Natural hazards
- Exist independently of people
- Have the potential to harm people or property
- Constitute a threat to society
- Contrasts with human caused hazards
Natural Hazardous Event
- A disturbance that injures or kills plants and animals
- Have occurred since Earth formed
Natural Disasters
- Occur from a natural hazardous event
- Cause human causalities, property destruction, and economic loss
- Victims require outside resources to survive and recover
Recurrence Interval (RI)
- The average time between successive events of a given size
- Requires a historical record
Annual Probability
- The likelihood an event will happen in a given year
- Requires an RI
- AP = 1/RI
(larger AP value = higher chance of event happening)
Primary Disaster
Casualties and
destruction from a
natural hazard event
itself
- (wind and wave damage from a
hurricane)
Secondary Disaster
Hazardous events
triggered by the
primary disaster
- (collapsed dikes and flooding
post-hurricane)
Tertiary Disaster
Long-term societal
disruptions due to
primary and
secondary disasters
- (Housing loss from decay and
mold after flood
recedes)
FEMA: Prep
- Evacuations may occur
- Emergency personnel arrive, shelters are established
FEMA: Response
Rescuing survivors and treating injuries
FEMA: Recovery
Clean-up and providing essential services
FEMA: Restoration
Rebuilding infrastructures and buildings
Would a large meteorite impact on the Moon be considered to be a natural disaster?
It can only be called a natural disaster if the impact has caused human casualties, extensive destruction of property, and significant economic loss
