UC Irvine

Natural disasters disproportionately affect older adult populations, who consistently account for a majority of disaster-related mortality. While prior research has emphasized the role of risk perception in motivating preparedness behaviors, less attention has been given to how psychosocial and structural factors shape these processes among aging populations. This dissertation addresses this gap by examining how risk perception, loneliness, and structural vulnerability interact to influence disaster preparedness among older adults in Japan. Guided by the Protective Action Decision Model, this research extends existing theoretical frameworks through the development of the Japanese Older Adult Preparedness Model (JOAPM), which integrates psychosocial and structural dimensions into traditional models of protective action. This approach conceptualizes preparedness as an emergent process shaped not only by cognitive evaluation, but also by social relationships and environmental constraints. This dissertation consists of three empirical studies. The first examines changes in risk perception and preparedness behaviors before and after the 2011 Tōhoku Earthquake and Tsunami using nationally representative survey data. Findings indicate that disaster experience significantly increases risk perception and is associated with changes in preparedness behaviors, including insurance uptake. The second study investigates loneliness as a psychosocial determinant of preparedness among older adults. Results demonstrate that loneliness is negatively associated with preparedness, while also exhibiting a small indirect relationship through increased risk perception. The third study examines structural vulnerability, focusing on mobility limitations and disability. Contrary to common assumptions, physical limitations alone do not fully explain preparedness behaviors; rather, broader social and infrastructural contexts play a more significant role. Together, these findings challenge the assumption that increasing risk perception alone is sufficient to improve preparedness. Instead, they demonstrate that preparedness is shaped by the interaction of psychological, social, and structural factors that influence both perception and the ability to act. By integrating these dimensions, this dissertation advances a more comprehensive understanding of disaster preparedness among older adults and provides a framework for developing more targeted and equitable disaster risk reduction strategies.