Parameter name: request
Translate Request has too much data
Parameter name: request
Japan faces up to failure of its earthquake preparations : Nature News Jump?to?main?contentJump?to?navigationnature.com homepagePublications?A-Z?indexBrowse?by?subjectSearchThis siteAll of nature.com Advanced?searchMy accountE-alert sign upRSS feedSubscribe
Login
nature news homenews archivespecialsopinionfeaturesnews blognature journal Published online 29 March 2011 | Nature 471, 556-557 (2011) | doi:10.1038/471556a News Japan faces up to failure of its earthquake preparations Systems for forecasting, early warning and tsunami protection all fell short on 11 March. David Cyranoski TOKYO
Japan has the world's densest seismometer network, the biggest tsunami barriers and the most extensive earthquake early-warning system. Its population is drilled more rigorously than any other on what to do in case of earthquakes and tsunamis.
Yet this month's magnitude-9 earthquake surprised the country's forecasters. The grossly underestimated tsunami destroyed the world's deepest tsunami barrier and caught people by surprise. And the early-warning system for earthquakes largely failed. What went wrong?
The first problem was the earthquake forecast. Japan's seismic hazard map, the latest version of which was released in March 2009, breaks the offshore area of northeastern Japan into five seismic zones and envisages seven different earthquake scenarios. Each is assigned a probability based on the historical record of earthquakes. The southern Sanriku offshore region, which included the origin of this month's earthquake, was given a 30–40% chance of rupturing in the next 10 years and a 60–70% chance in the next 20 years.
Click for larger imageAs earthquake forecasting goes, these are very high numbers. "That basically means it could happen any day," says Yoshinori Suzuki of the Earthquake Disaster Reduction Research Division within the science ministry, which coordinates the map-making. But the fault was expected to unleash an earthquake of around magnitude 7.7 — about as large as any in the historical record for the area (see Nature 471, 274; 2011).
For a separate fault segment offshore from the Fukushima Daiichi nuclear plant, the same forecasting approach postulated only a magnitude-7.4 earthquake, with a less than 2% chance of occurring over the next 10 years and less than 10% over the next 50 years. The government of Fukushima prefecture even refers to the seismic hazard map to boast on its website: "With firm geological foundations and major earthquakes rare, Fukushima is a safe and secure place to do business." What the risk maps didn't allow for, however, was the coupling of segments that allowed the rupture to propagate for some 500 kilometres, unleashing an earthquake of magnitude 9.0 (see 'False comfort').
Japan's earthquake forecasting has had its successes. In 2003, the magnitude-8.3 Tokachi-oki earthquake occurred right in the middle of a forecasted hotspot. But for the most part, earthquake forecasting, which really took off in Japan in the 1980s and 1990s, has had mixed results, with many devastating quakes hitting outside the expected zones. "We would like to see more hit the marks," says Kyoto University's James Mori.
Despite the surprisingly powerful earthquake, Japan's earthquake-resistant buildings seemed to hold up well. "There was shaking damage but not much considering how strong the earthquake was," says Mori. It was the tsunami that did most of the damage, overwhelming barriers and years of preparation.
“The system seems to break down around a magnitude-8 quake.”
The world's deepest tsunami barrier, a 2-kilo- metre-long edifice at the mouth of Kamaishi Bay on the northeast coast, was completed in 2008 after 30 years, at a cost of more than ￥120 billion (US$ 1.4 billion). Anchored to the sea floor 63 metres down and rising 8 metres above the water, the 20-metre-thick break- water was designed to withstand the impact of a tsunami like the one from the 1896 Sanriku earthquake, which produced waves rising to nearly 40 metres in some areas.
Koji Fujima, a specialist in tsunami wave propagation at the National Defence Academy in Yokosuka, says that this and other structures along the coast gave people a false sense of security. "The region probably gets 2- or 3-metre tsunamis more than once a decade, and people know that the breakwaters will protect them from those," says Fujima. With the hazard map forecasting earthquakes in the magnitude-7.5 range, people would have anticipated a maximum tsunami of 4–5 metres.
Tsunami risk underestimatedFaith in the barriers seems to have undermined Japan's legendary tsunami-preparedness drills. In northeastern Japan as elsewhere, university professors, research institutes, non-governmental organizations and local civic groups carried out several drills each year to train people in how and where to evacuate. "We were working as hard as we could to educate people," says Fujima.
Yet people apparently became relaxed about tsunami risks, says Yoshiaki Kawata, a disaster-management expert at Kansai University. A tsunami originating in Chile last year triggered an evacuation warning to 1.68 million people in northeastern Japan. Only 62,000 sought shelter, says Kawata.
"People thought the breakwater was enough," says Fujima. But he adds that "there was no way it could protect them" against the tsunami on 11 March, although it did diminish the wave. Rising an estimated 15–20 metres at sea and 50 metres at some points after hitting the shore, even higher than the 1896 wave, it destroyed the tsunami barriers at Kamaishi and elsewhere and has killed an estimated 20,000 people who had failed to find safe, higher ground. It also swamped emergency generators at the Fukushima Daiichi plant, disabling the cooling system (see page 555). Built in the 1960s, the plant was designed to withstand a tsunami of no more than 5.7 metres.
The early-warning system operated by the Japan Meteorological Agency, designed to alert people when an earthquake will create shaking at or above level 5 on Japan's energy intensity scale (severe enough to crack walls), fell short as well. Based on a seismic reading taken a few seconds after an earthquake hits, the system provides up to tens of seconds of warning before the major shaking begins. On 11?March it delivered accurate warnings to areas near the epicentre. But the greater Tokyo region, where many areas experienced level-6 shaking, received no warning. Bullet trains and nuclear reactors, which have their own warning systems, shut down promptly, as designed.
The problem, according to Kyoto University's Masumi Yamada, was that the system assumes a 'point source' for an earthquake. In this case, the point source led to an estimate of a magnitude-7.2 quake. But as the Sanriku rupture ripped hundreds of kilometres of fault line parallel to the coast, unleashing ever more energy and causing slips of 20 metres or more near the Tokyo region, the system didn't correct itself. The frequent aftershocks also confounded the system, which generated several false alarms and missed large aftershocks.
"The system seems to break down around a magnitude-8 quake," says Yamada. In April, she will start a three-year collaborative project with the Japan Meteorological Agency to convert the point-source warning system to a dynamic one that works in two dimensions.
ADVERTISEMENT
Japan's disaster defences can certainly be improved, says Fujima, but he thinks that people should recognize that there are limits to what can be done against a "once in a thousand or two thousand years earthquake". Sturdier breakwaters could be built in areas where the tsunamis hit hardest, but they are expensive and could never fully protect against the biggest waves. "People probably should just stop building in the areas where large tsunamis will come," he says.
Kawata, however, puts his faith in better engineering. He agrees that the most effective way to avoid damage is to have people live out of reach of tsunamis. But he envisages houses (and nuclear plants) built on an artificial coastline supported by 10-metre-high concrete pillars. "There are a lot of things we have to do urgently. If we have a vision and we pool our energies, we can do it."?
CommentsIf you find something abusive or inappropriate or which does not otherwise comply with our Terms or Community Guidelines, please select the relevant 'Report this comment' link. Comments on this thread are vetted after posting. #19434Perhaps Nuclear Scientists in Japan did not anticipate the Severity of Tsunami and earthquake. The Future Nuclear Reactors have to be designed with more safety.
Dr.A.Jagadeesh Nellore (AP), India
Report this comment2011-03-30 12:11:00 PMPosted by: A Jagadeesh #19480I agree with Koji Fujima that tsunami zoning banning building in vulnerable areas is the best protection. This occurred to me as soon as I heard of the tsunamis; zoning is an essential part of natural hazard mitigation. I have been doing my best to convey these thoughts to Japanese government officials.
Report this comment2011-03-30 06:52:34 PMPosted by: Jean SmilingCoyote #19483"Faith in the barriers seems to have undermined Japan's legendary tsunami-preparedness drills."
This sounds like a prime example of consumed risk reduction, a part of "risk homeostasis". It is eerie to read Malcolm Gladwell's 1996 treatise in the New Yorker on the topic (which is freely accessible online at:
http://www.gladwell.com/1996/1996_01_22_a_blowup.htm
)
Gladwell concludes: "The truth is that our stated commitment to safety, our faithful enactment of the rituals of disaster, has always masked a certain hypocrisy. We don't really want the safest of all possible worlds. The national fifty-five-mile-per-hour speed limit probably saved more lives than any other single government intervention of the past twenty-five years. But the fact that Congress lifted it last month with a minimum of argument proves that we would rather consume the recent safety advances of things like seat belts and air bags than save them. The same is true of the dramatic improvements that have been made in recent years in the design of aircraft and flight- navigation systems. Presumably, these innovations could be used to bring down the airline-accident rate as low as possible. But that is not what consumers want. They want air travel to be cheaper, more reliable, or more convenient, and so those safety advances have been at least partly consumed by flying and landing planes in worse weather and heavier traffic conditions.
What accidents like the Challenger should teach us is that we have constructed a world in which the potential for high-tech catastrophe is embedded in the fabric of day-to-day life."
Report this comment2011-03-30 07:36:15 PMPosted by: Alexander Maier #19516I feel there is danger of an expert 'urban myth' growing that this earthquake was unpredicted. Yet, if you go to the first Nature link in the article here, that 'Nature 471, 274; 2011' you will see at the end a further link to a pdf of Minoura et al 2001. Predictions don't get much better than Minoura et al. 2001, either in the expertise of the multidisciplinary authorship; the geographic range liable to be effected; the extent of inland penetration; the physical evidence gathered to back it up; the modelling that indicated that it was caused by a rupture extending hundreds of kilometers offshore; or the now chilling final sentence:
"The recurrence interval for a large- scale tsunami is 800 to 1100 years. More than 1100 years have passed since the Jogan tsunami and, given the reoccurrence interval, the possibility of a large tsunami striking the Sendai plain is high. Our numerical findings indicate that a tsunami similar to the Jogan one would inundate the present coastal plain for about 2.5 to 3 km inland."The article was by Japanese authors, and in English, although the journal is not included in, for example ISI Web of Science, so might be missed by those outside Japan. I believe the important lesson to ponder is perhaps how do we make a better job of responding to clear warnings whose implications are costly and inconvenient? Cities like Oslo, where there is no choice, have thriving residential areas built on hillsides. Even though it may be many hundreds of years before such an event is repeated, I hope the planners have the courage to rebuild, but put residential areas on the hillsides, with only agriculture and essential infrastructure tied to the sea on the plains, with memorial parks and gardens on a buffer up to 20 meters above sea level.
Report this comment2011-03-31 09:43:41 AMPosted by: Malcolm MacGarvin #19537Lesson of the M9 Japan Earthquake and Tsunami
Japan has the world's densest seismometer network, the biggest tsunami barriers and the most extensive earthquake early-warning system, but failed on the Kobe earthquake in 1995 and the Honshu earthquake in 2011. Why? The seismometer network does not work on prediction. First, it can not explain earthquake phenomena, e.g. the Bam cloud http://www.earthquakesignals.com/zhonghao296/Animation/20031220Bam0.2.gif etc. Second, it has not proved if yield strength of a rock drops by seismic data. Third, it has no reliable prediction in practice. Forth, it has false warning and loss.
By contrast, an earthquake vapor predicted the Honshu quake exactly on Feb. 23-25 by http://www.earthquakesignals.com/zhonghao296/images2009/201102230000Jap8.9d.jpg
http://www.earthquakesignals.com/zhonghao296/images2009/201102250300J2M9.jpg
During the time, temperature in Japan rose up a lot, e.g. the daily maximum in Tokyo increased 10oC from 10oC on Feb.22 to 20oC on Feb. 25, and 20oC was the highest on the same date in 15 years from 1997 to 2011. Thus, if the Japanese scientists and people had not ignored the Earthquake Vapor Theory, published by the United Nations http://www.earthquakesignals.com/zhonghao296/copies/BamSeminars.pdf and shared to its all members, including Japan in early 2005, they would have predicted this earthquake.
The Earthquake Vapor Theory is right. It can explain mysterious earthquake phenomena, can predict earthquakes on statistic significance, has a dehydration property that yield strength of a rock drops by temperature increase, and has neither false warning, nor loss. I hope the Japanese government not to ignore it again. Otherwise, new tragedy might come to Japan again.
Report this comment2011-03-31 08:25:30 PMPosted by: zhonghao shou Add your own commentThis is a public forum. Please keep to our Community Guidelines. You can be controversial, but please don't get personal or offensive and do keep it brief. Remember our threads are for feedback and discussion - not for publishing papers, press releases or advertisements.
You need to be registered with Nature to leave a comment. Please log in or register as a new user. You will be re-directed back to this page.
Log in / register comments on this story Stories by subjectEarth SciencesEnvironmental SciencePhysics Stories by keywordsJapanSanrikuEarthquakeTsunamiDisaster managementSeismic hazard mapBreakwaterNuclear reactorNuclear meltdownEarthquake early warning system This article elsewhere Blogs linking to this articleAdd to ConnoteaAdd to DiggAdd to FacebookAdd to NewsvineAdd to Del.icio.usAdd to Twitter Recent activitymost recent stories Crashing comets make rings ripple31 March 2011Muscular dystrophy findings fuel French stem cell debate
31 March 2011New Drugs for Hepatitis C on the Horizon
31 March 2011Dying for a long life
30 March 2011Seven days: 25–31 March 2011
30 March 2011 commented storiesGive postdocs a career, not empty promises 119 comments02 March 2011NIH firm on grant application rules 52 comments29 March 2011Virology: Fighting for a cause 24 comments14 March 2011Concerns over nuclear energy are legitimate 20 comments30 March 2011How the penis lost its spikes 14 comments09 March 2011 Related stories Giant shock rattles ideas about quake behaviour15 March 2011 Quake sparks nuclear crisis15 March 2011 Japan plans nuclear power expansion31 March 2010 Interplate seismogenic zones along the Kuril–Japan trench inferred from GPS data?inversion18 January 2009 Japan's monitoring system beaten by shallow quake16 June 2008 Japanese nuclear plant in quake risk04 June 2008 Japan's earthquake warning system fails again14 May 2008 Earthquake physics and real-time seismology16 January 2008 Quake shuts world's largest nuclear plant25 July 2007 Japanese nuclear reactor under-designed for earthquake?17 July 2007 nature jobsDirect Recruitment or DeputationNATIONAL AGRI-FOOD BIOTECHNOLOGY INSTITUTEMohali, IndiaPostDoc PositionMax-Planck-Institut fur Kognitions- und Neurowissenschaften LeipzigLeipzig, GermanyMore science jobsPost a job for freenature events 2011 International Social Insect Genomics Research Conference 30 June 2011 — 02 July 2011 Yankui Road, Shenzhen, Guangdong, 518083, China More science events Resources PDF FormatSend to a FriendReprints & PermissionsRSS Feeds elsewhere on nature.comJapan earthquake and nuclear crisis external links Japan Meteorological Agency Headquarters for Earthquake Research Promotion Hazard map (in Japanese) TEPCO Masumi Yamada’s analysis of the early warning system Yuji Yagi earthquake model TopNatureISSN: 0028-0836EISSN: 1476-4687About NPGContact NPGRSS web feedsHelpPrivacy policyLegal noticeAccessibility statementTermsNature NewsNature jobsNature AsiaNature EducationAbout Nature NewsNature News SitemapSearch:? 2011 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.partner of AGORA, HINARI, OARE, INASP, CrossRef and COUNTER
没有评论:
发表评论