zMessages from Departments and Centers of NILIM

Characteristics of damage in recent natural
disasters and initiatives aimed at mitigating
damagePhotoTERADA Hideki,DirectorResearch Center for Disaster Risk Management(Key words) Flood and sediment disasters, large-scale earthquakes, disaster-vulnerable persons, warning andevacuation, instantaneous damage prediction, local disaster prevention capability
1. Introduction
In 2009 alone, July brought torrential rains toChugoku and northern Kyushu, while August saw anearthquake with its epicenter in Suruga Bay and flood
damage caused by Typhoon No. 9. And no sooner had
the new year started than a powerful earthquake struck
Haiti, causing damage that threatened to ruin thisCaribbean island nation. As well as enumerating theissues that have come clear as a result of these disasters,
this paper will introduce initiatives being undertakenby the Research Center for Disaster Risk Management
to develop technology designed to mitigate the damage
caused by natural disasters.
2. Main disasters in 2009 and the issues theyhighlighted
The torrential rains that ravaged the Chugoku regionin July caused 22 deaths, mainly in the city of Hofu,
Yamaguchi Prefecture. There alone, a debris flowburied an old people’s home, killing seven people.
Throughout Japan, as many as 13,800 old people’s
homes and other facilities for disaster-vulnerable
persons are at risk of sediment disasters like this.
Conventionally, places like this have been subject topriority countermeasures; even the location in question
was said to have recently undergone a survey fordevelopment of sabo (erosion control) facilities. We
need to step up work for the development of sabo dams
and other facilities in places considered vulnerable tocalamitous damage.
Owing partly to fiscal constraints, however, it isinconceivable that sabo dams and other facilities will
all be developed at once. This increases the importanceof “soft” countermeasures, such as clearly specifying
the scope of hazards and making them publicly known
in line with the Sediment-Related Disaster Prevention
Act, controlling the use of land in hazardous areas, andgiving warnings and encouraging early evacuation attimes of danger due to heavy rains, etc.
The disaster location in question had already been
designated as a sediment disaster warning zone, and thedisaster occurred three and a half hours after theannouncement of sediment disaster warning
information. Boulders in the debris flow weresedimented on flat land upstream of the old people’shome, which was made of steel-reinforced concrete.
However, smaller debris entered the facility throughthe windows. When this happened, most of theresidents were evacuated to upper floors by staff, but
seven lost their lives.
Besides the conventional problem that, even when
sediment disaster warning information has beenreleased, no recommendation is made by the municipal
leader for residents to evacuate, or the recommendation
is delayed, other major issues emerge. For example,
even if an evacuation recommendation is issued, few of
the residents actually evacuate; or, as seen in thisdisaster with the old people’s home, issues remain in
deciding how to evacuate disaster-vulnerable persons
in need of assistance or care, and how to ensure theirsafety.
Meanwhile, when Typhoon No. 9 struck land in
August, the town of Sayo-cho in Hyogo Prefecture wasparticularly hard hit. Nine members of threehouseholds who were voluntarily evacuating from theirhomes to the evacuation site due to flooding from theMakuyama River were caught up in the deluge andtragically lost their lives. This was a “voluntary disasterprevention activity” prior to the issue of an evacuation
recommendation by the town, at a time when therainfall volume had increased dramatically. Since thehomes of the disaster-affected residents were only
damaged by flooding on the ground floor, problems
pointed out include the timing of evacuation inconditions of flooding at night, and the need forselective judgment of appropriate evacuation routes
and sites in accordance with the situation. On the otherhand, depending on the situation, in some cases it may
not even be completely safe to evacuate to the top floorof a house, as the house could be carried off in the flood
flow. In the damage at Sayo-cho, moreover, the local
council office, which should have become a focal pointat the time of a disaster, had its own floor covered inwater, creating a situation that hindered disaster relief.
From these facts, another issue was seen in creating andproviding information that would allow residents tochoose the appropriate action in the event of anemergency.
In these disasters caused by torrential rains, thedamage in both Hofu and Sayo was caused by sudden
heavy rains in excess of 70mm in one hour. From thesefacts, the speed with which information on torrential
rains, water levels and furthermore floodplain
situations, etc., can be ascertained and provided is ofzMessages from Departments and Centers of NILIM

4. Conclusion
Mainly based on notable disasters in 2009, I havedescribed the issues for damage mitigation that havebeen clarified by them, and have also introduced someof the support technology being developed by theResearch Center for Disaster Risk Management toimprove crisis response capability in the event of adisaster.
In Japan, a country where major disasters are prone
to occur, disaster countermeasures are a basic theme atthe very core of the nation. Although it is difficult toprevent disasters completely, we will continue ourefforts to develop technology that will mitigate theireffects as far as possible, as well as tackling technicalsupport aimed at reducing damage in the event of adisaster.
Research on techniques for instantaneous damage prediction in the event of anearthquake
Information for emergency response by facility managers immediately after an earthquake
Earthquake
occurs

Initialmobilization
systemestablished

Emergency checks
and emergency
measures

Emergency
recoveryEmergency
response

Passage of time, and volume and certainty of damage information
Individual
Meteorological Depends on time ofDamage
damageAscertaining state ofDamage
Agency earthquake occurrence, but about information
information fromdamage, studying
information frommagnitude stage 1-2 hours after disaster
fromemergency
and deciding
residents,information
helicopters, etc.
occurrence
media, etc.
checksrecovery measures
Blank time for damage information

Improved grasp and certainty of overall damage image from individual damage
information

Provision of outline damage
prediction information based onseismic motion characteristics
Objectives: x Share micro-image of damage
x Project locations requiring priority checks
x Start preparations for subsequent projected emergency
response (readiness for arrangement of personnel and materiel)

Research institute

Speedy start ofemergency response
preparationLocal office

Results of predictionof outline damage

Earthquake
occursResults of analysis of seismic
motion characteristics

Provision of instantaneous earthquake prediction information (seismic motion characteristics and outline damage)using seismograph data
Transmission and downloading ofseismic motion information

3. Developing support technology aimed at
improving crisis response capability
In the earthquake that struck Haiti on January 13th
this year, although the conditions differ greatly fromthose in Japan, catastrophic damage to urban andresidential facilities due to the earthquake striking amajor urban area led to a massive death toll in excess of150,000. It also led to the loss of administrative andinformation functions, and the rescue operation fordisaster victims is colossal in scale. At times of damageof this order, it is considered necessary, firstly, toascertain information on what sort of damage ordisaster phenomena have specifically occurred where,including forward projections, as soon as possible; andthen to incorporate this information into speedy
recovery measures as quickly as possible.
We are therefore researching techniques for
instantaneous damage prediction (Fig. 1) to support theinitial mobilization of local headquarters for disastercountermeasures in the event of an earthquake. With
this technique, we ascertain an outline of damage near
the epicenter and estimate damage to management
facilities, based on analysis of seismic motion dataobtained from the strong motion seismographs network
immediately after the occurrence of an earthquake.
Immediately after the occurrence of a disaster,
meanwhile, there is a period in which the local
residents have no choice but to cope by themselveswith self-help or helping each other until public supportfrom the government and others arrives. Even here,
support measures from the administration are
considered necessary to improve the disasterprevention capability of local residents, such as being
fully prepared for disasters in advance and safely
evacuating in the event of occurrence. We are therefore
studying techniques for improving local disasterprevention capability.
On this issue of improving local disaster prevention

capability, as a task common to disasters, we aredrawing on the center functions of the Research Center
for Disaster Risk Management and are studying theissue in a Disaster Risk Management Team set up inApril 2009.

Seismic motion information(seismograph network, NRIESDP,K-net, etc.)

paramount importance.
Also, to encourage early warning and evacuation,
another issue will be how to provide sediment disasterwarning information with an indication of imminence,
including supplementary information, and how toinform residents, as receivers of information, at bothnormal and abnormal times.
Furthermore, flood hazard maps are expected toprovide necessary information whereby residents canchoose appropriate evacuation in accordance with thesituation, such as the risk of homes collapsing or beingwashed away, etc., together with floodwater depth
information.
It is also thought important to study realistic safetyassurance methods, such as ascertaining and analyzing
the distribution and structures of old people’s homes
and other facilities for disaster-vulnerable persons in
anticipated flood zones and sediment disaster warningzones, and methods of evacuation in accordance withthe situation of the respective facilities.

Ministry, response
headquarters

Outline prediction of damage
Provision of data for judgement on response(Target: within a few hours after earthquakeoccurrence)

Seismic motion characteristics analysis information and facility damage prediction information based on seismograph data
Observed seismic motion(impact range prediction)

Seismic motion characteristics
analysis

Results of outline damage prediction(area, individual facilities)
Facility damage predictionareaÆOO Similar characteristics to earthquake
OO Significant earthquake damage possible

ÆOO Facility damage possible

Fig. 1 Research on techniques for instantaneous
damage prediction in the event of an earthquake