Spatio-Temporal Dynamics of Collective Disaster Event Cognition in the Digital Sphere: A Long-Term Case Study of the Great East Japan Earthquake (2011–2025)

How does public cognition (e.g., awareness, attention, memory) of a disaster event change over time and become distributed across geographical space after the event occurs? This question addresses the spatio-temporal characteristics of collective disaster event cognition (CDEC). This study focuses on the Great East Japan Earthquake, a catastrophic disaster that struck the coastal region of Japan’s Tohoku area on March 11, 2011, resulting in over 20,000 people dead or missing. Using long-term data from the Google Trends service (supplemented by long-term Wikipedia pageview data), the study investigates the spatio-temporal dynamics of CDEC. Key temporal findings include a seasonal effect, in which Google Trends scores increased during the annual month of remembrance, and a milestone effect, where scores rose relatively higher during major anniversary years, such as the fifth and tenth anniversaries. Additionally, an association effect was observed. For example, attention increased in response to other major earthquakes, such as the 2016 Kumamoto Earthquake and the 2024 Noto Peninsula Earthquake. In the spatial dimension, analyzing the relationship between Google Trends scores and distance from the affected areas revealed a distance decay effect. This effect was more accurately captured by nonlinear models than by linear ones. Finally, this study discusses the theoretical and social implications of these findings and offers perspectives for elucidating the phenomenon of CDEC and informing future disaster risk reduction efforts.