edge. The reported size of the rupture and the associated crustal deformation of 7500 sq miles compares poorly with the rupture and crustal deformation in AK in 1964 which was 20X larger. One now has to be concerned as to where the stress in the tectonic system has been relocated in the subduction zone-to the south towards the more populated centers of Japan or to the north up towards Russia. Remember that the 2004 Indonesian shock was followed by a high 8 down zone from where the 2004 rupture began not long after and that seismic gaps remain in that zone. I'm sure that this is of concern in Japan-their version of the "Big One" is a repeat of the horrific Kanto Plain earthquake of 1923. One other thing, I heard on a report last night that the authorities in Taiwan had advised fishermen to bring their boats back into harbor to ride out the tsunami there-I hope that was untrue because that's the last thing one wants to do.

Steve

Steve, thanks so much for your excellent analysis.

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a co-worker of my mine said he just heard on the radio that the japan coast shifted roughly 8ft !! cant confirm though, dont know which news organization is reporting this.

If it ends up being a subduction quake which sounds pretty likely from what is being reported, then yes a shift in the coastline is expected..

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have you seen ANY of the footage of this event? there was a huge tsunami that swept hundreds of people to their deaths in just one area. a city of 70K people is on fire. there is tremendous damage all over the country--we haven't even begun to see the extent of the devastation that sunrise will bring. the aftershocks are not the reason that a thousand people (and it'd be a miracle if only a thousand people) died.

please. read more and post less.

take it ez....ur on edge during the whole thread. people want to ask questions, let them. your not the law. stop trying to belittle folks......

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have you seen ANY of the footage of this event? there was a huge tsunami that swept hundreds of people to their deaths in just one area. a city of 70K people is on fire. there is tremendous damage all over the country--we haven't even begun to see the extent of the devastation that sunrise will bring. the aftershocks are not the reason that a thousand people (and it'd be a miracle if only a thousand people) died.

please. read more and post less.

:huh: Okay?? If I post video you are going to delete and say something cruel like earlier about my post and yes I have seen video all day today. I was saying something I heard off TWC.

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I have no idea what type of beaches Japan has but you have to think if this had been mid-summer this woulda been much worse as far as people on beaches/tourists along the coast as the tsunami came in.

If you take a look at Google Earth you see all sorts of medium size cities on the coast there; and keep in mind they would have had at most 15 minutes to try to get inland before the tsunami.

Also seems to be severe damage on Hokkaido, too.

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