--Please tell us about the contents of your research being conducted in
Disaster Control Research Center (Tsunami Engineering).
||This research center is the only institution in the world where Tsunami
is studied with the engineered approach. Based on the principle of provision
and control of the disaster, we perform the field work in both Japan and
abroad, develop advanced numerical prediction system for Tsunami, and support
Tsunami disaster provisions as our main research activities.
The tsunami analysis technology of this research center is being transferred
internationally especially to countries where Tsunami damage may occur
in the future. TIME(Tsunami Inundation Modeling Exchange) project is set
as a core of this transfer. Tsunami analysis code developed by this laboratory
has been transfered to more than 24 countries, 48 institutions, and are
being used to reduce the the damage of Tsunami disaster.
|Prof. Fumihiko Imamura, Disaster control center, Graduate School of Engineering,
||Building of the research center
--When did you decide to study the Tsunami disaster prevention ?
||I would never forget it. On May 26, 1983, the Middle Japan Sea Earthquake
occured off the coast of Akita prefecture.That was how I started the study
of Tsunami disaster prevention. I was a student of the departement of civil
engineering in Tohoku University at the time, and had surveyed the damage
of earthquake tsunami as a member of the investigation team for two weeks
carrying survey equipments.
Around 100 people in Oga city and Noshiro city, which are on the coast
of Sea of Japan, had died because of this earthquake. The numbers included
tens of elementary school students who were visiting the coast. The damages
done by Tsunami to these areas were shot by home video camera, and a number
of shocking footages were broadcasted on TV.
I didn't have the knowledge of sea having grown up in Yamashi prefecture
called "Area without sea". Therefore, I was shocked coming
in contact with the damage of Tsunami, and since then I decided to study
tsunami and to start researching on Tsunami disaster prevention.
--The code for Tsunami analysis program developed by the research center
is evaluated as having the latest function in the world, and the code is
used in the Tsunami analysis support service of FORUM8 by linking with
the real-time virtual reality system "UC-win/Road". Could you
explain what this program is.
||When the earthquake centered in the ocean bed occurs, the ground of sea
bed will upthrust and sink. The deformation of the sea surface by this
ground deformation is the mechanism of the generation of tsunami.
Tsunami moves in a wide area just as the tsunami occurred off the coast
of Chile, other side of the world, causes damage to Japan after traveling
through the Pacific Ocean. Sometimes, it can travel 18,000 Km from the
Southern Hemisphere to Northern Hemisphere. One of the characteristic of
Tsunami is its speed, which is several hundred kilometers per hour.
The Tsunami analysis code of the reseach center is developed to analyze
the tsunami moving at a very high-speed in real-time. The calculus of finite
differences of shallow-water equation was used for it. As for the input
condition, the following elements are required : the information of the
hypocenter including magnitude, depth, and position, the terrain data including
the sea bed (elevation and position).
As the earth rotates while tsunami moves within such a wide range, we are
required to consider the effect of its rotation for the analysis of wave
shape of tsunami, its energy, and the direction it is moving. Hence, tsunami
analysis code considers "Coriolis force" representing the effect
of self rotation. In addition, the code considers a theory of "wavenumber
dispersion", which is usually not known among general public, to perform
a more accurate estimation. We were finally able to use the wavenumber
dispersion by taking advantage of the numerical error which are normally
--They are saying damage done by tsunami that was triggered by Great East
Japan Earthquake on March of 2011 was beyond expectations.Professor Imamura,
could please you give us your thoughts on this?
||Academic record of tsunami damage only goes back as far as 100 years ago,
however, we can see that a major tsunami has occurred within a much longer
period such as 500 or 1000 years when we look at historical documents.
In Imamura laboratory, we are doing a survey by boring the grounds in inland
areas within Japan and the grounds in inland areas outside Japan and studying
and the distribution of stratum called "Tsunami sediments", which
are sea sands and sea shells that had been carried inland by tsunami. By
referring to historical document from the era when this stratum of tsunami
sediment was formed, we can estimate the specific year the tsunami had
occurred as well as the damage it had made.
Based on this survey, we were able to find out that Jougan tsunami that
attacked Sendai plains in Miyagi prefecture approximately 1100 years ago,
which is 869 A.D. (11th year of Jougan era), reached a point approximately
5 kilometers inland.
It has been confirmed that in the north eastern area of Japan, tsunami
sediments had been carried as far as 3 to 4 km inland from Pacific coast,
therefore, we can prove that tsunami has reached deep into the interior
in the past as it did this time around.
Results of survey based on ground survey to look for tsunami sediments
and survey based on historical documents can only be seen as "points",
but by integrating these results to tsunami simulation, we will be able
to find out the mechanism of tsunami formation and estimate the velocity
and destructive power of tsunami that has hit the shore as well as the
distribution of inundated area.
|Tsunami sediments carried by Jougan tsunami that hit Sendai Plains (Documents
written by Professor Fumihiko Imamura).
|Transmission of Chile Tsunami 2011(Documents provided by Mr.Fumihiko Imamura)
--Was the result of research helpful in this Great East Japan earthquake?
||There are many people who may hear tsunami once in 1000 years and do not
understand.Then, the simulation result of tsunami is made into an animation
and visualize the situation of tsunami, and then it makes it easier for
ordinary people to understand.
Last October, in Wakabayashi area in Sendai which suffered serious damage
from this tsunami, the lecture meeting of tsunami disaster prevention was
held using this simulation animation. About 300 people, such as local residents,
the police, and the Self-Defense Force participated. People who saw whether
what would happen if tsunami attacks the present town by simulation recognized
the necessity of escaping to high location and that the eastern Sendai
road is one of a few high area in Wakabayashi area. I heared that in this
time's earthquake, there were about 200 people who were heading to the
eastern Sendai road and was saved. Although there is no telling how many
people among these had participated in the lecture meeting, I believe that
it was useful to reduce the damage of tsunami.
--Evacuation simulation is also being researched in Professor Imamura's
laboratory. FORUM8 distributes EXODUS, evacuation simulation software.
How do you think you can utilize tsunami evacuation analysis?
||We are doing a research on evacuation simulation that can predict human
behavior at the time when tsunami occurs, as a research in area of human
behavior. For evacuation simulator at a time of fire, we analyze how people
react and evacuate after seeing fire or smoke; however, as for tsunami,
when you see it coming it's too late to evacuate. Therefore, we analyze
the behavior of people who hears tsunami warnings.
Memory and experience of a person will greatly affect when and where he/she
will evacuate. For example, a person's perception of distance to the place
of evacuation and the time it takes for him/her to get there after being
instructed to "Evacuate to the designated area of evacuation on the
mountain" will depend on his/her memory or experience. Those who know
their way to the area of evacuation very well will have a feeling that
place is very near, whereas, those who don't know very well on how to get
there will feel that the place is very far away. We are researching on
people's behavior during a disaster using a method of cognitive psychology.
As compared to a map that is measured and created quantitatively, a map
inside a person's brain has some distortion in terms of distance and direction.
A simple method of finding the distortion in that kind of map is called
"Cognitive map". In this method, we ask a person to draw a map
illustrating a route from a particular point to the place of evacuation.
When we ask several people to do this, we can find out that the direction
and distance drawn by each person is different.
In other words, time it takes for people to start evacuating and the route
they take after hearing tsunami warning will vary depending on each of
their memory and experience. There can be cases where the difference in
this time can separate those that will survive from those that won't. By
inputting this criteria of judgment (based on time it takes a person to
start evacuating) to EXODUS, we think that analysis of tsunami evacuation
can be realized.
--Q. What did Mr. Imamura learn and find problem from the Great East Japan
||Due to Tsunami in this time, everything was flown out. The size of flowing
items and the contents was far exceeding over our prediction. The big example
is vehicle. Previously, the flowing items were just like vessel, however,
in this Tsunami, the mass number of the vehicles was flown out and hit
into buildings and the glasses were broken as the disaster damage. Unusual
example that we never experienced before is the defense forest in coastal
area was flown out and carried into inside of the land as rubble.
In addition, this earthquake caused multi-disaster which caused earthquake
shake, Tsunami and land liquefaction simultaneously. Depending on kind
of building, the design by considering external force had been done. However,
the design has never considered only one factor, not multi factor.
Thus, Tsunami hit buildings whose base was already weaken by liquefaction
or earthquake shake, and then some of them were collapsed and some Tsunami
defense walls were destroyed.
|Damage condition in Onagawa town
Concrete building collapsed by Tsunami(Photo provided by Mr. Fumihiko Imamura)
||Damage condition in Kisennuma city
Ship coming in the urban area(Photo provided by Mr. Fumihiko Imamura)
--Please tell me about the direction of your future research, etc.
||For this Great East Japan earthquake, although the specialist of an earthquake
or tsunami had provided 100% of their knowledge, various "unexpected"
things happened. Accordingly, it is difficult handle by the specialist
in only one field, and I think it required for specialists, such as geology,
a history of the earth, history, to cooperate to treat it.
The Imamura laboratory also join the development of the next-generation
supercomputer "KEI" under development as the member. Forum 8
is planning to offer Supercomputer Cloud Service using KEI. In Imamura
laboratory, in collaboration with Forum 8 positively, we would like to
work on the publicity of tsunami analysis code through Supercomputer Cloud
Service and treatment to the parallel processing adjusted to the supercomputer
Moreover, since tsunami is transmitted into the sea and brings damage to
each country, international cooperation is indispensable to tsunami disaster
Then, I also wish to perform the activity about development and transfer
of international tsunami disaster prevention technology continuously.
--Finally, what is Professor Imamura's present dream?
||That is restoration of disaster area suffered by Great East Japan earthquake
--Thank you very much.
(Coverage/Writing : Ryuta Ieiri)
He was born in Yamanashi in 1961. The professor of the Tohoku University
graduate school engineering graduate course attached disaster control research
The fluid wave motion numerical computation of disaster science or tsunami,
history seismic wave trace investigation in and outside the country, an
evacuation simulation, the cognitive psychology that analyzes the memory
at the time of refuge and human action, etc. are tackling the research
in connection with tsunami disaster prevention. International tsunami disaster
prevention technical development, movement, fractal geometry, etc. are
engaged also in research of a snow-flowing gutter (2 phase fluid) etc.
As the forum 8's adviser, he performs technical guidance to a tsunami analysis
support service etc. and cooperation.
Personal history of Mr. Fumihiko Imamura
||1961 Born in Yamanashi
1984 Graduated from Tohoku University faculty-of-technology civil engineering
1986 Tohoku University graduate school engineering graduate course doctor
First half completion Civil engineering speciality
1989 Tohoku University graduate school engineering graduate course doctor
Second-half completion Civil engineering speciality
||1989 Department assistant of the Tohoku University faculty-of-technology
1991 Tohoku University faculty-of-technology disaster control research
1992 Tohoku University faculty-of-technology disaster control research
Center assistant lecturer
1993 The assistant professor of the Asia College of Engineering institute
1997 Kyoto University disaster prevention research institute huge disaster
The assistant professor of a research center associate member(Interlocking¤3
1998 The Tohoku University graduate school engineering graduate course
attachment The assistant professor of a disaster control research center
2000 Oceanics technical research center Visiting researcher
2000 Tohoku University graduate school engineering graduate course The
professor of an attached disaster control research center
|[Subject of research]
-Fluid wave motion numerical computation (Tsunami, etc. are objected.)
-International tsunami disaster prevention technical development and a
-History seismic wave trace investigation (In and outside the country )
-Geographical feature -Form(Fractal geometry etc. )
-Snow- flowing gutter(2- phase fluid)
-Evacuation simulation -Cognitive psychology