Hazard and Disaster Magnitude Units
Some disaster types may have a reported magnitude in the Magnitude and Magnitude Scale columns of the EM-DAT Public Table. EM-DAT disaster magnitude scales vary depending on the disaster type. The table below specifies the magnitude property, unit, and exact value found in the Magnitude Scale column for the related disaster types. Note that the Magnitude Scale column is filled for all disasters of these types, even when no magnitude value is reported.
| Disaster Type | Magnitude property | Magnitude Unit or Scale | Value in Magnitude Scale |
|---|---|---|---|
| Earthquake | Size of the earthquake derived from its physical properties | Moment Magnitude1 | Moment Magnitude |
| Flood | Flood extent (area) | km² (square kilometers) | Km2 |
| Drought | Drought extent (area) | km² (square kilometers) | Km2 |
| Extreme temperature | The recorded extreme temperature (maximum or minimum depending on whether it is a heat or a cold wave) | °C | °C |
| Epidemic | Number of vaccinated people | Vaccinated people2 | Vaccinated |
| Wildfire | Wildfire extent (area) | km² (square kilometers) | Km2 |
| Storm | Recorded wind speed | km/h (kilometers per hour) | Kph |
| Industrial accident (all types)3 | Chemical discharged volume | m³ (cubic meters) | m3 |
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See the following USGS Document. ↩︎
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As the magnitude column provides additional hazard-specific information, it is used to report the number of vaccinated people for epidemics. However, it may not be a good indicator of the magnitude of the epidemic, which is also captured by the human impact. ↩︎
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The
m3scale is set for all industrial accident types, but magnitude values are reported almost exclusively for chemical spills. ↩︎