.

10th IWSMRR meeting at GRIPS, September 25, 2013

Heights Distribution and Damage of theTsunami of the 2011 off thePacific Coast of Tohoku Earthquake on
the north part of the Sanriku Coast
Y. Tsuji, K.Satate, T.Ishibe, T. Harada, S.Kusumoto,
A.Nishiyama, H.Y.Kim, T.Ueno, S.Murotani, S.Oki, M.Sugimoto,
J Tomari M.Heidarzadeh
J.Tomari,
M Heidarzadeh (ERI,(ERI Univ.
Univ Tokyo),Tokyo)
B.H.Choi(Sungkyunkuan Univ.,Korea), K.O.Kim(KORDI),
H.W.Kim, S.H.Yoon, and J.S.Bae(Hannyang Univ., Korea)

LLessons
givenibyb theh TTsunamii off theh GGreatEastJJapanEEarthquake
hk off M
Marchh 11th,
2011－Disaster Prevention for Millennium EarthquakesqTsunamis
Yoshinobu Tsuji
g Research Institute,
Building
Tsukuba Science City, Japan

Plate Configuration around
the Japanese Islands

Characteristics
Ci i off the 2011
East Japan Earthquake• (A) Large size epicenterarea 500km X 200km•
sea bed upheaval•
2～4 meters• （B） Existence of small
sized core area•
100km X 70km
•where sea bed upheaved•
15m or moreComparison of the distributions ofthe tsunami heights of the 2011 East
Japan the 1896 Meiji Sanriku , andJapan,
the 1933 Showa Sanriku
Earthquakes

Human loss
killed andmissingg
18,879peopleRyorithat of the 1896Meiji
22,000p ppeopleof the 1933 Sanriku

Tsunami height
distributioni i i on thenorth part ofSSanriku
i CoastC

Maita Hill

Map
p of
Maita Hill
The coastline is not ani
innermostpoint
i off aV-shaped bay.

Maita Hill, sea water rose up to near the top of
the hillhill. runrun-up
up height: 32.0m
32 0m

Measurement work at the inundation limit on
Maita Hill

Down view from the inundation limit on Maita Hill

Horizontal
motion of Sea
bedattthe core area
measureddbbyGPSGeographycal ResearchI tit tInstitute,
Tsukuba Science City

Locations of two ocean bottom pressure gauges
set by ERI,ERI Univ.
Univ Tokyo

震央
★
M9.0

Sea level records obtained at the ocean bottom sensors

Photo taken on the 4th floor of the City
Hall of Miyako

Tsunami suddenly came at 30 minutes after themain shock ((HiyakoyCityy Hall))Railway station was lost at Shimanokoshi
19 9m
19.9m
●Shimanokoshi Stn.
●22 1m22.1m

Railway station “Shimanokoshi”
Shimanokoshi was washed away

• Unsuitable Tsunami Shelters
Failure Example 1.

Okawa Elementary School, Ishinomaki city,
Miyagi Prefecture
７４ students
dwere kill
killedd (total(l 108 students)d)
10 teachers were killed (total 13 teachers)

Location ofOkawa
Ok
Elementaryschool
h lKitakami River

Teachers guided students in red arrow

The hind slope
Childern could notclimb up on this slope
No hiking route!
Sea water rose
up to here→→ A zigzag
iclimbingli bi routeshould existed

Failurei
Example 2.
Gymnasium of Nobiru Elementary SchoolGymnasium of Nobiru Elementary School

Sea water rosu up to the level 3 meters above
the floor. 20 ppeople
p were killed here.

About 100 people sheltered here after the issuance of tsunami
warning.
i
We once entered here, we can not see outside.

Failure
Example 3.
Arahamaarea inSendai City.
Only the 4th
floor of theelementaryschoolbuilding wasnotsubmerged.

Tsunami hit
the coast!
Notice the channel
calledll d “Teizan-Bori”“T iB i”
which prevent
evacuation of peoplepeople.
これが避難を妨げた。

Failure Example 4：Tragedy on Suginoshita Hilli Kasen-numainKCit Miyagi
City,
Mi i Prefecture
P f t

▲

杉の下高台、12ｍ

Suginoshita Hill(height:12m) had been appointed asa shelter place from tsunamis, and about 100 people
were evecuated. Sea water passed over the top of thishill with making water layer thickness of twometwers, and 93 people were killed.

Tsunami heightg
distribution inKanto District

Damage off Ii
DIiokak TTown,
Chiba Prefecture• 13 people
l were killkilled,d 2 missingsi i•
at Iioka Town••

→ Tsunami Heights 7.6meters

Damaged houses at Iioka

Iioka●Iioka SpurThe tsunami of Jogan 11(AD 869)
had the same magnitude
gasSENDAI
that of the 2011

Sea water reachedSh d at thehcity area of Tagajo
Castle town
In the times of the 869
gJoganand the 2011 East JapanTsunamis.

Tagajo Castle●

Submerged area in Sendai Coastal Area2011 event (blue) and Jogan(869) event(red)Sugawara et al.(2012)

２．Disaster prevention for Future Tsunamis
We shouldh ld consider
idLevell A: Tsunamis
i forf once ini one hundred
h d d years
Thee 1946
9 Showa
S ow Nankai andd thee 1854 Ansei
se Nankai Tsunamissusfor West Japan. Tsunami Height 9 meters at maximum

Level B: Tsunamis for once in one thousand years“ ill i“MillenniumTsunami”i” Tsunamii Heighti h 20-40m
20 40
the 869 Jogan and the 2011 East Japan tsunamis (EJ)
the 1707 Hoei and the 1498 Meio Tsunamis (WJ)( )

Tsunami Escape Facilities
Construction of Escape Route for a Millennium
Tsunami.
Plan of Shimanto City,
City Kochi Prefecture ShikokuTsunami Escape Stairs (20m)They set each step on the surface ofa concrete wall byy anchor bolts

TsunamiiTEscapep Tower
in Shimanto
CityHeight 18 meters. The
top floor area has 500
square maters in order top 1,000,people.
p paccept

Life Jackets are kept in the Box
The door of the box will be broken bya young refugee

Pull up box equipped at a shelter place.
Leg weak people will be pull up by humanppower. ((Shimanto City)y)Tsunami Escape Station for a Millennium Tsunami at
Yoshida Town, Shizuoka Prefecture.
The construction was completed on 23rd September, 2013.
Deck Height is 10.5 meters above mean sea level. This
place of refuge can accommodate 1,000 people.

完成イメージ（完成イメージ（Ｋ街区）
Ｋ街区）