Journal of Natural Disaster Science, Volume 28, Number 2, 2008, pp85-90

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A Model Analysis Approach for Reassessment of the Public Shelter Plan Focusing both onAccessibility and Accommodation Capacity for Residents- Case Study of Nagata Ward in Kobe City, Japan1

Wei XU1, Norio OKADA2, Michinori HATAYAMA2 and Yukiko TAKEUCHI2
Academy of Disaster Reduction and Emergency Management, MOCA/MOE, Beijing Normal University, China
2
Disaster Prevention Research Institute, Kyoto University, Japan(Received for 7 Apr., 2006 and in revised from 13 Feb., 2008)

ABSTRACTIn this paper, we address the needs for reassessing and improving the implementability of the public shelter planthat has been completed exclusively by some local administrative bodies. Using a case study in Nagata Ward of
Kobe City, Japan, we propose a simulation and GIS-based model approach to reassess implementability by focusing on residents’ accessibility to nearby shelters and their accommodation capacity. The results show that there
are significant differences in evacuation time among Cho-Chome community areas within Nagata Ward. It wasalso found that communities vary in accommodation capacity risk. Policy implications have been derived to identify suspect areas for further investigation and possible improvement, by way of promoting local residents agreement on their temporary shelters, and adding new designated shelters in appropriate locations. The paper concludes with a list of further research needed in order to integrate the proposed approach for implementation of the
public shelter plan.

1. INTRODUCTION
When a disaster occurs, people who need to take refugee
should be accommodated and protected in a shelter with disasterrobust conditions, such as stable ground, aseismatic structure, fireproof walls and lifeline support system. Due to increasing preparedness and awareness of disaster, more and more countries havestarted to set up disaster shelters. In Japan, more than 1000 cities
or wards have set up disaster shelters (ANCE, 2005), and thus thisdisaster-prone country seems to be leading the world in disasterevacuation and shelter arrangement. In fact, local governments
have long examined and decided the location of shelters as part oftheir disaster planning ( Bosai Keikaku in Japanese).
In Japan most evacuation shelters designated by the local government are expected to be used for temporary relief for life security as well as for the use of long stay refugees for recovery. The
former type of shelter is called a temporary (primary) shelter andthe latter type of shelter is called an accommodation (secondary)shelter. In practice the above-mentioned designated shelters tend
to be selected from commonly used public facilities and spaces
such as elementary schools or public halls. In principle, they are
determined by considering multiple functions of shelters requiredin the event of a disaster such as the distance to shelters, its capacity to accommodate potential refugees, etc. However, in actual
administrative shelter planning, such systematic examination ofmultiple functionalities tends to be practiced rather implicitly, andnot so systematically. Moreover, local details are often not wellconsidered, which may affect implementablity (based on usability
and executability by local residents) of designated shelters. Actual
disasters that affected Japan after the Hanshin-Awaji Earthquake

Disaster have shown that such local focuses are often crucial tomaking the public plan implementable from the viewpoint of local
residents.
For the above reasons, this paper proposes a preliminarymodel in order to eventually develop a systematic approach to thistype of shelter planning problem.
2. CRITERIA DEVELOPED AND USED FOR
CONVENTIONAL SHELTER PLANNING
In conventional shelter location planning, assuming different
hazard types and shelter types, different countries have developed
and used different criteria, including location security, route condition, service distance (or evacuation distance), and accommodation
capacity (FEMA, 1998, 2000; Tokyo, 2000; Aichi, 2005; Beijing,2004).
Regarding the evacuation distance, many researchers have discussed methods of selecting shelter locations and deciding theirservice areas based on, for example, the Voronoi Diagram
approach (Kashiwabara et al., 1998; Kamiya et al., 2000; Hasobe
2005 and Morita et al., 2004a). The recent development of both
GIS and databases has increasingly advanced simulation technology, and evacuation routes can be considered when arranging the
shelter location by using evacuation simulation methods (Shima etal., 2002; Morita et al., 2004b). The shelter accommodation capacity for determining the maximum number of people who takerefuge is also considered when selecting shelter location andassigning residents to corresponding shelters (Yamada, et al.,2004).

KEY WORDS: disaster shelter plan, accessibility, accommodation capacity, Nagata Ward

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3. SCOPING AND STRUCTURING OF THE
PLANNING PROBLEM
We first assume that shelters are located and designated as
official shelters in the publicized administrative shelter plan. This
assumption is made because we will use a list of designated shelters as the outputs of an existing public shelter plan. Given such alist, the problem is to systematically assign potential victims (residents) from various neighborhood communities to the designatedshelters characterized by their own conditions such as accommodation capacity as mentioned above. This assignment problem is todetermine the optimal assignment of residents (potential refugees)
to their shelter facilities as constrained by their respective accommodation capacity.
We will use the findings of the Hanshin-Awaji earthquake inJapan in 1995, as a reference case to derive policy implications for
improvement of public shelter plans by formulating and analyzing
our assignment planning problem. Nagata Ward of Kobe City,
Hyogo Prefecture, which was heavily damaged during theHanshin-Awaji earthquake, is composed of 94 Chos (403 ChoChomes) and has a population of 103681 (Jan.1, 2006)(Nagata
Ward, 2006).
During the Hanshin-Awaji earthquake, there were about 70
accommodation shelters in Nagata Ward, while now there remain
only 25 designated accommodation shelters (Nagata Ward, 2005a)(Fig. 1). The residents who are supposed to evacuate from each
Cho-Chome to designated shelters are also determined nominallyby the local government based on the elementary school area
(Nagata Ward, 2005b). In this paper, we present a prototype toolwith which to evaluate the existing residents’ assignment to thedesignated disaster shelters in their officially approved evacuationand shelter planning. For this purpose, we examine the evacuation
time and accommodation capacity of each designated shelter in

Nagata Ward of Kobe City, Hyogo Prefecture, Japan.
4. ANALYSIS OF THE PLAN OF RESIDENTS’
ASSIGNMENT TO THE DESIGNATED SHELTER IN NAGATA WARD
4.1 Evacuation Time Analysis
1) Calculation of Evacuation Time
Evacuation time, which is calculated by dividing the evacuation distance by the evacuation velocity, is one of the most important indicators for evaluating the performance level of a resident
taking refuge immediately after a disaster occurs.
Evacuation means (evacuation mode) is one of the main factors affecting the evacuation velocity. During the Hanshin-Awaji
earthquake in 1995, about 73% refugees evacuated to shelters by
walking (Kashiwabara, et al., 1998), which is also designated as
the main evacuation means in many cities and wards in Japan.
Evacuation route status (conditions such as road width, road surface, slope, and barrier), refugees (gender, age, and physical status)
and weather, etc., can also affect the evacuation speed.
As for road conditions, the Ministry of Construction,
Government of Japan (1997) set the standard that roads that are
narrower than 4 meters are considered inappropriate as evacuationroutes, and the National Institute of Occupational Safety and
Health, Japan (2002) specified the evacuation speed of people fordifferent road surfaces and slopes based on experiments.
Accordingly, in this paper we assume:
・Roads wider than 4 meters are used to constitute evacuationroutes and there is no traffic congestion.
・The evacuation velocity is 1.10m/s for children (age<10)
and old people(age>=65), and 1.30m/s1 for adults when theslope of the evacuation route is flatter than 10 degrees; and0.80m/s and 1.10m/s1 respectively when the slope is steeper
than 10 degrees.
Based on the above assumptions, we developed a GIS-based
simulation model to calculate the shortest evacuation time of eachhousehold to the designated shelter, along available routes, inaccordance with the designated assignment plan developed by
Nagata Ward, Kobe City. The thus calculated shortest evacuation
time is averaged over all households located in the given area of
the ward. The averaged shortest evacuation time for each area issimply called the evacuation time of households (residents) in thearea .
Thus, the map of the evacuation time of households in each
Cho-Chome (Fig. 2) is developed with the help of GIS in this area,
based on the designated shelter plan (2005).
2) General Findings
In the entire Nagata Ward, the evacuation time of households
in 155 (38%) Cho-Chomes is less than 5 minutes (bright areas), in
184 (46%) Cho-Chomes it takes on a value ranging between 5 minutes and 10 minutes, and in 16 (4%) Cho-Chomes is longer than 15
minutes (gray areas) (Fig. 2). Those households with shorter evacuation time are found to be mainly concentrated in the middle areaof the ward.
1

Fig. 1 Accommodation shelters in Nagata Ward in 1995 and 2005

The data for adults are obtained according to on-site experiments conducted by theauthors and local people.

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87

Fig. 2 Evacuation time of households in each Cho-Chome of Nagata Wardaccording to the designated shelter plan in 2005

Fig. 3 Population Density of each Cho-Chome of Nagata Ward in 2005

3) Findings and Implications of the Middle Area
In the middle area, the evacuation time of 90% households isless than 10 minutes. There are, however, such light gray areas
with an evacuation time longer than 10 minutes Most of them arefound to distribute over the Cho-Chome areas of A, B, C, D, E, F,
G, H, all of which belong to the Middle Area (Fig. 2). In area B
where Hyogo Prefectural Minatogawa High School is located, andin area F which is an open area, population density (Fig. 3) is verylow (almost no people live there at night).
This implies that in order to reduce evacuation time here it
might be worth considering additional use of some already built
nearby public places (schools or open spaces) at least as temporary
shelters. If intended to be used mainly for temporary sheltering,
selection of the most appropriate shelter can be best made by local
residents under the guidance of the local government.
Areas F and I have high population density and relatively longevacuation time for households, and thus all are found to assume
high-risk for evacuation (access risk, the long distance potentiallycompounded by the high population density.)
Although in areas A, C, D, E and G, the population density ismoderate or low (Fig. 3), it takes households in these areas longer
to evacuate. Their evacuation risk is found to be relatively high but
less than in area F.
Therefore, in terms of evacuation time, there are significant
differences found among Cho-Chome community areas within
Middle Nagata Ward. Although based on very simplified assumptions, this analytical finding prompts us to question whether thisstatus should remain unchanged and whether such a gap amongcommunity areas is acceptable in light of equity. We should probably discuss this issue and proceed step-by-step.
First, it would be wise for respective communities, particularlyhigh evacuation risk areas to take this occasion to mutually examine whether there are any safe and secure commonly usable places
for temporary sheltering, which may not necessarily mandate
administrative commitment in official designation. Actually during the Hanshin-Awaji earthquake, other shelters were used in or
close to these areas. Areas both F and I are characterized by highpopulation density and a relatively long evacuation time for households. Obviously it is highly recommended for both local residents
and local government to work together to meet such a challenge.
Secondly, in a longer term, we recommend that the local government sets more explicit criteria including the allowable range ofevacuation time varying among communities, and to present a
more accountable procedure to administratively determine further
improved public shelter and evacuation planning and management.
4) Findings and Implications of the Southern Area
In the southern part of the ward, almost all of the Cho-Chome
communities are found to be situated far away from shelters, andthe evacuation time of households in this area is very long sincethese areas are far away from designated shelters. However, thisarea is a port area with very low population density. This explains
why there was no designated shelter located around, or newly set
up even during and after the Hanshin-Awaji earthquake disaster.
Therefore it may be appropriate to leave it as it is, given that nosubstantial increase in population will occur there in the near
future. Note that there are many people engaged in port and harborbusinesses and that their business continuity plan and management
including their employee’s evacuation are equally important. But
this is beyond the scope of this research.
5) Findings and Implications of Northern Area
In the northern part of the ward, a high-access (blank) corridor is benefited by those households with short evacuation time.

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W. XU, N. OKADA, M. HATAYAMA AND Y. TAKEUCHI

They are located near shelters No. 1, 2, 4, 5, 6, and 3, and households who have long evacuation time are located on both sides of
the corridor. The gray color areas are all hilly areas with lower
population density except area J, and there are no shelters found intheir vicinity. It may be appropriate to leave it as it is since there isno significant increase expected in population. As for community
J, it is recommended to determine their own temporary shelter intheir vicinity, under the guidance of the local government.
4.2 Shelter Accommodation Capacity Analysis
Shelter accommodation capacity is another important factor tobe considered in developing appropriate shelter planning. In ourmodeling, the following assumptions are made. The accommodation capacity of a shelter can be measured by the maximum acceptable number of refugees, which is considered to be determined primarily by the total area of the affordable living spaces and thevariety in type of lifeline facilities installed in the shelter. One
quick calculation method for measuring the acceptable number ofrefugees for a shelter is dividing the affordable living area by thenecessary living area per capita. So far, there is no internationallyor even domestically accepted norm of the necessary living area
per capita. For the purpose of illustration, we refer to the existingnorms and standards of the following cities, 1.65m2/person in
Higashiyamato City (2005) of Tokyo, Japan and Takatsuki City
(2003) of Osaka, Japan, 2m 2/person in Hinode Cho (2005) ofTokyo, Japan and Sendai City (2004) of Miyagi Prefecture, Japan,
2.5m2/person in Nihonmastu City (2006) of Fukushima Prefecture,
Japan, and 1.86m 2/person for hurricanes in the USA (FEMA,
2000). In the following analysis, we will primarily use the standard of living area per capita of Higashiyamato City of Tokyo,
Japan (1.65m2/person) to calculate the maximum acceptable numbers of refugees. Complementarily we will also use another threecapacities for comparison in Nagata Ward. They are:・2005-base-year estimated accommodation capacity of shelter measured by the number of designated residents in 2005 multiplied by 40%2 according to the designated residents’ assignment
in 2005 in Nagata Ward, and we denote it as C1.
・1995-base-year official record accommodation capacity of shelter - estimated by the numbers of refugees accommodated toeach shelter on Feb.1st, 1995 (Kashiwabara, et al., 1998). It is
the minimum of the already experienced accommodation capacity, and we denote it as C2.
・Affordable area-based accommodation capacity of shelter - measured by the estimated acceptable number of refugees, which is
calculated by dividing the affordable living area of each shelterby the necessary living area per capita (1.65m2/person, about one
tatami area per capita), and it is denoted as C3.
・1995-base-year official/non-official record accommodation
capacity of shelter - measured by the total number of refugees in
240%, the percentage of population that took refuge during the Hanshin-Awaji earth-quake in 1995 in Nagata Ward. Numbers of refugees were 55641 at the peak time
(http://www.city.kobe.jp/cityoffice/09/010/shiryokan/earthquake/earthquake04.html),
and total population is 129,978(http://www.city.kobe.jp/cityoffice/06/013/toukei/contents/tyoubetsujinkou.html).
Here, we assume that residents will only evacuate to their designated shelters.
3

The whole area where all the people locate should take refuge to a designated shelter

which was set by local government in 2005.

a refuge zone3 including non-designated informal shelters usedin 1995. It is the maximum of the already locally experienced
accommodation capacities, and we denote it as C4.
Based on the above four types of shelter accommodation
capacity indices, we propose the following four types of shelter
accommodation capacity risks (Table 1).
Type I - the 2005-base-year estimated accommodation capacity (needed) is found to be the largest. This corresponds to the caseof the highest capacity risk in terms of high probability of overcrowding and inability to cope with disaster, particularly in secondary sheltering.
Type II - the 2005-base-year estimated accommodation capacity is larger than both the 1995-base-year official record accommodation capacity and the affordable area-based accommodation
capacity, but is smaller than 1995-base-year official/non-official
record accommodation capacity. This corresponds to a high-moderate accommodation capacity risk.
Type III - the 2005-base-year estimated accommodation
capacity is smaller than the 1995-base-year official record accommodation capacity or the affordable area-based accommodation
capacity. The corresponding case is that of a moderate accommodation capacity risk.
Type IV - the 2005-base-year estimated accommodation
capacity is the smallest. This is the case of a relatively low accommodation capacity risk.
Accordingly we have derived the four types of cases in capacity risk for the designated shelters in Nagata Ward (Table 2).
From Table 2, we find that 18 (72%) shelters belong to type
III, and 5 (20%) to type IV, which have a relatively low accommodation capacity risk. Shelters No. 1, 2, 3, 4, 5, 6, 9, 10, 11, 12 and
14 are located in areas that suffered small percentage house damage during the 1995 Hanshin-Awaji earthquake disaster, and theratio or the total number of residents who took refuge is very low
or small, so their 1995-base-year official record accommodation
capacity and 1995-base-year official/non-official record accommo-

Table 1 Shelter accommodation capacity risks

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89

Table 2 Accommodation capacity and type of shelters in Nagata Ward in 2005

dation capacity are estimated to be very small from this analysis.
There is one shelter of type I - Hasuike Elementary School (No.8)
and one shelter of type II - Miyagawa Elementary School (No.13),
and households in both areas F and D with high evacuation risk (asmentioned in the foregoing discussions) are located in the refuge
zones of these two shelters, respectively (Fig. 4). Suppose alternatively such a scenario that the population density data in 1995
(after the Hanshi-Awaji earthquake) is used, the 2005-base-year
estimated accommodation capacity (needed) will become less thanboth the affordable area-based accommodation capacity and the
1995-base-year official/non-official record accommodation capacity of these two shelters, and they will move down to type III - lowaccommodation capacity risk. The population density has been,
however, increasing since then, which was the scenario based on
our above analysis. So plausible advice is to make more comprehensive investigation and analysis to examine whether these twoareas need to set up another designated secondary (accommodation) shelter.

5. CONCLUSIONS AND DISCUSSIONS

5.1 Conclusions
This paper presents a simulation and GIS-based model
approach to reassess implementability by focusing and detailingboth residents’ accessibility to the nearby shelter and its accommodation capacity. The main calculation results show that there are
significant differences found in evacuation time among ChoChome community areas within Nagata Ward. It was also foundthat communities vary in accommodation capacity risk. Policy
implications have been derived to spot suspect areas for further
investigation and possible improvement, by way of promoting local
residents to agree on their temporary shelters, and adding new designated shelters in appropriate locations.
5.2 Discussion
The proposed approach is at a preliminary stage and further
research is needed in order to integrate the proposed approach for
implementation of the public shelter plan. The presented approachand its analytical results are based on a set of assumptions and simplifications and thus care should be taken in leading to policy

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W. XU, N. OKADA, M. HATAYAMA AND Y. TAKEUCHI

Fig. 4 Shelter accommodation capacity type in 2005

implementation. Despite reservations, this paper provides significant policy implications and clues to the refinement and reassessment of public shelter plans already completed and put in place.
Continued follow-up and extension of this research such as
highlighting perceptions and the behavior of residents who evacuate is required. It is also important to set forth a more integrated
planning and management framework for safe and secure evacuation.
ACKNOWLEDGMENTS
The authors wish to thank the reviewers of this paper for theirvaluable comments and constructive opinions. Special thanks also
go to all those who helped us in collecting data and information as
well as in improving this paper.
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