‫ە‬Messages from Departments and Centers of NILIM
Actions which should be taken to reducethe damage caused by natural disasters
YAMASHITA Masaru,
Director of the Research Center for Disaster Risk Management(Key words) Natural disaster, disaster risk, warning and evacuation, technical guidance, Sediment Disaster
Prevention Act
1. Introduction The history of the postwar growth of Japan has also
been a history of a battle with natural disasters. An
examination of changing numbers of fatalities andmissing from natural disasters 1) shows that from 1945to 1960, earthquake disasters such as the Fukui
Earthquake and wind and flood disasters such as theIse Bay Typhoon struck the national land while coredisaster facilities were being constructed, claiming
between about a thousand to several thousand victims
each year.  After later progress in the construction of levees on
major rivers, by about 1983, the numbers of fatalities
and missing was down to a few hundred each year.
During this period, damage caused by large-scale
flooding fell, while a relative increase was seen in thepercentage of fatalities and missing as a result ofsediment disasters caused by torrential rainfall,volcanic eruptions, and earthquakes.  Since that time, the numbers of fatalities andmissing persons has fluctuated between several tens ofpeople to between 100 and 200 as a result of
aggressive implementation of non-structural measures
such as the establishment of warning and evacuation
systems in addition to the construction of disasterprevention structures. But, during the same years, theHokkaido Southwest Offshore Earthquake, the Kobe
Earthquake, and the Niigata-Chuetsu Earthquake andother sudden large-scale disasters caused severe
damage, while responding to disasters caused byguerilla type concentrated torrential rainfall triggeredby climate change and supporting elderly people andothers requiring protection during a disaster are now
urgent challenges. 
2. Natural disasters and their changing
environments As stated above, natural disasters and theenvironment surrounding them are changing
constantly. 
Sediment disasters which occurred in July 2010 in
Shobara City in Hiroshima Prefecture caused severe
damage including one fatality in a range limited toabout 5km square where rainfall was concentrated in
an extremely short time. A rainfall gauge at the site
recorded 173mm in 3 hours, but it is assumed thateven heavier rainfall fell at the actual disaster location.

In recent years, floods and sediment disasters causedby such extreme climate phenomena have tended toincrease, and it is vital that in the future, we takeaction in response to rising disaster risk accompanying
the decline of regional disaster prevention capabilities
caused by depopulation and aging etc. in addition tothis climate change.  When the Central Chili Coastal Earthquake
occurred on February 27, 2010, tsunami warnings
were issued over a wide area centered on the Pacificcoastline. More than 24 hours passed between theannouncement of a warning at 9:33 a.m. on February
28, and the cancellation of all precautionary warnings,
while on trunk highways along the Pacific Ocean
coastline, travel restrictions were enforced over long
distances for long periods, causing confusion
including severe congestion.  Evacuation advisories were issued to about 1.69
million people living in a total of 189 cities, towns,
and villages throughout Chili, but fewer than about
40% of the people actually evacuated, even in regions
warned of a large tsunami 2), leaving problems
concerning the people’s evacuation awareness andinformation dissemination including that performed atnormal times. 
On January 26, 2011, full-scale volcanic activity
began after about 300 years of inactivity at Mt.
Kirishima (Shinmoedake), spewing vast quantities ofvolcanic ash during repeated eruptions. In regions
where ash fell heavily, the danger that future rainfall
will trigger debris flows has increased, so in addition
to physical measures such as emergency removal ofrock from existing sabo dams, it is vital to clarify andto provide information directly relevant to theevacuation of the residents: critical rainfall for
warnings and evacuation, hypothetical debris flow
inundation areas and so on. 
3. Initiatives by the Research Center for Disaster
Risk Management Below, characteristics of natural disasters in recent
years and initiatives taken to resolve challenges areintroduced.
(1) Response to rising risk of disasters accompanying
climate change It is difficult for conventional observation systems
to clarify the actual state of recent guerilla type‫ە‬Messages from Departments and Centers of NILIM

concentrated torrential rainfall, posing a major
obstacle to implementing measures. So in upstream
regions where this has delayed river improvements
and the installation of observation equipment, and incities where severe disasters are predicted, X-bandradar will be used to boost the precision of rainfall
forecasts and water level predictions.  And technologies to provide real time information
revealing the state of inundation of cities by both outerwaters and inner waters is being developed as theconstruction of a framework for the sharing of
information among concerned organizations is being
studied. (2) Support for damage mitigation by reliablewarnings and evacuation  At the same time as public investment falls andsocial infrastructure facilities deteriorate, theestablishment of reliable warning and evacuation
systems is an important pillar of disaster prevention
and mitigation measures. A review of proper procedures for restricting traffic
in anticipation of tsunami has been initiated in
response to the earthquake tsunami which struck Chile,
but technical knowledge related to traffic restriction
measures to prepare for tsunami which should be
included in this review, and general knowledge
necessary for employees to take appropriate action in
the field will be compiled to ensure road users’ safety
and improve their response.
 In order to urge appropriate evacuation activities toprevent human loss when runoff or other disasters
occur, the most appropriate evacuation methods foreach form of residence and disaster situation will bestudied along with methods of transmitting
information based on residents’ acceptance of disasterprevention information. And by focusing on social capital in each region,
methods of continually improving regional disasterprevention capacity according to its characteristics arebeing studied.
(3) Technical guidance at disaster scenes Technical guidance on the sites of large-scaledisasters is one of the major roles of the National
Institute for Land and Infrastructure Management. The
NILIM dispatched an employee as a member ofTEC-FORCE, an emergency disaster countermeasureteam, to Shobara City in Hiroshima Prefecture in
response to the torrential rainfall disaster of July 16,
2010 caused by the early summer seasonal rain front,
and another employee as a member of the same teamto Amami in Kagoshima Prefecture in response to therainfall disaster of October 18, to survey the state ofdamage and provide technical support and advice
concerning restoration policies, etc.  The NILIM sent one more employee as part of agovernment support team to the eruption of Mt.
Kirishima (Shinmoedake) which started in January

2011 to provide technical advice concerning thepreparation of measures which need to be taken
quickly, the enactment of an evacuation plan in
anticipation of predicted debris flows for example. 
4. ConclusionsThe Sediment Disaster Prevention Act (Act onSediment Disaster Countermeasures for Sediment
Disaster Prone Areas) was revised and enforced inMay 1, 2011. Under this revision, when a large scale
sediment disaster is imminent, the national
government or prefecture provides information about
districts and time periods when a disaster is predicted
to cities, towns, and villages in order that theirofficials can make correct judgments concerning theissuance of evacuation orders appropriate to theirresidents.  Providing information which is directly linked to
the lives of residents requires advanced technical skills
and superior judgment at the same time as it is a heavy
responsibility.
 The Research Center for Disaster Risk Management
has, in order to prevent or lighten natural disasters,
helped promote facility provision under the revision of
the standards, develop disaster mitigation support
technologies for use during disasters, and researchdisaster information which will contribute toappropriate evacuation and methods of providing thisinformation. In the future, we must accompany these
activities by actively working to improve technicalcapabilities so that employees of the Ministry of Land,
Infrastructure, Transport and Tourism can makesuitable judgments at disaster sites and to do all in
their power to respond to increasingly diverse andsevere natural disasters. [Sources]
1) 2010 White Paper on Disasters: Cabinet Office2) Emergency questionnaire survey of residents
concerning tsunami evacuation following theearthquake with its hypocenter on the coast of central
Chile: Cabinet Office, Fire and Disaster Management
Agency