natural disasters Flashcards
Natural Hazards
Something that has the potential to harm people or property (Example: a volcano, a hurricane)
Natural Hazardous Event
Disturbance that injures or kills plants and animals, not people
Natural Disasters
- Hazardous event that causes human causalities, property destruction, and economic loss
- Victims require outside resources to survive and recover
U.N. Disaster Declaration
- A serious disruption of the functioning of a community or society
- Widespread human, material, economic, or environmental impact
- Exceeds the ability of a community to cope using its own resources
Rapid-onset disasters
Occur suddenly without
warning (Like earthquakes)
Slow-onset disasters
take days or weeks to develop (Regional flooding from prolonged rainfall)
* Some disasters can take years, like sea-level rise
Primary Disaster
Casualties and destruction from a natural hazard itself (Example: direct damage from an earthquake
or landslide)
Secondary Disaster
Hazardous events triggered by the primary disaster (Example: a fire triggered by an earthquake)
Tertiary Disaster
Long-term societal disruptions from primary and secondary disasters (Example: spread of disease among disaster
survivors in refugee camps)
A local, minor, or small-scale disaster
- Affects a small area
- Few casualties
- Small economic loss
- No long-term disruptions to society
A major or large-scale disaster
- Affects a broad region
- Large losses of life and property
- Major economic loss
- Long-term societal disruption
Recurrence Interval (RI)
The frequency of a disaster
* Describes how often a disaster will occur
* Several ways to define/calculate RI
* Depends if you want to consider magnitude
A simple RI is calculated by
dividing the number of years on record by the number of events
Annual Probability (AP)
- The likelihood that an event will happen in a given year
- Often expressed as a number between 0 and 1
- Requires an RI
- AP = 1/RI
impacts of disasters on people
-disaster can cause fatalities
-survivors become displaced (evacuees and refugees)
impacts of disaster on economics
-repairs to property and infrastructure
-value of lost economic activities
impacts of disaster on society
-globally 50,000 to 10,000 people die from disasters each year
exposure refers to
potential casualties, economic issues, social disruptions
vulnerability refers to
-the degree that structures can resist damage
-community preparation to minimize affected people and economic impacts
-resources available to rebuild infrastructure
both exposure and vulnerability are affected by
-wealth
-traditions
-politics
risk
-the probability of loss due to a natural disaster
-risk=hazard x exposure x vulnerability
you can lower risk by
-decreasing exposure and vulnerability (wealthy countries can do this)
what can increase risk
-population growth and density
-climate change
-land modification, urbanization, deforestation
disaster tiemeline
-response (rescuing survivors), recovery (clean up), restoration (rebuilding infrastructure, urbanization, deforestation)
disaster response depends on
time
a watch indicates…
-conditions are right for a hazardous event
a warning indicates…
-a hazardous event is happening
Realms/spheres of the earth
-a system that evolves, exchanges materials and energy
the different spheres
-atmosphere
-geosphere
-cryosphere
-biosphere
internal energy
-earths internal energy
-leftover heat from earths formation
-decay of radioactive atoms inside the earth
-internal energy drives plate tectonics and disasters such as volcanic eruptions and earthquakes
external energy
-comes from the sun (causes most weather-related disasters through convection/movement of air)
-gravity (causes landslides)
layers of the earth
-crust
-mantle
-core
crust
-outermost layer
-ocean, continental crust
Mantle
-82% of earths volume
core
-iron (90%) and nickel (5%)
-outer core-liquid iron flows and generates earth’s magnetic
-inner core is solid
-lithosphere- crust and upper, solid mantle
-asthenosphere- soft, upper mantle
divergent boundaries
-lithospheric plates move apart
-hot asthenosphere rises to create magma
-seafloor moves away from ridge, cools and denser
-ocean-ocean or continent-continent
-divergent boundaries start as continental rifts and create ocean basins
-young oceanic crust @ divergent boundary
-gets older as u move away
convergent boundaries
-plates move together
-ocean-ocean
-ocean-continent
-continent-continent
-they have deep sea trenches where subduction occur
transform boundaries
-plates slide horizontally
-Transform faults also link segments of mid-ocean ridges
-Some connect trench segments
-Some go through the continental lithosphere
subduction
-the process of an oceanic
plate slipping beneath an overriding plate (Have the largest
earthquakes Plate Boundaries)
Earthquakes
the shaking of the Earth, Caused by movement along a geologic fault
Fault
crack (fracture) in rock where movement (slip)
occurs, Tectonic plate boundaries are large faults
Faults are primarily caused by
tectonic
stresses
