Hazard Classification and Vulnerability: A Comprehensive Guide
Hazard Classification
Based on the origin, hazards are classified into:
Biological Hazards
Processes or phenomena of organic origin or conveyed by biological vectors, including pathogenic microorganisms, toxins, and bioactive substances. Examples of biological hazards include:
- Epidemic and pandemic diseases
- Plant or animal contagion
- Insect or other animal plagues and infestations
Geological Hazards
Geological processes or phenomena that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. Geological hazards include:
- Internal earth processes, such as earthquakes, volcanic activity and emissions
- Related geophysical processes such as mass movements, landslides, rockslides, surface collapses, and debris or mud flows
Hydro-meteorological factors are important contributors to some of these processes. Tsunamis are difficult to categorize; although they are triggered by undersea earthquakes and other geological events, they essentially become oceanic processes that manifest as coastal water-related hazards.
Hydro-meteorological Hazards
Processes or phenomena of atmospheric, hydrological, or oceanographic nature that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. Hydro-meteorological hazards include:
- Tropical cyclones (also known as typhoons and hurricanes)
- Thunderstorms, hailstorms, tornadoes, blizzards, heavy snowfall, avalanches, and coastal storm surges
- Floods, including flash floods, drought, heat waves, and cold spells
Hydro-meteorological conditions can also contribute to other hazards such as landslides, wildfires, locust plagues, epidemics, and the transport and dispersal of toxic substances and volcanic eruption material.
Anthropogenic Hazards
Hazards induced entirely or predominantly by humans, including technological and socio-natural hazards. Man-made hazards (also known as human-induced hazards or anthropogenic hazards) are a collective term that covers hazards resulting from human activities. They are distinguished from natural hazards. The range of man-made hazards includes technological and socio-natural hazards and those that may arise from relationships within and between communities.
Societal Risk Calculation Example
Given:
- Average number of road accidents per year = 44,076
- 1 death occurs in every 10 accidents
- Population of Kerala = 3.33 crores (33,300,000 people)
Calculate the total number of deaths per year:
Total deaths per year = (Total accidents per year) / (Deaths per accident) = 44,076 / 10 = 4,408 deaths
Calculate the societal risk:
Societal Risk = (Total deaths per year) / (Population) = 4,408 / 33,300,000 ≈ 0.0001324 deaths per year. This means that for every person in Kerala, the probability of dying in a road accident in a given year is approximately 0.0001324, or 1 in 7,554 people per year.
Individual Risk
Individual risk refers to the likelihood of an individual being killed in a road accident, assuming they are participating in road activities (e.g., driving or being a passenger). To assess individual risk, you would need to consider the fraction of the population that regularly engages in road activities, the frequency of travel, etc. However, if we assume every person in Kerala is equally likely to be involved in an accident:
Individual Risk per Year
Individual Risk per Year = (Total deaths per year) / (Population) = 4,408 / 33,300,000 ≈ 0.0001324
This can also be expressed as approximately 1 in 7,554 per year.
Vulnerability Types
Vulnerability denotes the characteristics and circumstances of an individual, community, or area that could be subjected to harm from a hazardous situation. There are four types of vulnerability (UNISDR):
- Physical
- Economic
- Social
- Environmental
In a disaster situation, the vulnerable population includes the poor, women and children, and the disabled. In general, they are the most affected. The vulnerable areas are those very close to the disaster site. In the case of a bomb explosion, assets and people living or present near the blast site are more seriously affected than those farther away.
Factors of Vulnerability
- Poorly designed and maintained infrastructure
- Inadequate safety awareness and safety measures for assets
- Lack of awareness and adequate information about hazards and risk
- Inappropriate management of risks identified and lack of preparedness to face hazards
- Lack of proper management of resources and environment
Physical Vulnerability
- Physical vulnerability may be determined by aspects such as population density levels, remoteness of a settlement, the site, design, and materials used for critical infrastructure and housing. Physical vulnerability also includes impacts on the human population in terms of injuries or deaths.
- Example: Wooden homes are less likely to collapse in an earthquake but are more vulnerable to fire.
Social Vulnerability
- Social vulnerability refers to the inability of people, organizations, and societies to withstand the adverse impacts of hazards due to characteristics inherent in society.
- It is linked to the well-being of individuals, communities, and society.
- It includes aspects related to levels of literacy and education, peace and security, access to basic human rights, systems of good governance, social equity, positive traditional values, customs and ideological beliefs, and overall collective organizational systems.
- Example: When a flood occurs, elderly people and children cannot protect themselves.
Economic Vulnerability
- The level of vulnerability is highly dependent upon the economic status of individuals, communities, and nations.
- The poor are usually more vulnerable to disasters because they lack the resources to build sturdy structures in their homes and put other engineering measures in place to protect themselves from being negatively impacted by disasters.
- Example: Poorer families may live in low-lying slum areas because they cannot afford to live in safer (more expensive) areas. They are more vulnerable when a flood occurs, and their belongings or even their homes get washed away.
Environmental Vulnerability
- Natural resource depletion and resource degradation are key aspects of environmental vulnerability.
- Example: People living in hilly areas become vulnerable because of environmental degradation. Their habitats have to necessarily be on hill slopes due to the terrain features. Deforestation and cutting of trees on hill slopes make them vulnerable to hazards from landslides.