Extra.3 October 31, 2013

Japan Society of Civil Engineers
International Activities Center

IAC News （Extra Issue.３）
Lessons learned from the Great East Japan Earthquake
Kenji Sakata, 98th JSCE President

Born in 1943. Graduate of Kyoto University. Served as professor at Okayama University; chaired
the Faculty of Environmental Science and Technology and the Graduate School of Natural Scienceand Technology; now Professor Emeritus. Served as president of the Japan Society of Dam

Kenji Sakata,
98th JSCE President

Engineers, the Japan Concrete Institute, and JSCE. Received the JSCE Outstanding PaperAward, Yoshida Award (Outstanding Paper Division and Research Accomplishment Division), andother honors.

Nearly two years have passed since the Great East Japan Earthquake. That earthquake of magnitude 9.0 andseismic intensity 7 was the largest ever recorded in Japan. The tsunami, much higher than 10 meters, has left
catastrophic damage along the Pacific coast from the Tohoku region to the Kanto region, and an accident at
the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Co. caused a nuclear disaster as well.
Many residents were driven from their communities and are still living as evacuees all over Japan. Immediately
following the disaster, the violence of the tsunami's attack on the seaside towns of the Sanriku Coast and theunbecoming stillness of the devastated communities were inexpressible. There was too great a gap between
the realities we saw before our eyes and the power of words to describe them. We could only remain silent inthose days.

Preparing for the unexpected
Protecting people from natural disasters is an important part of thejob of a civil engineer, and we have learned a great deal from theGreat East Japan Earthquake. This disaster has tested theappropriateness and effectiveness of the technical measures andsystems that we have developed on the basis of many disasters thatwere experienced in the past. It has also brought up new issues for
us to resolve. To sum up the lessons that I myself have learned in anutshell, it is necessary to prepare for the unexpected, because pastdisasters will be surpassed by future disasters. We have learned thelesson that without a doubt, disasters that we cannot predict oranticipate will occur at times.

Photo 1. Towns covered by rubble(Kesennuma, photo taken on April 5, 2011)

The Great East Japan Earthquake surpassed the 1995 Hanshin-Awaji (Kobe) Earthquake. The conditions of
this disaster made it different from any previous disaster, including not only the strength of the earthquake andflood height of the tsunami, but also the extensive size of the affected region, the presence of completelydevastated areas, and the nuclear accident. The Ise-wan Typhoon which struck Japan in 1959 was a massive
disaster, resulting in more than 5,000 fatalities and missing persons. Exactly 50 years later, in 2009, Typhoon
No. 18 followed practically the same course as the Ise-wan Typhoon and was basically the same in size, but its
effects were quite minor in comparison to the damage caused by the Ise-wan Typhoon. That was the result ofdams and river embankments that had been constructed over the past 50 years. It then appeared that we had
overcome disasters of that type. However, Japan suffered flooding of an unprecedented scale last year, withcontributing factors including the growing scale of typhoons due to climate change caused by global warming,back-building thunderstorms due to stationary seasonal rain fronts, and the extraordinarily heavy downpoursthat have occurred as a result.

Disaster mitigation
Preparing for the unexpected includes the concepts ofdeveloping fail-safe designs, preparing countermeasures forsevere accidents at nuclear power plants, and minimizing
residual risk. After the Great East Japan Earthquake, ourattention was drawn to the concept of disaster mitigation. Thisrefers to preparing for unexpected disasters with the top priorityof preventing the loss of human lives when disasters strike,while minimizing economic losses as well. Based on theexperiences of the Hanshin-Awaji Earthquake, changes have
Photo 2. Towns covered by rubble(Onagawa-cho, photo taken on April 4, 2011)

been made in earthquake resistant design and aseismic
reinforcement with the goals of preventing the loss of human

lives and limiting the extent of damage so that restoration can be accomplished within a short period of time,even when structures reflecting these new measures are damaged by enormous external forces. In otherwords, the goal is fail-safe design.
However, it is not an easy matter to establish specific civil engineering technologies and social systems for therealization of disaster mitigation. A variety of proposals have been put forward that call in very simplistic terms
for a general mobilization of "hardware" and "software" measures, but a great deal of hard work in researchand technological development will be required for this to become a reality. Since Japan experiences aparticularly large number of natural disasters, disaster mitigation efforts must include earthquakes, tsunamis,
volcanic eruptions, flooding due to heavy downpours, heavy snowfall, and nuclear accidents. To make"software" measures effective, it is important to provide evacuation drills and suitable disaster education led byexperts in schools and communities. It is also essential to develop the necessary "hardware" to secure the"software" measures, including the establishment of evacuation buildings and evacuation sites as well as
ensuring evacuation routes that lead to those places. Especially in coastal communities outside large cities, it
is desirable to establish "software" measures to cope with isolation and the needs of the elderly.

Let's take a look at the state of the energy policy debate in Japan, following the experience of the worst nuclear
power accident. A new administration was established with the lower house election in late 2012. The politicalparties have made various pledges such as eliminating the use of nuclear power or reducing the country'sdependence on nuclear power, but as of the time of this writing, it is still unclear what direction the government
will take. Considering the energy problems that Japan will face in the future, the development of renewableenergies is an urgent task. It is also important to pursue the redevelopment of dams in preparation for
unprecedented flooding caused by climate change due to global warming, as well as the restoration ofhydroelectric power as a clean source of energy.

Preparing for a massive Nankai trough earthquake
In March 2012, the Committee for Modeling a Nankai Trough Megaquake, established under the Central
Disaster Management Council of the Cabinet Office, issued new predictions concerning a massive earthquakethat is expected to occur along the Nankai Trough with an associated tsunami. Based on scientific researchand the lessons learned from the Great East Japan Earthquake 2011 and the massive tsunami that
accompanied it, the new prediction model indicates the maximum class of earthquake and tsunami that isanticipated, taking all possibilities into consideration. According to this model, an earthquake of magnitude 9.1
and seismic intensity 7 could strike 10 prefectures and 153 municipalities, causing a tsunami more than 20
meters in height that would threaten 23 municipalities. This is expected to be a massive disaster that will
surpass the Great East Japan Earthquake.
In a recent legal decision concerning earthquake predictions for the April 2009 L'Aquila Earthquake in central
Italy, seven persons, including earthquake scientists and a government official, were sentenced to six years inprison for negligence resulting in death on the grounds that the government's declaration of safety had theresult of magnifying the damage. It is not possible here to debate whether this decision was justified; however,
the issue that it brings into question is not the accuracy of earthquake prediction but the approach to providing
disaster information.
The Japanese government has issued predictions concerning a Nankai Trough Earthquake, and it should
continue to provide expert information, including the limits of prediction, in order to encourage the generalpublic to have a proper level of concern and make preparations on their own, as well as to enable themunicipalities in question to implement appropriate measures. There is concern that if figures such as atsunami height of 34 meters and seismic intensity of 7 are tossed around without the proper context, the effectmay be to actually discourage people from taking suitable actions for disaster prevention and developing
measures for disaster mitigation.
Meanwhile, there is concern that memories of the Great East Japan Earthquake will fade with the passing oftime. To prepare for a massive earthquake and tsunami along the Nankai Trough, it is necessary to compile athorough account, with an expanded scope ranging from the government's response to the experiences ofindividual disaster victims, in order to describe and analyze what happened in the Great East Japan
Earthquake, what lessons became clear, and what inadequacies were revealed. If this task is not completed, it
will not be possible to prepare properly for the next large-scale disaster.

The tasks set before us are many, including reconstruction after the Great East Japan Earthquake,
preparations for another massive earthquake that is expected to strike, development of infrastructure foradaptation to global warming, and steps to upgrade deteriorated infrastructure.
(This is an English translations from the Japanese version published in JSCE Journal, Vol. 98, No. 3, March2013)

What’s Happening

Nov 7-9：39th PICE National Convention (2013), (Davao, Philippines)
Nov 8-9：Symposium of 40th Year Celebration of Diplomatic Relationship Japan between Vietnam(Hanoi, Vietnam)
Nov 22：2013 CICHE Annual Meeting (Taipei, Taiwan)
Nov 28：Joint Seminar of PICE and JSCE-Philippines: Civil Engineering Responses to EnvironmentalIssues (UP-Diliman- National Center for Transportation Studies, Manila, Philippines)

Updates

The summary of feature articles in the JSCE Magazine is available on the JSCE website.
http://www.jsce-int.org/pub/magazine
Concrete Committee International Newsletter No. 34
http://www.jsce.or.jp/committee/concrete/e/newsletter/Newsletter.htm

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