5:15 PM - 6:30 PM
[HDS08-P06] Effect of synchrony bias on excitation of evacuation behavior during tsunami-From the evacuation behavior of residents in Noto Town, Ishikawa Prefecture during the 2019 Yamagata-oki Earthquake-
Keywords:Tsunami, Evacuation, Synchronous bias, 2019 Yamagata-oki Earthquake
Research objectives
Japan is one of the world's highest affected countries by disaster. Within those disaster, the tsunami disaster is one of the most damaging. As a characteristic of disaster prevention actions against tsunami disasters, it may be possible to reduce human damage by evacuating using seismic motion and/or tsunami information prior to the arrival of the tsunami. and there are many studies and activities have been done to encourage evacuation.
In previous studies, psychological studies have also been conducted on the relationship between evacuation behavior and disaster experience / disaster prevention awareness. According to them, it has been clarified that human cognitive bias has a great influence as one of the factors that cause "evacuation delay" and "people who do not evacuate".
Therefore, in this study, we conducted a questionnaire survey of residents living in the tsunami inundation area of Noto Town, located in the northern part of the Noto Peninsula, Ishikawa Prefecture. And we investigated and analyzed how cognitive bias affected the evacuation behavior. At the time of the Yamagata-oki earthquake (MJMA6.7), Noto Town are shaken of seismic scale 3 by JMA and only a tsunami advisory was issued. However, more than 500 residents moved to evacuation site. The area around the study area is the area where one-sixth of the seismic intensity was observed in the Noto Hanto earthquake in 2007. And the tsunami hazard map revised after the Great East Japan Earthquake in 2011.
Result
The questionnaire was distributed and collected by mail to 999 households in the district. The number of collections was 255 (25.5%), 55% for men (N = 141), 40% for women (N = 103), and 4% for others (N = 11). By age, the elderly aged 60 and over account for 65% (N = 165). The fact that household representatives are respondents to the questionnaire and that the aging rate in the target area is close to 50% influences the high proportion of elderly respondents in the questionnaire.
As a result, it was found that 25% of the respondents were evacuated from the tsunami. Respondents were classified into the following four patterns. (1) Evacuated during both of the Noto Hanto and the Yamagata-Oki earthquakes, (2) Evacuated only during the Noto Hanto earthquake, (3) Evacuated during the Yamagata-oki earthquake even though did not evacuated during Noto Hanto earthquake, ④ Did not evacuated during both the earthquakes. The composition of the respondents was (1) 4% (N = 9), (2) 3% (N = 6), (3) 19% (N = 43), and (4) 75% (N = 174). The important point is there were some cases where people who did not evacuate during the Noto Hanto earthquake evacuated this time.
Focusing on the residents who responded as (3), we asked for them multiple answers about the reasons for evacuation. As a result, the answers were obtained that "due to earthquake motion (20 people)", "due to tsunami information (19 people)", and "because they live in the inundation area (16 people)". In addition, the following answers followed. "Because I was instructed to evacuate (8 people)" "Because my neighbors were evacuating (8 people)" "Because someone told me to evacuate (7 people)". These results mean that in addition to the sense of crisis and information, "synchronization bias" such as "evacuation behavior of surrounding people and voices from others" acted positively. Furthermore, among the categories (1) to (4), the highest percentage of those with synchronization bias affected was in (3), and the percentage was 30%.
Discussion
In the context of disaster prevention, synchronization bias is often cited along with normalcy bias as a reason for residents not to evacuate. However, the results of this study showed that by intentionally biasing the population in synchronization, people who did not evacuate voluntarily may be able to evacuate. It is also able to pointed out the importance of social capital to enhance disaster prevention capabilities, such as community disaster prevention leaders who calling for evacuation in emergencies and communities where residents can communicate on a daily basis.
In disaster prevention and mitigation, not only physical measures such as stockpiling but also psychological measures are important. As part of education for disaster prevention, we need to learn about cognitive bias.
Japan is one of the world's highest affected countries by disaster. Within those disaster, the tsunami disaster is one of the most damaging. As a characteristic of disaster prevention actions against tsunami disasters, it may be possible to reduce human damage by evacuating using seismic motion and/or tsunami information prior to the arrival of the tsunami. and there are many studies and activities have been done to encourage evacuation.
In previous studies, psychological studies have also been conducted on the relationship between evacuation behavior and disaster experience / disaster prevention awareness. According to them, it has been clarified that human cognitive bias has a great influence as one of the factors that cause "evacuation delay" and "people who do not evacuate".
Therefore, in this study, we conducted a questionnaire survey of residents living in the tsunami inundation area of Noto Town, located in the northern part of the Noto Peninsula, Ishikawa Prefecture. And we investigated and analyzed how cognitive bias affected the evacuation behavior. At the time of the Yamagata-oki earthquake (MJMA6.7), Noto Town are shaken of seismic scale 3 by JMA and only a tsunami advisory was issued. However, more than 500 residents moved to evacuation site. The area around the study area is the area where one-sixth of the seismic intensity was observed in the Noto Hanto earthquake in 2007. And the tsunami hazard map revised after the Great East Japan Earthquake in 2011.
Result
The questionnaire was distributed and collected by mail to 999 households in the district. The number of collections was 255 (25.5%), 55% for men (N = 141), 40% for women (N = 103), and 4% for others (N = 11). By age, the elderly aged 60 and over account for 65% (N = 165). The fact that household representatives are respondents to the questionnaire and that the aging rate in the target area is close to 50% influences the high proportion of elderly respondents in the questionnaire.
As a result, it was found that 25% of the respondents were evacuated from the tsunami. Respondents were classified into the following four patterns. (1) Evacuated during both of the Noto Hanto and the Yamagata-Oki earthquakes, (2) Evacuated only during the Noto Hanto earthquake, (3) Evacuated during the Yamagata-oki earthquake even though did not evacuated during Noto Hanto earthquake, ④ Did not evacuated during both the earthquakes. The composition of the respondents was (1) 4% (N = 9), (2) 3% (N = 6), (3) 19% (N = 43), and (4) 75% (N = 174). The important point is there were some cases where people who did not evacuate during the Noto Hanto earthquake evacuated this time.
Focusing on the residents who responded as (3), we asked for them multiple answers about the reasons for evacuation. As a result, the answers were obtained that "due to earthquake motion (20 people)", "due to tsunami information (19 people)", and "because they live in the inundation area (16 people)". In addition, the following answers followed. "Because I was instructed to evacuate (8 people)" "Because my neighbors were evacuating (8 people)" "Because someone told me to evacuate (7 people)". These results mean that in addition to the sense of crisis and information, "synchronization bias" such as "evacuation behavior of surrounding people and voices from others" acted positively. Furthermore, among the categories (1) to (4), the highest percentage of those with synchronization bias affected was in (3), and the percentage was 30%.
Discussion
In the context of disaster prevention, synchronization bias is often cited along with normalcy bias as a reason for residents not to evacuate. However, the results of this study showed that by intentionally biasing the population in synchronization, people who did not evacuate voluntarily may be able to evacuate. It is also able to pointed out the importance of social capital to enhance disaster prevention capabilities, such as community disaster prevention leaders who calling for evacuation in emergencies and communities where residents can communicate on a daily basis.
In disaster prevention and mitigation, not only physical measures such as stockpiling but also psychological measures are important. As part of education for disaster prevention, we need to learn about cognitive bias.