Hazards

Natural hazards are hazards attributed to natural phenomena, which can imply a significant threat to people, infrastructure, economic assets and the environment and result in a disaster.

The magnitude of a disaster is not entirely due to natural phenomena as human activity can aggravate or mitigate risks through, for example, the level of consideration to where and how settlements are built, or how natural resources are exploited. Disasters are, therefore, complex events and the problem of disaster prevention and mitigation has many facets.

Natural hazards are usually classified based on their causes and are thus subdivided in “Geological hazards” and “Hydro-Meteorological hazards” and “Biological hazards”.

Geological hazards are caused by earth processes either internal (volcanic eruptions and earthquakes) or external (landslides). Tsunamis can be included among them as they are most often triggered by undersea earthquakes; Tsunamis may also be generated by other events.

Hydro-Meteorological hazards are most often weather-related phenomena (such as floods, droughts/desertification landscape fires, avalanches, hurricanes/storm surges and sea level rise).

Biological hazards are hazards attributed to biological substances that poses a threat to the health of living organisms, primarily humans. This could include a sample of a microorganism, virus, medical waste or toxin that can adversely affect human health. Biohazards could also be harmful to other animals.

It is important to underline that a type of natural hazard can trigger another natural hazard (e.g. a storm can trigger floods, an earthquake can trigger tsunamis and landslides, a volcanic eruption can cause wild fires) or even a technological accident (e.g a tsunami can cause a nuclear accident, a dam failure can cause floods).