Study on Casualty and Tsunami Evacuation Behavior in Ishinomaki City – Questionnaire Survey for the 2011 Great East Japan Earthquake

Home , Ishinomaki

Tenth U.S. National Conference on Earthquake Engineering Frontiers of Earthquake Engineering July 21-25, 2014 10NCEE Anchorage, Alaska

STUDY ON CASUALTY AND TSUNAMI EVACUATION BEHAVIOR IN ISHINOMAKI CITY – QUESTIONNAIRE SURVEY FOR THE 2011 GREAT EAST JAPAN EARTHQUAKE -

H. Murakami1, S. Yanagihara2 Y. Goto3, T. Mikami4, S. Sato5, and T. Wakihama6

ABSTRACT

This paper classified evacuation mobility patterns and travel means and indicated that a half of respondents evacuated by cars, 40 % of those who evacuated on foot moved to places such as schools within 1km distance, and 40 % of those who evacuated by cars moved less than 1km. A quarter of those evacuating by cars came back to their homes, and had only 17 minutes in average left to evacuate, losing critical time for evacuation. Two fifths of those evacuating by cars faced traffic jams.

Tenth U.S. National Conference on Earthquake Engineering Frontiers of Earthquake Engineering July 21-25, 2014 10NCEE Anchorage, Alaska

Study on Casualty and Tsunami Evacuation Behavior in Ishinomaki City - Questionnaire Survey for the 2011 Great East Japan Earthquake –

H. Murakami2, S. Yanagihara2 Y. Goto3, T. Mikami4, S. Sato5, and T. Wakihama6

ABSTRACT

Ishinomaki city suffered largest human loss including missing of about 4,000 mostly by tsunami in the 2011 Great East Japan Earthquake Disaster. Human loss rate reached 3.52% of population in inundated area in the city. Questionnaire survey was conducted in Ishinomaki city to clarify tsunami evacuation process, factors affecting success and failure by special study group on Great East Japan Earthquake Tsunami in Oct. Dec., 2011, and 797 cases of data were obtained. This paper classified evacuation mobility patterns and travel means, and indicated that a half of respondents evacuated by cars, 40 % of those who evacuated on foot moved to places such as schools within 1km distance, and 40 % of those who evacuated by cars moved less than 1km. A quarter of those evacuating by cars came back to their homes, and had only 17 minutes in average left to evacuate, losing critical time for evacuation. Two fifths of those evacuating by cars faced traffic jams.

Introduction

The 2011 Off Tohoku Pacific Coast earthquake occurred at 14h46m, March 11, Friday and caused extreme human loss of 18,493 people killed and 2,683 missing (as of Mar. 26, 2013 by Fire Defense Agency, Japanese Gov). Ishinomaki city had population of 160,826 and 57,871 households (Oct. 2010 National Census) and is the second largest city after Sendai in Miyagi prefecture. Among many cities and towns along the Pacific coast damaged in Miyagi, Iwate and Fukushima prefectures, Ishinomaki city had largest inundated area and largest human loss (Table 1). The past tsunami damages in 1896, in 1933, and in 1960 was severe along rias coast, however, they were moderate or small in urban Ishinomaki. The pre-2011 tsunami hazard maps in Miyagi prefecture was based on the scenario of off Miyagi coast earthquake (M=8.0) showing nominal inundation along the ports and Kitakami river in urban Ishinomaki.

Inundation map is shown with some topography in Fig. 1. The urban area of Ishinomaki extends approximately 10km EW and 4km NS having two ports of industrial and fishing. In the central city, Kyuu-Kitakami river turns around and flows down to south and Hiyoriyama hill (55mTP in

1Associate Prof., Dept. of Environmental Science and Engineering, Yamaguchi University, Ube, 755-8611, Japan 2 Civil Engineering Division, East Japan Branch, Okumura Co., Minato ward, Tokyo, 108-8381, Japan 3 Earthquake Research Institute, The University of Tokyo, Bunkyo ward, Tokyo, 113-0032, Japan 4 Tono Reearch Institute of Earthquake Science, Mizunami, 509-6132, Japan 5Geology & Geotechnology Dept., Nippon Koei Co., Chiyoda ward, Tokyo, 102-0083, Japan 6Graduate Student, Dept. of Environmental Science and Engineering, Yamaguchi University, Ube, 755-8611, Japan elevation) densely inhabited with some schools and public places is located on the west bank of the river. Mt. Makiyama (218mTP in elevation) with mostly forest and parks as land use is located on the east bank of the river. The area of inundation depth more than 4m extends around Minamihama, Kadonowaki, Minato. As for the tsunami arrival time, JMA reported max tsunami hit Ayukawa port (Oshika), Ishinomaki city at 15h26m. According to the municipal disaster report [1], rapid increase of sea level was observed at 15h25m at Tsukihama (Kitakami), at 15h40m to 15h50m at Kadonowaki, at 15h45m at Nobiru (Higashi Matsushima city). Major tsunami seems to have hit Ishinomaki urban area around 15h 40m.

At the beginning of the survey, a group was established consisting of researchers and engineers who were interested in determining facts about the people’s evacuation from the giant tsunami. The group was chaired by Prof. F. Imamura of Tohoku University. It was separated into several task teams, which were assigned to different areas to avoid further traumatizing evacuees by repeated surveys. The task team for Yamada town and Ishinomaki city consists of 22 members and coordinated by Dr. Y. Goto of the University of Tokyo. Goto et al (2012) compares evacuation characteristics and human casualty of Yamada town and Ishinomaki city [2]. The survey team first started interview survey visiting temporary housing complex in urban Ishinomaki, and then conducted the survey by posting method (Table 2).

Table 1. Damage Statistics in Ishinomaki city. Table 2. Outline of the questionnaire survey. Survey period Dec. 2011 Number of Dead 3,510 Temporary housing in urban Number of Missing 447 Survey area Ishinomaki Total collapse 19,957 Distibution 3300 Partial collapse 13,114 Collection 797 Number of population 160,826 (collection rate 24%) Number of population in inundated area 112,276 Great East Japan Tsunami % of people dead or missing among population 2.46 Survey team Evacuation Joint Investigation Team % of people in inundated area 3.52 (Yamada town and Ishinomaki city Source: Statistics Beurow as of Sep. 17, 2013 Team)

Makiyama (218mTP) Hiyoriyama (55mTP)

Figure 1. Inundation map of urban area in Ishinomaki city. (Source GIS data of inundation [3]) The survey population is regarded as those who lost housing and faced life threat without evacuation. The number of temporary housing in urban Ishinomaki was 4302 units with approximately 8604 people assuming 2 persons per household. Assuming the same number of people relocated in other places, approximate 19000 is survey population. We collected 797 cases (4% of population).

Fatality Distribution in Ishinomaki

A List of 3483 people who lost lives was provided by Ishinomaki municipal office with date of birth and address as of Sep. 30, 2011. Age and sex distribution of human loss (Fig. 2) indicates that human loss is far greater for elderly people. Human loss rate against registered inhabitant population for each age and sex group (Fig. 3) shows that it increases extremely for elderly population and is little higher for elderly males. Koyama et al (2012) analyzes age effects on tsunami human casualties in Tohoku municipalities in inundated area [4]. Mikami et al (2012) investigated location and behaviors of people who lost lives in Ishinomaki city and Yamada town and indicated that most of those either could not evacuate due to disabilities or did not try to do so because tsunami would not come [5]. Sato and Tanaka (2012) analyzed distribution of housing damage and human loss vs. tsunami inundation depth and distance from coast and river front, and indicated strong correlation between heavy damage rate and human loss rate, and housing damage and human losses are serious for areas within 1km from water front [6].

250 10% Female 9% 200 8% Killed

Male 7% Female 150 6% Male Rate

People 5% of 100 4% 50 Fatality 3% Number 2% 0 1% 4 9 ‐ ‐ 99 94 89 84 79 74 69 64 59 54 49 44 39 34 29 24 19 14 0 5 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 0%

104 ‐ 4 9 ‐ ‐ 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 14 19 24 29 34 39 44 49 54 59 64 69 74 79 84 89 94 99 0 5 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 104 ‐ 100 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Age Group Age Group 100

Figure 2. Age and sex distribution of human Figure 3. Age and sex distribution of human loss (n=3483 as of Sep. 30, 2011) loss rate for registered population in the city. (n=3483 human loss as of Sep. 30, 2011, and resistered population as of Sep. 30, 2010)

Travel Means of Evacuation and Warning Exposure

In this section, statistics of all questionnaire data from Ishinomaki is indicated. Fig. 4 shows immediate thought of tsunami crisis right after shaking vs. age groups. Most people thought tsunami will come, but not that large. About 30% of people either thought tsunami will not come or didn’t think of tsunami. Elderly people tend to have thought large tsunami will hit, probably based on the past experience of the 1960 Chilean tsunami. Fig. 5 shows information media to get first tsunami warning. Twenty nine% got warning from municipal wireless speaker outdoors, while 23% got it from radio. Information from family or neighbors is 16%.

As for travel means of evacuation (Fig. 6), majority is by car either driving oneself or getting a car ride, while about 44% is on foot. Elderly people tend to evacuate more on foot and getting a car ride, while percentage of people driving a car decreases. Kai square value is 27.507, DOF is 6, and p value is 0.0001, so that there is statistical difference of travel means by age groups. 0% 100% 1 on foot 2 by bicycle 4 driving a car 5 car ride 30s and under 1 Thougt large (124) tsunami will hit 0% 20% 40% 60% 80% 100%

40s to 60s 2 Thought tsunami 30s and under (106) (480) will come, but not that large 40s thru 60s (378) 70s and over 3 Thought tsunami will not come (176) 70s and over (141) 4 Didn't think of total (780) tsunami all (625)

Figure 4. Immediate thought of tsunami crisis right Figure 6. Age groups and travel after shaking and age groups (p=0.118). means of evacuation (p=0.0001).

Internet one‐seg TV municipal mobile 1% wireless disaster inf.1% indoors mail others 4% 0% 13% municipal community wireless organiz. outdoors 4% family or neighbors 29% 16% fire volunteers callingindoor police, fire 1%message autos TV radio 23% 3% 2% 3%

Figure 5. Types of media to get first tsunami warning (n=765).

Fig. 7 shows actions taken (multiple response: MR) after shaking until starting to evacuate for 3 groups of delay time. As for the group of immediate evacuation within 10 minutes, 50% did so, and 20% collected items to take. As for the group evacuating between 10 and 40 minutes, various actions were taken such as collecting items to carry, observing conditions, seeing neighbors, and returning to home. As for the group evacuating 40 minutes and after, 30% returned home, 35% made phones or sent mails.

Fig. 8 shows relation of traffic jam conditions (MR) vs. delay time to start evacuation. Up to 20 min. 20% answers there was no traffic jam, while approximately 80% answers either one was in traffic jam or saw it. Road conditions apparently became worse for those starting to evacuate 40 minutes to 1 hour after shaking, and there are about 15% hit by tsunami, and 10% abandoning a car to run away facing terrible life threat.

60 50 40 Immediate evac. cases 30 within 10 min. of

% 20 10 Evac. after some actions between 10 0 and 40 min. Critical evac. 40min. and after

Figure 7. Actions taken after shaking until starting to evacuate for 3 groups of immediate, moderate and critical evacuation delay time (MR, n=456). 180% Abandoned my car to run 160% away 140% Was in a car hit by tsunami 120% 100% Impassable due to debris 80%

60% Impassable due to accidents 40% 20% Saw traffic jam 0% within 5 to 10 10 to 20 to 40 min over 1 all Was in traffic jam 5 min min 20 min 40 min to 1 hour hour

Figure 8. Frequencies of traffic jam conditions vs. delay time to start evacuation (MR, n=332, cases of evacuation by driving a car or getting car ride).

According to the report by national police agency [6] on human loss due to the 2011 East Japan earthquake disaster, bodies found from automobiles are as follows; 575 bodies (6.1%) found from automobile out of 9384 in Miyagi prefecture (as of Aug. 7, 2011). 102 bodies (2.2%) found from automobile out of 4616 in Iwate prefecture (as of July 30). Special notes of Police report explains that there could be more fatal cases of people who were evacuating by car. According to Murakami et al. [7], 71 bodies (7.8%) were found from automobiles out of 910, in case of Natori city in Sendai coastal plain area. Those percentages reflect that evacuation by car were more frequent in coastal plain area in Miyagi rather than in Iwate. Evacuation Pattern and Distances by Travel Means

According to the interview survey for 355 cases in Ishinomaki city by the joint tsunami evacuation investigation team for the Great East Japan Earthquake Disaster [2], the following tendency was observed. (1) There were many cases evacuating Hiyoriyama and Makiyama hills, and some schools in neighborhood. (2) There were many cases evacuating by car and major cross sections and entrances to evacuation places were in traffic jam. (3) There were many cases evacuating on foot to near-by evacuation places within 1km. (4) Since the earthquake occurred during day time of a week day, there were many cases of returning homes for several km, and then evacuating, and were some cases of those hit by tsunami in a car. Table 3. Classification of cases to be MLIT conducted hearing survey on tsunami analyzed. evacuation, starting time, means of travel, time to start evacuation, time to finish evacuation, evacuation route and so on in 6 prefectures damaged by tsunami, and published report of recommendations for evacuation routes, location of evacuation places, guiding for evacuation [9].

Yanagihara and Murakami (2013) made analysis of evacuation patterns and distances Table 4. Comparison of evacuation based on this questionnaire data in Ishinomaki distances vs. travel means. [10]. In this chapter, major findings are moving distance (m) introduced. Based on the 797 questionnaire travel means no. of cases average maximum minimum data in Ishinomaki, cases in urban Ishinomaki on foot 133 474 2100 20 was analysed on evacuation distances, travel by car 303 2285 14000 10 by bicycle 16 1923 4400 80 means, moving pattern within local area, evacuation from work place returning homes, and relation with traffic jams.

Moving distance is defined as distance one could move before tsunami hit, as follows. (1) As for the cases of safe evacuation, distance is sum of direct line connecting work place, home, evacuation place according to one’s specific pattern. (2) As for the cases of hit by tsunami on the way, the distance is the sum up to the point hit by tsunami. (3) Travel means are classified as on foot, by car, or by bicycle. In case of multiple travel means, that of longest distance is regarded as the travel means. Evacuation on foot does not include those who evacuated hours after tsunami, and those moving upstairs of the same building.

Summary of travel means classification is shown in Table 3. There are 585 cases with clarified evacuation distances and travel means in urban Ishinomaki. Evacuation by car shares 303 cases (52%) , while evacuation on foot is 23%, and those staying or couldn’t evacuate is 23%. Table 4 shows traveling distances by travel means. Average distance on foot is 500m, and is reasonable since public schools, Hiyoriyama, and Makiyama hills are located within 1km from most neighborhood. The average distance of moving by car is 2300m. Evacuation by bicycles of 16 cases is few, however, the moving distance of 1923m in average is comparable to that of automobiles (2285m).

Fig. 9 shows moving distances and cumulative frequency on foot and by car. In case of evacuation on foot, 90% are within 1000m distances suggesting near-by schools and hill places are used. On the other hand, cases evacuating by car tends to move long distances, however, 40% of those moved such short distances within 1000 m.

100% 90% 80% A 70% D 60% B frequency 50% 40% C 30% on foot

cumulative 20% by car 10% 0% 0 500 1000 1500 2000 2500 3000 3500 4000 moving distance (m) Figure 9. Relation of moving distance and cumulative frequency by travel means.

Origin and Destination of Evacuation

Urban Ishinomaki area is divided into 9 districts as shown in Fig. 10 to analyze origins and destinations of respondent evacuation. Locations of typical evacuation places, either hill places or public buildings are sown in red circles. Fig. 11 compares distribution of respondents with human loss and population among 9 districts. Data seem to reflect severely damaged districts.

Fig. 12 compares evacuation movement patterns for travel means of on foot and by car (p=0.000). In case of evacuation on foot, majority of 87% move within the same district, while in case of that by car, 36% move to near-by district and 10% crossing Kyuu-Kitakami river, and 9% moving outside of urban area. Fig. 13 shows frequency of movement patterns and average distances traveled by car. In case of evacuation crossing the river, and moving outside of urban area, the distance apparently increases to 4500m and almost 6000m respectively.

Kyuu-Kitakami river

evacuation place

North of station North of watanoha Hebita Minato Kazuma

South of canal Hiyorigaoka Watanoha Sakanamachi

about 10 km

Figure 10. Division of 9 districts and locations of typical evacuation places in urban Ishinomaki.

Watanoha

no. of responses Kazuma Watanoha north Minato no. of human loss Sakana machi Hiyorigaoka Station north population South of canal Hebita

0% 20% 40% 60% 80% 100% Other

Figure 11. Comparison of respondents with distribution of human loss and population for 9 districts

According to the hearing survey, many cases were observed in which people return from work places or visiting places to homes to check safety of family members. During such movement, there were some cases of being hit by tsunami, and spending time to return home and then head for evacuation places seem to make critical effects on success or failure of safe evacuation. Fig. 14 depicts evacuation patterns by travel means. In case of evacuation on foot, returning from visiting or working places to home is only 5 cases out of 133, while in case of evacuation by car, those returning to home share 78 out of 303 (25%). For those returning homes and evacuating by car (78 cases), time spent for each segment of movements and actions are shown in Fig. 15. As total moving distances increase, time spent for returning home clearly increases. Total times spent for each distance group are from 33 to 40 minutes. Considering major tsunami hit approximately 40 minutes after shaking started in Ayukawa, Rias peninsula and 54 minutes after the shaking in urban Ishinomaki, spare time was seriously critical.

160 7000 (m) 140 6000 120 5000 100 distance

4000 cases 80 of 3000 60 No. moving 40 2000 20 1000

0 0 average within near by crossing outside of district district river urban area Figure 12. Comparison of evacuation patterns Figure 13. Evacuation movement (all cases include 134 cases staying at home and pattern and average distance by car 15 cases evacuating by bicycle). (n=303).

40 from home to evac place 7.1 35 4.4 evacuating trip 7.2 6.3 from other place to home & evac 30 5.7 (min)

from other place to evac 25 drop by while eva. time 20 17.1 15 18.2 14.5 all 272 83 81 8.0 11.6 stay home 10

evacuation 5 11.0 by car 168 78 57 9.1 6.5 7.2 7.9 returning home trip 0 on foot 104 5 24 drop in while 0% 50% 100% returning home prepare to evac.

Figure 14. Travel means and total moving distance (m) evacuation patterns (n=436, p=0 Figure 15. Comparison of time spent break 000). down for cases returning home and then evacuating by car (n=78).

Concluding Remarks

This study examined questionnaire survey results conducted in Ishinomaki city totally destroyed by the 2011 Great Tohoku Earthquake and Tsunami in view of travel means and moving patterns, and risk of traffic jam. Major findings are as follows.

1) Those who drove a car and those who got a car ride share more than half. Forty % of car users were in traffic jam, which became worse as time passed and 6% of those were hit by tsunami waters. 2) Bicycle users were minorities, though there were 3-4% and they tend to evacuate quicker and travel distance is similar to automobiles, suggesting benefit as travel means. 3) 90 % of respondents who evacuated on foot moved to places within 1km distance. 40 % of respondents who evacuated by cars moved less than 1km. 4) A quarter of those who evacuated by cars came back to their homes once and they had only 17 minutes in average left to evacuate.

Acknowledgments

The authors express sincere appreciation of people in disaster area in Ishinomaki who kindly responded the questionnaire and interview survey. We also thank Ishinomaki city office for providing various information and support for the survey. The study was conducted with cooperation of volunteer survey team members. This study was supported by J-RAPID of JST and partially supported by JSPS KAKENHI Grant Number 25350475.

References

1. Ishinomaki city, PASCO Co. Evaluation of Great East Japan Earthquake Disaster, March 2013. 2. Goto Y., Mikami T., Nakabayashi I. Fact-Finding about the evacuation from the unexpectedly large tsunami of March 11, 2011 in East Japan, Proc. 15th World Conf. on Earthquake Engr., Paper No. 5140. 3. GIS data of inundation [2]) provided by Urban Department, MLIT for Reconstruction Assistance Survey Archives, http://fukkou.csis.u-tokyo.ac.jp/dataset/show/id/1111 4. Koyama M., Ishii N., Furukawa A, Kiyono J., Yoshimura A. Municipality’s mortality rate according to inundation level and age classes on the 2011 Great Tohoku Earthquake, in Japanese with English abstract, Proc. 32th Earthquake Engineering Conference, JSCE, 2012, paper ID ?? 5. Mikami T., Goto Y., Satoh S. The survey about where casualties were and what hey did in Ishinomaki-shi under tsunami by the Great East Japan Earthquake, Proc. 32th Earthquake Engineering Conference, JSCE, 2012, paper ID 6. Sato S., Tanaka T. The influence of the inundation depth and distance from water area to tunami damage in Ishinomaki, in Japanese with English abstract, Proc. 32th Earthquake Engineering Conference, JSCE, 2012, paper ID 5-364 7. National Police Agency, Results of hearing survey to police officers and evacuating people by Iwate and Miyagi Prefectural Police, Report 1, Number of bodies found in automobiles, 2011, http://www.bousai.go.jp/jishin/chubou/higashinihon/9/1.pdf 8. Murakami H., Takimoto K., Pomonis A.: Tsunami evacuation process and human loss distribution in the 2011 Great East Japan Earthquake – A case study of Natori city, Miyagi prefecture-, Proc. 15th World Conf. on Earthq. Engineering, Paper No. 1587, 2012. 9. MLIT: Evacuation route, allocation of evacuation places, and guidance against estimated tsunami sinario (rev.), 2012. 10. Yanagihara S., Murakami H. A Study on travel means and distances of tsunami evacuation in Ishinomaki urban area after the 2011 Great East Japan Earthquake Disaster, (in Japanese with English abstract), Journal of Japan Society of Civil Engineering.