Authorities in Japan's Ishikawa Prefecture are now looking at ways to prevent disaster-related deaths at evacuation centers after the earthquake on January 1.

Disaster-related deaths occur mainly due to stress and changes in environment even after surviving the initial event. It can be characterized by high rates of stroke, infarction and other illness.

A government report on the 2011 earthquake on northeastern Japan says nearly 3,800 people died from causes related to the disaster.

The report also says after the 2016 Kumamoto earthquake in southwestern Japan, more than 200 people died. That is over 4 times the death toll directly linked to the quake. Poor hygiene and sanitation are also major factors.