Disaster and Disaster Risk – Comprehensive Study Notes

Basic Concepts of Disaster and Disaster Risk

Etymology & Definition of “Disaster”

  • Originates from the French word désastre

    • “des” → “bad”

    • “astre” → “star”

  • Modern usage:

    • A tragic event resulting in significant loss of life, major destruction of property, and/or severe environmental degradation.

Classification of Disasters

  • Natural Disasters (result from natural processes)

    • Rapid/Acute onset: earthquakes, tsunamis, floods, hurricanes, tornadoes, volcanic eruptions, avalanches, heat waves, wildfires.

    • Progressive/Gradual onset: drought leading to famine, slow‐moving environmental degradation.

  • Man-Made (Human-Induced) Disasters

    • Technological failures (industrial accidents, nuclear meltdowns, chemical spills).

    • Terrorism & violence (bombings, armed conflict).

    • Complex humanitarian emergencies (civil war, large-scale displacement, collapse of essential services).

Disaster Risk (DR)

  • Expresses the likelihood of loss of life, injury, or destruction within a specified time frame.

  • UN-ISDR definition: the potential loss of lives, health status, livelihoods, and assets—often difficult to quantify precisely.

    • Mathematically: DR = (\text{Hazard}) \times (\text{Exposure}) \times (\text{Vulnerability})

    • Although not explicitly in the transcript, this conceptual formula connects hazard theory to practical risk assessment.

Two Categories of Disaster Risk

  • Intensive Risk

    • Large numbers of people/assets concentrated in one geographic location.

    • Extreme events → catastrophic impacts with high mortality & massive asset loss.

  • Extensive Risk

    • Dispersed population & infrastructure exposed to numerous low- or moderate-intensity hazards.

    • Losses accumulate over time (e.g., recurrent seasonal flooding, small landslides).

Impacts of Disaster

  • Impact types: Direct, Indirect, Intangible

    • Direct Losses

    • Physical destruction of people, buildings, vehicles.

    • Cleanup & debris-removal costs.

    • Immediate reduction in operational capacity of infrastructure.

    • Indirect Losses

    • Disruption of utilities (water, power, telecom) & local businesses.

    • Revenue loss, cost escalation, supply-chain interruption.

    • Intangible Losses

    • Psychological trauma, stress, decreased quality of life.

    • Erosion of social cohesion & sense of security.

Social Impacts

  • Housing

    • Floods & earthquakes destroy dwellings → homelessness.

    • Long-term effects: displacement, community fragmentation, impaired household income.

  • Health

    • Damage to hospitals & clinics impairs emergency response.

    • Equipment loss means fewer patients can be treated, worsening morbidity & mortality.

  • Education

    • Schools double as evacuation/relief centers → classroom disruption.

    • Long-term learning gaps for students; increased stress for teachers.

Economic Impacts

  • Greater severity in countries burdened by debt & poverty.

  • Government funds diverted to: reconstruction, rehabilitation, medical aid.

  • Possible GDP contraction; weakened capacity for import/export.

  • Spikes in unemployment, especially in agriculture, tourism, & small enterprises.

Environmental Impacts

  • Flooding:

    • Submersion of trees & root crops; soil erosion; water contamination.

  • Drought:

    • Ecosystem stress via reduced water availability; biodiversity decline.

  • Earthquakes:

    • Land degradation, landslides, altered river courses.

  • Tsunamis:

    • Long-term marine & coastal ecosystem damage; loss of fisheries; salinization of arable land; destruction of coastal infrastructure.

Practical, Ethical & Philosophical Considerations

  • Disaster preparedness is both a technical and moral imperative—prioritizing vulnerable populations upholds social justice.

  • Long-term recovery hinges on resilience building—integrating engineering, environmental stewardship, and community engagement.

  • Transparent risk communication fosters public trust and informed decision-making.

Connections to Broader Frameworks

  • Aligns with the Sendai Framework for Disaster Risk Reduction (2015-2030), which stresses:

    • Understanding risk → governing risk → investing in resilience → enhancing preparedness.

  • Reinforces principles from prior lectures on hazard assessment, sustainable development, and climate-change adaptation.

Key Takeaways & Exam Triggers

  • Memorize distinctions: Intensive vs. Extensive Risk, Direct vs. Indirect vs. Intangible Losses.

  • Be able to list examples of natural vs. man-made hazards.

  • Understand socio-economic feedback loops: disaster → economic decline → heightened vulnerability → future disaster risk.

  • Link “disaster risk” to its component factors: hazard, exposure, vulnerability.

  • Reflect on ethical dimensions: prioritizing aid, equity in resource allocation, protecting marginalized groups.