Wednesday, March 30, 2011

[californiadisasters] Japan Rethinks Tsunami Safety



The disaster in Japan put sea walls, warning systems, emergency preparedness training and building standards to the test. What worked and what didn't?


Structural engineer Kit Miyamoto was giving a speech in Japan on earthquake safety when this month's record quake struck, giving him a front-row seat for the unfolding disaster and what steps might save lives next time.

"This disaster basically paralyzed the whole country," said Miyamoto, president of West Sacramento-based Miyamoto International, standing amid the wreckage in this battered coastal city. "We can learn a lot of lessons for California."

What worked, and what didn't?

Sea walls

Although some of the lessons will take years to nail down, experts said some things stand out already. One problem, some said, was Japan's overreliance on the massive sea walls that were favored by its politically powerful construction industry and that provided a false sense of security.

Photos: Japan's earthquake, tsunami and nuclear crisis

More than 40% of Japan's coast is lined with breakwaters, sea walls and other structures, according to the Japanese government. Although some say the damage could have been worse without them, many of the structures were overrun or even collapsed, including the 1.2-mile Kamaishi sea wall, the world's largest, built at a cost of $1.5 billion.

"The cost-benefit ratio of these enormous investments needs to be reassessed," said Antonios Pomonis, a disaster-prevention expert based in Greece, who studied the 1995 earthquake in the Japanese city of Kobe.

At the Fukushima nuclear reactor, few thought about ensuring that the power supply was secure, because few thought the 17-foot wall could be breached. But the diesel generators designed to cool the core and spent fuel rods during shutdown were on low ground and quickly flooded.

"The wave went higher than we predicted," said Tatsuyuki Kumagai, an official at Miyako City Hall.

California has two coastal reactors — Diablo Canyon and San Onofre — near active faults, both protected by sea walls. Although its geology is less prone to local tsunamis, California is still considered vulnerable to distant and some locally generated tsunamis.

<SNIP>

View entire article here: http://www.latimes.com/news/nationworld/world/la-fg-japan-quake-seismic-20110329,0,4581825,full.story

--
Check out http://groups.yahoo.com/group/californiadisasters/
Read our blog at http://eclecticarcania.blogspot.com/
Visit me on Facebook at http://www.facebook.com/derkimster



__._,_.___


Be sure to check out our Links Section at http://groups.yahoo.com/group/californiadisasters/links
Please join our Discussion Group at http://groups.yahoo.com/group/californiadisasters_discussion/ for topical but extended discussions started here or for less topical but nonetheless relevant messages.




Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe

__,_._,___

No comments:

Post a Comment