Contribution from meteorology, hydrology and DRR for thePlatform on Water Resilience and Disasters
2019 WBF

Lessons learned from the 2011 Tohoku earthquake andtsunami for the mitigation in the future
One of investment for future risk

Fumihiko Imamura, Prof. and directorof International Research Institute ofDisaster Science(IRIDeS),TOHOKU University

1March 11, 2011 disaster and IRIDeS• March 11, 2011 disaster– Worst disaster in history from triple tragedy• JPY 16.9 trillion ($210 billion)• e.g. JPY 6.5 trillion($81 billion ) for Hurricane Katrina– Uncovered limitations of modern science and technology• Large-scale disaster impacts can’t be prevented• Need longer time horizons for better understanding;importance of referencing ancient documents and geologicalevidence– Holistic approach is needed to respond to mega-scale disasters• Need wider spatial horizons for getting enough cases andexperiences : International cooperative research
2IRIDeS: A new institution in a disaster stricken area
• Principle:– Promote world’s leading research on natural disasters
through:• learning from the Tohoku earthquake and tsunami;• contributing to the regional recovery; and• set an international paradigm on disaster management
studies3

Unfolding the 3.11 event:
Triple Tragedy and Damages• Triple Disasters: ONE – The Earthquake– Time: March 11, 2011, 2:46pm– Scale: Mw 9.0(4th largest in the world
since 1900 (USGS))– In 5 days: 2 additional
Mw 5+ earthquakes(black X)– In a month: 400 +aftershocks continues
4Historical tsunamis in Tohoku for 400 years and the 2011 Tohoku Eq.

40m in slip

releasingStressaccumulating•400 years

T.Hatori，Distributions of Seismic Intensity and Tsunami of the 1793 Miyagi Oki Earthquake, Northeastern
5Japan, Bulletin of Earthquake Research Institute, University of Tokyo, 62, 297-309 (1987).

• Triple Disasters: TWO – Tsunamis
NHK– Tsunami evacuation order and warning,
immediately after – all around coastal
Japan– Time reaching the coast:less than 20-30 min– 7 tsunamis in the first 6 hrs after
the shock, continue for 2 days

– According to the information:

Highest wave recorded: 9.3m
n Highest run up-height : 35 m
n Farthest inland reached: 8kmn

Reuters/Mainichi Shimbun

6• Triple Disasters:
THREE – Nuclear Power Plant Failure– One of the worst nuclear incident,
triggered by the earthquake andtsunami– Temporarily assessed as level 7 onINES– Emergency state is still on-going

Digital Globe via Wiki7NHK8

Other damages• Inundated area:560km2• Liquefaction• FireBoston Globe?
Reuters/
Kyodo

Boston Globe?

BeforeBoston GlobeProf. Yasuda, Tokyo Dentsu University

After9ABC News

Tsunami Warning (JMA,2010) Non-stuctural measure
Time Sequence to Issue Earthquake Information and Tsunami Warning
Earthquake Early Warning
TsunamiWarning
Tsunami Information

Seismic Intensity
Information(Estimated Tsunami Heights andArrival Times)

Earthquake Information(Hypocenter and Magnitude )Earthquake and Seismic
Intensity Information

Tsunami Information(Observed Tsunami Heights andArrival Times)

Seismic Intensity
Information at each
Site10JMA Tsunami information updated on 11 March 2011
1st issue only 3 min. after the Eq. , but warning
underestimated the wave height and impact, reducing theeffectiveness of evacuation

11

Improvement of earthquake/tsunami observation in real time
- More stations to detect tsunamis shortly

12
http://www.bosai.go.jp/inline/tsunami/tsunami01.html

Applying a new way; Instant tsunami prediction based on AIAIInput

Learn

Coastal tsunami
Wave height

Offshore Tsunami Observation
Wave height

inferenceReal
dataSimulation
DataTimeTime

Wave height

Wave height

Kawasaki
CityTimeTime

Offshore
Observation
Quake

Early Prediction Update Update Update ・・・・・・ Update Tsunami
Warning
ArrivalRegionally-customized

Predictions

relocation
destination

People stayand rebuild
individually

A. Relocation

Not suitablewithin the affectedarea the local
authority define
the area
unsuitable forhabitation andrelocation en mass

B. Aggregation on siteC. Land raising

Within theaffected area thelevee next to thecoastline andsecondary levee
to increase
security andconcentrate thehabitable areLand is raised using
agricultural soil tomake suitable forresidential use(excludes works
related to
substance ordecontamination)

notsuitableforhousing

notsuitableforhousing

coastlevee

relocation
destination

Sea wallLand raising

D. Relocation& land raising

Categorized as either
relocation or landraising depending on
the numbers ofdwellings affected

E. On site with defence facilities

Not
suitableforhousingPeople can remain in their existinghomes or rebuild on-site following
improvement to levees, sea walls,
or road maintinance -i.e. basic
infrastructure improvement

Sea wallMulti-layers Protection for Resilient CityThe 2011 Tsunami
inundated in Sendai (Kyodo,2011)

Before 2011, Sendai
constructed byMr.Date, Samura in 1601

Green belt

Canal
Less damage and latearrival by green
Rice field

Canal
Sandy beach
Cyranoski (Nature, Vo.483,2011)

Only two shrines were damaged
among 100 with 1,000 years history
in the affected area15Fundamental Strategy for Tsunami Disaster Measures
Tsunami level 1
・ Aim to ensure protection of human lives, assets and national land(coastal line), etc against comparatively frequent tsunami (50 -150years) on the basis of constructing coastal protection facilities.
・Conduct technical development and improvement of structures so thatthey cannot be easily broken even when the tsunami height exceeds thedesign level.
Tsunami level 2・Aim to prevent as much human damages as possible against maximum
tsunami level by “Integrated Protection” combining structural and nonstructural measures such as land use regulation, building code andemergency/evacuation procedures.

16ʻBuild Back Betterʼ Approach in Reconstruction Projects
In Sendai

Tsunami evacuation facility

Restoration of damaged
residential areas

Nanakita Ri
verDisaster reconstruction
municipal housing

Restoration of a wastewater treatment plantTozai Subway Line

Send
ai To
bu R
oad

Evacuation stairs
Coastal embankment

Elevated roads

Farmland reclamation
NatoriRiver17

Remarks- the 2011 Great East Japan Earthquake and tsunami• "Triple Disaster": multi-hazards of earthquake,tsunami and NPP accident• Underestimate of tsunami warning and the Limits ofHazard Maps => Improving real time observation• A New Approach to Countermeasures: Experienceand Enhancement => Level 1 and 2, multi-layers
protection for resilient city18