EM-DAT distinguishes two generic categories for disasters (natural and technological), the natural disaster category being divided into 5 sub-groups, which in turn cover 12 disaster types and more than 30 sub-types.
For a disaster to be entered into the database at least some criteria must be fulfilled.
When a disaster occurs, the related information is entered at three different levels:
1. The event/disaster level.
2. The country(ies) level.
3. The sources level.