Journal of Natural Disaster Science, Volume 35, Number 2, 2014, pp35-42

3D Tsunami Hazard Map and Models of Safe Shelters
for Disaster Preparation
Qinglian GUO
Ayumi MATSUSHIMA(Received September 19, 2013 Accepted July 23, 2014)
ABSTRACTIn this paper, we describe a project to generate new tsunami hazard maps (for Hakui
city in Japan) that change dynamically with the 3D landform and possible tsunami heights.
We also generate 3D models of safe shelters in the city to help familiarize citizens withthe facilities. Furthermore, we generated a website to enable the citizens to download thehazard maps and the shelters’ images. The website is linked to the official website of Hakui
city and it provides comprehensible and clear information to assist citizens in preparing forpotential tsunamis.
Keyword: Disaster Preparation, CG, image processing, 3D Hazard map, 3D models

1. Introduction
On 11 March 2011, the most powerful earthquake to strike Japan occurred off the Pacific coast of
Tohoku (Oskin B., 2011). The earthquake caused
powerful tsunami waves that reached heights of up to
40.5 meters in some areas. The tsunami was far more
destructive than people had expected, resulting in inconceivable damage. The existing tsunami walls of
about 10m high were considered sufficient barriers toblock any tsunami. As such, many people did not
move quickly to safe shelters because their houses
were in high locations. Some buildings in low locations were assigned as safe shelters by the city officebut these flooded.
The tragic experiences in Tohoku demonstratethat hazard maps (Fujiwara, H., 2006) that show detailed and accurate information about the city’s landscape and safe shelters are essential for citizens to
prepare for a disaster. A questionnaire survey (Sonpo
and NRI, 2010) shows that 55% of responders answered “No” to the question “Do you know the locations of safe shelters in the city?” For those who answered, “Yes,” there was another question “Do you

know the route from your home to the shelters?” 58%of the people answered “No.” This clearly shows thatpeople are not prepared for disasters. To make a clear
decision and act quickly in an emergency it is necessary for citizens to have sufficient information and to
be prepared for possible natural disasters.
With the support of Hakui city government(Hakui city), we conducted a project to generate newtsunami hazard maps that dynamically change withthe 3D landform of the city and possible tsunami
heights. We applied three-dimensional computer
graphics (3D CG) to represent the geomorphologicalfeatures of the landform and developed a simple dynamic flowing model to estimate the areas with flooding risk. We also generated 3D models of safe sheltersin the city to help citizens become familiar with them.
Furthermore, we generated a website to enable thecitizens to download the hazard maps and the shelters’
images. The website is linked to the official website
of Hakui city, and it provides comprehensible information to assist citizens in their preparation for the
possible impact of a tsunami. In this paper, we describe our project in detail and present the visualized35

Q. GUO, A.MATSUSHIMA

results.

dardized design are installed in coordination with tsunami disaster management maps. Such signboards
will be necessary for people to decide their route ofevacuation and make quick decisions. They are helpful not only for local residents, but also for tourists
who are not familiar with the town.

2. Previous Hazard Map
Hazard maps show predicted inundation risk areas and illustrate information related to disaster prevention. Now almost all coastal cities in Japan havemade their hazard maps available to citizens on theInternet. We looked at the hazard map links to websites, and classified them into 5 groups according totheir visional techniques.

● 3D model based hazard maps
For coastal cities with a large population andmany buildings close to the beach, there are hazard
maps of 3D CG showing the buildings and streets. By
using 3D building models, it is possible to estimate
tsunami wave pressure and fluid velocity. As shownin Fig. 2, the red bars indicate tsunami damage tobuildings, and the damage expansion over time.

● Traditional 2D hazard maps
These are 2D maps with inundation areas shadedin different aposematic colors illustrating the flooding
height of water (Fig. 1). Conventionally, 2D hazard
maps are printed on paper and delivered to residents
from city offices. On the paper map, there is also a listof phone numbers, information on safe shelters, andnotices from governments. We can see such hazard
maps also on the Internet, where you can click andzoom to see scaled maps with details. Although thesemaps are designed for ease of comprehension, users
still need to learn how to read them since they have tomentally convert colors to flooding heights.

● Photograph-based hazard maps
These maps use aerial photographs, high-resolution satellite photographs, or street views to represent
people’s living area, while using graphics or video torepresent tsunami flooding. Photograph-based hazard
maps give people such a strong impression of tsunamis that they will act quickly when an earthquake occurs and take suitable disaster prevention measures.
The strong impression is due to the realism of thephotos and the dynamic representation of water flooding. However, it is still difficult to change the perspective, i.e., movies and animations can be seen only
from one specified direction.

● “Marugoto Machigoto Hazard Map” projectThis project presents a unique and effective way
for people to evacuate from tsunami risks (Fujii, R.,
Morino, K., 2006). They installed tsunami-warning
signboards to show the water levels during a previous
flood disaster experience. These signboards of stan-

Figure 2. The 3D model based hazard map for Paricity (Sinnakaudan K. S., Ghani A. A., Ahmad S. M., Zakaria A. N., 2003)● Interactive hazard maps
Such hazard maps are an integration of the above
described hazard maps with a GPS system. If you
click a concurrent position on the map, possible evacuation routes to the nearest safe shelter will be shown
interactively. Since the hazard map can be accessedby using a smart phone, it is useful for providing tsunami disaster management advice according to indi-

Figure 1. The 2D tsunami hazard map of Hakui city36

3D TSUNAMI HAZARD MAP AND MODELS OF SAFE SHELTERS FOR DISASTER PREPARATION

of devastating floods is a concern. On a specified
evacuation route, there would be danger spots due tolower land height. Although the city officials haveidentified tsunami risk as a high priority, it would be
difficult to rely on the old hazard map to provide citizens with detailed and more accurate information.
The issue of how to select a safe shelter is rather
complex. Which shelter would be more competent forevacuation in the event of a tsunami? Without advance preparations many people would be confusedin an emergency. For example, there are two buildings
with heights of 11.1m and 12.0m, which are about
900m from the seashore. The city previously designated the two buildings as tsunami safe shelters.
Based on the knowledge acquired from the Tohoku
event, another building that is 1200m away from theseashore but 14.4m high is now given priority because
building height is considered the most important factor for evacuating from a tsunami. It is necessary to
inform the citizens not only of the location but also
the height of every safe shelter. Such informed citizens are able to take quick and correct actions according to the individual situation, which in turn decreases
the damage of a tsunami disaster.
Our project, therefore, focused on solving theabove problems by applying 3D computer graphics(CG) to hazard map generation as well as building a
website to provide clear and comprehensible information to citizens.

vidual needs and minimizing damage in a self-help
manner.
Many cities have been very conscious of tsunami-related issue and use hazard maps as non-structural countermeasures for minimizing damage. However,before 3.11, the existence of tsunami hazard maps
was virtually unknown to residents, except for experts, researchers, civil engineers, and governments incharge of disaster prevention. After 3.11, tsunami hazard maps become popular among ordinary citizens,
who realized that all coastal cities may be prone totsunamis during an earthquake in submarine trenches,and measures have to be taken quickly to deal with
them.
With a latitude of 36o N and longitude of 136o E,
Hakui city is on the Sea of Japan (East Sea) coast in
the Noto peninsula. It covers an area of 82 km2, andhas a population of 23,675. In 2006, the local government made a tsunami hazard map based on an expected earthquake of magnitude 7.8, originating 25 kilometers offshore from the Noto peninsula. The
earthquake was expected to generate a 5.1m high tsunami that would travel inland towards Hakui city. The
map showed the forecasted areas with flood risk andinformation about evacuation. The map was easy tounderstand, and quickly distributed to each householdin the city. The map has been updated every year according to the increase in the number of safe shelters
and the new simulation data. Figure 1 is the new version used from 2012.
The Hakui city local disaster prevention plan
was also published in 2013. The number of safe shelters has increased. High buildings near the coast andopen spaces on high land are particularly used for
shelter in emergencies. In 2013, Hakui Coop discussed with other cities near Tokyo providing mutual
help when a disaster occurs. It includes providing water, food, and other essentials, transporting these materials to the affected area, and providing human help.
In other words, people of other cites may come andwork here when a disaster occurs.
The experience of Tohoku has made us realizethat more powerful earthquakes and higher tsunamis
may occur anywhere in Japan. On the old hazard mapof Hakui, the variation in the height of tsunami waves
was not clearly illustrated. If a tsunami was muchhigher than 5.1m, a larger area would be flooded.
Since Hakui has a 10km long coastline, the possibility

3. 3D Landscape Model and Tsunami Hazard Maps
To forecast flooding area patterns and generate
tsunami hazard maps, we build firstly a three-dimensional (3D) landscape model. We used contour mapsand LiDAR data provided by the city office as thebase for constructing the landscape model.
The contour maps are based on a long-term land
survey in this area. They have been used to establish
land maps and boundaries for ownership or governmental purposes. In contrast, airborne LiDAR (ArcGis
resources: Light Detection and Ranging System) is arelatively recent technology for capturing data of theearth’s topography. It is considered a feasible andpractical technology due to the special attributes oflasers and the Global Positioning System (GPS). LiDAR data is produced by attaching a laser-scanner toan aircraft. A laser-beam is fired at the ground and37

Q. GUO, A.MATSUSHIMA

measured when it is reflected back to the aircraft,which saves a great number of measurement points
across the landscape. The LiDAR data we used is adataset of points spaced between 25cm to 2m apart,with a vertical tolerance of up to 20cm.
To build a 3D landscape model of Hakui, we
conducted a sequence of creative works using image
processing and 3D modeling software:(1) Overlay LiDAR data with the contour maps
by using the image processing functions of
Photoshop (Adobe Photoshop, 1986).
(2) Manually select the necessary feature points
from LiDAR data, so as to generate a newcontour map that has more detailed contours
for the areas of high population density. Here,both Photoshop and Illustrator (Adobe Illustrator, 1986) software are used.
(3) Transform the new contour map into a net oftriangular polygons, and save the coordinatesof the three vertices for each polygon. Use an
original program to calculate the slope angle
and slope orientation for each polygon.
(4) Represent the net of triangular polygons byusing a 3D software Shade (Shade 3D, 1986).

Figure 3. The 3D landscape model of Hakui city

Figure 4. Simulated flooded areas according to possible tsunami height and tsunami ascending
up the river.

Figure 3 shows an image of the 3D landscape ofHakui. There are mountains on its northwest andsoutheast sides. In its center area there is a lake and ariver that flows into the sea. The 3D model makes it
easy to calculate and determine flooded areas and inturn to generate tsunami hazard maps (Fig. 4 and Fig.
5). When estimating water flooding areas, we havetaken into account not only the height of the tsunami,
but also the tsunami ascending up the river. Since atsunami usually travels up along a river quickly, theareas near the river may be flooded even when thetsunami height is low.
Our hazard map belongs to the group of 3D CG
based hazard maps. It has three advantages over previous hazard maps:(1) It uses 3D topographical models to show
three important and related factors, the heightof the tsunami, the geographical features ofthe land, and the simulating result of flooding, in a single image with dynamic variation.
Our hazard map provides a new method forcommunication with residents. It can be used
as an educational tool to increase publicig. 4 Simulated flooded areas according to possib
tsunami height and tsunami ascending up the river.

Figure 5. Hazard maps for tsunami of different
heights38

3D TSUNAMI HAZARD MAP AND MODELS OF SAFE SHELTERS FOR DISASTER PREPARATION

awareness of the topography in their living
area. Even those who are familiar with theircity do not know the features of the landform.
(2) Compared with photograph based hazard
maps, our hazard map has the advantage that
it is possible to provide vision from any direction at any location. This is a useful feature of 3D CG that should be employed in disaster prevention activities.
Compared to the traditional hazard map of Hakui
city, our 3D hazard map simulates the low-chanceworst case of flooding. For those residents living in
high-risk areas, self and mutual-support activities fordisaster prevention will be seen in a new light.

(a)4. CG and Animations for Introducing the Safe
Shelters
Another remarkable feature of our project is thedigital models of safe shelters reconstructed using
computer graphics. Compared with the photos ofshelters, CG models have significant advantages:
firstly, it is possible for the user to get a view of the
shelter from multiple directions (Fig. 6); secondly,
CG models place emphasis on representing the special features of the shelters so that citizens can remember them easily and distinguish them from common houses clearly. For example, the two shelters in
Fig. 7 are both open spaces, but their surrounding environment and magnitude are different. Users canclearly understand these differences from the CG
models.

(b)(c)

Compared with the pictures or street view thathave been used in Hakui city’s website for showing
safe shelters, 3D CG models of shelters have the following merits:● Since 3D models emphasize the features of thebuilding not only in form but also in color, it isuseful for educating children, who will in turntake charge of disaster prevention. When these
3D images were displayed to children in
Hakui, they showed great interest in finding
the name and location of the shelters from themap. Children were attracted by the realistic
3D CG models that represent shelters in theirown living areas.
● 3D shelter models can provide additional information when a street view is not available.

(d)Figure 6. One of the safe shelters: Awanoho Primaryschool, (a) real pictures of the school; (b)3D CG model viewed from the southeast;(c) 3D CG model viewed from the northwest; (d) an overview of the 3D CG model.

39

Q. GUO, A.MATSUSHIMA

Only the center area of the city has a street
view. Around the high areas, such as the shelters of Eikouji and the closed Kashimaji Primary School, where few people live, there is
no street view. In a street view, a building canonly be seen from the side facing the street. It
is difficult to obtain information about a side if
there is no street. The 3D CG model enables
people to see a building from any direction.
● The street view may have privacy issues regarding the neighborhoods of safe shelters.
Furthermore, shelters such as city hall may
have a back door, center controlling room, or
security spaces only known to staff. For security reasons it would be better not to put detailed information about these spaces on a
website that everyone can access.
There is little such concern with 3D CG models
since we can control the information provided by themodels.
For providing more information on and stimulating citizens' interest in safe shelters, we created CG
animations and characters that tell a story about every
shelter. Figure 8 shows some images of the animations. The location, land height, distance from theseashore, and the manager of every shelter are reported in the animations.
Children and young people are particularly interested in these animations and characters. They canlearn our information best when they enjoy these digital media. Using animation to provide information on
disaster preparation is not only fun but also effective.

((a)

  (b)(b

5. Website for Disaster Preparation
Hakui city has created a website for distributing
hazard maps and a variety of related information(Hakui city). To meet the need of the devised methods
to present inundation damage of the tsunami risk, ournon-funded research was initiated. Since 2013, Hakui
city has put our 3D hazard map on its website as additional information to the conventional hazard map.
Citizens can see both types of hazard maps and areaware of the possible risk so they can communicate
with others and take action when necessary.
We also generated a website for providing theimages, hazard maps and animations to the citizens.
The website equips disaster managers, planners, gov-(c)(d) (d)Figure 7. CG models of other safe shelters: (a) pictures of Bijoudaichi sports ground; (b) 3D
CG model of the sports ground; (c) picturesof Closed Kashimaji Primary school; (d)3D CG models of the closed Kashimaji Primary school, which is now being used as anopen space for parking.
40

3D TSUNAMI HAZARD MAP AND MODELS OF SAFE SHELTERS FOR DISASTER PREPARATION

Figure 9. Acquire tsunami hazard maps for various
possible scenarios

Figure 8. Animations and characters are created for
informing citizens about the safe shelters
ernments, and the general public with instant accessto comprehensible and clear geospatial information to
support risk assessment, early warning, response andother disaster management activities. Figure 9 andFig. 10 show some pages of this website. Recently,
this website has been linked to that of Hakui city.

Figure 10. Search for possible shelters from area
name, obtain information and see 3D CG
models of shelters

6. Conclusion
trations, so citizens will get not only the WHY ofdealing with measures, but also the HOW.
In future, we will release new versions of thehazard maps for Hakui city, which will be based on
more accurate simulation of flooding inland. We will
also continue the research on the application of LiDAR data and extend the 3D landscape model to represent the surrounding cities. Furthermore, we will
create more animations for informing people about
the history of disaster in this city, the communities,
and the new technologies for disaster preparation.

Through the experience of the Tohoku earthquake and tsunami, many Japanese people learned
about the importance of knowing their living environments, having the hazard maps of their city, and preparing measures to deal with possible natural disasters. Here, we explored the possibilities of using
computer graphics and multi-media to help people.
Through using our hazard maps, enjoying our animations, and accessing our website, the citizens in Hakui
city will acquire more knowledge on which areas will
be inundated, how to use safe shelters, and apply thisknowledge in a practical situation. Our project is balanced between theoretical studies and practical illus41

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