٨Research Trends and Results

Tsunami Inundation Estimation System to Improve
Reliability of Evacuation Information
SUWA Yoshio, HeadKATO Fuminori, Senior Researcher
Coast Division, River Department

Database might be too high. It is now possible toimprove the precision of inundation estimations byentering the state of opening/closing of sluice gates tothe Tsunami Inundation Calculation System toperform an inundation calculation. This system caneven be used in the case of a far-field earthquake,when tsunamis arrive a long time after the earthquake.
The Tsunami Inundation Estimation System formedby supplementing these with the Tsunami Inundation
Attenuation Prediction Model has the potential for
application not only to disaster responses by facilitymanagers, but also to the evacuation of residents.

Inundation
estimationහᤨᶐ᳓ᗐቯAt riskᶐ᳓䈱ᕟ䉏
of inundation

Closureof sluice gates᳓㐷㐽㎮䈏⏕⹺䈘䉏
confirmed,preventing䈢䈱䈪ᶐ᳓䈚䈭䈇
inundation

Disaster
response systemෂ㒾ᕈ䈮ᔕ䈛䈢ἴኂ
accordingኻᔕ૕೙to dangerTimeᤨ㑆

Inundation estimation
based
on tsunamiᵤᵄᶐ᳓⸘▚ࠪࠬ࠹
inundation
calculationࡓߦࠃࠆᶐ᳓ᗐቯsystemᣉ⸳ታᘒߦහߒߚ
ᶐ᳓ᗐቯߩᦝᣂ

Inundation estimationᵤᵄᶐ᳓࠺࡯࠲ࡌ࡯
based
on a tsunamiࠬߦࠃࠆᶐ᳓ᗐቯ
inundation
database

Revision of inundation
estimation according to actual
status of facilities

Tsunamiwarningᵤᵄ⼊ႎᶐ᳓ᷓ
1. Introduction
When the Chilean earthquake tsunami struck Japan
at the end of February 2010, many residents did notevacuate despite the tsunami warnings, evacuation
directives and recommendations which were issued,
and the tsunami formed tidal bores which flowed
upstream in several rivers, forcing the long-term
closure of roads along the coastline, which was theregion targeted by the tsunami warning. In order thatfrom immediately after an earthquake until the dangerof inundation by a tsunami has ended, river managers
and other facility managers make appropriate
decisions to send out patrols and to set the range ofthese patrols and take other disaster response measures
such as restricting access to areas at risk, it is essential
to predict the range and depth of inundation according
to the predicted tsunami height announced in tsunami
warnings instead of the largest predicted inundation
range of tsunami shown on tsunami hazard maps.
 This research is intended to improve facility
managers’ disaster response to tsunami warnings bybuilding the Tsunami Inundation Database, which canreflect the most recent progress in the seismic
retrofitting of coastal dikes etc. to rapidly estimate therange and depth of a tsunami inundation according to
the predicted tsunami height announced in a tsunami
warning, and at the same time, the Tsunami
Inundation Calculation System, which can accurately
revise the inundation estimation range at an
appropriate time by reflecting the state of
opening/closing of sluice gates, and the Tsunami
Inundation Attenuation Prediction Model, which canpredict the duration of the tsunami inundation.

2. Outline of the systems
The Tsunami Inundation Database is a database ofinundation estimations calculated in advance bytsunami height in line with the state of seismic
retrofitting of coastal dikes etc. In the case of anear-field earthquake, the predicted tsunami heightannounced immediately after the earthquake is entered
to the database, which can then confirm the range anddepth of inundation estimated according to thetsunami height. If it is later confirmed that the sluicegates are closed and the dikes are not damaged, theinundation estimated by the Tsunami Inundation

Inundation depth

Research Trends and Results(Key words) Tsunami, inundation prediction, disaster response, evacuation

Tsunami inundationᵤᵄᶐ᳓ᷫ⴮ᗐቯattenuation prediction

Figure 1. Outline of the Tsunami Inundation
Estimation System
3. Future plans
This research is scheduled to continue for threeyears beginning in 2011.
[Reference]
F. Kato, Y. Suwa: Survey of evacuation from theChilean Tsunami of 2010, Technical Note of NILIM622