Hazards

HAZARDS

Hazards may either be natural or human-made phenomena potentially causing losses to human settlements and economic activities. These are events or physical conditions that has the potential to cause fatalities, injuries, damage to property, or interruption of livelihood.
The physical parameter of the hazard event is that "it causes harm".
Geologic or environmental events become hazards once they threaten to adversely affect society or the environment.
- A physical event like an earthquake that does not affect human beings is termed Natural Phenomenon.
- A natural phenomenon that occurs in a populated area is a Hazardous Event.
- A hazardous event that causes unacceptably large numbers of fatalities and/or overwhelming property damage is a Natural Disaster.



Classification of Hazards (extent to which hazards are natural)

1. NATURAL HAZARDS
2. QUASI-NATURAL HAZARDS
3. TECHNOLOGICAL/ANTHROPOGENIC (MAN-MADE) HAZARDS

Natural hazards arise from purely natural processes like earthquakes and floods.

Quasi-natural hazards arise through the interaction of natural processes and human activities like smog and desertification.

Technological / Anthropogenic (Man-made) hazards arise directly as a result of human activities like toxicity of pesticides to fauna, accidental release of chemicals, and radiation from a nuclear plant.

• includes hazardous materials incidents.
• usually, little or no warning precedes incidents involving these types of hazards
• chemicals are found everywhere (e.g. in purifying drinking water, in increasing crop production, use of household cleaners)
• risks occur during production, storage, transportation, use or disposal
• sources: service stations, hospitals, waste sites

Modern Hazard Terminology

• Secondary Hazards - hazards that follow as a result of other hazard events (earthquake can lead to fires, tsunami, water pollution, and dam failure)
• Chronic Hazards - group of hazards that do not stem from one event but arise from continuous conditions which accumulate overtime (famine and resource degradation)
• Rate of Onset - speed of onset of a hazard is important variable since it conditions warning time (rapid onset and slow onset)
• Spatial Dispersion - pattern of distribution of a hazard over the geographic area in which te hazard can occur.
• Temporal Spacing - refers to the sequencing and seasonality of events (random, seasonal)
• Hazardscape - the landscape of many hazards