Households’ Intended Evacuation Transportation Behavior in Response to Earthquake and Tsunami Hazard in a Cascadia Subduction Zone City

Abstract

Earthquakes along the Cascadia subduction zone would generate a local tsunami that could arrive at coastlines within minutes. Few studies provide empirical evidence to understand the potential behaviors of local residents during this emergency. To fill this knowledge gap, this study examines residents’ perceptions and intended evacuation behaviors in response to an earthquake and tsunami, utilizing a survey sent to households in Seaside, OR. The results show that the majority of respondents can correctly identify whether their house is inside or outside a tsunami inundation zone. Older respondents are more likely to identify this correctly regardless of any previous disaster evacuation experience or community tenure. The majority of respondents (69%) say they would evacuate in the event of a tsunami. Factors influencing this choice include age, motor ability, access to transportation, and trust in infrastructure resiliency or traffic conditions. While the City of Seaside actively promotes evacuation by foot, 38% of respondents still state they would use a motor vehicle to evacuate. Females and older respondents are more likely to evacuate by foot. Respondents with both higher confidence in their knowledge of disaster evacuation and higher income are more likely to indicate less time needed to evacuate than others. Generally, respondents are more likely to lead rather than follow during an evacuation, especially respondents who report being more prepared for an evacuation and who have a higher perceived risk. This study showcases a unique effort at empirically analyzing human tsunami evacuation lead or follow choice behavior.

Earthquake Evacuation Choice and Management in a Developing Archipelagic Country—A Case Study of Surigao City, Philippines

“…Sociodemographic characteristics of gender, household size, number of children aged less than 5 years, presence of elderly people and pets, residential period, and individual and household incomes were not statistically significant at the 0.10 significance level in affecting the evacuation and travel mode choice. Contrary to tsunami evacuation behavior observed in Cascadia Subduction Zone City, evacuees with high income were more likely to travel by vehicle than walking, but females had a higher baseline likelihood than males to evacuate by foot [17]. Married people were least likely to evacuate by walking.…”

“…The presence of PWDs in households discouraged the residents to evacuate, probably due to difficulties in moving. The same finding was also confirmed: that households with the presence of PWDs may decide against evacuating [17]. Household evacuees with PWDs were most likely to travel by two-and threewheeler, followed by walking.…”

“…The presence of other vehicles in the household discouraged residents to leave home when there was an earthquake, but it did not influence the decision on evacuation duration for residents leaving home. Contrary to the tsunami evacuation behavior observed in a Cascadia Subduction Zone City, vehicle disability and lack of transportation modes discouraged residents to evacuate in an event of a tsunami [17].…”

“…Ao et al showed that the impact of the age factor on earthquake evacuation choice was not statistically significant [14]. A study of earthquake and tsunami evacuation behavior revealed that older people were more prone to evacuate by foot [17]. Residents with a high school degree were more likely to stay home.…”

“…A recent study of tsunami evacuation in Indonesia indicated that a strong relationship among people in local communities is a key factor to decrease the number of fatalities; 83% of respondents decided to evacuate because they saw other people evacuating [16]. A study of tsunami evacuation behavior and travel mode choice in the Cascadia subduction zone showed that two-thirds of respondents evacuated, and older citizens and females were more likely to travel by foot during evacuation [17]. A study on flooding evacuation in Quezon City, Philippines, showed that evacuation choice was mainly influenced by household characteristics (i.e., gender, educational level, presence of children, years in residence, house ownership, number of dwelling stories, and type of house material) and hazard-related factors (i.e., distance from flood source, level of flood damage, and source of warning) [18].…”