Mt. Ontake (3,067m), Japan's second-highest volcano, erupted without warning on September 26, 2014, leaving 58 dead and five people missing. More than 20,000 rescue workers were mobilized from all over the country. The findings on rescue operations and subsequent advances in emergency preparedness and rescuer education are presented.

After the disaster, public data was obtained from the Cabinet Office by conducting interviews. Photographs and videos were collected from the military, the police, and the Fire and Disaster Management Agency sources, as well as from local governments and the Volcano Research Institute.

The volcanic eruption received governmental disaster designation. The leading cause of death and the rescued survivors were traumatic injuries caused by sudden falling rocks. Volcanic tremors and landform upheaval were observed immediately before the eruption, but they were too short-lived to lead to evacuation. The location of the victims at the time of the eruptions seemed to be the most critical determinant of survival. What medical care could do at this point was very limited. No rescuers died, but some suffered acute mountain sickness and hypothermia. In the following year, education for rescue organizations began, and volcano information was released to the public in real-time as raw data, regardless of whether they could be understood. In 2022, shelters were constructed near the summit of Mt. Ontake.

A severe volcanic eruption leaves little time for people to evacuate, and emergency medical care can play only a minor role. In Japan, where there are many volcanoes, measures are underway to support self-help to increase the possibility of saving lives for climbers and rescuers in an eruption that is difficult to predict.