INTERNATIONAL INSTITUTE OF SEISMOLOGY AND
EARTHQUAKE ENGINEERING (IISEE)REPORT OF STUDY TRIP(TOHOKU)
14 – 18 November 2011

Prepared by: Dwi Hartanto
T course(Indonesia)0DAY 1: NOVEMBER 14, 2011
On March 11, 2011, a giant earthquake struck in Japan followed by tsunami. The earthquake
and tsunami caused many casualties in Japan, approximately 20,000 people died or missing. The
purpose of the study trip in Tohoku-Sanriku is to know the current conditions of Miyagi Prefecture
and Iwate Prefecture after hit by the tsunami, to learn real condition when tsunami struck in Japan,
and to learn how tsunami warning system worked when tsunami came to Miyagi Prefecture andIwate Prefecture. First, we visited Tohuku University where we saw the Faculty of Civil
Engginering building damaged at the second floor.

Figure 1. Damage in Faculty of Civil Engginering.

Next, we visited Arahama beach which is located in Miyagi Prefecture, Tohuku, withcoordinate: 38.042 N, 140.905 E. Dr. Daisuke Sugawara(Disaster Control Research Center(DCRC)), specialist in geology and paleotsunami, guided us to explain tsunami hit on Arahama
beach.
In Arahama we found deposit tsunami from the Jogan Earthquake in 869, the sediment can betraced up 4 km from the coastline.
Volcanic ash(915)

Layer deposit
jogan
earthquake(869)

Figure 2. Layer deposit from Jogan
Earthquake with thickness 3 cm.

Layer deposit
jogan
earthquake(869)

Figure 3. Layer deposit from Jogan
Earthquake using drill hand method (auger).

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The sediment deposit from Jogan tsunami with thicknesses approximately 3 cm, upper the layer it’s
volcanic ash (915), below the layer we found another deposit from the previous tsunami. In figure
3 we find the similar deposit from the jogan tsunami.The sample data were taken at 2.7 km from thecoastline by using a drill hand (auger). I asked Dr.Sugawara how to estimate the time the Jogan
earthquake occured. He said, distribution of sample data and dating molusca or any sediment on
Jogan sediment layer we can estimate time of occurence the tsunami, of course the result maybe any
residual error, to minimilize the error we can compare from the historical records.
In Arahama approximately 200 – 300 people died due to the tsunami on march 2011, wefound an elementary school building still standing. Only 1 student died in the elementary school.
The sirens we found were broken near the coastline.

Figure 4. Elementary school building
still standing in Arahama beach.

Figure 5. Siren has broken, nearcoastline.

Subsidence in Arahama was 30 cm. After the tsunami on March 11, 2011, local governments
now prohibit to construct a building or a house near the beach in Arahama.

2DAY 2: NOVEMBER 15, 2011The first place we visited was Matsushima in Miyagi prefecture which is one of the 3 mostbeautiful places in Japan. The other two places are Amanohashidate in Kyoto prefecture andItsukushima in Hiroshima prefecture. Matsushima consists of many tiny islands (shima) of some
260 and it is covered with pines (matsu). The size of the tsunami hit the coastline in Matsushima
was not too big, because Matsushima was sorrounded by many islands. Tsunami hight inMatsushima was about 2-3 m with inudation around 250 m from the coastline or near the ZuiganjiTemple (38.372178 N, 141.059597 E). The victims of the tsunami evacuated to the Zuiganji temple.

Figure 1. Matsushima sorrounded bymany islands.

Figure 2. Some little damaged but still visible on thebeach of Matsushima.

The second place we visited was Ishinomaki ( 38.42 N, 141.3 E) known as the large fish
market. We found a manga museum and a replica of the statue of liberty there (Figure 3). Tsunami
hight in Ishinomaki was about 10 m, and the total number of confirmed dead were 3000 inIshinomaki. Subsidence in Ishinomaki was about 0.78 m. Okawa Elementary school in Ishinomaki
was completely destroyed and 75 of 108 students and 10 of 13 teachers and staff were killed. The
teachers and students evacuating from the school
were killed when tsunami crossing a nearby river
bridge. One teacher and 3 students were saved
since they went up to the hill. According to thestory of a teacher in the classroom, they did not
immediately evacuate. Since a tsunami warning
said that tsunami hight would be only 3 m, theteacher still stayed in the school. After she knewthat the tsunami was more than 3 m, theyevacuated by going up the hill. From here welearn the lesson that when there is a tsunami
warning, we should evaquate quickly and wemust know whether the area around us is safe andevacuation is needed or not.
Figure 3. Replica of the statue of liberty
still standing after hit by tsunami.
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The last place we visited was Onagawa (38.44 N, 141.45 E). Tsunami hight in Onagawa wasapproximately 20 m with inudation about 1 km. Over 1,000 people died or missing in Onagawa.
Most people evacuated to Onagawa Hospital (Figure 5).

Figure 4. Situation at Onagawa Town
November 15, 2011.

Figure 5. Onagawa hospital is used forevacuation building.

Near Onagawa, we found a region far from the coast line at which the tsunami reached.
Tsunami reached this place due to the overflow of the river (Figure 6). Inudation of tsunami wasaffected by topography of the region. In this region we saw a municipal house which will be used as
the Onagawa Tsunami Memorial Museum (Figure 7).

Figure 6. Tsunami follows the flow of the river.

Figure 7. Municipal house.

4DAY 3: NOVEMBER 16, 2011
Minami Sanriku (38.68 N, 141.45 E) is a town with large fish market with population about
18.000. Mr. Kazuma Goto, one of the survivors of the tsunami, gave us an explaination about thetime the tsunami hit the Minami Sanriku. After the Chili tsunami hit Japan, Minami Sanriku built
the break water (sea wall) with hight around 5 m. Now the break water was broken after the tsunami
on March 11, 2011. The shake of Earthquake on March 11, 2011 was about 6 minute with intensity
6 (jma intensity). I asked Mr. Kazuma Goto how the tsunami hit Minami Sanriku 9 times in March
11, 2011. He said, like a stone dropped into water, the first wave was large, followed by otherwaves. He gave us advice that “we should make friends with nature and neighbors around us. Now
the town of Minami Sanriku almost dissapear with 2,188 people missing or died”.

Figure 1. Crisis Management Department.

Figure 2. Elemantary school in Minami Sanriku
stiil standing, all students were safe.

One of the officials in Crisis Management department died as a hero. According to theexplanation, she stayed in the building (Figure 1.) to give warning to people, and when tsunami
came, she did not have enough time to evacuate. One example to show how important it is for us tomake friends with nature is the case of an elementary school in Minami Sanriku. All students in theelementary school were safe, the teacher quickly evacuated them to the safe place. Before theearthquake of March 11, 2011, they had experince of the earthquake on March 9, 2011 (38.440°N,142.840°E, 168 km E of Sendai, Honshu, Japan. Mag 7.3 (USGS)) after the earthquake they
discussed how they evacuated if a big earthquake occur in the future.
In Kesen’numa (38.88 N, 141.58 E) the break water (sea wall) was broken, the subsidence in
Kesen’numa was about 0.74 m, we found the big ship stranded about 100 m from the coastline.
Rikuzen-Takata (39.02 N, 141.38 E) is a city in Iwate prefecture. One famous place in
Rikuzen-Takata is Takata-Matsubara with a green pine forest of about 70,000 trees which are over
300 years old. Now after the earthquake on March 11, 2011 only one pine tree is still standing. Thepine tree is a symbol of hope for people who lost everything after the earthquake. Subsidence inRikuzen-Takata was about 0.84 m, a list of all subsidences in Japan is shown in Table 1 (original
source: http://www.gsi.go.jp/sokuchikijun/sokuchikijun40003.html).

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Figure 3. Break water in Kesen’numa was broken.

Figure 4. Pine tree symbol of hope.

Table 1. Subsidence around Japan.
NoCitySubsidence (meter)

1234
5678910111213

Miyako, IwateYamada, Iwate
Otsuchi, Iwate
Kamaishi, Iwate
Ofunato, Iwate
Rikuzentakata, Iwate
Kesennuma, Miyagi
Minamisanriku, Miyagi
Oshika Peninsula, Miyagi
Ishinomaki, Miyagi
Higashimatsushima, Miyagi
Iwanuma, Miyagi
Soma, Fukushima

0.5 m
0.53 m0.35 m0.66 m0.73 m
0.84 m0.74 m0.69 m1.2 m
0.78 m0.43 m0.47 m0.29 mThe last place we visited was Ofunato (39.07 N, 141.72 E). Ofunato is a coastal city in Iwate
Prefecture with population approximately 42,000. Tsunami on March 11, 2011 caused heavy
damageinOfunato,
tsunami hight was around23.5 m with inudation
about 3 km. Subsidence in
Ofunato was about 0.73 m.
In Ofunato, we found oldmonument for Showasanriku tsunami hit anddisappeared by tsunami on
March 11, 2011, butanother old monument for
Meiji sanriku tsunami still
Figure 5. Old monument of Showa
Figure 6. Old Monument ofstanding.
tsunami disappear.

Meiji tsunami still standing.

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DAY 4: NOVEMBER 17, 2011
On the Day 4, the first place we visited was Kamaishi (39.27 N, 141.88 E). The break water inKamaishi was the deepest in the world with 1,950 m long and 63 m in depth. After the earthquake
on March 11, 2011 the break water was broken, but the break water succeeded in reducing thepower of the tsunami. Mr Kawai from MLIT (Ministry of land, Infrastructure, Transport, andTourism) explained the break water can reduce the run up until 50% and make additional time forevacuation about 6 minutes. I asked Mr Kawai if the break water will be rebuilt in the future. Hesaid, yes, and the target to rebuild the break water is 5 year. The target is very short, bacause thecommunity need mental readiness to prepare tsunami in the future.

Figure 1. Break water on Kamaishi port was
broken after the earthquake on March 11,
2011.

Figure 2. Kamaishi East Junior High School
after the earthquake March 11, 2011.

Approximately 2,000 people died or missing inKamaishi port. Subsidence in Kamaishi was about 0.66 m.
In Kamaishi about 2,900 students as well as Kamaishi EastJunior High School survived. The teachers and students very
quickly responded and evacuated to the higher place. Thestudents had a learning and participated in tsunami drills
guided by the disaster prevention education program tolearn how to escape from an earthquake and tsunami.
The next place we visited was Aneyoshi, Miyako. InAneyoshi we visited a memorial statue of the great tsunami.
The statue told us “Remember the calamity of the greattsunamis. Do not build any houses below this point”.
Tsunami on March 11, 2011 did not reach at this point (thememorial statue) but run up in this place was highest about
40 m.

Figure 3. Memorial statue of greattsunami.

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Figure 4. Run up at Aneyoshi about 40 m.

Then, we visited Miyako (39.64 N, 141.96 E). Tsunami hight on Miyako city was about 2–3
m, the sea wall reduced the power of tsunami. Figure 5 shows the situation of Miyako city right
now which was cleaned very quickly.

Figure 5. Situation at Miyako City November 17, 2011.

The final destination we visited was Jodogahama (beach of heaven), a beautiful beach inJapan. We saw the monuments of Showa tsunami and Chili tsunami. The damage by the Tsunami
on March 11, 2011 was not so much in Jodogohama.

8DAY 5: NOVEMBER 18, 2011
Taro (39.734 N, 141.968 E) is a town in Miyako city in Iwate prefecture. Taro had breakwater and 4 seawalls with hight of 10 m from sealevel, but after the earthquake and tsunami on
March 11, 2011, break water was broken and the east part of the seawall was broken as well
We can compare the situation of Taro town before March 2011 (Figure 1) and after March2011 (Figure 2).

East partof seawall

Figure 1. Taro before March 2011
(picture from Dr. Yushiro Fujii).

Figure 2. Situation of Taro on November 18,
2011 .

The east part of taro town was totaly broken, of course because the seawall in east part broken,
compare than the west part. West part of Taro town we found tsunami high about 4.5 m, and ineast part we found tsunami high about 12 m. Actually in Taro town the highest tsunami is around 20
m. Subsidence in Taro (Miyako area) is about 0.5 m.

Water mark oftsunami high5m

Figure 3. Tsunami hight in west part of Tarotown, 4.5 m.

Tsunami high upto Third floor

5m

Figure 4. Tsunami hight in east part of Tarotown (Taro Hotel), 12 m.
9In Taro town we visited the sign of Meiji Sanriku Tsunami (1896) about 15 m, and Showa
Sanriku Tsunami (1933) about 10 m. The tsunami on March 11, 2011 was bigger than Meiji andShowa by about 20 m. The final place of Tohuku-Sanriku trip we visited was Koborinai Fishing
Port (Miyako), in this place tsunami hight was about 37.9 m (Tsuji et al., 2011).
From this trip, we concluded that condition of the cities in Miyagi Prefecture and IwatePrefecture now are better than March 11, 2011. The streets, electricity and water networks wererepaired. In real condition if tsunami will hit around us we must know the safe area for evacuation
and we must quickly evacuate if we see or hear tsunami warning. Tsunami early warning system
has been running well, warning message, sirens, evacuation routes, break water, sea wall etc. haveworked well to reduce casualties. In the future we should be able to improve the quality of tsunami
early warning system.

Meiji (1896) 15 mShowa (1933) 10 m

Roadblock broken
struck by tsunami

5m
Figure 5. Tsunami sign on the stone.

Figure 6. Koborinai Fishing Port, tsunami run up
in this place about 37.9 m.

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