Hazard

Hazard

According to the United Nations International Strategy for Disaster Reduction (UNISDR), a hazard is a natural process or phenomenon that may pose negative impacts on the economy, society, and ecology. It includes both natural factors and associated human factors.

A hazard can be defined as a potentially damaging physical event, social and economic disruption or environmental degradation. Hazards can be the creation of man or the environment. 

A hazard is always present and it simply acts as a catalyst to bring adverse effects into focus. A hazard is defined as a potential cause which is activated when the right configuration of factors present themselves. A hazard may or may not lead to an event. 

A hazard is defines as “a potentially damaging physical event, phenomenon or human activity that may cause the loss of life or injury, property damage, social and economic disruption or environmental degradation.” Hazards could be, natural (geological, hydro-meteorological and biological) or induced by human processes (environmental degradation and technological hazards).

Hazards can be single, sequential or combined in their origin and effects. Hence, Hazard analysis entails the identification, study and monitoring of a hazard to determine its potential, origin and characteristics. 

Hazards are generally classified as:

• Sudden onset hazards: geological and climatic hazards such as earthquakes, tsunamis, floods, tropical storms, volcanic eruptions, and landslides.
• Slow onset hazards: (environmental hazards) drought, famine, environmental degradation, desertification, deforestation, and pest infestation.
• Industrial/Technological: system failures/accidents, spillages, explosions, and fires.
• Wars and civil strife: armed aggression, insurgency, terrorism, and other actions leading to  displaced persons and refugees.
• Epidemics: water and/or food-born diseases, person-to-person diseases (contact and respiratory spread), vector-born diseases and complications from wounds.

Hazards could also be classified as direct and indirect. 

Examples of "Direct Hazards" include:

• Ground shaking
• Differential ground settlement
• Soil liquefaction
• Immediate landslides or mud slides, ground lurching and avalanches
• Permanent ground displacement along faults
• Floods from tidal waves, sea surges & tsunamis

Examples of "Indirect hazards" include:

• Dam failures
• Pollution from damage to industrial plants
• Delayed landslides.

Site risks in an earthquake prone area include:

• Slope risks
• Natural dams (formed by landslides in irregular topographic areas and are susceptible to collapse when filled leading to catastrophic avalanches after strong seismic shaking)
• Volcanic activity

Hazards can also be classified as long-term of short-term as per the classification proposed by K. Smith

Identification of hazards involves analyses of scientific data to trace the causal path of

events leading to a disaster.