Natural hazards Flashcards
Hazard risk
The probability or chance that a natural hazard may take place
Natural hazard
A natural event that threatens people or has a potential to cause damage destruction and death
Earthquake
A sudden or violent movement within the earths crust followed by a series of shocks
Immediate responses
The reaction of people as a disaster happens and in the immediate aftermath
Long-term responses
Later reactions that occur in the weeks, months and years after the event
Monitoring
Recording physical changes, such as earthquake tremor is around a volcano, to help forecast when and where a natural hazard might strike
Plate margin
The marginal boundary between two tectonic plates
Planning
Actions taken to enable communities to respond to, and recover from, natural disasters
Prediction
Attempts to forecast when and where are natural hazard will strike based on current knowledge
What are Primary effects?
The initial impact of a natural event on people and property, caused by it directly, for instance the ground buildings collapsing following an earthquake
What is Protection?
Actions taken before a hazard strikes to reduce its impact
Secondary affect
The after effects that occur as indirect impact of a natural event, sometimes on a longer timescale
Tectonic hazard
A natural hazard caused by movement of tectonic plates
Tectonic plate
A rigid segment of the earths crust which can float across the heavier, semi molten rock below
Volcano
An opening in the earths crust from which lava, ash and gases erupt
Earth structure
-inner core
-outer core
-mantle
-crust
Characteristics of Oceanic crust:
Dense and thin
Continental crust
Less dense and thick
Convection currents
Heat from the core causes convection currents in the mantle
Plate boundaries: constructive
Rising magma add new material to places to diverging or moving apart
Plate boundaries: destructive
Two plates are converging all coming together and oceanic plate is subducted.
Plate boundaries: conservative
Two tectonic plates slide past each other
Plate boundaries: destructive
Two continental plates are converging all coming together neither is subducted so the land above is forced and folded upwards
Haiti: LIC case study
-25th of April 2015
-destructive plate Boundry
-7.9 Richter scale
Primary Effects:
-9000 people died
-3 million people homeless
-1.4 million people needed food, water and shelter in the days and weeks after the earthquake
Secondary Effects:
-ground shaking triggered landslides and avalanches
-avalanche killed 19 people
-risk of flooding from the Gandaki River
Immediate Responses:
-search and rescue teams arrived from UK, India and China
-Financial aid pledged from many coutries
-helicopters rescued people on Mount Everest
Long term responses:
-roads repaired and landslides cleared
-stricter controls on building codes
-Heritage sites reopened to help boost tourism
-people rehoused damaged homes repaired
Christ Church: HIC Case Study
-22nd of February 2011
-conservative plate boundary
-6.3 Richter scale
Primary Effects:
-185 people died, 6659 major injuries
-10,000 homes damaged, 3500 homes demolished, power outages, the port was damaged and many buildings collapsed
-water supplies and communications/roads were disrupted
Secondary Effects:
- Schools were shut
-many businesses remained closed
-Christchurch couldn’t host five rugby World Cup matches
Immediate Responses:
-international aid was provided ( around six to seven million dollars )
-aid workers from charities such as Red Cross came to help
-areas were zoned to assess damage
-300 Australian police officers were flown in
