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9.0 Earthquake strikes Japan


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Wait-- I'm confused. The USGS map now shows the center E of Tokyo, near the E coast of Honshu. Did it shift from the initial estimate?

Looks like there were two 6+ aftershocks at about the same time:

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc00023fx.php#maps

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0001xka.php#maps

One east and one west of Tokyo? Really?

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Looks like there were two 6+ aftershocks at about the same time:

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc00023fx.php#maps

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0001xka.php#maps

One east and one west of Tokyo? Really?

Yeah, that's what confused me. That is crazy for two big events like that to happen on either side of a major megalopolis. I wonder how hard Tokyo shook in each of these.

It's just out of control. Any one of these events by itself would be a major newsmaker. It's seismic diarrhea.

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Wow-- that is really, really shallow. The shaking at the surface must have been crazy.

For whatever reason, it's "only" estimated to have a maximum shaking intensity of around VII:

http://earthquake.usgs.gov/earthquakes/pager/events/us/c00023fx/exposure_small.png

Maybe the fact that it was centered in a mountainous area? Or maybe it's a kind of fault that doesn't produce as strong surface waves.

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For whatever reason, it's "only" estimated to have a maximum shaking intensity of around VII:

http://earthquake.usgs.gov/earthquakes/pager/events/us/c00023fx/exposure_small.png

Maybe the fact that it was centered in a mountainous area? Or maybe it's a kind of fault that doesn't produce as strong surface waves.

Yeah, mountainous areas will generally shake a lot less than flat areas. Or, maybe like janetjanet said, the initial depth estimate is way off. Or... maybe they don't have all the reports in yet. The MM values rely heavily on actual observations, I believe.

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Hrm.

That 6.3 showed up as "red" when I first clicked on it (<1 hr old).

But yes, you're right. Looks like the 6.1 west of Tokyo is the only new one.

I don;t think that site is updating that fast..i noticed that yesterday...sometimes 90 minutes would go by without a quake showing up then a bunch of missing old quakes later on in that time frame would show up

1435: Following earlier reports, it appears there has been more than one strong aftershock in Japan - AP reports two tremors measuring over 6.0 within three minutes of each other.

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So if I understand it, this 6.4 happened in an area where they've been expecting a large earthquake for some time. The JMA said today's earthquake is not the one they've been waiting for. Is it possible this earthquake released some strain however?

If they were expecting one along that fault, it's quite possible that the stress changes due to the larger earthquake helped to trigger this one. And yes, it would certainly release some of the stress on the fault. I don't know how much had built up before this 'quake, but if it was enough for a 7.0 (just for example), then a 6.1 would release something like ~10% of that stress.

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If they were expecting one along that fault, it's quite possible that the stress changes due to the larger earthquake helped to trigger this one. And yes, it would certainly release some of the stress on the fault. I don't know how much had built up before this 'quake, but if it was enough for a 7.0 (just for example), then a 6.1 would release something like ~10% of that stress.

Eh, it's a little over 30 times the ENERGY for each magnitude, so it only released a bit more than 1/30th of the stress of a 7.0.

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CNN keeps referring to the video that was posted on FB three days ago by an American who lives in Japan as being taken by him, in fact it was taken by a Japanese photojournalist. They misstatements these networks keep repeating are appalling, hard to trust anything they say at all.

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1958: Tsunamis on the scale that hit north-east Japan on Friday may strike the region about once every 1,000 years, a leading seismologist has said. Dr Roger Musson, the head of seismic hazard at the British Geological Survey (BGS), said there were similarities between the last week's event and another giant wave that hit the Sendai coast in 869AD.

BBC

http://www.bbc.co.uk/news/world-middle-east-12307698

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[4:13 p.m. ET Tuesday, 5:13 a.m. Wednesday in Tokyo] The governor of Tokyo has apologized for saying the earthquake and tsunami were God's punishment for Japanese egoism, the country's official news service reported.

"I will take back (the remark) and offer a deep apology," Tokyo Gov. Shintaro Ishihara said at a news conference, according to Japan's official Kyodo News.

On Monday, Ishihara had told reporters, "I think (the disaster) is tembatsu (divine punishment), although I feel sorry for disaster victims," according to Kyodo News.

CNN

http://news.blogs.cnn.com/2011/03/15/japan-quake-live-blog-fire-erupts-in-fourth-reactor-radiation-warning-issued/?hpt=T1

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[4:39 p.m. ET Tuesday, 5:39 a.m. Wednesday in Tokyo] The official number of missing people in Japan has risen to 7,558, and 1,990 have been reported injured. The death toll remains at 3,373 but is expected to rise as rescuers reach more hard-hit areas.

http://news.blogs.cnn.com/2011/03/15/japan-quake-live-blog-fire-erupts-in-fourth-reactor-radiation-warning-issued/?hpt=T1

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1958: Tsunamis on the scale that hit north-east Japan on Friday may strike the region about once every 1,000 years, a leading seismologist has said. Dr Roger Musson, the head of seismic hazard at the British Geological Survey (BGS), said there were similarities between the last week's event and another giant wave that hit the Sendai coast in 869AD.

BBC

http://www.bbc.co.uk...e-east-12307698

Uh, Taro in the Sanriku district was hit by a 30 meter high tsunami in 1896 and a 10 meter one in 1933. They are referred to as the Great Meji and Great Showa tsunamis respectively.

Steve

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All the focus on the nuclear issue tends to obscure the ongoing tragedy; people are still dying from the affects of the tsunami. From the BBC:

2208: Lyn Francis, in the UK, told the BBC she received a text message from a friend who is trapped by floods on the fifth floor of a university building in Ishinomaki. "He and his colleagues have very little - or by now possibly no - food, no water and no heating. I received a text from him at 2100 GMT it read: 'It's bad. Love to you all'. It sounds like the last text someone would write if they were dying."

Eerily reminiscent of the voicemails from the North Tower.

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Uh, Taro in the Sanriku district was hit by a 30 meter high tsunami in 1896 and a 10 meter one in 1933. They are referred to as the Great Meji and Great Showa tsunamis respectively.

Steve

Those quakes weren't quite as big as this one, and ruptured a portion a bit north of this quake.

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