Symposiums Open Symposium I: Let's Learn Correctly and ... - j-stage

Symposiums The

Spring

Meeting

Open

of the

Association

Symposium

I: Let's

Southern -On

the

Kanto

Tokyo Earthquake

Next

Correctly

ENDO

Capital Disaster

Kunihiko*

, Chairman of Commission **Tokyo Metropolitan

of Disaster University

seven

& governmental

entation

by

nection

board

the

presentations

specialists

resident of local

this

as

by

and

the

disaster

one

leader

quake

is the

Imminently Region,

-from

Assessment Disaster

Earthquake Directly Results Research

Management

Disaster Under

the

con or

Occurring Capital

of Damage Conducted

by Central

Council - NAKABAYASHI

Itsuki

Tokyo Metropolitan University, Member of CDR, AJG In

southern

Kanto

Region

where

the

it can

be

hundreds

no such

inferred

8 level years

earthquake

that

occurred

or

more.

occurred

In

in the

not

been

80 years

Earthquake

21st

of

hit

by

since occurred.

Magnitude

century.

The

that

probability

is 70%

a big 1923

the within

earthquake when

the

Therefore 7 level

national

several

will

occur

government of the

for Great

first

in an

earth

30 years.

In 2004, the Central Disaster Management Council conducted a damage assessment of Earthquake occurring directly underneath the Capital region. The eighteen earthquakes are as sessed in various conditions of seasons, time and wind. The probability of Northern Tokyo Bay Earthquake is highest among them. The Saitama Earthquake will be caused the most severe dam age in Saitama Prefecture than in case of the other earthquakes. If these Earthquakes occur on a winter evening of a weekday with 15 m/sec ond of wind, the results of these assessments are as fallows; Magnitude of Northern Tokyo Bay Earthquake: M. 7.3 (30km in depth.) Number of collapsed houses: 195,000 buildings Number of burnt-down houses: 650,000 build ings Number of the killed: 11,000 persons

aca

of

has

nounced

Geographers

of Magnitude

of two

earthquakes the

and

century and several earthquakes of 7 level occured in latter century.

than

Kanto

for

Itsuki**

is located,

interval,

more

pres

management

Prefecture

earthquake

Tokyo

Steadily Under

Association of Japanese of CDR, AJG

of Tokyo

previous magnitude

2006

it-

at intervals

ganizations. What

Response, , Member

a big

planned by both the Commission of Disaster Re sponse, AJG, and Saitama Prefecture Govern ment, with the motivation that the residents of Saitama Prefecture understand the seismic prob ability not only in Saitama Prefecture but also in the Capital region, and prepare the countermea sures against the next big earthquake by them selves. programmed

Prepare

NAKABAYASHI

city

Taking the opportunity of the spring meeting of The Association of Japanese Geographers (AJG) in Saitama University, the open sympo sium as a social contribution of AJG were

March

Directly

Region in Saitama

and

ENDO Kunihiko Chairman of Commission of Disaster Response, Association of Japanese Geographers, Nihon University

We

and

Against

The Aim of the Symposium

demic

27-29

Occurring

Countermeasures

Organizers: University

Learn

Geographers,

Earthquake

the

*Nihon

of Japanese

capital 738

Let's

The ure

other

which

damages are

of telephone weeks, cut

failure

off and gas

supply

is

eight

Hanshin-Awaji

and

Correctly

in

are

days,

are

recovered

whose

or less,

Earthquake

fail

and

is of

recovered

of these damage

dam in

the

in 1995.

Magnitude of Saitama Earthquake: M.6. 9 (10km in depth.) Number of collapsed houses: 67,000 buildings Number of burnt-down houses: 190,000 build ings Number of the killed: 3,400 persons In this case of Saitama Earthquake, the vol ume of damage is twice that of the Hanshin - Awaji Earthquake in 1995 The earthquake occurring underneath the Cap ital Region of Tokyo Metropolis hits directly the largest mega-city with the highest density of population and buildings. These is the "super urban disaster" in contrast of the Hanshin-Awaji Earthquake Disaster in 1995 is termed as an "urban disaster" . Super urban disaster means that not only the volume of various damages in creases but also the functional quality of damage influence is higher than in Kobe of 1995, because this earthquake hits directly the heart land of Tokyo where central functions of economics, na tional trated.

administration

and

politics

are

for

Southern

275

into a big wave near the afore

Active

Seismic

Fault

and

Prefecture,

Central

Investigation

Hazard

in Saitama

Japan-Importance

into

Ayasegawa

the

of

Properties

of the

Fault - WATANABE

Mitsuhisa

Toyo University

concen

It is necessary bility

and its Predictions

Earthquake

other and growing said terrace cliffs.

that

However,

Earthquake Disasters Saitama Prefecture

Kanto

few years before middle deep-focus earth tremors in the eastern Kanto. The southwestern Kanto area has been subject to frequent very shallow earthquakes when some volcanoes de veloped in the northern most part of the Fuji vol canic zone erupted. These seismo-volcanic dis turbances have occurred at intervals of about fif teen years. The focal zone has suffered from disasters owing to the strong motion of upthrusting. More over, the Uemachi fault in the base rock of Osaka does intensify the surface motion when Kobe was visited by the 1995 Southern Hyogo Earthquake. It may well be that such seismic focusing coin cides exactly with a narrow belt of consistently catastrophic damage in the Saitama Plain. Alluvial plains developed in the southern part of the above-mentioned plain bounded by terrace cliffs on the north. Such a geographical aspect was possibly brought about that seismic surge and backwash from the south overlapping each

in two supply

1,200,000

volume the

Steadily

1,100,000

water

a month,

The

Prepare

of power

in six

suspended

so on.

times,

and

1,600,000

which persons

recovered

in a month, ages

are

recovered

11,000,000

piped

Learn

in

it

evaluate active

TSUNODA Fumio Saitama University

to take

earthquakes

into

account

can

occur

is significantly

and fault

more

the

zones.

The

1995

2004

Mid-Niigata

earthquake

and

earthquake

were

generated

caused

severe

possi

important

assess

the

hazard

the

anywhere.

that

Southern

by

to

is specific

to

Hyogo Prefecture

regional

active

The Japanese Alps were upthrusted in the past some million years ago. This elevation originated in magmatic activities and has caused a distri bution of underground pressure in which the up ward bending pressure area lies to the west and the downward thrust in pressure area to the east. As these geological forces may be stored in the depths of the Ara-kawa River, subterranean seismic stress has possibly concentrated there. It is the Arakawa seismic belt that is subject to fre

faults

and

on the

particular

source

tention

to the

distribution

quent great earthquakes. Very shallow-focus earthquakes in the south western Kanto district have often happened a

pensable for detecting recent and making sure we have not

crustal missed

movement any active

fault.

explain

the

erwise other

almost active

in tragedy

the fault

739

area

concentrated

We should of active

same

disaster

zone:

the

will

whole

draw

at

faults,

oth

recur

in an

affair

will

end

again.

Prospected always

damage

coincide

records with

and

takes

precedence

over

active

tectonics.

Deformed

Geomorphologist

geological

surface the

should

data

data. former,

landforms

The in

do not latter

clarifying are

indis

direct

276

Symposiums

relevance This

of

tectonic

relieves

is an important

reduce

seismic

The and

office

in

Saitama

drawn

by

them

in the are

are

Fault

already

been

in this

sessment

that

This

discrepancy

Ayasegawa

active

banized

area

is the

Fault

and

fault

seismic

hazard

surface,

tivity

of the

Kanto

to try

ple to develop

snowfall, action,

(dry

avalanche)

and check

should

active

across

the

the

urgently.

regarding

by

Failure

The

slope

failure

speed

landslide,

falling

stone

measures cause

the

place vary mechanism surface and

formation,

of escape

mechanism collapsed

the the

can

shearing

special the

area crush

be

discussed

resistance.

zone

for life to be lost,

earthquake

in

Western The

earthquake end

earthquake

that

amount it is

stone

of

peo

curred

mit

the

big

cliff,

Western several dry

in and

earthquake

condition.

flow,

possibility

of slope to

measures

the

of

are

in

dry

and

1984,

the

oc

Ontake

in

flowed A sim

Izu-Oshima

1978. of

slope

failure

difficult

under

the

slopes

which

have

failure

earthquake.

failure

soil

avalanche.

with

by

rainfall

Therefore,

corresponding

slope

Mt

a

rainfall,

which

in

prediction

However,

nerable

be

as

The are

The

failure

occurred

forecast

there.

of

Earthquake

kilometers

Earthquake

The the

mountain

avalanche

amplitude

earthquake

avalanche.

the

Nagano

failures

the large

by

slope

failure

surface since

scale

up

the and in

slope

comparison

dry

oc by

2004,

of

becomes

called

the

halfway

high

slope,

motion

exam

Earthquake

much

the

For

October,

Fukuoka

of

earthquake

brought

characteristics are

at the

flow damage

landslides

was

therefore

to

should

be

a high

are

also

the

expected

by

present

Vul

counter occurrence

taken.

occurrence

The shearing landslide and by

Preparation

of

Countermeasures

Earthquake

by

Saitama

against

Prefecture

occurs

in the

Tertiary

and

solfataric

because

the

soil.

Authority

YOSHINO

shearing

A landslide

of mudstone

damage

ac

different

of

and

the

counter

soil and

failures

in

debris

are

in these failure types. of landslide, high speed

failure

at the

is rare

means

area.

water

University

Preventive

in the

of

of landslide,

failure,

erosion.

failure of the

a kind

surface and

and

behavior

has

failures

much

the

Kinkai

Saitama

be

landslide,

Much

epicenter

small

Hidehiko

and

debris

the

surface

2005.

are

stone.

damage

by Earthquake KAZAMA

falling

flow

disaster

are

often

slope at

Niigata

ilar

of Slope

these

and

down

Disaster

and

debris

for motivating

by

fails,

failure,

of

igation.

force

on

occur

Precise

cause

and

earthquake surface

characteristic

of

destructive

particularly

of

recent

moun

earthquake

water

by

motion

March,

the

large a

provoking

unstable

landslide,

many

by

second.

down

groundwater,

more.

which

That

for real

shaking

Fault

is necessary

also

flow

The

and

movement per

in

speed.

and

disasters

speed

active

high

25•‹ the

meters

water

other where

a trigger.

high

Mid

of

several

the

place

since

phenomenon

becomes

artificial

On

every

slope

powerful.

rainfall,

ur

long

to reduce

awareness

slope

curred,

Fukaya

Plain

we

information

This

to prepare

dislocation

Ayasegawa

a

ground

trend

of the

a 100km

In order

and

from

ground

as

southeastern

Prefecture.

the

which

appears

faults

WNW-ESE

extension

of Japan.

very

slow.

lost

and

at

is

Slope

it

lead

stream

ple,

compose

through

resulting

local

of Saitama

area

active can

in the

southeastern

going

capital

However,

a

soil

power

the

are than

is of

comes

it is rea

some

is the

locating

may

they earth

issues.

Fault

fault

fault

earthquake.

unreal

earthquake

zones,

reported

area.

into

The

an

simulate

tain

very occur

on

lives

quantities

while

is

exists

seismic

areas, in the south If these city areas fault

many

flow

fanciful

active

soil

Then,

soil failures

is greater

Prefecture,

some

failed

Debris

conclusions

a big

of the

about

in

of

surface

speed

officially:

generate part

located to

exist

ing

will

only

speed hand,

Promo

of the

of future The

in highly urbanized part of the prefecture.

sonable has

prospect

announced

northwestern

not

to

government

Research

Prefecture. are

concerned

quakes eastern

faults. how

Committee

Earthquake the

hazard

Fukaya

Japanese

Research

for

demonstrated

the

active

surface

of the

Earthquake

Headquarters tion

to

on examining

hazard.

cabinet

the

stance

Saitama We Mid

It

learned Niigata

Fukuoka-oki

movement 740

many Earthquake Earthquake.

lessons

from and Both

the

Jun-ichi Prefecture

both 2005 earthquakes

the

2004

Western oc

Let's

Learn

Correctly

and

Prepare

Steadily

for

Southern

Kanto

Earthquake

277

work. On the other hand, it is important for every citizen to implement preparedness and reduction of damage by themselves. The lessons and drills for citizens are promoted to increase disaster management consciousness and to disseminate disaster management knowledge. It is also an im portant measure not only to establish local vol untary disaster management organizations in every community, but also to organize disaster management teams in every private company. It is most important measures to increase local power of disaster management by collaborating with local residents and local companies in each community.

curred in blank areas of earthquake. There is a high probability of an earthquake of Magnitude 7 level occurring in the near future, because of a high probability of earthquake occurring un derneath Southern Kanto Region. We have to im plement not only preparedness of disaster re sponse measures against earthquake but also re duction of damages. Therefore, Saitama Prefec ture expanded the disaster management organi zation into an emergency and disaster manage ment organization as a forerunner in Japan. We have to develop new countermeasures against various damages as a result of new dam age assessment of Earthquake occurring directly beneath the Capital region. Many employees, stu dents and shoppers lose transportation for re turn journey to home. The number of people who would find it difficult/impossible to return home on foot are estimated as 6.5 millions per sons in the Capital region. More than a million

Regional Effort toward Disaster Mitigation around Nagoya SUZUKI Yasuhiro* and SAKAUE Hiroyuki** *Nagoya University, Member of CDR,AJG **Falcon Corporation , Member of CDR,AJG Although the general strategies for disaster mitigation are presented by the national govern ment, the effort by regional communities is es sential to mitigate disaster. Since 2001, in line with the major revisions in Japan's disaster pre vention strategy, Aichi Prefecture and its envi rons were successively designated both as Areas to Strengthen Earthquake Disaster Management Measures, as related to the Tokai earthquakes, and as Areas to Further Earthquake Disaster Management Measures, as related to the Tohnankai (Eastern Nankai) and Nankai earth quakes. The research focusing on disaster pre paredness strategies tailored to the particular characteristics of this region, therefore, has be come a matter of great urgency. In response to these circumstances, cooperative projects by re gional governments, universities, and citizens have started. The most important preparedness to mitigate earthquake disaster is the improvement of the seismic performance of dwelling houses. The re gional government has been conducting many ac tivities such as convening workshops or distrib uting hazard maps to motivate people to prepare for disaster mitigation or establishing financial support systems to check and reinforce build ings. Despite these activities, it is difficult to mo tivate and direct people for disaster prepared

people commute and go to school from Saitama Prefecture to Tokyo. We develop new measures to support their return journey with private com panies whose facilities/shops are located along major streets. Due to regional issues such as long return walk journey of a mass of people and nation wide cen tral function obstacles which influence beyond the boundary of prefectures, we continued the Disaster Management Drills practiced by 8 Pre fectures and Mega-cities of the Southern Kanto Region (Tokyo, Kanagawa, Saitama and Chiba prefectures and Yokohama, Kawasaki, Saitama and Chiba cities). In 2005, this Disaster Man agement Drill was conducted by Saitama Prefec ture. For reduction of building damage, Saitama Prefecture is promoting a retro-fitting of old buildings. Especially located along major streets, in collaboration with not only local authori ties(cities and towns) but also associations of re lated private companies such as building con struction companies and so on. And also for a quick response of search, rescue and recovery after an earthquake, Saitama Prefecture got var ious agreements with associations of related pri vate companies of building construction, civil en gineering works, electrical works, traffic works, and so on. Through these agreements, Saitama Prefecture is enlarging disaster management 741

278

Symposiums

continued to practice disaster management drill with neighboring communities since 1997. In 2005, our district was selected as a model project area on arrangement of station for com munity safety and security. The station is estab lished in Mizutani Higashi Community Center, which is the central facility in our district, and branch stations are established in every local community meeting hall. The activities of our station are both crime prevention movement for community security and disaster management drill for supporting the elderly in each neigh borhood. In addition to these activities, we made a list of persons with specific technologies such as nurse, doctor, carpenter, electrical engineer and so on, in every community. We also established the Safety and Security Network in Mizutani Higashi Elementary School District, involving local voluntary disaster man agement organizations, associations of parents and teachers in elementary and junior high school, local companies, hospitals, associations of shops in the community, fire department, police, local authorities and other related organizations. We hold meetings periodically to create a dis aster management programs, to practice a vari ous disaster management drills and to support activities of organization each other, for the in terception of the next big one in the near future.

ness.

In response to this problem, a joint project by Nagoya University, Aichi Prefecture, and Nagoya City was carried out from 2004 with the support of the Japan Ministry of Education, Science, Sports, and Culture, and some breakthroughs were achieved. This project will finally present a prototype of a simulator system to promote seismic retro fitting. It will consist of the following: (1) a high resolution hazard map through which the hazard to each residence can be determined, (2) a com puter graphics system that educates people about the reasons why damage occurs and how people die during earthquakes, and (3) a system that guides people to retrofit their houses and fix furniture in their houses. Furthermore, this proj ect will record and document the examples of successful workshops held in regional communi ties. Residents' Activities for Growing Safety and Security of our Community-Report on Implementation of Arrangement Model Project of Station for Community Safety and Security - SHIMIZU Minoru Leader of Connection Board of Local Disaster Management Organizations in Mizutani Higashi Elementary School District Our district

Application Damages

is located in the lowland of the

junction between Shingashi river and Yanase river, where were formerly paddy fields and marshy land. In the mid 1960s, urban expansion reached here and urban development was pro moted through land reclamation of paddy fields and marshy lands. At present, our community is very high in population density with aging soci ety. And 90% of houses are wooden houses, 60% of which were built before the new standard of earthquake-proof structure in 1986. We learned many lessons from the 1995 Hanshin-Awaji Earthquake and recognized risks such as flood ing and earthquake disaster, especially collapse of houses built before 1986 and the danger by fire in districts of crowded wooden houses. We established local voluntary disaster management organization in each community and connected the boards of four organizations in Mizutani Hi gashi elementary school district in 1995. We have

of Maps to Mitigate

Earthquake

UNE Hiroshi Geographical Survey Institute, Member of AJG 1. Maps to mitigate earthquake disaster In July 2004, The Association of Japanese Ge ographers presented a recommendation towards mitigation of earthquake damage. It appeals that "it is necessary to produce detailed hazard maps to make people concretely realize the images of earthquake disasters. Active use of land condi tion maps and Geographic Information Systems (GIS) shall be sought that are useful to assess and visualize the local hazards." This concept has been well accepted by disaster policy makers. In this context, micro landform classification data derived from land condition maps are im portant. The Geographical Survey Institute (GSI) released "digital map 25000 (land condition)" in March 2006. It consists of vector-base digital 742

Expected

data

of 1:25,000

land

condition

maps.

Training

for Talent

GSI also

of Geography

were

taken

old maps

presents various kinds of geographic information such as old aerial photographs, outdated maps

copies

aster

ural

These

1)

2)

3)

Useful map information for earthquake dis aster mitigation of Saitama Prefecture Land condition map GSI's 1: 25,000 land condition map series cover the major part of the Kanto Plain in cluding the eastern half of Saitama Prefec ture. Information of micro landforms repre sented on the land condition map is useful to evaluate earthquake damage hazard at the regional level.

5)

data

for

survey ters.

the

the

Prefecture

derived whose

This

data

ferences

levee

and

local

disaster

management

and

companies

and

recognized

two

were

Saitama

elevation of Saitama

airborne

LiDAR is 5 me

for GIS-based even

the

between

analy small

dif

such

forms

as

riverbed

can

be

automatically

various

discussions

of Ayasegawa Fault

in this

hundred,

continued

743

nat

using

com

system.

probability

ticipants

the

former

Fluvial areas

There

digital

because

of elevation

natural

that

GSI.

the

urbanization

resolution

is useful

by Ayasegawa

photographs

of

artificial

part

from

Land classification map for flood control

aerial

rapid

horizontal

Discussion

historical

the

detailed

puter

GSI stores

the

southeastern

sis of landforms,

in

at the

branch

Digital Elevation Model

clearly

old maps

are available

before

by

stores Printed

area.

GSI also publishes 1:25,000 active fault maps for the major part of Saitama Prefec ture. Detailed surface traces of Fukaya, Kushibiki, Ayasegawa Faults etc. are indi cated on these maps.

Aerial Photographs,

It also 1870s.

regional

brought

GSI publishes

are covered

the

for understanding

Map of active faults in urban area

of the major rivers

1945.

conditions

of Saitama

by 1:25,000 land classification maps for flood control. These maps were produced to use for flood control, but the contents can be used for earthquake hazard mapping.

4)

useful

land

as since

materials and

are

changes

2.

early

of these

Headquarters

level.

as

published

and detailed digital elevation data that are use ful to produce realistic images of earthquake dis at the regional

279

damage

hour

The

The beyond

caused

was

were

local

earnest the

of

by residents

number

symposium

of whom

and

enlargement

activities

so on.

Prefecture. a half

Fault,

earthquake,

open

most

on activity

of par more

than

residents discussion

program.