Tokyo at risk from massive aftershock, expert says (w/ Video)

March 16, 2011

( -- Tokyo may be at serious risk from a massive aftershock and associated tsunami as a result of the devastating March 11 earthquake near Sendai, Japan, according to UC Davis seismologist John Rundle.

Friday's magnitude 9.0 temblor has been followed by hundreds of powerful aftershocks that have migrated southwards, noted Rundle, who is professor of geology and physics at UC Davis.

"Initially, the major aftershocks were confined to the region near Sendai, but the steady southward march of the aftershocks is cause for alarm for Tokyo and surrounding regions," Rundle said.

There is historical evidence of major earthquakes off the coast of Japan being followed by another similarly large earthquake nearby within a relatively short period of time, he said.

John Rundle on Tokyo earthquake. Videography by Academic Technology Services/MediaWorks

These include the magnitude 8.4 Ansei-Nankai and Ansei-Tokai earthquakes of 1854, separated in time by only 31 hours; and the 1944-1946 Tononkai and Nankai earthquakes, with magnitudes of 8.0 and 8.1, respectively. Typically, an earthquake of magnitude 9 would be followed, in no particular order, by one of magnitude 8, ten aftershocks of about magnitude 7 and many smaller aftershocks.

That 8.0 aftershock has yet to occur. If it happened in Tokyo Bay, it could set off a tsunami that would devastate the densely populated region, similar to the events of September 1, 1923 during the great Kanto earthquake (magnitude 7.9).

This video, made with KeckCAVES visualization software, first shows global earthquakes over the past 110 years (green dots) then zooms in on Japan to show earthquakes in the past week. Green dots are the smallest earthquakes and red the largest. Videography by Cara Harwood, Oliver Kreylos, Braden Pellett and Louise Kellogg

Rundle's research uses computer modeling to understand systems that can go through abrupt and catastrophic changes, such as earthquake faults and financial markets. He has collaborated with researchers at NASA's Jet Propulsion Laboratory and other universities on Quakesim, which studies systems and has produced earthquake forecasts for California and other parts of the world.

In a blog entry posted July 30 on the website, Rundle forecast that of four Japanese cities -- Tokyo, Osaka, Niigata and Sendai -- Sendai was the second-most likely to be hit by a major within 150 miles over the next year. Tokyo was the most at risk, he calculated. He has updated this forecast as of 3 p.m. on March 13.

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3.8 / 5 (17) Mar 16, 2011
Kinda looks that way-
not rated yet Mar 16, 2011
So, heads-up Tokyo and California. He (John Rundle) didn't mention Oregon, but huge 9+ earthquakes are not unheard of just off the coast of Oregon.
not rated yet Mar 16, 2011
Scary stuff. Living in Osaka, I've seen a bit of news about the Nankai quake. It will happen, it will be big too. There are systems in place to handle it, but I'm hoping they'll get a little more beefing up now that a major distaster is on everyone's minds. I imagine Tokyo is a bit more proactive though, since they've been getting it worse.

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