Journal of Natural Disaster Science, Volume 34, Number 1, 2012, pp105-113

Damage to the Railway System along the Coast
Due to the 2011 Tohoku Earthquake Tsunami
Soichiro SHIMAMURA*
Fumihiko IMAMURA**
Ikuo ABE****Department of Civil and Environmental Engineering, Tohoku University
6-6-11-1106, Aoba, Sendai, 980-8579, JAPAN**International Research Institute of Disaster Science, Tohoku University***Department of Social Environment, Fuji Tokoha University(Received May 2, 2012 Accepted November 2, 2012)
ABSTRACTThe enormous Mw 9.0 earthquake with a hypocenter off Sanriku-oki that occurred at
approximately 14:46 (JST) on March 11, 2011, and the subsequent tsunami, caused serious
damage along the Pacific coast of Iwate, Miyagi, and Fukushima. The damage toinfrastructure was remarkable, and the damage to the railway caused by the tsunami was thegreatest damage ever to occur to the railway. JR-East reported that they checked the damage
caused by only the tsunami along seven lines, which had a total distance of 325 km, and theform of damage varied by line.
This paper summarizes the damage to the railway (including damage to vehicles) and theevacuation guidance situation for each line and investigates how the trains were damaged
based on the numerical analysis of the 2011 Tohoku Earthquake Tsunami.
Keyword: The 2011 Tohoku Earthquake Tsunami, Train, Numerical Analysis

1. Introduction

was checked along 7 provincial routes over a total of
approximately 325 km.
This paper presents an outline of the 2011 Tohoku
Earthquake Tsunami, and, because the degree andform of damage differed by route, examples of train
damage are summarized for each route. In addition, anumerical analysis of the tsunami, using the seismic
deformation model of the 2011 Tohoku Earthquake
Tsunami (Tohoku University model version. 1.0), wasperformed to determine the flow conditions in the area
where the damage to the railway occurred. A new fallmodel of the damage to trains caused by the tsunami is
proposed, and the mechanism of damage is discussed
by comparison with the results of analysis.

On 2011 March 11th 14:46 (JST), an enormous Mw
9.0 earthquake occurred with a seismic center on the
coast of Sanriku. Due to a strong shake ranging from
6 to 7 on the Japanese scale and a subsequent tsunami,
approximately 19,000 persons died or were missing(as of March, 2012) along the Pacific coast (including
Iwate, Miyagi and Fukushima). Damage to the infrastructure, such as roads, bridges, plants, water andsewage, was also remarkable, and the damage to therailway caused by the earthquake and tsunami was thegreatest damage ever to occur to the railway. According to JR East, the damage caused only by the tsunami
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S. SHIMAMURA, F. IMAMURA, I. ABE

2. Outline of the 2011 Tohoku Earthquake Tsunamion the right (Fig. 1). These shocks caused a very hightsunami in the area along the shore, and evidence ofthe great height of the tsunami can be seen in various
places (Fig. 2). In particular, along the Iwate rias
coast, the run-up height was nearly 40 m.
This tsunami, with the greatest wave force everand causing the greatest area of flooding also seriously affected the railway. Figure 3 shows damage in the
JR East province. The form of damage, including
damage to electrification pillars, displacement of therailway track, washout and burial of bridge beams,
failure of signal and communication equipment, andAs described above, the 2011 Tohoku Earthquake
Tsunami of Mw 9.0 caused enormous damage to mostareas of the Pacific Ocean coast. Within a broad floodarea (about 560 km2), the tsunami caused the collapseof reinforced concrete structures and the outbreak offires. The waveform of the offing (Fig. 1) is an important feature of tsunami action. On March 11th, immediately after the main Mw 9.0 shock, three consecutive Mw 7 aftershocks occurred, causing an increasein wave height in two stages, as shown in the graphFig. 1. Sea-level change recorded by the ocean floor cable seismometer off of Kamaishi (Earthquake ResearchInstitute, The University of Tokyo)

Fig. 2. The field survey result projected in the direction of latitude(The 2011 Tohoku Earthquake Tsunami Joint Survey Group)106

DAMAGE TO THE RAILWAY SYSTEM ALONG THE COAST DUE TO THE 2011 TOHOKU EARTHQUAKE TSUNAMI

Fig. 3. Damage to railway caused by the tsunami (JR East)ballast outflow, varied significantly. In this paper, togive top priority to human life, the damage to trains is
considered and summarized.

at Tsugaruishi Station, which is approximately 1 km
from the coast.

3. Damage to the railway
This chapter introduces examples of train damage
caused by the tsunami.
3.1. Yamada-Line・St. Tsugaruishi(Iwate, Miyako : Photo. 1)
The interrupted section of the Yamada Line is thelongest in the nine main disaster-affected routes, andthe route passes through areas that were enormously
damaged by the earthquake disaster, such as Yamada
town and Otsuchi-Cho along the railway line. At
Tsugaruishi Station, while the train for Miyako Station from Kamaishi Station stopped, it was affectedby intense shaking. As the tsunami alarm from the operation management center was sounded promptly,
the passengers evacuated to nearby Tsugaruishi Elementary School, but, because the tsunami reached theelementary school, they then evacuated to safety on
the hill behind the school. According to JR staff, atapproximately 15:20, the train was washed along in
the Toyomane Station direction from Tsugaruishi Station, and it drifted approximately 80 m along the railway line from where it had stopped. The tsunami numerical analysis also shows that the tsunami arrived

Photo 1. Yamada-Line・St. Tsugaruishi(Provided by JR East)
3.2. Ofunato-Line・Ofunato-Shimofunato(Iwate, Ofunato : Photo. 2)
Along Ofunato Line, a train with a two-car formation was heading to Shimofunato Station from
Ofunato Station at the time the earthquake occurred.
Although the train came to an emergency stop at a location that was several meters higher than the surrounding land, the crew who received the evacuation
directive helped the passengers down and proceededwith evacuation. They did not evacuate to Ofunato
Elementary School, which is the designated evacuation building, due to the advice of a local passenger
but rather went to Ofunato Junior High School, which
107

S. SHIMAMURA, F. IMAMURA, I. ABEcrew were safe, the train was derailed and drifted approximately 60 m in the direction of the tsunami.

is the same distance from the train as the elementary
school but at a higher altitude. As a result, although
the tsunami reached the schoolyard of the elementary
school, they evacuated safely to the junior highschool. The train, which had come to an emergency
stop, was approximately 240 m from the coast andwas spared derailment and drift, but the train chassis
was covered with water and the train was immobile.

3.4. Ishinomaki-Line・St. Onagawa(Miyagi, Onagawa : Photo. 4 and Photo. 5)
Along Ishinomaki Line (the whole line section(44.9 km)), the damaged section was only 700 m from
Onagawa Station to Onagawa Tunnel but sufferedcrushing damage from the shape of the bay.
A train with a two-car formation was at rest andready for departure in Onagawa Station yard when theearthquake occurred, but this train and the train used bysome hot spring institutions were carried away by thetsunami. Among the trains in the two-car formation thatdrifted, one train drifted approximately 200 m and wascompletely destroyed, and the other train drifted 100 m
more inland and stopped at a graveyard on a hill. In addition, damage to the station building and the railway
track were serious, and both were severely damaged.

Photo 2. Ofunato-Line・Ofunato-Shimofunato(Provided by JR East)
3.3. Kesennuma-Line・Matsuiwa-Saichi(Miyagi, Kesennuma : Photo. 3)
A train with a two-car formation to Kogota wasrunning between Matsuiwa and Saichi when the earthquake occurred. After the train made an emergency
stop, the train driver received the tsunami alarm, had
the passengers disembark and started the evacuation.
It was necessary to walk approximately 200 m along
the railway track, and the train driver saw the sea level decrease suddenly and evacuated at a hurried paceto the Junior High School, which is situated approximately 1 km inland. Although the passengers and the

Photo 4, Photo 5. Ishinomaki-Line・around St. Onagawa
3.5. Senseki-Line・Tona-Nobiru(Miyagi, Hagashimatsushima : Photo. 6)
Senseki Line connecting Sendai and Ishinomaki
runs approximately 200 trains a day as a route for

Photo 3. Kesennuma-Line・Matsuiwa-Saichi(Provided by JR East)

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DAMAGE TO THE RAILWAY SYSTEM ALONG THE COAST DUE TO THE 2011 TOHOKU EARTHQUAKE TSUNAMI

main factors included the explosion at Fukushima
First Nuclear Power Plant, but the damage caused by
the tsunami was too serious. In particular, a train thatwas stopped and the station building at Shinchi Station of Fukushima were destroyed. In addition, there
was damage to a freight train on the Joban Line. Between Hamayoshida to Yamashita, all of the containers that had been piled up were washed away and collided with private houses, and they were a factor in
the extent of the damage. The damage to Sendai Airport access lines and North Rias Line, South Rias Lineand Hachinohe Line were confirmed in other reports.

Photo 6. Senseki-Line・Tona-Nobiru(Provided by JR East)
commuters and school goers. Two trains were runningwhen the earthquake occurred in this area, and one ofthem was the train to Aoba-Dori Station. The passengers evacuated according to the instructions of thecrew to Nobiru Elementary School, which was the
nearby evacuation building, but the tsunami reachedthis elementary school. Immediately afterwards, thetrain was derailed by the tsunami, turned at a right angle and stopped when it hit a house behind it. Anothertrain (Photo. 7) for Ishinomaki that was stopped at
this place went ahead approximately 1.5 km in the
Ishinomaki direction from the train that was derailed.
This train was stopped on a hill that was a little morethan 10 m high. The crew decided to stay in the train
with the passengers on the advice of local people, andthey escaped the tsunami and were safe. The difference of a slight distance and a slight altitude areclearly distinguished by the light and shaded areas.

Photo 8. Joban-Line・St. Shinchi

Photo 9. Joban-Line・Hamayoshida-Shimoyama(Provided by JR East)
4. Tsunami Numerical Analysis
Tsunami numerical analysis was performed for eachdisaster area to examine the mechanism of the train
damage caused by the tsunami, which is given in detail in the previous section. As described above, theseismic deformation model uses the Tohoku University model version 1.0 (Fig. 4). For the calculation conditions, a shallow water theory that integrates the

Photo 7. Senseki-Line・Tona-RikuzenOno(Provided by JR East)
3.6. Train damage in other areas
The Joban Line had the longest section interrupted by the East Japan great earthquake disaster. The
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S. SHIMAMURA, F. IMAMURA, I. ABE
138 E

140 E

142 E

144 E

40 N

38 N

[m]

36 N

15

-5

34 N
0

100

200

Fig. 4. Tohoku University model(Version 1.0)

400km

Fig. 5. Computational region

method described in H. Yeh (2007) in this model,
which has been examined previously and expresses
the fall limit of the train caused by tsunami using only
the inundation depth.

equation of continuity and the Navier-Stokes equationin the depth direction is the dominant equation andwas calculated by the Leap-Frog difference method.
In addition, public data from the Geographical Survey
Institute (before the earthquake disaster) was used forthe topography data, rough degree data, and dike data
and the mesh size of the region was calculated at
1,350 m> 450 m> 150 m> 50 m. In five regions (Fig.
5, from the north, Yamada-Line, Ofunato-Line, Kesennuma-Line, Ishinomaki-Line, and Senseki-Line),
analysis was performed using two patterns to represent shore structures functioning and failing entirely
to show the lower limit and the upper limit of the actual damage, respectively. A reproducible examination
was also performed by comparing the numerical analysis result in each region with the information in the
train damage archive.
In addition, the damage was measured using amodel (Fig. 6) that expresses the falling limit of the
train caused by the tsunami with the balance of the
moment. I used the tsunami force (Ft) calculation

Fst : Hydrostatic Forces, Fb : Buoyant Forces, Fd : Hydrostatic Forces, ρ : fluid density [kg/m3], g : acceleration of gravity [m/s2], B : width of train [m], L :length of train [m], h : inundation depth [m], u : velocity [m/s], Cd : Drag Coefficient(=2.0), R : runup
height [m]This value is referred to as the “Falling Limits” and it
was calculated to be 1.1 m. The precision of the “Falling Limits” was checked by comparison with the train
damage archive.
The analysis results are shown in Fig. 7 and Fig. 8.
Figure 7 shows the maximum inundation map in the
train damage area (red frames of Fig. 5) in each region in two ways, including the shore structure andnot including the shore structure. In addition, themesh where the maximum inundation depth exceeded
the Falling Limits (1.1 m) is shown in red, and lessFig. 6. Fall moment model
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DAMAGE TO THE RAILWAY SYSTEM ALONG THE COAST DUE TO THE 2011 TOHOKU EARTHQUAKE TSUNAMI

Inundation Depth[m]6

Senseki-Line・NobiruーTona5

Dike
N_DikeFull_Limits [1.1m]

4
3
2
1
0
0

20

20

40

60
Time[min]

80

100

120

Ishinomaki-Line・St.Onagawa

15
10
5
0
0
7

20

40

60

80

100

120

40

60

80

100

120

40

60

80

100

120

60

80

100

120

Kesennuma-Line・

6
5
4
3
2
1
0
0

4

20

Ofunato-Line・

3
2
1
0
0
10

20

Yamada-Line・Tsugaruishi

8
6
4
2
0
0

20

40

Fig. 8. The time-series wave height

nato, the only damage was due to the flooding of the
train chassis by the tsunami, and the flooding depth
reached 3.2 m in the case without the shore structureand did not reach 1.1 m in the case with the shore
structure. In other words, the agreement with the realdamage was because possibility that the inundation
was only 1.1 m in two cases could not be denied, indicating the lower limit and the upper limit of the true
phenomenon. However, for the inundation depth
along the railway track, this analysis result is overestimated because the height of the railway track, whichis the height of the railroad embankment, cannot be
considered. Furthermore, Table 1 shows the tsunami
arrival time and the influence start time (the falling
limit time) determined from the time-series wave
height at the train damage points. At Nobiru – Tona,
Onagawa and Matsuiwa – Saichi Stations, the tsunami
arrival time and the influence time were not signifi-

Fig. 7. Maximum inundation map(a:Senseki-Line, b:Ishinomaki-Line,c:Kesennuma-Line, d:Ofunato-Line,e:Yamada-Line, −1: with a shore structure,−2: without a shore structure)than this limit is shown in gray. Most of the inundation area in the region analyzed here exceeds 1.1 m.
The graph in Fig. 8 shows the time-series wave heightat each train damage point. As described above, thetrue phenomenon depends on whether there wereshore structures, but the inundation was over the Falling Limits (1.1 m) regardless of the presence of shore
structures at the points where the derailment and fallof the train were due to the tsunami, except along
Ofunato – Shimofunato Line. In Ofunato – Shimofu111

S. SHIMAMURA, F. IMAMURA, I. ABE

Table 1. The tsunami arrival time, the influence start time (the falling limit time), and the maximum inundation
depth at the train damage points
Nobiru-Tona St. Onagawa Matsiwa - Saichi
Arrivaltime of Tsunami [min]Time of falllimits [min]Max inundati on depth [m]Ofunato - Shimofunato St. Tsugaruishi

65

42

39

40

47

65

42

39

37

42

66

43

39

−

48

65

42

39

39

42

4.21

12.7

5.50

0.25

2.13

5.46

17.3

6.12

3.23

8.70

cantly influenced by the presence of a shore structure,
but an apparent difference caused by the presence ofthe shore structure along Ofunato - Shimofunato Lineand at Tsugaruishi Station.

method for the train damage mechanism that uses
only the inundation depth is limited, and it is necessary to establish a detailed evaluation method thattakes into account the velocity, flow direction, among
others. However, the evaluation method that uses only
the inundation depth is very useful because it has theadvantages of versatility and being easy to fit withexisting predictive inundation maps.

5. Examination of the drifting behavior in Tsugaruishi
In this report, the fall of trains caused by the tsunami was examined and the archived data and the results of tsunami numerical analysis were compared.
However, Nagase (2011) notes that the diesel train
that was stopped at Tsugaruishi Station might havefloated and drifted for a long time. For most of the
trains that were damaged by this tsunami, their behavior, such as rolling, sliding, and floating, is notknown, but it is certain that they drifted several tensof meters. In Nagase (2011), the train might havefloated because the waterline trace (1.76 m) left on
this train was smaller than the trace (2.58 m) that remained at the station where this train was stopped, so
he set “Floating Limits” from the balance of the massof the train and the buoyancy due to the seawater. The
result was 1.7 m. However, this analysis is only applicable to the sealed train model. A graph superimposedon the Floating Limits of the time-series wave heightof the analysis result is shown in Fig. 9. Figure 9shows that a wave height greater than 2 m occurred
for a long time according to the pattern where theshore structures are considered, and it approached theFalling Limits earlier than the Floating Limits. However, this train approached the Floating Limit earlier
than the Falling Limits and drifted because it could
not fall down before floating by tsunami because
there is no trace of contact with the train in the station
yard where it stopped when the earthquake occurred,
according to the field survey. Thus, an evaluation

10

Yamada-Line・Tsugaruishi

N_Dike8
Inudation Depth[m]Dike
Falling_Limits [1.1m]
Floating_Limits [1.7m]

6

4

2

0
0

20

40

60
Time[min]

80

100

120

Fig. 9. The time-series wave height (Falling Limits &Floating Limits) In the figure above, change
Inudation to Inundation
6. Conclusion
The train damage data was collected from the archive on train damage caused by the 2011 Tohoku
Earthquake Tsunami and numerical analysis was performed using the Tohoku University model version
1.0 as the seismic deformation model and the maximum inundation map and the time-series wave height
were output for each train damage point. In addition,a new fall moment model for train damage caused by
the tsunami was suggested and the “Falling Limits”(1.1 m) were calculated using the tsunami wave force
calculation of H. Yeh (2007). The correctness of the112

DAMAGE TO THE RAILWAY SYSTEM ALONG THE COAST DUE TO THE 2011 TOHOKU EARTHQUAKE TSUNAMI

analysis results (Falling Limits) was confirmed by theactual damage according to the archive.
Nagase (2011), who considered the train behavior at Tsugaruishi Station as the train damage point,suggested that the Floating Limit at which the train
floats due to the tsunami is 1.7 m and assumed thatfloating occurred before falling. This study limitedly
examined train damage by considering the inundation
depth alone, and thus further examination of the damage mechanism taking into account the velocity andflow direction is necessary.

References
H, Yeh. (2007): Design Tsunami Forces for Onshore Structures, Journal of Disaster Research, Vol.2, No.6,
pp.531-536
SHIMAMURA, S., IMAMURA, F., ABE, I., and SHIMAMURA, M. (2012): Damage on the Coast Railway
due to the 2011 Tohoku Earthquake Tsunami, Japan
Society of Civil Engineers Tohoku Branch, Ⅱ -31
Nagase, K. (2012): Trains Tossed by the Tsunami Attributed
to the Massive Quake Shocked the Northeastern Section of Japan in 2011, J-RAIL2011, pp.413-416

Acknowledgment
This study was supported by JR East. JR East
through offering various information and photographs.

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