SCI03 CO1

1. Basic Concept of Hazard

• Definition of Hazard:

  • A dangerous phenomenon, substance, human activity, or condition that may cause loss of life, injury, or other health impacts, property damage, loss of livelihoods, social and economic disruption, or environmental damage. (UNISDR, 2009)

• Categories of Hazards:

  • Natural Hazards: Geologic, Biological, Hydrometeorological, Extraterrestrial.

  • Anthropogenic Hazards: Technological, Environmental, Socio-economic, Political, and Security Hazards.

• Examples of Hazards:

  • Geologic: Earthquakes, tsunamis, volcanic eruptions.

  • Biological: Epidemic diseases, insect plagues.

  • Hydrometeorological: Floods, droughts, tropical cyclones.

  • Extraterrestrial: Asteroids, meteoroids.

2. Basic Concept of Disaster

• Definition of Disaster:

  • A serious disruption of the functioning of a community or society involving widespread human, material, economic, or environmental losses, which exceeds the ability of the affected community to cope using its own resources. (UNISDR, 2009)

• Components of Disaster:

  • Exposure: People, property, systems, or other elements present in hazard zones.

  • Vulnerability: Characteristics that make a community susceptible to the damaging effects of a hazard.

  • Capacity: Ability to reduce or cope with potential negative consequences.

• Impacts of Disasters:

  • Human: Loss of life, injury.

  • Economic: Damage to property, loss of livelihoods.

  • Environmental: Destruction of habitats, pollution.

3. Types of Hazards

• Natural Hazards:

  • Geologic: Earthquakes, tsunamis, volcanic eruptions.

  • Biological: Epidemic diseases, insect plagues.

  • Hydrometeorological: Floods, droughts, tropical cyclones.

  • Extraterrestrial: Asteroids, meteoroids.

• Anthropogenic Hazards:

  • Technological: Industrial accidents, nuclear radiation, chemical spills.

  • Environmental: Pollution, toxic wastes.

  • Socio-economic, Political, and Security Hazards: Civil strife, terrorism.

• Hazards According to Onset:

  • Sudden Onset: Earthquakes, tsunamis.

  • Slow Onset: Droughts, civil strife.

4. Effects of Hazards

• Primary Effects:

  • Collapse of buildings during earthquakes, water damage during floods.

• Secondary Effects:

  • Fires due to earthquakes, flooding caused by landslides.

• Tertiary Effects:

  • Loss of habitat, crop failure, long-term economic impacts.

5. Disaster Risk

• Definition of Disaster Risk:

  • The potential for a calamity resulting from various hazards and their effect on the susceptibility of infrastructure, communities, and the economy.

• Disaster Risk Formula:

  • Disaster Risk = Hazard x Vulnerability x Exposure

• Disaster Prediction and Forecasting:

  • Scientists use predictable patterns in natural events to forecast disasters, though exact predictions are not possible.

6. Recurrence Interval

• Definition:

  • The average time between occurrences of a natural event of a certain magnitude.

• Calculation:

  • Recurrence Interval (R) = (N + 1) / M

    • Where N = Number of data, M = Rank.

• Example:

  • For a flood event, the recurrence interval can be calculated to estimate the likelihood of future floods.

7. Relationships Among Events

• Anatomy of a Tsunami:

  • Tsunamis are often caused by underwater earthquakes or landslides.

• Feedback Effects:

  • Some processes, like melting ice sheets, can accelerate due to global warming.

• Precursor Events:

  • Smaller events that precede a larger disaster, such as small tremors before an earthquake.

8. Mitigating Hazards

• Definition of Mitigation:

  • Efforts to prepare for a disaster and reduce its damage.

• Examples of Mitigation Solutions:

  • Soft Solutions: Zoning, building codes.

  • Hard Solutions: Riprap, spur dikes.

  • Land-Use Planning: Restricting development in hazardous areas.

  • Insurance: Financial recovery after a disaster.