13th World Conference on Earthquake Engineering
Vancouver, B.C., Canada
August 1-6, 2004
Paper No.1306

DEVELOPMENT OF THE METHOD OF ESTIMATING THE NUMBER
OF PEOPLE AT EVACUATION CENTER IN CASE OF URBAN
EARTHQUAKE DISASTER
Reo KIMURA1, Haruo HAYASHI2, Shigeo TATSUKI3, Keiko TAMURA4

SUMMARY
In this paper, we developed a method to estimate the number of people who would stay at the evacuation
centers in the impacted area after an earthquake occurs. This estimation is based on the results obtained
from the random sampled social survey we conducted in 2003 which monitored human behavior andrecovery processes from the 1995 Hanshin-Awaji(Kobe) earthquake disaster. We applied the results ofthis study to risk assessment of the next urban earthquake disaster. Whereabouts of the people in theimpacted area at the first 10-hour, the first 100 hour, and the first 1000 hour after the earthquake wereanalyzed in relation to the estimated ground shaking intensity distribution to yield the evisceration rate atdifferent shaking intensity. It was found that at the first 10 hour, about 10% of the people evacuated tothe shelter if the ground shaking intensity exceeded JMA 5.5, about 30% at JMA 6.0, and about 50% at
JMA 6.5. At the first 100-hour, evacuation rates were lowered to about 5% at JMA 5.5, 15% at JMA 6.0,
and 25% at JMA 6.5. At the first 1000 hour, evacuation rate became lower 5% at JMA 6.0 and 15% at
JMA 6.5.
INTRODUCTION
Background of the StudyAt the disaster area of the Great Hanshin-Awaji Earthquake, to clarify the disaster processing of victims(emergency measures, restoration and reconstruction) systematically, we implemented three random
sampling surveys in 1999, 2001 and 2003 (to be implemented in 2005). Among the survey results theauthors examined, were those especially focusing on the "recovery of dwelling": that is the basis of thevictim’s life, clarified change to the victims dwelling locations after the earthquake, along the logarithmic
axis through which victims behavior changes. It was revealed that those victims who fled from theirhomes eventually returned to their homes using various "connections" such as kinship, territorial society
and personal relationships (connections at work and friends) other than conventional nonlinear public
support path of "occurrence of the earthquake”, “shelter”, “provisional housing". Among victims who
1

Disaster Management Office, Nagoya University
Disaster Prevention Research Institute, Kyoto University
3
Department of Sociology, Doshisya University
4
Graduate School of Informatics, Kyoto University
2

still stayed in shelters after 1000 hours (two months after the seismic disaster), more than 70% were those
who were aiming at the reconstruction of their homes, and victims who moved to provisional housings
were a little over 10%.
Objectives of the Study
Using the "instrumental seismic intensity" of every address block, data of "the number of shelteredrefugees" and social survey results, we formulated an estimate equation on the number of shelteredrefugees by seismic intensity. Using as our study object the "six earthquakes with significant damage"that occurred after the Great Hanshin-Awaji Earthquake with which the measurement of their seismic
intensity over a wide area was made possible by the installation of measurement hardware, we clarified
how many refugees were generated when an earthquake occurred, and how the numbers changed as time
elapsed, to formulate an estimate equation for the number of sheltered refugees (hereinafter, refugees
stands for sheltered refugees).
FORMATION OF ESTIMATE EQUATIOM
Estimation of rate of sheltered refugees using the social survey result
In the "life recovery survey in 2003", implemented by the Disaster Prevention Research Institute, Kyoto
University, we asked people whether they evacuated or not and their evacuation center or shelter. Then
we investigated the address of the respondents (in block unit) and instrumental seismic intensity of theaddress, clarified relationship between the "instrumental seismic intensity" and "rate of shelteredrefugees". As a result, it was revealed that there was a strong correlation between "instrumental seismic
intensity" and the "rate of sheltered refugees". It was revealed that people started to evacuate when theseismic intensity reached to 6 lower, and 20% evacuated at 6 upper, and more than 30% of people
evacuated to shelters at 7. Obtained estimate equation is shown in Figure 1.
1

Rate of remaining at home

0.9

y = -0.1383x2 + 1.3068x - 2.1764
R2 = 0.9196

0.8

0.7

0.6

Estimateequation on rate of sheltered refugees＜避難所避難率推定式＞

0.5x:
x: Instrumental
計測震度 seismic intensityy:Rateof sheltered refugees
y: 避難所避難率0.4

Ifx<5.1,の場合
then
x＜5.1
y=0
y = 0.0863x2 - 0.7935x + 1.8108
x≧5.1
の場合
If
x≧5.1,then2
R2 = 0.8662
y= 0.0863x -0.7935x +1.8108

0.3

0.2

Rate of sheltered refugees

0.1

0
4.9

5

5 lower

5.1

5.2

5.3

5 upper

5.4

5.5

5.6

5.7

5.8

6 lower

5.9

6

6.1

6.2

6.3

6 upper

6.4

6.5

6.6

6.7

6.8

6.9

7

Figure 1: Estimation of rate of sheltered refugees using the social survey result

7

7.1

7.2

Estimation of ratio of sheltered refugees for six earthquakes since the Great Hanshin-Awaji
Earthquake
The estimate equation obtained in the previous chapter was based on the data of the Great Hanshin-Awaji
Earthquake. We added a further six earthquakes with significant damage that occurred after the Great
Hanshin-Awaji Earthquake, to examine how many refugees were generated, and how such numbers
increased or decreased as time elapsed based on administration data, to improve accuracy of the equation.
The reason why we selected earthquakes after the Great Hanshin-Awaji Earthquake is that seismometers
were widely installed in Japan after this earthquake and, it became possible to measure seismic intensity
over a wide area. Table 1 shows six earthquakes with significant damage that occurred after the Great
Hanshin-Awaji Earthquake.
For each earthquake, we clarified the relationship between instrumental seismic intensity and the rate ofsheltered refugees. For the analysis, we used an hour’s axis of 10 and 100 hours after the seismic disaster,which are revealed to be the "turning point of victims behavior" as a result of social survey. Figure 2
shows the plotted relationship between the refugee rate and instrumental seismic intensity in 10 hours
after the seismic disaster, while Figure 3 represents 100 hours, in each block unit. With these two figures,
we see that for all five earthquakes except the Tokachi-oki Earthquake, there was a significant
commonality in the relationship between the instrumental seismic intensity and rate of refugees. As to theTokachi-oki Earthquake, there were two features. 1) People evacuated with lower seismic intensity. 2) At
100 hours after the seismic disaster, evacuation behavior was completed. The evacuation was assumed tobe those caused as a result of tsunami, and the behavior pattern of refugees is clearly different from thoseof the other five earthquakes.

Table 1: Six earthquakes with significant damage

1．Great Hanshin-Awaji Earthquake (Jan. 17, 1995 )M 7.3, Maximum JMA seismic intensity scale of 7
2．Tottori-ken-seibu Earthquake (Oct. 6, 2000)
M 7.3, Maximum JMA seismic intensity scale of 6 upper
3．Heisei Geiyo Earthquake （Mar. 24, 2001)
M6.7, Maximum JMA seismic intensity scale of 6 lower
4．Miyagi-ken-oki Earthquake （May 26, 2003)
M7.1, Maximum JMA seismic intensity scale of 6 lower
5．Miyagi-ken-hokubu Earthquake （Jul. 26, 2003)
M6.4, Maximum JMA seismic intensity scale of 6 upper
6．Tokachi-oki Earthquake （Sep. 26, 2003)
M8.0 Maximum JMA seismic intensity scale of 6 lower

Rate of sheltered refugees
0.35

Hanshin-Awaji

0.30
0.25
Tokachi-oki

0.20

Tottori-ken-seibu

0.15
0.10
0.05

Miyagi-kenhokubu

0.00

Geiyo

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Instrumental seismic intensity
Figure 2: Relationship between the refugee rate and instrumental seismic intensity in 10 hours

Rate of sheltered refugees
0.35

Hanshin-Awaji

0.30
0.25
0.20
0.15
0.10

Tottori-ken-seibu

0.05

Miyagi-kenhokubu

Tokachi-oki

0.00

Geiyo

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Instrumental seismic intensity
Figure 3: Relationship between the refugee rate and instrumental seismic intensity in 100 hours

For all five earthquakes except the Tokachi-oki Earthquake, we calculated the refugees estimate equationfor 10 and 100 hours after the seismic disaster, and obtained the estimate equations shown in Figure 4 andFigure 5. Features of these estimate equations are as follows. 1) People begun to evacuate when theseismic intensity got stronger than 5 lower. 2) Rate of sheltered refugees was higher when instrumental
seismic intensity was larger. 3) Rate of sheltered refugees in 10 hours after the seismic disaster was higher
than in 100 hours. It was especially revealed that 1) and 2) had the same trend as that of the social survey
data.
Using the obtained estimate equation, we calculated the estimated value rate of refugees at 10 and 100
hours after the seismic disaster, and verified such refugee rate with measured data. As a result, it was
revealed that there was strong correlation between the estimated value and the observed value at 10 hours
after the seismic disaster. At 100 hours after the seismic disaster, the correlation was relatively high, but
this high correlation could be interpreted due to the fact that the refugee rate of the Great Hanshin-Awaji
Earthquake has a large proportion in the overall trend. As to other three earthquakes, factors other thaninstrumental seismic intensity might be influencing behavior to evacuate to shelters. Therefore, we further
formulated an estimate equation using analysis results of the social survey for 100 hours after the seismic
disaster.
Formulation of estimate equation on rate of sheltered refugees at 100 hours after the seismic
disaster using social survey
To formulate an estimate equation for 100 hours after the seismic disaster, we obtained factors that define
the rate of sheltered refugees from replies to social surveys. Variables used for the analysis are personal
attributes (sex, age, number of family members, family member structure, profession, type of the dwelling,house structure, total income per household), external force (instrumental seismic intensity), damage(personal damage, damage to buildings and furniture, ratio of total damage, lifeline damage). We obtained
an estimate equation with a generalized linear model, and found that three variables are effective for theestimate: the number of refugees in 10 hours, the number of inhabitants in completely collapsed buildings
and the number of inhabitants in completely destroyed buildings. The completely collapsed building
stands for those with certain stories completely crushed or turned into rubbish without leaving any spacefor people to survive in destroyed houses.
In the social survey, the average number of family members per household of respondents at the time ofthe seismic disaster was 3.38, while the number of family members in Kobe City at the time of theseismic disaster was 2.63, we multiplied the coefficient of estimate equation by 1.3 and we used the figure
obtained from the calculation as the final coefficient for the estimate equation. We estimated the numberof shelter refugees and observed value at 100 hours after the seismic disaster using the estimate equation.
As a result, we obtained a correlation between the estimated value calculated by the estimate equation andthe observed value.
Formulation of estimate equations for time point other than 10 and 100 hours after the seismic
disaster
The turning points of victim’s behavior are at 10 and 100 hours after the seismic disaster. However, social
surveys revealed that decision making, for example, such as a "period when information on houses was
required" or "the period when they made decisions on their dwellings" are not limited within these timeframes. Therefore, we tried to formulate an estimation equation that can estimate by seismic intensity fortime frames other than 10 and 100 hours after the seismic disaster. The process of our estimation
measures is as follows. 1) By integrating all data from the six earthquakes, we compiled data on thenumber of refugees by seismic intensity. 2) We calculated the ratio of the number of refugees (timefactor) as time elapsed taking the 100 hours after the seismic disaster as the reference point. 3) To

Rate of sheltered refugees
0.35
0.30

X: Instrumental seismic intensity
Y: Rate of sheltered refugees

0.25

・If X≧5.5, then
Y=0.1208x2-1.1833x+2.861 (r2=.66)

0.20
0.15

・If X< 5.5, then
Y=0

0.10
0.05
0.00
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Instrumental seismic intensity
Figure 4: Refugees estimate equation for 10 hours after the seismic disaster

Rate of sheltered refugees
0.35
0.30

X: Instrumental seismic intensity
Y: Rate of sheltered refugees

0.25

・If X≧5.6, then
Y=0.1227x2-1.2105x+2.9445 (r2=.57)
・If X< 5.6, then
Y=0

0.20
0.15
0.10
0.05
0.00
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Instrumental seismic intensity
Figure 5: Refugees estimate equation for 100 hours after the seismic disasterobtain approximated curve for transition of the number of refugees as time elapses, we formulated an
estimate equation by seismic intensity. Figure 6 shows the result.
Features of the formulated estimate equation are listed below. 1) The number of refugees decreased astime elapsed. 2) The number of the refugees was largest on the day of the seismic disaster or on thesecond day after the disaster. 3) The larger the seismic intensity, the higher the rate of sheltered refugees.
4) When an approximated curve was drawn, it revealed that it was expressed as logarithmic function withelapsed time.
Then we verified the formulated estimate equations. We performed verification with the following
process. 1) We used two estimation equations to examine the relationship between observed value andestimated value. The two equations are equation for intensity 6 upper that represents the maximum
estimated number of refugees and equation for intensity 5 upper that represents the minimal estimatednumber of refugees. 2) Taking 10 and 1000 hours after the seismic disaster as examples, we examined therelationship between the estimate equation and the observed value. With only the Great Hanshin Awaji
Earthquake, there were refugees generated 1000 hours after the seismic disaster, so we tried to verify thiswith data from the Great Hanshin Awaji Earthquake. As a result, 1) Both for maximum estimated value
and minimal estimated value, these values matched fairly well for 10 hours after the seismic disaster. 2)
However, those values did not match well in case of the 1000 hours data. Estimated value of 1000 hours
after seismic disaster will not be used in urgency after the occurrence of a disaster. It may be appropriate
to use the value as a reference for formulation of proactive measures and expost measures.

2.5

Instrumental 計測震度6.0-6.4（震度６強）（n=10)
seismic intensity
計測震度5.5-5.9（震度６弱）（n=9)
6.0-6.4 (JMA
scale 6 upper) (n=10)2

計測震度5.0-5.4（震度５強）（n=4)

5.5-5.9 (JMA scale 6 lower) (n=9)
5.0-5.4 (JMA scale 5 upper) (n=4)
1.5

1y = -0.2302Ln(x) + 1.184
R2 = 0.8969
y = -0.232Ln(x) + 1.1321
R2 = 0.6993
y = -0.415Ln(x) + 1.3557
R2 = 0.8627
0Day211

Day204

Day197

Day190

Day183

Day176

Day169

Day162

Day155

Day148

Day141

Day134

Day127

Day120

Day113

Day99

Day106

Day92

Day85

Day78

Day71

Day64

Day57

Day50

Day43

Day36

Day29

Day22

Day15

Day8

Day1

0.5

Figure 6: Approximated curve for transition of the number of refugees as time elapses by seismic intensity

The number of people
250,000
the number of lunchboxes

200,000

the number of refugees
difference between

150,000

and

100,000
50,0000
1/17

2/7

2/28 3/21 4/11

5/2

5/23 6/13

7/4

7/25 8/15-50,000-100,000
Figure 7: Number of refugees who stayed in shelters and the number of lunchboxes distributed in Kobe City

Table 2: Food Coefficient (FC)
Day
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

FC
1.00
1.00
1.00
1.00
1.00
1.10
1.14
1.21
1.28
1.32
1.37
1.37
1.44
1.49
1.50
1.55
1.50
1.50
1.51
1.50
1.47
1.47
1.53
1.52
1.59
1.75
1.73
1.74
1.73
1.74
1.69
1.68
1.70
1.75
1.77
1.82
1.81
1.84
1.89
1.94

Day
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80

FC
1.96
1.98
2.00
1.99
1.95
1.93
1.96
1.88
1.87
1.86
2.01
1.98
1.94
1.92
1.90
1.79
1.78
1.87
1.87
1.85
1.84
1.83
1.77
1.77
1.82
1.73
1.74
1.74
1.69
1.50
1.49
1.50
1.43
1.41
1.41
1.39
1.40
1.36
1.35
1.39

Day
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120

FC
1.36
1.35
1.35
1.33
1.30
1.29
1.31
1.28
1.28
1.28
1.31
1.28
1.28
1.30
1.23
1.23
1.23
1.24
1.21
1.21
1.25
1.23
1.24
1.23
1.25
1.23
1.23
1.26
1.24
1.24
1.24
1.24
1.23
1.23
1.24
1.21
1.21
1.21
1.24
1.22

D ay
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160

FC
1.23
1.25
1.24
1.24
1.24
1.25
1.22
1.23
1.26
1.25
1.25
1.25
1.25
1.24
1.24
1.26
1.21
1.21
1.21
1.21
1.19
1.18
1.20
1.19
1.19
1.19
1.21
1.19
1.19
1.22
1.20
1.20
1.20
1.22
1.19
1.20
1.23
1.22
1.21
1.21

Day
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200

FC
1.22
1.19
1.19
1.20
1.20
1.13
1.11
1.08
1.07
1.07
1.08
1.11
1.12
1.12
1.12
1.11
1.11
1.13
1.13
1.13
1.12
1.13
1.11
1.11
1.12
1.12
1.12
1.12
1.12
1.11
1.11
1.11
1.11
1.11
1.11
1.10
1.17
1.14
1.12
1.07

Day
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215

FC
1.07
1.08
1.08
1.08
1.09
1.15
1.11
1.11
1.11
1.12
1.11
1.12
1.16
1.16
1.18

Estimation of the volume of necessary food
For the Great Hanshin Awaji Earthquake, there are two types of refugees in Kobe City. They are those
who stayed in the shelters and those who did not stay in the shelters but came to the shelters to getlunchboxes. As we think that shelters have a variety of functions, it will be insufficient to estimate thenumber of refugees who stayed in shelters, we formulated an estimate method for the number oflunchboxes. However the number of the lunchboxes might be influenced by many factors, so we took
Kobe City as an example, we calculated "food coefficient" first, and then we calculated the amount ofnecessary food by multiplying food coefficient to the number of refugees.
We defined the food coefficient as follows. As shown in Figure 7 and Table 2, the food coefficient wascalculated from the ratio of the number of refugees who stayed in shelters and the number of lunchboxes
distributed in Kobe City. In the data of Kobe City, the number of refugees exceeds the number ofrefugees staying in shelters except in the first five days after the occurrence of the seismic disaster. From
the ratio of “refugees/refugees stayed in shelters" during each time frame, we calculated the foodcoefficient. However, in the first five days after the seismic disaster, the food coefficient was smaller than
1.0, so we rounded them all up to 1.0. It is because it is logically estimated that "all refugees who stayedin shelters were obliged to take food at shelter". By combining these four factors: 1) rate of refugees
estimate equation on the day of the seismic disaster (10 hours), 2) the number of refugees estimate
equation at 100 hours after the seismic disaster 3) time coefficient of estimate equation, 4) foodcoefficient, we formulated an estimate method for the number of refugees who evacuated to shelters.
REFERENCES
1.

2.

3.

4.

5.

6.
7.

Aono, F., Tanaka, S., Hayashi, H., Shigekawa, K., and Miyano, M. (1998), “Disaster Victim's
behavior after the great Hanshin-Awaji Earthquake Disaster ~the case of Nishinomiya-city~,” Papersof the Annual Conference of the Institute of Social Safety Science, Shizuoka, Japan, October, 1998,
No.8, 36–39.
Hayashi, H., and Shigekawa, K. (1997), “Producing Disaster Ethnography for the Development ofDisaster,” Papers of the Annual Conference of the Institute of Social Safety Science, Shizuoka, Japan,
October, 1997, No.7, 376–379.
Kimura, R., Hayashi, H., Tatsuki, S., and Tamura, K. (2001), “Determinants and Timing of Housing
Reconstruction Decisions by the Victims of the 1995 Hanshin-Awaji Earthquake Disaster‐ A 2001
Replication ‐” Journal of Social Safety Science, No.3, 23-32.
Kimura, R., Hayashi, H., Tatsuki, S., and Tamura, K.(2002), “Socio-economic Recovery from the1995 Hanshin-Awaji Earthquake Disaster” The Proceedings of the 11th Japan Earthquake
Engineering Symposium (JEES).
Kimura, R., Hayashi, H., Tatsuki, S., and Urata Y.(2002), “Clarifying the human behavior of thedisaster victims after the Great Hanshin-Awaji earthquake” Journal of Social Safety Science, No.1,
93-102.
Tanaka, S. (1999), “Behavior of Disaster Victims along the Course of Disaster Process,” Journal ofJapan Society for Natural Disaster Science, 18(1), 21–29.
Tanaka, S. et all. (1996), “Report of Questionnaire Seismic Intensity of Hanshin-Awaji Earthquake”
Civil Engineering Studies Department of Architecture and Civil Engineering, Faculty of Engineering& Graduate School of Science and Technology, Kobe University, 1-592.