Development of High Precision Tsunami Simulation

Based on a Hierarchical Intelligent Simulation

Taro Arikawa

Chuo University

Damage of Otsuchi

Taken by resident

Kamaishi Tsunami Breakwater

SugaHirata

IzumiMouth of Port

Kamaishi Port

Tsunami Breakwaters

Sea Side

Harbor Side

Inside of Port

Outside of Port

Failure of Breakwater at North Part

TOHOKU REGIONAL BUREAU MINISTRY OF LAND , INFRASTRUCTURE AND TRANSPORT

Cross section of damage of North Breakwater

DL=0.00

DL=-50.00

港　外　側 港　内　側DL=0.00

DL=-50.00

港　外　側 港　内　側

– h” g’ çŒv‰æ– @• ü

DL=0.00DL=0.00

DL=-50.00DL=-50.00

港　外　側 港　内　側港　外　側 港　内　側DL=0.00DL=0.00

DL=-50.00DL=-50.00

港　外　側 港　内　側港　外　側 港　内　側DL=0.00

DL=-50.00

港　外　側 港　内　側DL=0.00DL=0.00DL=0.00

DL=-50.00DL=-50.00DL=-50.00

港　外　側 港　内　側港　外　側 港　内　側港　外　側 港　内　側DL=0.00

DL=-50.00

港　外　側 港　内　側Sea Side Harbor Side

From video by public people15:18 (1st positive wave, 32 minutes after)

15:28( negative tsunami started, 42 minutes after)

Casualty Rate in Different Municipalities

Minumum

Maximum

Kesennuma

Onagawa

Higashimatsushma

Sendai

Natori Rikuzentakada

Yono Fudai

Ofunao

Kamaishi

OtsuchiMinamisankriku

New Earthquake Model(Nankai Trough)

the Disaster Management Council of the Cabinet Office, 2012

Time after earthquake (min)

Wa

ter

su

rfa

ce

ele

va

tio

n (

m)

with breakwater

without

Effect of breakwater (Tomita et. al, 2012)

With Breakwater

Tsunami height (m)

Arrival time

6 minutes delay

(tsunami height of 4 m)

Without Breakwater

Tsunami height

13.7 m → 8.0 m

9

Design policy of physical countermeasures

Tsunami Level Definition Planning or design

Tsunami

Prevention Level

（L1）

Tsunamis that occur frequently

and cause extensive damage

even though they are not high

To prevent the protected lowland

from being flooded, it plans and it

designs.

⇒Continued mitigation through

physical countermeasures

Tsunami

Reduction Level

（L2）

The largest class of tsunami,

which occurs at an extremely

low frequency, but which causes

enormous damage when it does

It plans and it designs so that it is

made easily not to destroy and to

collapse, and damage should not

expand though the flood of the

protected lowland is permitted.

That means ‘resilient’ structures

⇒Disaster mitigation by evacuation

It is necessary to estimate two levels of tsunamis, and develop measures

to mitigate damage for both of them.

HOW TO PREDICT DAMAGES?

Direction of Research

• In order to evaluate the damage due to giant tsunamis,

influence of destruction of structures, debris, etc. is

required.

• The power of the tsunami is greatly different depending on

the place and the condition

• 3 dimensional numerical simulator should be required to

analyze overflow, scour, flood into buildings and so on.

• The system which connects tsunami propagation

simulator and 3-D numerical simulator should be

developed.

The STOC-CADMAS system

STOC-ML

Tsunami source

STOC-IC

3D model Calculates the free water surface with a vertically integrated continuity equationComputation load: moderate

Quasi-3D model (multi-level model)

Assumes hydrostatic pressures at each level

Computation load: light

CADMAS-SURF/3D

3D model Estimates the free

water surface with the VOF

method

Computation load: heavy

Coupled

with

DEM/FEM

STOC system (Tomita et. al., 2005)CADMAS system (Arikawa et. al., 2005)

Connections between simulator calculations

STOC-ML

STOC-ML

STOC-IC

CADMAS-

SURF/3D-MG

STOC-ML STOC-ICCADMAS-

SURF

/3D-MG

Communication

by MPI

Communica

tion by MPIMust not

touch

All connections are made using MPI communications.

Although all three models are capable of segmenting their respective areas of interest, when different calculation methods are used in the same area (for example, STOC-IC calculations are used in an STOC-ML area), the parent area containing the different calculation methods is regulated to prevent segmentation.

Consequently, when a CS3D area is made sufficiently large, the STOC-IC area that contains it ultimately becomes larger as well, as a single area.

Image of calculation at Onagawa

Domain for CADMAS-SURF

Domain for STOC-IC

Information of each domain

No.

Lay

er

Grid

Size(m)

Ratio

of

Grid

size

Number

of grid

(X)

Numb

er of

grid

(Y)

Numb

er of

grid

(Z)

Number of

gridCode Name

Numbe

r of

Core

1 2,916.0 － 500 365 1 182,500 STOC-ML 1

2 972.0 3 510 390 1 198,900 STOC-ML 1

3 324.0 3 405 387 1 156,735 STOC-ML 1

4 108.0 3 900 600 1 540,000 STOC-ML 1

5 36.0 3 930 930 1 864,900 STOC-ML 1

6 12.0 3 1,020 780 1 795,600 STOC-ML 1

7 4.0 3 870 627 1 545,490 STOC-ML 1

8 4.0 1 390 285 13 1,444,950 STOC-IC 3

9 1.0 4 600 800 32 15,360,000CADMAS-

SURF/3D32

Tsunami Source: 1) Fujii-Satake ver. 4.0 model with scaling adjustments to match the tsunami waveform obtained with

GPS wave sensors off the southern Iwate coast.2) Fujii-Satake ver. 8.03) Central Disaster Prevention Council(2011)4) Takagawa and Tomita (2012)

Domain 01, ML

Tsunami Source; Takagawa and Tomita 2012

STOC-IC to CADMAS-SURF/3DDomain 07 to 08

Tsunami Source; Takagawa and Tomita 2012

Domain 08, CADMAS-SURF/3D

Comparison of Maximum Inundation height(Tsunami Source: Takagawa andTomita (2012)

measured

Comparison of Flow depth

Fujii, Satake –ver 4.0

Central Disaster Prevention Council

PROGRAM’S EXECUTION PERFORMANCE

Flow Charts and Locations of Synchronization of each Program

The data are synchronized to be handed over at boundaries. Therefore, in the domain of STOC-ML for example, even when the calculation has been completed, if the calculations of the domains of STOC-IC or CS3D are not completed, in order to synchronize them, the computer goes into synchronicity standby state.

Number of grids around 120 million for CS3D

Domain 10(CADMAS-SURF/3D)Δx=1m, Num. of Grids 120 million

Domain 8(STOC-ML)

Domain 9(STOC-IC)

Divided 2 part

DomainMesh size

(m)Mesh

ratio

Number of meshes Calculation program

name

Number of

nodesX Y Z Total

1 5400 － 256 205 1 52,480 STOC-ML 1

2 1800 3 78 177 1 13,806 STOC-ML 1

3 600 3 48 75 1 3,600 STOC-ML 1

4 200 3 108 141 1 15,228 STOC-ML 1

5 100 2 166 110 1 18,260 STOC-ML 1

6 50 2 240 150 1 36,000 STOC-ML 1

7 10 5 1100 690 1 759,000 STOC-ML 1

8 5 2 1970 1000 1 1,970,000 STOC-ML 2

9 5 1 480 360 13 2,246,400 STOC-IC 1

10 1 5 2000 1500 40 120,000,000 CS3D 48

Each node has 8 cores

K computer

Result of reduction in execution costs Ration of number of node: ML:IC:CS=9:1:48

Ration of number of node: ML:IC:CS=9:1:90

With thread parallelization

With thread parallelizationTotally, more than three times reduction in execution costs

Synchronization time becomes almost zero.Next step, more improvement in the speed of calculation of an individual program should be investigated and more larger area of CADMAS-SURF would be tried

Including communication time in each program

The average of dt is around 0.005s. If 1 hour calculation would be required, it takes around 10 to 20 days

Total number of cores are 800

Number of grids around 12 billion for CS3D

Calculation time per

one step by using

900 nodes is almost

10 times as the

calculation time for

120 million grids by

using 90 nodes

The number of iteration

for convergence of

matrix analysis is

increasing

Calculation time

=（the rate of increase of grids）×（ the rate of increase of iteration）= proportional to the square of the rate of increase of grids

The results say that the calculation time by using 9000 nodes is almost

same as that for 120 million grids by using 90 nodes

COUPLING ANALYSIS

Coupling with structure analysis and evacuation simulator

Cross section of damage of North Breakwater

DL=0.00

DL=-50.00

港　外　側 港　内　側DL=0.00

DL=-50.00

港　外　側 港　内　側

– h” g’ çŒv‰æ– @• ü

DL=0.00DL=0.00

DL=-50.00DL=-50.00

港　外　側 港　内　側港　外　側 港　内　側DL=0.00DL=0.00

DL=-50.00DL=-50.00

港　外　側 港　内　側港　外　側 港　内　側DL=0.00

DL=-50.00

港　外　側 港　内　側DL=0.00DL=0.00DL=0.00

DL=-50.00DL=-50.00DL=-50.00

港　外　側 港　内　側港　外　側 港　内　側港　外　側 港　内　側DL=0.00

DL=-50.00

港　外　側 港　内　側Sea Side Harbor Side

Experimental Video under tsunami overflow

Numerical Simulations

30

(2) CADMAS-STR PCT-girder

System of CADMAS-SURF/3D-STR (Arikawa et al., 2009)

Main program

CADMAS-SURF/3D(VOF method)

STR3D(FEM)

calculation step calculation step

Data on pressure

Data on displacement

call subroutine call subroutine

Images of CADCADMAS-SURF/3D

Numerical Conditions

31

CADMAS dx=dy=dz=0.10 m

STR

Young's modulus ： 2.35e11Poisson's ratio ： 0.333Density

test body ： 2135dummy caisson ： 2349

Coefficient of frictionstatic ： 0.6dynamic ： 0.2

dummy

Overflow Animation

32

Kamaishi Area

Outer areas are STOC-ML

CS-STR

Breakwaters in Kamaishi Bay

𝑝𝑑𝑤:動水圧

𝑘ℎ:震度

𝜌𝑤𝑔:水の単位体積重量

𝑦:水面から動水圧を求める点までの長さ

𝐻:水深

𝑝𝑑𝑤 =7

8𝑘ℎ𝜌𝑤𝑔 𝐻𝑦

水深変動が影響する項

圧力集中緩和のための改良の必要性

浸透流問題

洗堀問題（粒子法との連成）

Calculate results

Experiment results

Numerical Simulations (2) CADMAS-STR PCT-girder

38

OBST

Bridge

POROUSSlope 1:1

Girder

1.31

0.5

4.0

10.0

1.85

1.35

0.7

0.52.2

OB

ST

PO

RO

US

Girder2.4

0.2

0.1

0.2

0.1

Calculation Conditions

Numerical Simulations (2) CADMAS-STR PCT-girder

39

Physical Property

Young's modulus ：2.0E11Poisson's ratio ：0.333Density ：2450Coefficient of static friction ： 0.6Coefficient of dynamic friction： 0.2

Calculation Conditions（STR)

Numerical Simulations (2) CADMAS-STR PCT-girder

40

Animation

(Arikawa, 2016)

EVACUATION

Domain 08, CADMAS-SURF/3D

Comparison of Flow depth

Fujii, Satake –ver 4.0

Central Disaster Prevention Council

Condition for the evacuation against tsunami to be successful

Total time to evacuate＝ Time to start to evacuate

(Judging time whether they evacuate)＋Time to move the evacuation place

Total time to evacuate < Tsunami arrival time

and

Height of evacuation place > Maximum Tsunami inundation height

国土地理院地図

2015.09.16. Illapel Earthquake Tsunami

410 k

m in a

str

ait lin

e

Base map: Contour map of

the shake in the MMI scale,

presented by USGS

Casualty Rate in Different Municipalities

Minumum

Maximum

Kesennuma

Onagawa

Higashimatsushma

Sendai

Natori Rikuzentakada

Yono Fudai

Ofunao

Kamaishi

OtsuchiMinamisankriku

The relation between the seismic intensity and evacuation rate

Evacuation rate and Intensity linein Chile

Evacuation rate and Intensity linein Japan

The relation between the Intensity of the shaking and evacuation rate in the 2011 Tohoku Earthquake

52

Now we are analyzing the reason

Data :archives for reconstruction support, http://fukkou.csis.u-tokyo.ac.jp/

Chile

Japan

Calculation Conditions by STOC-ML

Talcahuano Tongoy

Resolution in Space

5.0m 10.0m

Number of grids 1090×595 675×850

Fault Parameter 2010 earthquake by USGS 2015 earthquake by USGS

Bathymetry Data Making the bathymetry map GEBCO

Talcahuano Tongoy

Calculation Domain for the smallest domain 53

Evacuation Route and Points

• The height of evacuation points is more than 30m

• Initial position of evacuee is set randomly

• The evacuation route is set by using the city map

Talcahuano Tongoy

54

Relation between the evacuation start time and mortality rate

Talcahuano• Second tsunami is enough large to inundate,

so if they start to evacuate after second wave

coming, the fail rate is increasing.

• If they start to evacuate within 10 minutes,

the risk of evacuation fail is increasing.

55

Tongoy• Under this calculation conditions, if they

start to evacuate within 20 minutes, there is

some risk of fail.

Coupling with Evacuation SimulationCoupling STOC, CADMAS-SURF and PARI-AGENT

STOC

CADMAS-SURF

Arikawa and Tomita (2014)

PARI-AGENT

Now under development

57

Tsunami Evacuation Simulator (1)(PARI-AGENT)

CADMAS-SURF/3D

3D model Estimates

the free water surface

with the VOF method

Determinate Moving Route

is determinated by superposed two potentials.

② Crowd Potential

Follow the direction in which there are evacuees.

① Evacuation Route Potential

Evacuees select the shortest distance

to evacuation place.

58

Tsunami Evacuation Simulator (2)(PARI-AGENT)

Death JudgementWhen the inundation height reach the 1.0m,

evacuees are dead.

Walking Speed is corrected by the evacuation route slope

and the inundation depth.

If evacuee is flooded, walking speed become slow.

Reproduction at the earthquake on 1st of April in 2014

59

Iquique city in Chile

Setting the evacuation places at which more than 5 the evacuees were gathering.

Initial positions and Routes Initial Positions and Evacuation places

Calculation conditions of PARI-AGENT

60

Item Detail Note

Number of People 285From the results ofQuestionnaire

Start time to evacuate

0sec

Time steps for calculations

0.1sec

End time 7,200sec

Moving velocity foragents

Initial velocity 1.0 to3.0 m/s

With hiking function

Depth to die 1.0m

Number of evacuation places

22カ所From the results ofQuestionnaire

Evacuation Sign No

Calculation Conditions for STOC-ML

61

項目 詳細 備考

Calculation Domains See the slide after

Topography From Dr. Okumura in Kyoto University Without buildings

Grid sizeDomain 1 ：810m～Domain 5 ：10m

1:3 all domains

Time steps 0.5sec

End time 7,200sec

Tidal level 0.0m

Tsunami Source From Dr. Okumura

Animation

62

Tsunami Source; Mw8.8，Virtual Fault in Iquique city

Comparison of Evacuation distance and places Almost good agreement with actual evacuation distance and places（concordance

rate 66.3%）．

So many people chosen the minimum evacuation distance.

One of the main reason of this phenomena is the simple route to the evacuation places from the shore lines

63

0

5

10

15

20

25

0 5 10 15 20 25

計算による避難箇所

実際の避難箇所

0

500

1000

1500

2000

2500

3000

3500

4000

0 500 1000 1500 2000 2500 3000 3500 4000

計算による避難距離 (m)

実際の避難距離 (m)

Evacuation distance

Cal

Actual

Cal

Actual

Evacuation places

Calculation at Kamaishi

64

Item Value NoteCalculation Domain Kamaishi

Grid size 5.0mTotal number of grids 1425×550

Time step 0.1sNumber of evacuees 27 From Questionnaire

Number of evacuation places 21 Kumagai et. al. (2013)Sign for evacution 0

Weight coefficient of minimum distance potential

ak,1

1.0

Weight coefficient of CrowdPotential

ak,2

0

Setting of Initial Positions and Evacuation Places at Kamaishi

65

Start Position

Evacuation Point

Evacuation Route

Comparison of Evacuation distance

66

0

500

1000

1500

2000

2500

3000

3500

4000

0 1000 2000 3000 4000

実際の避難距離 (m)

経路探索による最短避難距離 (m)

Making more simple evacuation route decreases the mortality rate

Evacuation distance

Calculation(m)

Actual (m)

Rising speed is usually Around to 2 meter per minutes

Inundated speed is around 50 to 100 meter per minutes.

Rising speed of tsunami Inundated speed of tsunami

Total time to evacuate < Tsunami arrival time

and

Height of evacuation place > Maximum Tsunami inundation height

Effect of delaying the inundated time

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0.00 0.20 0.40 0.60 0.80 1.00 1.20

Mo

rtal

ity

Rat

e（％）

Target; Coastal towns in Iwate and Miyagi Pref.

10-15分後

16-20分後

21-25分後

26-30分後

31-35分後

36-40分後

Averaged Evacuation start time

Rikuzentakada

Miyako City

𝐻𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑆𝑒𝑎𝑤𝑎𝑙𝑙

𝐻𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑇𝑠𝑢𝑛𝑎𝑚𝑖

Relation between the mortality rate and Non dimensional seawall height

It is important to consider that the balance of the safety sense increasing and the tsunami height decreasing

Case study by using Tohoku tsunami in 2011

69

Sample areas

背景図出典：電子国土

1)Averaged Evacuation start time：20 minutes2)Height of seawall：5m

1. Takada town, Rikuzentakada city, Iwate Pref.

2. Taro town, Miyako City, Iwate Pref.

1)Averaged Evacuation start time：14 minutes2)Height of seawall：10m

70

Calculation ConditionsItem Takada Taro

Resolution 10.0m 10.0mNumber of Grid 270×240 120×115

Duration time 0.1s 0.1s

Number of Agents 1000 1000Evacuation Speed 1.0m/s 1.0m/sEvacuation start

time0 to 35 min 0 to 35 min

Height of seawall 0 to15 m 0 to 15 m

Number of evacuation Points

10 3

Evacuation Sign 0 0

The coefficient of route potential

1 1

The Coefficient of crowded potential

0 0

Judging to death 1.0m 1.0m

Evacuation route and Inundation area

Takada Taro

復興支援調査アーカイブより

71

Relation between height of seawall and mortality rate

Reduction rate on inundation area

0.0

20.0

40.0

60.0

80.0

100.0

0 5 10 15 20 25 30 35

Mo

rtal

ity

Rat

e （

%）

Evacuation start time（MIn）

Takada

0m

5m

10m

15m

Height of Seawall

13.8%Down79.9%

0.0

20.0

40.0

60.0

80.0

100.0

0 5 10 15 20 25 30 35

Mo

rtal

ity

Rat

e（%）

Evacuation start time（MIn）

Taro

0m

5m

10m

15m

Height of seawall

63.0%Down

14.4%Down

Height of Seawall

Reduction Rate（%）Takada Taro

0m 0.00 0.00

5m 1.13 0.28

10m 5.13 1.63

15m 5.61 4.48

This result is depend on the tsunami height!

VISUALIZATION AND SPREAD

72

x,z：10mm Grid size

74

x,z：1mmx,z：5mm

Breaking wave

【Wave Conditions】h=20cm，H=2.0cm，T=2.0s

（Regular Wave）

1.5 x 107 Grids

1.0 x 108 Grids

12 x 108 Grids

By using AWS

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0 50 100 150 200

Ti(s

/Ste

p/I

tr)

threads

1instance

2instance

4instance

8instance

8instance[1.0*10^8]

If we want to calculate the simulations for 1s, (the integral times), it takes

Ttotal=Ti*(Number of ITR)*(Number of STEPS )

That means Ttotals= 0.01* 100 * 1000 (Δ t= 1.0*10-3)=1000 s

1.0*10^7

C4.8 x large

=17US$*1000/3600=5US$

30 s x 5 $ =150 $

Which is cheaper?

• Physical Experiments needs • construction cost

• Running cost• Model

• Operation

• Water

• And so on..

Thank you for your attention !

80

Iquique, Chile

誰もが気軽にできる高精度かつ安価な計算システムを目指して