In-Depth Notes on Fragile Systems and Natural Disasters

Flash Card Deck: Fragile Systems

  • Risk Equation:

    • Risk = Hazard × Vulnerability × Exposure

  • Definition of Disaster:

    • A disaster is defined as a significant event when a hazard affects a vulnerable population, leading to damage or casualties.

  • Energy and Natural Disasters:

    • Energy is crucial in understanding natural disasters as it drives processes: kinetic, potential, thermal, and latent energies are involved in earthquakes, tsunamis, and storms.
Mass Extinctions & Impacts from Space

  • Big 5 Mass Extinctions:

    1. End-Ordovician
    2. Late Devonian
    3. End-Permian
    4. End-Triassic
    5. End-Cretaceous

  • End-Cretaceous Extinction:

    • Likely caused by the Chicxulub asteroid impact, evidenced by iridium layers and shocked quartz.

  • Torino Scale:

    • A scale from 0–10 that measures asteroid impact risk.
Waves & Tsunamis

  • Wave Types:

    • Deep-water wave: Depth > ½ wavelength
    • Shallow-water wave: Depth < 1/20 wavelength.

  • Causes of Tsunamis:

    • Sudden displacement of water due to earthquakes, landslides, or volcanic eruptions.

  • Signs of Tsunami:

    • Ground shaking, rapid sea level changes, loud ocean roar.
Storms

  • Fuel for Thunderstorms and Hurricanes:

    • Warm ocean water and moist air provide latent heat energy.

  • Tornado vs. Hurricane:

    • Tornado: Small, fast-spinning, short-lived
    • Hurricane: Large, slow-moving, powered by warm ocean water.

  • Storm Surge:

    • Highest on the right of the hurricane eye during landfall in the Northern Hemisphere.
Earthquakes

  • Types of Seismic Waves:

    1. P-waves (fast, compressional)
    2. S-waves (slower, shear)
    3. Surface waves (slowest, most damaging).

  • British Columbia Tectonic Setting:

    • Subduction of the Juan de Fuca plate beneath North America, with risks of megathrust earthquakes.

  • Seismograph:

    • Instrument used to measure earthquakes.
Landslides

  • Main Causes:

    • Steep slopes, water saturation, weak materials, earthquakes, deforestation.

  • Types of Landslides:

    • Fall: Free fall of material
    • Slide: Movement along a plane
    • Flow: Chaotic saturated movement.

  • Mitigation Strategies:

    • Drainage control, slope reinforcement, vegetation, hazard mapping, warning systems.
Volcanoes

  • Types of Volcanoes:

    1. Shield (gentle slopes, basaltic)
    2. Stratovolcano (explosive, layered)
    3. Cinder cone (small, steep).

  • Tectonic Settings:

    • Subduction zones produce stratovolcanoes; rift zones produce shield volcanoes; hot spots can produce both.

  • Key Hazards:

    • Pyroclastic flows, lahars, ashfall, lava flows, toxic gases.

  • Monitoring Tools:

    • Seismometers, tiltmeters, GPS, gas sensors, satellite imagery.
Summary of Key Quiz Facts
  • Developed countries tend to lose more property rather than lives during disasters.
  • Population growth amplifies disaster risk.
  • Kinetic energy is dependent on velocity; 2 orders of magnitude indicates 100x more energy.
  • Density influences stratification; high viscosity equates to lower flow rates; plastic deformation results in permanent changes under stress.
Disaster Preparedness Recommendations
  • Utilize reliable sources for disaster information (e.g., USGS, Environment Canada)
  • Promote preparedness and advocate for sustainability practices.