Flashcards in Chapter 5 - Hazards - Complete Deck (126)
Define a hazard?
Something that's a potential threat to human life or property
Define natural hazard?
A hazard caused by the earth and our atmosphere
Define geophysical hazard?
Caused by land processes
- Volcanic eruptions
Define atmospheric hazards?
Caused by climatic processes
- Tropical cyclones
- Extreme hot/ cold weather
Define hydrological hazards?
Caused by water movement
When a hazard actually seriously affects humans.
What's the difference between a natural hazard and a disaster?
A natural hazard is a volcano erupting in a deserted place but becomes a disaster when it affects people.
The likelihood that humans will be seriously affected by a hazard.
How susceptible a population is to the damage caused by a hazard.
Define 5 factors that affect peoples perceptions of a hazard?
- Wealth = rich people afford to move house.
- Religion = view hazard as act of God.
- Education = More education better understanding of risks.
- Past experiences = People live in hazard-prone areas, adapt and know circumstances.
- Personality = People fear hazards/ others think they're exciting.
Define 4 things governments try to do to reduce their vulnerability of a hazard?
- Preparation to reduce its magnitude. Building flood defences. Cost risk sharing.
- Prediction of hazard, when, where a hazard will occur.
- Protection of property.
- Fatalism - accept the hazard cannot be avoided.
Define the Park Model?
Shows the different phases of response to a hazard.
Define the 5 stages in the Park Model?
Define PRE-DISASTER in the Park Model?
Before the event, situation is normal.
Define DISRUPTION in the Park Model?
During & directly after the hazard occurred, destruction of property, loss of life.
Define RELIEF in the Park Model?
In the aftermath of event, rescue efforts focus on saving people & preventing further damage.
Define REHABILITATION in the Park Model?
Once the immediate impacts are under control, people start to resolve longer-term problems (shelter, aid).
Define RECONSTRUCTION in the Park Model?
Involves rebuilding permanent houses, infrastructure.
Define the 4 phases in the hazard Management Cycle?
- Mitigation = minimise impacts in future, build defences.
- Preparedness = Planning how to respond in future, warning systems.
- Response = How people react in disaster situation, emergency services rescue people.
- Recovery = Getting affected area back to normal, repairing rebuilding houses, restoring services.
Define the Earth's core?
- Centre of earth
- Inner core = solid ball containing Iron & Nickel.
- Outer core = semi-molten containing Iron & Nickel.
- 6000oC hot
Define the Earth's mantle?
- Around core is mantle (Silicate rock).
- Nearest to core/ quite rigid.
- Asthenosphere above mantle (semi-molten).
- 1000-3500oC hot.
Define the layers of the Earth?
- Inner core
- Outer core
Define 2 types of Crust?
- Continental = Is thicker (30-70km thick) less dense.
- Oceanic = Is thinner (6-10km thick) more dense.
Define tectonic plates?
- Lithosphere divided into many slabs, which move in relation to each other.
- Plates meet at plate boundaries/margins.
Define 3 theories why tectonic plates move?
- Convectional currents
- Slab pull
- Ridge push (Gravitational sliding)
Define CONVECTIONAL CURRENTS as a theory why tectonic plates move?
- Parts of asthenosphere heat up from core, less dense, slowly rise, then cool down and slowly sink.
- Circular movements of semi-molten rock called convection currents.
- Create drag on base of tectonic plate, making them move.
Define SLAB PULL as a theory why tectonic plates move?
- At destructive plate margins, denser crust is forced under less dense crust.
- Sinking plate edge pulls rest of plate towards boundary.
Define RIDGE PUSH as a theory why tectonic plates move?
- Constructive plate margin, magma rises to surface forms new crust.
- Surrounding rock heats, expands, rises above surface forming slope.
- New crust cools down, dense, gravity shifts denser rocks downslope, away from plate margin.
- Puts pressure on tectonic plate, causing then to move apart.
Define sea-floor spreading?
- As tectonic plates diverge, magma rises to fill gap.
- Sea bed gets wider as plates diverge, more magma fills gap.
- Creates mid-ocean ridges.