Disaster Classification System
A Brief History of the EM-DAT Classification System
EM-DAT’s classification system originally started with a simple 20-type list1. However, in 1992, CRED and other international stakeholders proposed a hierarchical classification system2 that distinguishes natural and man-made disasters (described as technological disasters in EM-DAT). A further distinction was based on the timing of disasters: slow vs. rapid onset disasters.
In the 2000s, CRED collaborated with Munich Re and other stakeholders on a common classification system3. Since then, EM-DAT’s main classification system has followed the logic of referring to the hazard or event triggering the disaster. Consequently, some disasters were reclassified, and some types were removed from the primary classification system. This was the case for famines reclassified as drought for the most part4. However, “famine” offers more information than “drought.” Therefore, in order not to lose this added value, EM-DAT has adopted the secondary classification system of Associated Disasters. This describes disasters that coincide with or result from the primary type.
In 2014, the Integrated Research on Disaster Risk (IRDR) working group, which included CRED, established a new reference called the Peril Classification and Hazard Glossary. This document is currently the primary reference for classifying natural hazards in EM-DAT, which divides them into six main groups: Geophysical, Hydrological, Meteorological, Climatological, Biological, and Extra-terrestrial. EM-DAT also includes more detailed subtypes.
NoteMore recently, in 2021, the ISC and UNDRR released Hazard Information Profiles (HIPs). This document regroups and defines more than 300 hazards that have the potential to impact a community. In March 2023, the CRED discussed HIPs during its Scientific and Technological Advisory Group (STAG) meeting in Brussels. As a result, the CRED is working on a roadmap to make its classification system interoperable with HIPs.
Main Classification Tree
Changes in the Classification TreeIn September 2023, the EM-DAT Classification Tree was updated and simplified to facilitate user queries and filtering. The current tree, which is based on four depth levels, replaces the former tree with three plus two optional depth levels. If you wish to establish the correspondence between new and former disaster types, you may download this backup of EM-DAT prior to the update and join the two datasets based on the ‘Dis No.’ column.
The main classification tree has four levels of depth, so disasters are divided into groups, subgroups, types, and subtypes, as presented in the EM-DAT Public Table columns. The three EM-DAT disaster groups are ‘Natural’, ‘Technological’, and ‘Complex’. Disasters from the Complex group are marginal (14 entries). These were former famines that did not appear to be triggered by a drought event (see A Brief History of the EM-DAT Classification System). The table below shows the complete tree for the ‘Natural’ and ‘Technological’ groups, with the occurrence for each subtype. Their corresponding definitions are available in the Classification Glossary.
|nat-bio-ani-ani||Natural||Biological||Animal incident||Animal incident||1|
|nat-bio-epi-dis||Natural||Biological||Epidemic||Infectious disease (General)||142|
|nat-cli-glo-glo||Natural||Climatological||Glacial lake outburst flood||Glacial lake outburst flood||3|
|nat-cli-wil-lan||Natural||Climatological||Wildfire||Land fire (Brush, Bush, Pasture)||92|
|nat-ext-spa-ene||Natural||Extra-terrestrial||Space weather||Energetic particles||0|
|nat-ext-spa-geo||Natural||Extra-terrestrial||Space weather||Geomagnetic storm||0|
|nat-ext-spa-rad||Natural||Extra-terrestrial||Space weather||Radio disturbance||0|
|nat-geo-mmd-ava||Natural||Geophysical||Mass movement (dry)||Avalanche (dry)||5|
|nat-geo-mmd-lan||Natural||Geophysical||Mass movement (dry)||Landslide (wet)||30|
|nat-geo-mmd-roc||Natural||Geophysical||Mass movement (dry)||Rockfall (wet)||9|
|nat-geo-mmd-sub||Natural||Geophysical||Mass movement (dry)||Sudden Subsidence (wet)||1|
|nat-geo-vol-ash||Natural||Geophysical||Volcanic activity||Ash fall||249|
|nat-geo-vol-lav||Natural||Geophysical||Volcanic activity||Lava flow||10|
|nat-geo-vol-pyr||Natural||Geophysical||Volcanic activity||Pyroclastic flow||4|
|nat-geo-vol-vol||Natural||Geophysical||Volcanic activity||Volcanic activity (General)||9|
|nat-hyd-flo-ice||Natural||Hydrological||Flood||Ice jam flood||0|
|nat-hyd-mmw-ava||Natural||Hydrological||Mass movement (wet)||Avalanche (wet)||121|
|nat-hyd-mmw-lan||Natural||Hydrological||Mass movement (wet)||Landslide (wet)||609|
|nat-hyd-mmw-mud||Natural||Hydrological||Mass movement (wet)||Mudslide||79|
|nat-hyd-mmw-roc||Natural||Hydrological||Mass movement (wet)||Rockfall (wet)||3|
|nat-hyd-mmw-sub||Natural||Hydrological||Mass movement (wet)||Sudden Subsidence (wet)||1|
|nat-hyd-wav-rog||Natural||Hydrological||Wave action||Rogue wave||0|
|nat-met-ext-col||Natural||Meteorological||Extreme temperature||Cold wave||311|
|nat-met-ext-hea||Natural||Meteorological||Extreme temperature||Heat wave||259|
|nat-met-ext-sev||Natural||Meteorological||Extreme temperature||Severe winter conditions||79|
|tec-ind-che-che||Technological||Industrial accident||Chemical spill||Chemical spill||108|
|tec-ind-col-col||Technological||Industrial accident||Collapse (Industrial)||Collapse (Industrial)||181|
|tec-ind-exp-exp||Technological||Industrial accident||Explosion (Industrial)||Explosion (Industrial)||778|
|tec-ind-fir-fir||Technological||Industrial accident||Fire (Industrial)||Fire (Industrial)||219|
|tec-ind-gas-gas||Technological||Industrial accident||Gas leak||Gas leak||61|
|tec-ind-ind-ind||Technological||Industrial accident||Industrial accident (General)||Industrial accident (General)||124|
|tec-ind-oil-oil||Technological||Industrial accident||Oil spill||Oil spill||8|
|tec-mis-col-col||Technological||Miscellaneous accident||Collapse (Miscellaneous)||Collapse (Miscellaneous)||305|
|tec-mis-exp-exp||Technological||Miscellaneous accident||Explosion (Miscellaneous)||Explosion (Miscellaneous)||220|
|tec-mis-fir-fir||Technological||Miscellaneous accident||Fire (Miscellaneous)||Fire (Miscellaneous)||788|
|tec-mis-mis-mis||Technological||Miscellaneous accident||Miscellaneous accident (General)||Miscellaneous accident (General)||275|
In addition to the main classification system, EM-DAT makes it possible to refer to “associated disasters” to describe disaster events in more details (see
Associated Dis in EM-DAT Public Table). They represent subsequent or co-occurring hazards that may have contributed to the disaster impact. These associated disasters may not fit into the main classification system and do not have a hierarchical structure. This additional tagging system allows for a better description of disaster events, particularly multi-hazard ones. The figure below shows the main associations found in the database.
About 14% of disaster entries in EM-DAT have an associated disaster type, and only 3% mention two associated types. The most common associations are floods with landslides (24% of associations), storms with floods (21%), and storms with landslides (8%). Earthquakes are sometimes associated with landslides (4%) and tsunamis (4%) when their damage is deemed negligible compared to ground movement damage.
Guha-Sapir, D. and Misson, C.: The Development of a Database on Disasters, Disasters, 16, 74–80, https://doi.org/10.1111/j.1467-7717.1992.tb00378.x, 1992. ↩︎
DHA-UNDRO, IDNDR, UNEP, WFP, WHO/PAHO, USAID/FHA, IFRC, and CRED: Proposed principles and guidelines for the collection and dissemination of disaster-related data, Brussels, Belgium, 1992. ↩︎
Below, R., Wirtz, A., and Guha-Sapir, D.: Disaster Category Classification and peril Terminology for Operational Purposes, Centre for Research on the Epidemiology of Disasters, Munich Re, Brussels, Belgium, 2009. ↩︎
Below, R., Grover-Kopec, E., and Dilley, M.: Documenting Drought-Related Disasters: A Global Reassessment, The Journal of Environment & Development, 16, 328–344, https://doi.org/10.1177/1070496507306222, 2007. ↩︎
Number of disasters that occurred at the country level in EM-DAT (1900-present) as of September 5, 2023. ↩︎