JSCE Journal of Disaster Factsheets, FS2024-E-0003, 2024

Preliminary Report of the Damage by the 2022 Off
Fukushima Prefecture Earthquake Mj7.4, JapanKazuma INOUE1, Keita UEMURA2, Keita SAITOH3,Kento ASAMI4 and Kotaro Uchiyama5
1Member of JSCE, Associate professor, Dept. of Civil Eng., National Institute of Technology, Gunma College(580, Toriba, Maebashi, Gunma 371-8530, Japan)
E-mail:inoue@cvl.gunma-ct.ac.jp
2Member of JSCE, Assistant Professor, Dept. of Civil and Earth Resources Eng. , Kyoto University(Kyoto daigaku-katsura, Nishikyou-ku, Kyoto, 615-8540, Japan)
E-mail: uemura.keita.3n@kyoto-u.ac.jp
3Member of JSCE, Student, Dept. of Urban Management, Kyoto University(Gokasho, Uji, Kyoto, 611-0011, Japan)
E-mail:saito.keita.53j@st.kyoto-u.ac.jp
4Member of JSCE, Student, Dept. of Environmental Eng., National Institute of Technology, Gunma College(580, Toriba, Maebashi, Gunma 371-8530, Japan)
E-mail:ae22901@gunma.kosen-ac.jp
5Member of JSCE, Student, Dept. of Environmental Eng., National Institute of Technology, Gunma College(580, Toriba, Maebashi, Gunma 371-8530, Japan)
E-mail:ae22903@gunma.kosen-ac.jp

Key Facts・ Hazard Type: Earthquake
・ Date of the disaster: March 16th, 2022
・ Location of the survey: Fukushima and Miyagi prefectures, Japan・ Date of the field survey: March 18th and 19th, 2022
・ Survey tools: Digital Camera, GPS・ Key findings:(1) The superstructure collided against the western side abutment in the Date bridge.
(2) The bearing pin was unfastened in the Showa Bridge.
(3) The steps of intermediate piers can be confirmed in the Danzaki bridge.
(4) The viaduct tilt due to Shear failure of columns was observed in Kunimi Town.

Key Words: Offshore the Fukushima Prefecture Earthquake, Geotechnical damage, Damage to bridges,Damage to Shinkanssen structure

cm/s2 was observed at KiK-net Kawasaki(MYGH07). The JMA announced that long-period
seismic motion class 4 was observed in northern
Miyagi Prefecture.
About one year before this earthquake, a similar
Mj7.3 earthquake occurred off the coast of Fukushima Prefecture. Table 1 shows a summary of these
two earthquakes and epicenters are shown in Figure
1: their epicenters are close to each other and theirmagnitudes and maximum seismic intensities are almost equal.
We conducted a survey of earthquake damage in Fukushima and Miyagi prefectures on March 18 and 19,

1. INTRODUCTION
At 23:36 on March 16, 2022, a Mj7.4 earthquake
occurred off the coast of Fukushima Prefecture. TheJapan Meteorological Agency (JMA) estimates that
it was an aftershock of the 2011 off the Pacific coastof Tohoku earthquake. The epicenter of this earthquake was at 37°41'8" N, 141°37'3" E, and the depthof the epicenter was about 57 km. It was a fault-typeearthquake with a pressure axis in the northwestsoutheast direction. The maximum intensity of thisearthquake was 6+ observed in Tome City, Zao Town,
Kunimi Town, Soma City, and Minami-soma City. Inparticular, a rather large peak acceleration of 1232.7
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JSCE Journal of Disaster Factsheets, FS2024-E-0003, 2024

2022. We focused on structural damage of the viaducts and bridges of the Tohoku Shinkansen (Tohokubullet train), and road bridges crossing the Abukuma
River.
In this report, ground motions during the 2021 andthe 2022 earthquakes are compared and findings ofour survey of the seismic damage of the structures areshown.

2. STRONG GROUND MOTION RECORDNEAR THE TOHOKU SHINKANSEN IN
THE NAKADORI AREA OF FUKUSHIMAPREFECTURE(a) Location of epicenters and seismic stations.

We compare the ground motions observed near theTohoku Shinkansen during the two earthquakes.
Figure 1 shows the location of the K-NET seismicstations operated by NIED1) near our survey site. KNET Shiroishi(MYG016) is close to the location
where a Shinkansen bullet train was derailed. K-NETYanagawa(FKS002) is located near the road bridges
crossing the Abukuma River.
Figure 2 show the acceleration time histories observed at the four seismic stations during the twoearthquakes. They are rotated to the directions perpendicular to the Shinkansen lines close to the seismic stations (Table 2). At MYG016 and FKS002, theacceleration observed in the 2022 earthquake waslarger than in the 2021 earthquake; at K-NET Fukushima (FKS003), the observed acceleration was similar for the 2021 and the 2022 earthquakes; at K-NETKoriyama(FKS018), the acceleration observed in the2022 earthqu¸ake was smaller than in the 2021 earthquake. At FKS002, peak acceleration is 709 cm/s2 inthe direction perpendicular to the Tohoku shinkansen
line.
Figure 3 shows the acceleration response spectra ofground motions shown in Figure 2 for the 2022 earthquake. Among four seismic staion, response spectra
for FKS003 is the largest in the long period range (1.0to 2.0 sec.) and that for FKS002 is the largest in the
short period range (shorter than 0.2 sec).

(b) Location of damaged structures surveyed.
Fig.1 Location of the damage survey sites and seismic stations
with the focal mechanism of the 2021 and the 2022 earthquake2), 3).
Table.1 Outline of the earthquakes of the 2021 and the 2022 that
occurred at off Fukushima prefecture.
DateFebruary 13rd 2021

March 16th 2022

Time

23:07

23:36

Epicenter

37°43.7’N,
141°41.9’E

37°41.8’N,
141°37.3’E

Epicenter depth

55km

57km

Magnitude

7.3

7.4

Maximum seismic
intensity

6+

Areas of maximum
seismic intensity

SomaCity
KunimiTown

6+Shinchi
Town
Zao
Town

Tomecity

Zao
Town

Kunimi
Town

Soma
City

Minamisoma
City

Table.2 Directions perpendicular to the Shinkansen viaducts
near the four seismic stations.

MYG016

Directions perpendicular
to the Shinkansen viaducts
N131°EFKS002

N99°E

FKS003

N100°EFKS018

N99°E

Seismic stations

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JSCE Journal of Disaster Factsheets, FS2024-E-0003, 2024

20210213

Acc. (gal)20220316400
2000-200-400
010203040Time (sec)506070(a) K-NET Shiroishi (MYG016)
20210213

Acc. (gal)20220316

Fig.4 Ratios of the acceleration response spectra of the 2022
earthquake to the 2021 earthquake for the ground motions
shown in Figure 2.

800
4000Figure 4 shows the ratios of the acceleration response spectra of the 2022 earthquake to the 2021
earthquake for the ground motions shown in Figure
2. The response spectra of the 2022 earthquake tends
to be larger except for FKS018. At FKS002, the response spectrum of the 2022 earthquake is about 2.5
times larger than that of the 2021 earthquake aroundthe natural period of 1 second. At MYG016, the response spectrum of the 2022 earthquake is larger thanthe 2021 earthquake at many natural periods. AtFKS003, the 2022 earthquake is prominent on theshort period side. At FKS018, the response spectrumof the 2022 earthquake is smaller than that of the2021 earthquake.

-400-800010203040Time (sec)506070(b) K-NET Yanagawa (FKS002)
20210213

Acc. (gal)20220316

4002000-200-4000

10203040Time (sec)506070(c) K-NET Fukushima (FKS003)
20210213

Acc. (gal)20220316

3. SEISMIC DAMAGE OF BRIDGES
400200(1)Date Bridge
Date Bridge is located at 37°49'11.2"N,140°30'37.6"E, crossing the Abukuma River in theeast to west direction. It is a four-span truss bridge
completed in 1967. In Date Bridge, the superstructure
collided against the western side abutment. Photo1(a) shows a large step occurred on the west side.
Photo 1(b) shows a large clearance occured at the expansion joint and the broken bearing on the east side.
Emergency restoration of the bridge is expected totake from two to three years, and the bridge replacement is also considered4). When our survey was conducted, the damage to the soil behind the abutment
and surrounding ground was not observed. Therefore,
the damage to Date Bridge is considered to be caused
by inertial forces during the earthquake.

0-200-400010203040Time (sec)506070(d) K-NET Koriyama (FKS018)
Fig.2 Comparison of acceleration waveforms observed at four
K-NET stations near the Tohoku Shinkansen line during
the 2021 and 2022 earthquakes: rotated to the directions
perpendicular to the Shinkansen axis (Table 2).

(2) Showa Bridge
Showa Bridge is located at 37°50'14.7"N,140°32'17.0"E, crossing Abukuma River in the east
to west direction. It is a four-span truss bridge completed in 1993, and is equipped with a bridge fall prevention system.

Fig.3 Acceleration response spectra (h=0.05) of the ground motion shown in Figure 2 for the 2022 earthquake.
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JSCE Journal of Disaster Factsheets, FS2024-E-0003, 2024

At the time of our survey, there was no apparent
damage in the ground behind the abutment or the surrounding ground, but cracks was appeared in thepavement (Photo 2). In addition, the bearing pin wasunfastened, as shown in Photo 2(b). The bridge wasscheduled to be opened to traffic on March 19, 2022,
from the rehabilitation work after the 2021 earthquake, but was closed due to the earthquake damage
from the 2022 earthquake.
(a) The pavement cracked.

(3) Danzaki Bridge
Danzaki Bridge is located at 37°50'55.0"N,140°33'39.0"E, crossing Abukuma River in the east
to west direction. It is a seven-span PC simply supported bridge completed in 1961. There was no apparent damage near the abutments, but the step between girder ends and abutment was caused by seismic damage to bearings as shown in Photo 3. In addition, cracks were found on the end of the girder asshown in Photo 3(d). There was no apparent damageon the behind of the abutment and the surrounding
ground. Therefore, these damages are considered tobe caused by the inertial force from the earthquake
ground motion.

(b) North Side.

(c) South side.
(d) The bearing pin unfastened.
Pthoto.2 Damage of Showa Bridge.
(37°50'14.7"N, 140°32'17.0"E)(a) West Side of Date Bridge.

(a) Danzaki Bridge.
(b) East Side of Date Bridge.
Photo.1 Damage of Date Bridge.(37°49'11.2"N, 140°30'37.6"E)

4. DAMAGE TO SHINKANSEN STRUCUTURE(b) Abutments of Danzaki Bridge.

(1) Shear damage to horizontal middle beams ofthe two-story RC frame
Damage to the transverse beams of the two-story RC
frame of the virducts of the Tohoku Shinkansen wasobserved over a wide area, from Koriyama City, Fukushima Prefecture, to Shiroishi City, Miyagi Prefecture. In particular, significant damage, concrete spalling and rebar exposure, was observed at several viaducts from Date City, Fukushima Prefecture, to Shiroishi City, Miyagi Prefecture (Photo 4, Photo 5). In(c) Intermediate Piers.
(d) The End of Girder.
Photo.3 Damage of Danzaki Bridge.
(37°50'55.0"N, 140°33'39.0"E)4

JSCE Journal of Disaster Factsheets, FS2024-E-0003, 2024

these areas, the seismic waves were observed to belarger than those of the 2021 earthquake, and thedamage to the transverse beams was observed to besignificant. In addition, in Shiroishi City, Miyagi Prefecture, the damage that considered to be developed
from repair scars of the past earthquake was observed.
(2) Flexure damage of RC pierIn the area from Date City to Shiroishi City, someflexure damage in the RC frame piers were observed.
In the damaged columns, the longitudinal bars buckled, and the concrete was spalling (Photo 6, Photo 7,Photo 8). In particular, the survey revealed that thenumber of damaged columns was higher near Shiroishi City, Miyagi Prefecture than in other areas. However, compared to the number of damaged transverse
beams described in (1), the number of damaged columns is small.Furthermore, damage occurred only tocolumns that had not been seismically retrofited; nodamage occurred to columns that had been seismically retrofitted with steel jacketing.

Photo.6 Flexure damage of RC pier in Shiroishi City, MiyagiPrefecture(Saikawa BV).(37°58'14"N, 140°36'44"E)

Photo.4 Shear damage to horizontal middle beams in Date City,Fukushima Prefecture. (37°49'30"N, 140°29'39"E)
Photo.7 Flexure damage of RC pier in Shiroishi City, Miyagi
Prefecture.(37°58'25"N, 140°36'54"E)(3) Shear damage to RC pierShear failure of columns was observed in Kunimi
Town, Fukushima Prefecture. The photographs show
significant shear cracks in the columns, indicatingthat the loss of the capacity to support the axial loadof some columns caused the viaduct to tilt (Photo 9).
For the viaduct, the damage occurred only on the columns that were not seismically retrofitted; the columns above the middle beams were not damaged because they had been seismically retrofitted with steel
jacketing.

Photo.5 Shear damage to horizontal middle beams in Shiroishi
City, Miyagi Prefecture.(37°59'33"N, 140°37'50"E)

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JSCE Journal of Disaster Factsheets, FS2024-E-0003, 2024

abutment were observed. At the Showa Bridge, bearing pins were unfastened. At the Danzaki Bridge,steps on the intermediate piers were observed. For theTohoku Shinkansen railway structures, we observed
shear damage to the horizontal middle beams of thetwo-story RC viaduct and shear and flexure damage
to the RC piers.
As described above, the survey revealed several issues regarding the seismic safety of civil engineering
structures to be taken seriously.

ACKNOWLEDGMENT: In this report, we haveused the seismic motion records published by NIED.
REFERENCES
1)
Photo 8 Flexure damage of RC pier in Shiroishi City,
Miyagi Prefecture.(37°59'13"N, 140°37'33"E)
2)

3)

4)

Photo 9 The viaduct tilt was caused by shear damage to RC
frame pier in Kunimi Town, Fukushima Prefecture.
(37°52'43"N, 140°32'06"E)

5. SUMMARY
This report shows our survey of the seismic damage
to the various structures in Fukushima and southern
Miyagi prefectures during the 2022 earthquake withsome analysis of observed ground motions aroundthe survey sites. We surveyed damege on bridges
crossing the Abukuma River, the viaducts of theTohoku Shinkansen, and bridges of the Tohoku
Shinkansen. At the Date Bridge, large steps and separation and the collision of the superstructure to an6

National Research Institute for Earth Science and Disaster
Resilience (2019)：NIED K-NET, KiK-net, National Research Institute for Earth Science and Disaster Resilience,
doi:10.17598/NIED.0004
Japan Meteorological Agency :https://www.jma.go.jp/jma/press/2102/14a/202102140110.
html
Japan Meteorological Agency :https://www.jma.go.jp/jma/press/2203/17a/202203170130.
html
Fukushima-Minpo Co.,LTD. :https://www.minpo.jp/news/moredetail/2022031995440(Received April 4, 2022)