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Chapter:
1. Explain hazards.
A hazard is any object, situation, or behavior that has the potential to cause injury, ill health, or damage to property or the environment.
According to Varnes, hazard is defined as probability of occurrence of a potentially damaging phenomenon within a specific period of time.
CLASSIFICATION OF HAZARDS:
Biological
bacteria, viruses, insects, plants, birds, animals, and humans, etc.,
Chemical
depends on the physical, chemical and toxic properties of the chemical,
Ergonomic
repetitive movements, improper setup of workstation, poor design of equipment, workstation design, (postural) or workflow, manual handling,etc.
Physical
Slippery floors, unsafe or misused machinery, excessive noise, poor lighting, fire radiation, magnetic fields, pressure extremes (high pressure or vacuum), noise, etc.
Psychological
Dealing with the public, harassment, discrimination, threat of danger, stress, violence, etc.
Safety
Slipping/tripping hazards, inappropriate machine guarding, equipment malfunctions or breakdowns.
MEASURING CRITERIA OF HAZARDS (PHENOMENON OF HAZARDS):
Relative hazards:
It is assessed by assigning ratings to different factors contributing to hazards.
Absolute hazards
It is expressed deterministically. Eg -factor of safety or probability.
Monitored hazards
It is assessed by the actual measurement of the effects. Eg- deformations.
RISK:
Risk is defined as the probability that a potential hazard will be realized and the probability of the harm itself.
Varnes defined risk as the combined effect of the probability of occurrence of an undesirable event and the magnitude of the event.
`Risk=Hazard * (VULNERABILITY)/(Capacity)`
Where,
`(VULNERABILITY)/(Capacity)=EXPOSURE`
S.NO. | HAZARD | RISK |
1 | Hazard is defined as the probability of occurrence of a potentially damaging phenomenon within a specific period of time. | Risk is defined as the combined effect of the probability of occurrence of an undesirable event and the magnitude of the event. |
2 | It is the source of risk. | It is the potential loss of life and property. |
3 | Hazard is an unavoidable danger. | Risk is caused only by chance. |
4 | It is the potential to cause harm. | It is the likelihood of harm. |
5 | It may be measured as a relative, absolute and monitored. | Risk analysis involves analysis of physical risks, combination of two or more principal types of movement. |
DISASTER:
A disaster is a natural or man-made event that negatively affects life, property, livelihood or industry often resulting in permanent changes to human societies, ecosystems and environment.
DANGER:
Danger (also risk or peril) is the possibility of something bad happening. A situation in which there is a risk of something bad happening, is called dangerous, risky or perilous.
FACTORS OF GEOLOGICAL HAZARDS:
Lithology of area
Groundwater condition
Rainfall
Geotechnical properties of soil
Weathering of rock
Natural slope
Vegetation cover
Climate change
Erosion by glaciers, streams etc.
Geological factors causing hazards in nepal:
Steep topography
Geological structures such as folds, faults,thrusts etc.
Groundwater condition
GLOF (Glacial lake outburst flood )
Weathering of rocks etc.