Knowledge from the 2011 Japan tsunami andtsunami disaster management perspectives
under COVID-19 pandemic

Anawat Suppasri
Tsunami Engineering Research Field,Hazard and Risk Evaluation Research DivisionInternational Research Institute of Disaster Science (IRIDeS)
Tohoku University

Contents• Historical tsunamis in Japan• The 2011 Japan tsunami:
Knowledge and improvement• Practical information based on recent tsunamis• Tsunami evacuation during COVID-192

Tsunami hazards from the last 400 years
1600-1969（64 events）
Over 2 m

1970-2016（39 events）
Atlantic Ocean

AlaskaCascadia
SouthAmerica

Damaging tsunamis that exceeded 2 m canbe seen virtually everywhere, especially along
the Pacific Rim including 1700 Cascadia(M9.0), 1755 Lisbon (M8.5), 1833 SW
Sumatra (M8.3), 1868 Peru (M8.3), 1906
Ecuador (M8.8) and 1960 Chile (M9.5).

Only two major events, the 2004 Indian
Ocean (M9.3) and Great East Japan (M9.0),
classified as recent damaging tsunamis thatexceeded 2 m and caused global impact
meanwhile no major damaging tsunami in theeast Pacific and Atlantic Ocean.

This observation demonstrates the importance of assessing or recognizing thehazards based on historical events beyond recent experiences.

Historical tsunamis in Atlantic Ocean
A region having no major tsunami
in this generation:

Lisbon1755 Lisbon and 1843 Caribbean Sea tsunamis

Maximum tsunami amplitude

2m

AfricaTsunami from Lisbon could also arrive otherCaribbean Sea
parts of the region such as Caribbean Sea. ThisMax. amplitude
finding shows an importance in assessing bothnear-field as well as far-field tsunamis at thesame time.

Tsunami arrival time
For the NW Africa, tsunami from Lisbon
arrives after 1-2 hours but tsunami with thesame size from Caribbean Sea arrives NW
Africa after 7 hours. This finding shows animportance in assessing in global scale.

7 hours
AfricaArrival time869 Jogan tsunami

http://www.kunaicho.go.jp/e-okotoba/02/address/koen-h24az-mizuforum6th.html

5Learning step by step from historical tsunamis in Japan•

Early period:
 Felt a shake = tsunami is coming & No tsunami in Japan Sea side• 1896 Meiji Sanriku tsunami: tsunami-earthquake type
 Small shake but large tsunami (38.2 m / 22,000 deaths)• 1933 Showa Sanriku tsunami: Outer-rise earthquake Large shake and large tsunami (28.7 m / 3,000 deaths)• 1960 Chile tsunami: Far-field tsunami from M9.5 earthquake No shake but large tsunami (10.7 m / 142 deaths)• 1983 Japan Sea tsunami: The first recent tsunami in Japan Sea
 Warning after 14 mins but tsunami arrived after 12 mins (14.9 m / 104 deaths)• 1993 Okushiri tsunami: Just 10 years after the 1983 event Waning after 5 mins but tsunami arrived after 2-7 mins (32.0 m / 230 deaths)• 2011 Tohoku tsunami: M9.0 never record in Japan Large shake and large tsunami (40.5 m / 19,000 deaths)
1923 Great Kanto

1995 Great Hanshin

2011 Great East Japan

Mw

7.9

6.8

9.0

Time

11:58

05:46

14:46

105,385

6,434

18,579Fire = 87.1%

Shake = 83.3 %Tsunami = 92.4 %Shake = 10.5 %Fire = 12.8 %Shake = 4.4 %Casualty

6

Condition before March 2011
Tokai-Tonankai-Nankai earthquake
Earthquake possibility in Japan

SapporoSendaiTokyoNagoya
OsakaFukuoka

20xx Heisei
1946 Showa1854 Ansei
1707 Hoei
1605 Keicho
Meio
1361 Shohei
1099 Kowa

20xx
158 years1944

1498
1096

887 Ninna
684 Hakuho
http://www.jishin.go.jp/main/chousa/07_yosokuchizu/img/f1-3-2.jpg

http://www.jma.go.jp/jma/en/Activities/earthquake.html

7

Earthquake early warning system in Japan Quick estimation of Hypocenter, Magnitude and depth Seismic Intensity at a few stations around the source
 Broadcasting the information before ground shaking
 JMA starts this service in October 2007

Source: JMA http://www.jma.go.jp/jma/en/Activities/earthquake.html

8Tsunami warning systems in Japan
Assumed faults around Japan(100,000 cases)

Numerical simulation results stored in database

Seismic Network

Sea Level Network

Elapsed time(minutes)

30

Source: JMA

25
20
15
10

1983 tsunami
arrived 7 min
100 casualties

1993 tsunami
arrived < 5 min
230 casualties

501952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004yearSanriku tsunamis and Miyagi Sea tsunamis
41

1896
M8.5
40

39

Iwate

Latitude

1933
M8.1
1611
M8.1

Miyagi Oki
M7.5 - 8.0

869
M8.3

3837

2011 Heisei

Miyagi

36

1896 Meiji

2011
M9.01611 Keicho

2011

3509Earthquake
magnitude

1896

1933 Showa

8.5

1793
M8.2

87.5
71790

Miyagi Sea earthquake
1835 1861
M7.3 M7.4
1830

1870

1897
M7.4
1910
Year

1936
M7.4
1950

2011
M9.0

10

20

30

40

Maximum tsunami hegiht (m)

1978
M7.4
1990

2030

10

Tsunami warnings during the 2011 tsunami
Local
EventInformation----------------------------------------------------------------------------------------------------14:46
Earthquake
14:49
Mjma = 7.9 MajorTsunami Warning Iwate, Miyagi and Fukushima
14:50
Tsunami Information Iwate: 3m, Miyagi: 6m,Fukushima: 3m, etc.
Only up to M8.0 in the database
15:10
GPS buoys > 3m
15:14
Tsunami Warnings/Advisories extended
15:14
Tsunami Information Iwate: 6m, Miyagi: over 10m,Fukushima: 6m, etc.
Tsunami hit the nearest coast
15:21
Tide gauges at Kamaishi (Iwate) > 4.1m (scale out)
15:30
Tsunami Warning extended
15:31
Tsunami InformationIwate, Miyagi, Fukushima: over 10m, etc.
16:00
Mjma = 8.4
17:30
Mw = 8.8
13th MayMw = 9.0
Hayashi et al (2011) and http://www.jma.go.jp/jma/en/2011_Earthquake.html

11

Recorded wave amplitudes

http://www.pari.go.jp/info/tohoku-eq/

122011 Tohoku earthquake

20xx Nankai earthquake

Shallow region
Deep region

Interplate
earthquake

Tsunamiearthquake

Source: NHK
13

The 2011 tsunami:
Large different intsunami hazard map

TaroOfunato

Red: 2011 tsunami inundation area
Blue: Predicted inundation area

Ishinomaki

Sendai14

Advance observation technology
http://www.jamstec.go.jp/jamst
ec-e/maritec/donet/index.html

http://www.bosai.go.jp/activity_special/the_third/ev/earthvol-04.html

15

New tsunami warning classification
Old system (8 levels)
New system (5 levels)
Announce tsunami height Number Message Estimated tsunami height> 10 m> 10 m> 10 mMajor tsunami
Major
8 m, 6 m
10 m
5 m - 10 m
Warning
4 m, 3 m5m
3m-5m
Tsunami2 m, 1 m
3m
High
1m-3m
Advisory Tsunami advisory
0.5 m
1m
20 cm - 1m

Tsunami warning and watch

Source: JMA

16

Questionnaire survey related to tsunami evacuation (1)By Cabinet Office, Fire Agency and Japan Meteorological Agency-Total answers: 870 (Iwate = 391, Miyagi = 385 and Fukushima = 94), period: During July 2011
-A: Soon evacuated (57%), B: Evacuated after some actions (31%), C: Tsunami came during doing some actions (11%)
and D: Did not evacuated (they were already in high ground) (1%)-[A+B] Main reasons for starting evacuation: large shaking (48%), were asked to evacuate by family or surroundingpeople (20%) and surrounding people start their evacuation (15%)
 Less amount of calling out for evacuation-[B+C] Why they did not evacuated as soon as possible: Went back home (22%), looking for family or picking up
family (21%), tsunami did not come in the past (11%) and did not think about tsunami coming (9%)
 Have to reduce the amount of people going back home or seeking family
Condition of evacuation shelter- C has the highest ratio of people who were inside the inundation area (38%)- A and B are both mostly evacuated to designated evacuation shelters but C is large on the highest floor of the samebuilding

Blue = outside
inundation area
Red = inside
inundation area
Green = could
not identify
Source: Cabinet office of Japan17

Questionnaire survey related to tsunami evacuation (2)Evacuation method- In general, about 57% of people evacuated using car.
- Reason for using car: Not enough time without usingcar (34%), wanted to evacuate together with family(32%), far from safe place (20%)- About 34% of them were trapped in the serious
traffic.
- In general, limit distance for evacuation by walking
was about 500 m and by car was 2 km.

By walk

Moving distance to the first evacuation shelter by evacuation method
Median distance

TotalIwate
Miyagi
Fukushima

By walk
By carBy walk
By carBy walk
By carBy walk
By carBy carTsunami hazard map- Number of people who had seen tsunami hazard map
or had hazard map in their house was less than 20%
Source: Cabinet office of Japan18

Questionnaire survey related to tsunami evacuation (3)By Weathernews- Target area: Hokkaido, Aomori, Iwate, Miyagi, Fukushima, Ibaraki and Chiba- Total answers: 5,296 (3,298 from survivors and 1,998 related to people who were casualty)
1) Time from earthquake generation to starting evacuation- Survivor = 19 min and casualty = 21 min
2) Reason for starting evacuation- Major tsunami warning or tsunami warning and only 28 % of the survivors soon evacuated3) Evacuation condition- Reason for not evacuated was they believe they were safe and 20% of victim could not evacuated4) Selected evacuation place- 75% of survivor could evacuated to safe place while 75% of victim could not- 40% could not evacuate to high ground and 50% evacuated to non-designated evacuation place5) Why they could not evacuate from the tsunami- 18% of victim was because they were obstructed during their evacuation
6) Evacuated elevation from tsunami- Approximately 2.9th floor for survivor and 1.7th floor for victim
7) Moving from evacuation place- 60% of victim moved to tsunami inundation zone again
8) Reason for moving from evacuation place- Looking for their family was the main reason

19

Lessons # 1: Tsutsujigaoka Elementary School
Number of evacuee = 2,500 !! (four times over than the estimation!!)--Sendai station suffered serious damage  Failed to serve asevacuation shelter
Just 10 min by walk from Sendai station
Estimated no. of evacuee was only based on the local
residence population which was 600
About 1,200 meals were stored for 600 persons (1 person = 2meals). After asking from other community, finally got 3,080
meals on the following day
Most evacuee started leaving the school from 12th night
The school served as evacuation shelter until 24th March

Sendai Station

Source: Kahoku Shinpo
http://www.kahoku.co.jp/spe/spe_sys1071/20110726_01.htm

School20

Lessons # 2: Arahama Elementary School
Most children survived excepted those who went back home with family-Tsunami as high as 10 m (tree level)
Spent three days pumping water out
Rescue by helicopter and boat

After tsunami

Estimatedinundation limit
M8.0 EQ
http://www.city.sendai.jp/fukko/__icsFiles/artimage/2011/09/
09/c_70_70/110311tunami2.jpg

http://pub.ne.jp/ebinet/image/user/1312539194.jpg

Before tsunami

http://blog-imgs-36.fc2.com/j/o/s/josua1113/20110331204858158.jpg

21

Lessons # 3: Unosumai Disaster Prevention Center
One actual disaster differ from million drills-34 survived and 128 or more becoming deaths
Original evacuation places are on the high groundThe center was newly opened on Feb 2010 and were used as a goal of tsunami
evacuation drill on 3rd March 2011 or just 8 days before the event
Tsunami reached almost the roof of the second floor
As results, 150-200 residences selected this center as their evacuation destination

http://www.at-s.com/news/2012/03/07/images/11.jpg

http://www.chunichi.co.jp/article/earthquake/sonae/20120
312/images/PK2012031202100063_size0.jpg
22

Lessons # 4: Unosumai Elementary and Junior high schools
Miracle of Kamaishi…Awareness for expected event- All nearly 3,000 students survived
Three principles- First, don't put too much faith in outdated assumptions. “Inother words, don't trust hazard maps.
- The second rule of thumb is for people to make their best
efforts to deal with the situation. They urged the teachers tokeep moving higher, adding that the older kids also
remembered to help the younger ones.
- And finally, to takeCasualty
the initiative in any
distribution
evacuation.
of deaths
http://mnj.govonline.go.jp/kamaishi.html

on hazard
map

Hazard map

SchoolSchool

Historicaltsunamis

Actual tsunami

http://insite.typepad.jp/.a/6a0120a6885bf1970b01543336c30e970c-320wi

http://www.chunichi.co.jp/article/earthquake/sonae/20120
312/images/PK2012031202100063_size0.jpg
23

Tsunami countermeasures in Japan• 1896 Meiji-Sanriku tsunami: by individualMoving high ground• 1933 Showa-Sanriku tsunami: by country and prefecture
Moving high ground + Seawall in some areas• 1960 Chile tsunami: Structural measures
Seawalls, breakwaters and tsunami gates• 1993 Okushiri tsunami:
Structural measures, town planning and combination
with soft measures• 2011 Great East Japan tsunami:
Prevention  Reduction24Breakwater: Kamaishi

Water gate: Fudai

Structural measures for tsunamis

Seawall: TaroSea

Land

Control forest: Rikuzenakata
Highland residence: Toni-hongo

川25

Level 1 & Level 2 tsunami
Level 1:High frequency (30-200 years) but small to moderate tsunami.
Community should be mostly protected by coastal defense structures.
Height of coastal structures were decided by past Level 1 tsunami
eventsLevel 2:
Low frequency (200-1,000 years) but very high tsunami.
Forget about properties but secure evacuation routes for safeevacuation.
Coastal structures should be strong enough even in case of theovertopping.

http://www.bousai.go.jp/kaigirep/chousakai/tohokukyokun/4/pdf/2-2.pdf

http://www.pa.thr.mlit.go.jp/kakyoin/PDF/sankou.pdf

Level 1

Level 226

New height of seawalls in Miyagi prefecture

After 2011

Before 2011

2011 tsunami

27

Reconstruction plan of Miyagi prefecture

http://www.pref.miyagi.jp/seisaku/sinsaihukkou/keikaku/index.htm

28

Characteristics of the 2016 Fukushima tsunami
The highest observed tsunami was in Sendai
The second wave was the largest
Tsunami threat level was elevated from “advisory” to “warning”

Local runup was higher than the observed amplitude
Tsunami intrusion into rivers
Tsunami warning and broadcastingThe highest observed tsunami was in Sendai

Locations of study area, tide gauges and surveyed
areasThe highest observed tsunami was in Sendai
Fault
orientation

Observedmaximum tsunami
amplitudes

The second wave was the largest

Earthquake

1st wave

2nd wave
Sendaiport
Fukushima

Observed tsunami waveforms

Source: JMA

The second wave was the largest

Tsunami propagation to Sendai Bay

Tsunami threat level was elevated from “advisory” to “warning”

Miyagi Prefecture
Fukushima
Prefecture
Ibaraki Prefecture

Tsunami warning

Tsunamiwarning

Status of the tsunami warnings and advisories

Local runup was higher than the observed amplitude
T.P. +1.4 m

Local tsunami runup
Observed tsunami amplitude
T.P. +4.1 m

Sendai port

Miyato area

T.P. +3.6 m

Based on our preliminary survey,
tsunami runup higher than theobserved tsunami wave amplitude of
1.4 m at Sendai Port was measured
at several sites. In the Miyato area ofHigashi-Matsushima City in Miyagi
Prefecture, tsunami runup heights ofmore than 2–3 m were found causedby nearshore processes over thecoastal topography.

Tsunami intrusion into rivers
This phenomenon was clearly observed atSunaoshi River in Tagajo City, where the tsunami
propagated over 3 km into the river. The tsunami
speed is estimated to be about 14 km/s and themaximum rising of the river level reached 0.9 m(0.6–0.7 m above the normal level).

Tide gauge

Tsunami warning and broadcasting

Source: NHKIn contrast to the calm voice used during the 2011 tsunami, terms such as “Evacuateimmediately!”, “Tsunami! Evacuate!”, etc. were used to warn people to evacuate fromlocations expected to be hit by the tsunami. Also, some phases such as “Pleaseremember the Great East Japan Earthquake and move to higher ground”, were used toremind the audience of the 2011 devastation. The warnings were also released in
Chinese and Korean languages.

2018 Sulawesi tsunami

BMKG - http://lipi.go.id/public/uploads/berita/berita_palu.jpg

39験潮記録（2）at Mamuju

40験潮記録（3）at Pantonloan

41

Location of the landslides

42Difficulty of tsunami prediction
EX: 2018 Palu tsunami

1) Horizonal movement of slope (Tanioka and Satake, 1996)

2) Aerial or submarine landslide (Imamura et al., 2001

43

Difficulty of tsunami prediction
EX: 2018 Sunda Strait tsunami

44

5th November: World Tsunami Awareness Day
Story of saving lives as well as reconstruction for resilience city
http://www.pref.wakayama.lg.jp/prefg/000200/nagomi/web/nagomi01/tour.html

People evacuated to thehigher ground by fires
Tsunami festival for memoryof hiro; Mr.Hamaguchi

Seawalls
1854
tsunami1946
tsunamiReconstruction with the wall to reducetsunami inundation in 1946

Tsunami evacuation during COVID-1946

Tsunami evacuation during COVID-1947

Tsunami evacuation during COVID-1948

Tsunami evacuation during COVID-1949

Tsunami evacuation during COVID-1950

Thank you
SendaiNatori
IwanumaWatari

Yamamoto