Seismic intensity and mental stress after the Great Hanshin-Awaji Earthquake

Abstract

For 1,361 victims of the Great Hanshin-Awaji Earthquake, to evaluate the usefulness of seismic intensity information for mental health activities, we examined the quantitative relationship between experienced seismic intensity and earthquake-related life events or mental health. Questionnaires were administered concerning seismic intensity, life events and mental health to the victims. The incidence of serious life events, such as death of a close family member and mental disorders were higher in areas of high seismic intensity than in low-intensity areas. Victims who experienced intensity 7 (Japan Meteorological Agency) scored 11 or more on the Modified Mercalli (MM) scale, perceived more depressive symptoms [odds ratio (OR) 2.11, 95% confidence interval (95% CI), 1.49-2.98)] and lower mental health status (OR 1.87, 95% CI 1.34-2.61) than those who suffered intensity 4 or less, who scored 7 or less on MM scale after controlling for various sociodemographic factors. Higher seismic intensity was associated with each severe life event and ill mental health among earthquake victims.