On March 11, 2011, Japan experienced the largest earthquake in its history. The undersea earthquake launched a tsunami that inundated much of Japan's eastern coastline and damaged nuclear power plants, precipitating multiple reactor meltdowns. We examined open-source disaster situation reports, news accounts, and disaster-monitoring websites to gather event-specific data to conduct a trauma signature analysis of the event.

The trauma signature analysis included a review of disaster situation reports; the construction of a hazard profile for the earthquake, tsunami, and radiation threats; enumeration of disaster stressors by disaster phase; identification of salient evidence-based psychological risk factors; summation of the trauma signature based on exposure to hazards, loss, and change; and review of the mental health and psychosocial support responses in relation to the analysis.

Exposure to this triple-hazard event resulted in extensive damage, significant loss of life, and massive population displacement. Many citizens were exposed to multiple hazards. The extremity of these exposures was partially mitigated by Japan's timely, expert-coordinated, and unified activation of an evidence-based mental health response.

The eastern Japan disaster was notable for its unique constellation of compounding exposures. Examination of the trauma signature of this event provided insights and guidance regarding optimal mental health and psychosocial responses. Japan orchestrated a model response that reinforced community resilience. (Disaster Med Public Health Preparedness. 2013;0:1-14)