INTERNATIONAL INSTITUTE OF SEISMOLOGY AND
EARTHQUAKE ENGINEERING (IISEE)REPORT OF STUDY TRIP
(Niigata & Miyagi Prefectures)
14 – 17 November 2011
Prepared by: Biana Rahayu Wulandari
S course(Indonesia)

1. INTRODUCTION

On 14 November and 15 November 2011, we visited Nagaoka city and Yamakoshi village in Niigata
prefecture to observe the damages which were affacted by unpredictable Chuetsu earthquake onOctober 2004 and observe how the village survived and recovered from this earthquake. We alsoobserved Ojiya’s hospital in Ojiya city which survive from the earthquake. Dr. T. Yokoi and Dr. Isharasupervised us, and also Mr. Ajima, our coordinator accompanied us during this fieldtrip
On 16 November – 17 November 2011, we visited Onagawa town and Wakabayashi ward in Sendai
city, Miyagi prefecture which were affected by the great Tohoku earthquake and tsunami on March2011 to observe the damages, run up and inundation of tsunami March 2011. We also visited Aoba
Ward to observe the ground failure caused by the earthquake and Tohoku university. During ourfieldtrip in sendai, Dr.T. Hara joined and supervised us.
The Chuetsu Earthquake
At 17.56 JST (Japan Standard Time) on Saturday, October 23, 2004, an earthquake with measuring
magnitude 6.8 occured 13 km beneath the chuetsu region in Niigata prefecture. As shown in fig 1, anintensity level of 7 was recorded in Kawaguchi Town, and theintensity level of 6+ was recorded in Ojiya city, Oguni Town
and Yamakoshi village. In Nagaoka city, the intensity levelwas6- . Strong afterschock recorded on the same day,measuring magnitude 6.0 at 18.11 and 6.5 at 18.34 JST with
the intensity level was 6+. The Geographical Survey Institute(GSI) of the Government of Japan published preliminary
estimates that a fault having a length of 22 km and a width of
17 km moved approximately 1.4 m.
Fig 1. The shakemap of Chuetsu earthquake (source: JMA)
The Niigata prefecture area effected by the earthquake that we visit were :The Nagaoka Earthquake Disaster Archieve center at Nagaoka city
Nagaoka city is located in the center of Niigata prefecture and the surrounding Chuetsu region.
The intensity level of 2004’s Chuetsu earthquake in this area was 6-. The Nagaoka Earthquake DisasterArchieve Center (fig. 2) act as core of 7 memorial facilities established to apply the memories, records
and lessons from disasters to the safety and security in the futue. Here, we learned about the Chuetsu
earthquake while holding an ipad (fig. 3). By pointing ipad’s camera on Niigata prefecture map thatlies on the floor we can get the damaged information of the areas affected by Chuensu earthqueake (fig.
4). Mr. Higushi from Nagaoka Earthquake Disaster Center gave guidance and explaination during ourvisit here.

Fig 2 The Nagaoka Earthquake Disaster Archieve centerFig 3. Learn about Chuetsu earthquake

Fig 4. The damaged information provided on ipad

while holding an ipad
Ojiya Hospital at Ojiya CityIn Ojiya city, the level of intensity 6+, the damage was mostly to the infrastructure of the city, thewaterworks, sewage, telephone poles and roads. Only the very old and weak structural houses in Ojiyacollapsed. The average house was not damaged structurally, only the items inside were damaged.
However because of lack of running water and continuing aftershocks, all homes in Ojiya city wereevacuated and the town people were living in civic centers, town halls or in tents in parking lots, parks,and even camped out in greenhouses in the country or slept in the car. The greenhouses were warm onsunny days but cold at night. The temperature drops down to 3 degrees celsius (37F) or just a little

above freezing. But there were plenty of blankets for those sleeping there.
The Ojiya General Hospital (fig. 5 ) is one of survived buildings located in downtown Ojiya city, near
the epicenter of the earthquake. This building was constracted with the base isolation. Base isolation(fig. 6) is structural elements which protecting a building or non building structure’s integrity fromearthquake ground motion shaking. Approximately 15 cm displacement was recorded within theChuetsu earthquake 2004 and no damage occured in this building.

Fig 5. Ojiya general hospital building

Fig 6. Base isolation

Yamakoshi village
Yamakoshi village lies on a mass of old landslide in a valley. The area is dotted with slope terracedpaddy fields and carp ponds (fig. 7). The mountanious district of which Yamakoshi forms part is
known as a landslide hazard area during the spring snow melt. The epicenter of the earthquake was
Yamakoshi village which is about 8 kilometers east of Ojiya. It was devastated and the houses become
uninhabitable. All residents evacuated from the area. The roads from Ojiya to Yamakoshi wereimpassible. Only helicopters were able to go there. Apparently the average house in Yamakoshi had
been structurally damaged. Most of the heaviest damage was east of the Shinano River whereYamakoshi and other damaged villages are located. Before Chuetsu earthquake in 2004, there were nolarge natural dam and big river in Yamakoshi village but then the large scale of landslide blocked theImo river flooded houses in its flow area (fig. 8) and created several natural dams (fig. 9). The
typhoons that attacked Yamakoshi village just before the earthquake and the heavy snow after theearthquake, made the area became the most vulnerable place at that time.

Fig 7. Terraced paddy fields and ponds inthe Yamakoshi village

It was a hill here before
earthquake occurred

Fig 8. flooded house caused byFig 9. Natural dam caused by the landslide

blockage of Imo riverand blockage of Imo river

The Great Tohoku Earthquake and Tsunami
On Friday, March 11, 2011 at 14.46 JST , earthquake with measuring magnitude 9 occured 32 km
beneath Pasific ocean, 72 km eastern Tohuku, Miyagi prefecture. The duration of the earthquake wasapproximately 6 minutes, with the eneregy released more less 600 milion times than the energy ofhiroshima bomb. The tsunami hit coastline area in the eastern Honsu with the wave height 3-40 m andinundated the land more than 5 km. The highest tsunami run up, 40.5 m was recorded in Miyako in
Tohuku’s Iwate prefecture. In sendai area, tsunami wave travelled up to 5 km in land. The earthquake
also generated landslides, fires, and caused severe damages of infrastructure building, caused anumber of nuclear accidents which was released radiation. More than 900 aftershock has beenrecorded since the earthquake.
Fig. 10 shows shakemap of Tohoku earthquake and tsunami 2011. The intensity level of 7 was felt inKurihara, Miyagi Prefecture, Intensity level of 6+ felt in Fukushima, Ibaraki and Tochigi. And Intensity
level of 6- was measured in Iwate, Gunma, Saitama and Chiba, and in Tokyo the level intensitisy was5+.

Fig 10. Shakemap of Tohoku earthquake and tsunami (source:JMA)

Sendai 3rd Joint Goverment Building
The Sendai 3rd Joint Goverment Building building (Fig 11) experinced 6- intensity level of March2011 Tohoku earthquake. Seismoscope record 18 cm displacement of this building caused by theearthquake Seismoscope is a tool to measure the oscillation of earthquake (Fig 12). Mr. Kangaya fromLand and Infrasructure gave us guidance and explaination during our visit here.

Fig 11. Sendai 3rd Joint Goverment Building

Fig. 12 Seismoscope

Research Center for Prediction of Earthquake and Volcanic Eruption, Tohoku University
Tohoku University was established in 1912. Research Center for Prediction of Earthquake andVolcanic Eruption consists of three laboratories; the Crust Physics Laboratory related to earthquake
prediction, the Physical Volcanology Laboratory related to the prediction of volcanic eruptions, andthe Marine Geophysics Laboratory to study the plate dynamics in subduction zones. More than 60
observation stations operated by the center are distributed widely in Tohoku district to provide
invaluable data for prediction studies and also for fundamental studies in geophysics. The center is theleading center for solid earth physics in northeastern Japan, and also contributes to the education ofstudents in earth science. Prof. Norihito Umino, the director of earthquake observatory of Tohoku
University gave us guidance during our visit in Research Center for Prediction of Earthquake andVulcanic eruption, Tohoku University.

Fig. 12 Research Center for Prediction of Earthquake and Volcanic

Eruption building, Tohoku University

Fig 13. Seismometer in borehole below

Fig 14. Seismic signal from seismometer

Research Center for Prediction of Earthquake
and Volcanic Eruption building
Onagawa town
Onagawa town is a small fishing town with population of 10 thousand people. The Tohoku earthquake
A hill just behind the port was designated as an evacuation route where public hospital is situated (fig15). Traces of run up of tsunami height record on the first floor of hospital building in the hill which
was nearly 16 meters. Tsunami run up height was also recorded through over the rooftop of three-floor
hotel building (fig. 16). Some buildings looked survived from the earthquake, but collapsed with its
foundation uprooted from the ground during the giant tsunami hit this port area several times (fig. 17)

Traces of tsunami
Evacuation route

run upFig 15. Traces of the tsunami run up record in first floor

Fig 16 Tsunami run up record of

hospital building which located on the hill

through over the rooftop of threefloor hotel building

uprooted
foundationbuilding

Fig 17 Collapsed building with the uprooted foundation

Tohoku Regional Development Bureau
Tohoku Regional development bureau is incharge of 6 prefecture in Tohoku region and has 1,880
cctv installed along major national highways. There are 8 of 50 inci monitor in the midle and 48 of 20inci monitor in the left and right side wall which display cctv (fig. 19). Mr. Kawashima from Tohoku
Regional Development Bureau gave explaination during our visit in Tohoku Regional Development
Berau. when Tohoku earthquake occured, monitor displays in Tohoku Regional Development Berau
office were blank, because some cctv cameras damaged and washed away by tsunami and also
communication with this office broken. The standard procedure for Tohoku Regional Development
Berau if disaster occured is emergency restoration for the area affected immediately. But, in March 11
earthquake, street and road were totaly damaged because of tsunami, so there was no access to theaffected area. It took only 2 month from 6 month planned to built a temporary bridge to connect with
the isolated area.

Fig 18. Tohoku Regional Development BerauFig 19. Display monitor of cctv camera (courtesyof D. Mungunsuren)Aoba Ward (ground failure)
Aoba ward is located in hill zone. Landslide caused by the Tohoku March 11 earthquake made damged
house, ground failure and collapse of retaining wall (fig 20& 21).

Fig 20. Landslide and dameged house

Fig 21. collapse of retaining wall

Wakabayashi ward (coastal area)
The landscape of Wakabayashi ward is flat and has long straight coastaline (Fig 22),
different from Onagawa city which is hilly. Level intensity of the earthquake here was 6-,
severe building damaged and traces of tsunami run up around 3 m height measured in thisarea (Fig. 23).

Trace of thetsunami runcoastline

Fig 22. Wakabayashi coastalineup

Fig 23. trace of tsunami run up in one floor
building

Conclusion
The Chuetsu eartquake and the Tohoku earthquake are different types of earthquake. The Chuetsu
earthquake occured beneath the hill area, and triggered the landslide. There were also river flowchanged and natural dam created by the landslide. The Tohoku earthquake occured beneath sea andtriggered tsunami giant wave. Many building survived from the earthquake but totaly damaged by
giant tsunami which hit the coastal area several times. Mostly the building and houses in Japan built
based on the seismic code so it can survive from the earthquake.
Quick response and well cooperation between Japan’s government, society and other related
institutions make affected area by disaster recover soon. And ofcourse it also depend on the survivors
willingness to recover after disaster. However, it is not easy to recover from disaster. we can not beavoid disaster and victim, a good preparedness and early warning system can save many peoples lives.
The preparation of disaster prevention, also can reduce and minimize casualities of disaster.
Indonesia has the same experience of the great earthquake and tsunami in Sumatra last Dec 2004. And
until now the recovery process is still in progress. Since Indonesia prone to earthquake and tsunami,
similar to Japan, we have no choice other than learn how to live in harmony with the disaster.
References1.

http://www. aob.gephys.tohoku.ac.jp/aob-e2.

http://www.pref.miyagi.jp/english/index.htm

3.

KONOGAI, Kazuo, Preeliminary Report: Mid-Niigata Prefecture Earthquake, 2004