INTERNATIONAL INSTITUTE OF SEISMOLOGY AND
EARTHQUAKE ENGINEERING (IISEE)REPORT OF STUDY TRIP(TOHOKU)
10-14 JULY 2011

PREPARED BY: MAZNI BINTI AZISMALAYSIASUBMISSION DATE: JULY 29, 2011

TSUNAMI DISASTER MITIGATIONINTRODUCTION
The world was shocked by the catastrophic earthquake and tsunamis that hit Japan on March 11, 2011at 14:46 JST (5:46 GMT). The Mw9.0 magnitude earthquake that sparked the tsunami and resulting
destruction of social infrastructure, housing and corporate facilities would cost between 16 and 25
trillion yen (Cabinet Office’s estimate) and 23,000 death and missing (F. Imamura, 2011). Tsunami
course participants had the opportunity to join this study trip to the Tohoku District from July 10,2011 until July 14, 2011. The purpose of this study trip is to look more closely at the effects of thetsunami and action taken to reduce the impact of the tsunami. We were escorted by four supervisors
and one coordinator.
1st Day, July 11, 2011 (Monday)
On the first day we had a lecture by Prof. Imamura at Disaster Control Research Center (DCRC),Tohoku University. Prof. Imamura is one of the famous tsunami experts in Japan. Buildings here werealso affected by the earthquake on March 11, 2011. Since we arrived earlier, we could review thesituation around and see the cracks and sediments around the building. Prof. Imamura briefly
described about seismic activities (main shock and aftershocks) of the March 2011 Tohoku
earthquake. Tsunamis caused by this earthquake happened continuously up to 2 days. Mutsu,Hachinohe, Miyako, Kamaishi, Ofunato, Ayukawa and Soma are areas heavily damaged. Prof.
Imamura also explained the tsunami attacks in Sendai area as well as planning, research in the future
and the lessons learned from this earthquake and tsunami.
We continued our study trip in the afternoon to several areas around Sendai accompanied by atsunami deposit expert, Dr. Sugawara. Dr. Sugawara also shared his research on the Jogan earthquake
and tsunami. The Jogan earthquake occurred on July 13, 869 at offshore of Northeast Japan produceda large-scale tsunami that the Low-Lying Damaged coastal zones of Northeast Japan (K. Minoura et.
al., 2001). With Dr. Sugawara we looked around Arahama village, Arahama beach and theNatorigawa river that were affected by the tsunami. He also took us to the area where he found Jogan
tsunami deposits. Figure 1 shows some photos that I captured at Arahama village and Arahama beach.

(a)

(b)
Figure 1(a): Mud layer top ofsand truly came from tsunami.
Figure 1(b): Sand from tsunamis
about 30cm thickness.

(c)

Figure 1(c): A small temple
survived from the tsunami
probably because of the Heliportand trees around the temple.

(d)Figure 1(d): Signage “Tsunami
Hazard zone” falls down by
tsunami.

(e)(f)

Figure 1(e): Breakwater at
Arahama beach not damaged bytsunami.
Figure 1(f): Tsunami sirens falldown.

Figure 1 (Photo taken by Mazni Azis)
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A study of Tsunami deposit is very important in order to evaluate source and history ofearthquakes and tsunamis such as recurrence earthquakes, magnitude and inundation area. Mega
thrust tsunami has recurrence with interval of 500-1000 years. Figure 2(d) shows the result of fieldobservation that we did with Dr. Sugawara using a hand auger equipment. The Jogan tsunami deposit
from the Jogan earthquake occurred more than 1000 years ago. Source Volcanic ash deposit is about
300km from our observation field. For me, research on tsunami deposit is very interesting and I wantto know more about this. In Malaysia research about this is very limited.

(d)

(a)

Mud(Peat)(b)
Volcanic ash(AD 915)

Figure 2(a): The photo showsthe effect of combination ofliquefaction phenomenonand scouring due to falling
flow (hydraulic jump) behindthe elevated roadway.
Figure 2(b): Thick mud fromtsunami.
Figure 2(c): Dr. Sugawara
shows how to observe Jogan
Tsunami deposit using a handauger.
Figure 2(d): The result fromthe field observation of theJogan tsunami.

Jogantsunami
deposit(AD 869)(c)
Handauger

Figure 2 (Photo taken by Mazni Azis)
At the Natorigawa river I asked a question to Dr. Sugawara about the different effect of the tsunami at
the left and the right sides of the river, because the right side seemed to be less damaged than the leftside. Dr. Sugawara said that it was probably because the river and the dike at the right side of the riveris higher compare to the left side (Figure 3 and Figure 4). In addition, he said that the right side wasalso suffered from the tsunami but it was only the first floor of building.

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Right side ofNatorigawa river

Right side ofNatorigawa river

Figure 3 (Photo taken by Mazni Azis)

Figure 4 (Photo taken by Mazni Azis)

2nd Day, July 12, 2011 (Tuesday)On the second day, we visited Matsushima and Onagawa. Damages of the two places were very
different. Matsushima was not affected so much compared to Onagawa. The tsunami height atMatsushima was about 1-3m and that at Onagawa was about 40m at a maximum and it caused heavydamage. First, we visited Matsushima which has been called one of the most representative places inJapan that can offer the view with many beautiful islands truly brings the splendid and exhilaratingtime in each season. The small islands help to reduce tsunami height at Matsushima (Figure 5(a)).
Although not heavily damaged, this area also experienced inundation and one of the evacuation areas
was also inundated.

(a)Small islands

Figure 5(a): Small islands
around Matsushima function as
natural “break water” which
can reduced tsunami wave.
Figure 5(b): Damage bytsunami at Matsushima.

(b)

(c)

theFigure 5(c): Signage “Tsunami
Evacuation” shows 400m to“Zuiganji Temple” which istsunami
evacuation
area.
Unfortunately this temple wasalso inundated by tsunami.

Figure 5 (Photo taken by
Mazni Azis)

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After visiting Matsushima, we moved to Onagawa through Ishinomaki. Ishinomaki is one of
the areas that were also badly affected by the Tohoku tsunami 2011. On the left and the right, we saw
clearly the buildings collapsed, houses damaged (Figure 6(b)), trees in changed colour to brownleaves as a result of sea water arrived up to there (Figure 6(c)). When we went through the area of thebeach connected to the sea, we were able to see the water level very close to the road at the time ofhigh tide (Figure 6(a)). It is because of the subsidence.

(a)

(b)

(c)

Figure 6 (Photo taken by Fatimah Zaharah Saleh)
Onagawa was heavily damaged and I saw many buildings collapsed and destroyed by the tsunami.
According to the witnesses, residing wave was also strong in this area. Many people did not want tolive here again because of the trauma of the tsunami. I asked Prof. Okazaki’s opinion about thetime needed to recover this area. He said it may take 2-3 years to be reinstated as it was very
terrible destruction.
Onagawa
Tsunami Memorial Park andOnagawa
TsunamiMemorial Museum will be built to mark the terrible tsunami disaster and to educate people about theimpact of the tsunami in this area. Four damaged buildings will remain as the Onagawa
Tsunami Memorial Park. Onagawa Tsunami Memorial Museum proposed by Prof. Shuto as a signof place near to tsunami run-up. For myself, it was very surprising to see the situation in Onagawa in
which buildings were destroyed, turned over and some of them moved up to 70m by tsunami wave
although they were constructed using the RC structure.

Figure 7: Heavily damaged buildings atOnagawa city (Photo taken by Mazni Azis)

Figure 8: Building moved about 70m(Photo taken by Mazni Azis)

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Water mark fromtsunami about 8.0m

Figure 9: Measurement of tsunami terrace(Photo taken by Mazni Azis)

Figure 10: Because of subsidence, sea levelis only about 35cm from the road.
(Photo taken by Mazni Azis)

3rd Day, July 13, 2011 (Wednesday)
We headed to Rikuzen-Takata, Ofunato and Kamaishi (Iwate Prefecture) accompanied by Mr.
Moritsugu KANEKO who explained the effect of the tsunami that occurred in Iwate Prefecture.
Along the way in Rikuzen-Takata, the process of cleaning was underway. We stopped at an area tosee the destruction there. I found that all debris is collected by type, such as cars, concrete, iron, woodand I asked Mr.Kaneko about the debris management. According to Mr. Kaneko, after the disasterthere were some stages in its management. In the first stage, a local government hires a private
contractor to clean everything. He added that what we were seeing was the second stage in whichcollection and transporting of debris underway. Funds for hiring a private contractor are available
from the central government. I also asked about the strength of the temporary houses as there wasvery active seismicity and many aftershocks of magnitude greater than Mw6 occurred. Mr. Kaneko
said he did not know much about it, but until now there was no incident of a temporary housecollapsed due to the earthquakes. The problem there was a leaking since it was built in a short time.

5Figure 11: Damaged flood gate caused by tsunami at Rikuzen-Takata. (Photo taken by Fatimah Zaharah )Figure 12: All debris is collected by type. (Photo taken by Mazni Azis)
Our next destination was Ofunato city. Ofunato city is a coastal city and suffered fromfrequent earthquakes of various scales for example the 1896 Meiji-Sanriku earthquake, the 1933
Showa-Sanriku earthquake and the 1960 Chile earthquake. In Ofonato, our arrival was greeted by Mr.
Taiji Iwaki. He was a chairman of a nonprofits organization (NPO) called Yume-net Ofunato. He told
Ofunato had many tsunami countermeasures such as break waters, siren system, evacuation buildings
and a lot of evacuation signage. They also periodically conducted a drill and just did an evacuation
drill before the tsunami attack. Tsunamis occurred this time was two times more excruciating than thetsunami that hit the Ofunato city in 1960 (the Chile earthquake).
Railway station was also heavily damaged. Mr. Taiji Iwaki told us that the area might require
10 or more years to completely recover as well as a very high expense. As of July 08, 2011, 325
deaths, 124 people missing, 3,629 houses destroyed or partially destroyed is reported in this area
(http://www.city.ofunato.iwate.jp/www/contents/1303015440244/index.html). At Ofunato, I asked thetsunami siren system was working or not during the incident. Mr. Taiji Iwaki told the siren system
was working well and tsunami warning was announced less than 0.5m when it was first issued. People
did not evacuate immediately and in some cases people went close to the beach to see the6tsunami. When warnings were increased streets were already jammed because the traffic light did notfunction.
A lesson from this tsunami is to make traffic lights with alternative energy such as solar
energy because if the tsunami happens and power supply stops, traffic light cannot function and makea traffic jam. Another lesson is to establish an organization to conduct an emergency shelter
community because they did not have an emergency shelter community. In this tsunami, local people
conducted the emergency teams after three-day tsunami occurred. Other than that, they want people toevacuate first without thinking about their family because the tsunami comes very fast and some ofthem do not have ability to move very fast like elderly people.

Figure 13: Damaged railway. Thisis very important transport in
Ofunato city.
(Photo taken by Mazni Azis)

Figure 12: This pair of before-and-after photos shows theremoval of tsunami destruction and debris covering the road in
Ofunato city, Iwate prefecture on March 14, 2011, three-daysafter the tsunami disaster and after the road was cleaned ofdebris, on April 15, 2011. (Toshifumi Kitamura/AFP/GettyImages)
http://www.theatlantic.com/infocus/2011/04/japanearthquake-the-long-road-to-recovery/100047/#img24
We proceeded our journey to Kamaishi port. Kamaishi is a historic city located on the Sanriku
coast of Iwate Prefecture, Japan. It is famous in modern times for its steel production and mostrecently for its promotion of eco-tourism. Fishing and shellfish production are also importanteconomic activities. Kamaishi was heavily damaged by the 2011 Tohoku earthquake andtsunami. Our arrival was greeted by Mr. Nagao and Mr. Yamada at the temporary office because theport office was destroyed by tsunami. Mr. Nagao presented us about a report of the damage atKamaishi port and damage of Kamaishi break water. Inundation height in and around Kamaishi port
was about 8.1m-11.7m inside the bay while 12.5m-18.3m outside the bay. Many wooden houses
drifted away with the tsunami while Reinforced Concrete (RC) buildings were damaged but notcollapsed. There was much debris swept into the sea where they needed to carry debris to the groundso that the Kamaishi port can be used. Kamaishi port started temporary operations on March 17, 2011a week after the 2011Tohoku earthquake and tsunami.
7We got the opportunity to board a boat to visit Kamaishi break water that was damaged by thetsunami. The Kamaishi break water, 1.950m (6.400ft) long and 63m (207ft) in depth, was completed
in March 2009 after construction work started in 1978 with a cost of $1.5 billion. It was once
recognized by the Guinness World Records as the world's deepest Breakwater.
Http://community.guinnessworldrecords.com/_DeepestBreakwater/BLOG/2699333/7691.html). Mr.
Nagao explained how its constructions worked and it was very interesting for me. We were allinterested to know about break water’s plan in the future. Mr. Nagao told that at the moment they did
not plan to build it back but would probably remove it if the fishermen asked them to do so. Although
there are many stories about the failure to break water in the tsunami countermeasure, according to theresult from the tsunami simulations conducted by Port and Airport Research Institute (PARI), thebreak water is able to reduce tsunami run-up to two times. In the result from the simulations, tsunami
run-up is about 20.2m if there is no break water while in observation tsunami run-up is 10.0m. Seawall is also found to delay the tsunami waves for six minutes.

(a)

(b)

Figure 14(a): Temporary
Kamaishi Port Office.
Figure 14(b): Damaged at
Kamaishi Port.

(c)

Figure 14(c), Figure 14(d)Figure 14(e): Damaged ofsome part at Kamaishi breakwater.

(d)Figure 14(f): Lighthouse at
Kamaishi Break water tilt anddamaged caused by tsunami.

(e)

(f)

Figure 14 (Photo taken by Fatimah Zaharah Saleh)8Figure 15: Tsunami Course Participants with Supervisor, Coordinator and Mr. Nagao andMr. Yamada (Kamaishi Port staff) at Kamaishi Break Water. (Photo source: Fujii Sensei)

CONCLUSION
Japan is one of
the well-prepared countries in theworld to deal with a threat of tsunami. They
have good tsunami countermeasures suchas sea wall,
break water, dike, controlling forest,
tsunami warning, evacuation building, education and awareness about the past tsunami monument.
The tsunami that occurred on March 11, 2011 was already predicted but seismologist and geologist
did not expect its magnitude up to Mw9.0. This caused destructionsof break waters,
sea walls and evacuation buildings. Many people died because evacuations buildings were also
destroyed and washed away by the tsunami. In my opinion, when it comes to natural disaster, it ishard to predict and what can be done is to reduce the consequences. Looking at
the effects of tsunami impact on the areas that we visit, I am now completely aware of
the strong tsunami wave as it can cause damage to a few kilometers from the beach. Awareness ofthe disaster should also be kept by the community because we quickly forget as human. For me, inpreparing tsunami countermeasures, make a wide area of forest is the best solution for reducing theeffect of the tsunami and that it is environmentally friendly. I'm very impressed by
the Japanese government in disaster management. Most of the affected areas continue to be wellmaintained and have theirownplanning. Hopefully, theJapanese continues
toprosper and stay strong in the face of this disaster.
REFERENCES
F.Imamura, 2011, Tsunami Disaster and Impact due to the 2011 Tohoku Earthquake, IISEE Lecture
Note 2010-2011.
K.Minoura, F.Imamura, D.Sugawara, Y.Kono, T.Iwashita, 2001, The 869 Jogan tsunami deposit andrecurrence interval of large-scale tsunami on the Pacific coast of northeast Japan, Journal of Natural
Disaster Science, Volume 23, Number 2, pp83-88.
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