Hazards And Tectonics Flashcards
What is a natural hazard?
An event that threatens people or has the potential to cause damage, destruction and death e.g. volcano, earthquake, tropical storm
What is a conservative plate margin?
A tectonic plate margin where two tectonic plates slide past each other
What is a constructive plate margin?
Tectonic plate margin where rising magna adds new material to plates that are moving apart or diverging.
What is a destructive plate margin?
A tectonic plate margin where two plates are converging or coming together and the oceanic plate is subducted. It can be associated with violent earthquakes and explosive volcanoes.
What is a earthquake?
A sudden or violent movement within the earths crust, followed by a series of shocks.
What are Immediate responses?
The reaction of people as a disaster happens, and in the immediate aftermath
What are Long-term responses?
Later reactions that occur in the weeks, months and years after an event has happened.
What is Monitoring?
Recording physical changes, such as earthquake tremors around a volcano, to help forecast when and where a natural hazard might strike.
What is a plate margin?
The margin of boundary between 2 tectonic plates.
What is Planning?
Actions taken to enable communities to respond to, and recover from, natural disasters, through measures such as emergency evacuations plans.
What is Prediction?
Attempts to forecast when and where a natural hazard will strike, based on current knowledge. This can be done for some extent for volcano eruptions.
What are Primary effects?
The initial impact of a natural event on people and property, caused directly by it; for instance, buildings collapsing following an earthquake
What is an atmospheric hazard?
Created in the atmosphere, by the movement of air and water.
Examples of atmospheric hazards
Heatwave, tropical storms, drought, flooding, forest fires
What are terrestrial/ geological hazards?
Created by the movement of the earths tectonic plates or surface rock and soils
Examples of terrestrial/ geological hazards
Earthquake, volcano, land slides, tsunamis
What are water based hazards?
Created by rivers, sea or oceans
Example of water based hazards
Flooding
What are biological hazards?
Any biological substance that poses a threat to the health of people
Example of biological hazard
Disease
What are the 4 different types of natural hazards?
Atmospheric hazards, terrestrial/ geological hazards, water based hazards, biological hazards
What factors affect the IMPACT of a natural hazard?
Population, frequency, location, magnitude, level of development and wealth
What are the layers of the earth from outer to inwards?
Crust, mantle, outer core, inner core
What is the crust?
The crust is solid and is the layer we live on. The crust is usually between 10km - 60km thick.
What is the mantle?
This is the thickest section of the earth, with a diameter of about 2900km. The mantle is often described as being semi-molten, but in reality the top is hard rock and as you near the outer core it is beginning to melt (magma) 
What is the outer core?
This layer is believed to be liquid and largely made of iron and nickel. It is extremely hot with temperatures up to 5,500 degrees centigrade.
What is the inner core?
This layer is believed to be solid, because of the immense pressure placed upon it. It contains the centre of the earth which is about 6,378km from the surface, it is also extremely hot at about 5,500 degrees centigrade.
Why do convection currents make tectonic plates move?
- The hot core cause magna to rise in the mantle and sink towards the core when it cools.
- Convection builds pressure and carries plate with it
- only limited evidence of this so far
Why does slab pull make tectonic plates move?
- the denser plate sinks back into the mantle under the influence of gravity.
- it pulls the rest of the plate along behind it
Why does ridge push make tectonic plates move?
- magna rises as the plates move apart.
- the magma cools to form plate material.
- as it cools it becomes denser and slides down, away from the ridge.
- this causes tectonic plates to move away from each other.