Geography END OF YEAR EXAM Revision Flashcards
Magnitude
How large an event is
Difference between natural event and natural hazard
Natural hazards carry a risk to life, natural events don’t
Frequency
How often an event occurs
Focus
Point underground where the earthquake starts
Epicentre
Point on the surface where the most damage will be caused from the earthquake
Seismometer
Machine that measures the shaking of the ground from an earthquake
Constructive Boundary
Where two tectonic plates move apart
Destructive Boundary
Where two tectonic plates move together, usually an oceanic and a continental, where the oceanic slips below the continental plate (subduction)
Conservative Boundary
Where two tectonic plates slide past each other
Hazard risk
The probability that a hazard will take place
Natural factors
Natural factors, that effect hazard risk
Inner core temp
7000°C
Outer core temp
4000°C
Mantle temp
1000°C
Convection currents in the mantle: Step 1
Rock in the mantle is heated up
Convection currents in the mantle: Step 2
Heated rock rises as it is less dense
Convection currents in the mantle: Step 3
The semi molten rock spreads out, moving the tectonic plates
Convection currents in the mantle: Step 4
The rock cools and sinks back down towards the core
Oceanic crust rock type
Basalt
Continental crust rock type
Granite
Which is more dense? Oceanic Crust or Continental Crust
Oceanic
Which is renewable and can be destroyed? Oceanic Crust or continental Crust
Oceanic
Which is deeper? Oceanic crust or Continental
Continental
Destructive plate boundary landforms and hazards
Volcanoes, earthquakes and oceanic trenches
Constructive plate boundaries landforms and hazards
Small volcanoes and oceanic ridges
Conservative plate boundary landforms and hazards
Earthquakes, but NO LANDFORMS
Destructive plate boundary example
Pacific ring of fire
Constructive plate boundary example
Mid Atlantic ridge
Conservative plate boundary example
San Andreas fault
Conservative Boundary Earthquakes happen when…
Two plates slide next to each other in opposite directions, until they get stuck. Pressure builds up until one plate gives way releasing seismic waves causing an earthquake.
Richter Scale
Logarithmic scale measuring the amount of energy released by an earthquake
Mercalli Scale
Scale for earthquakes based on a description NOT ENERGY released
Primary effects
Direct results of the event eg. Buildings collapse
Secondary effects
Results of primary effects eg. Homelessness
Christchurch earthquake basic info
2011, 6.3 on Richter Scale, destructive plate boundary
Christchurch earthquake effects
185 dead, 4000 injured, 50% of buildings in the city centre severely damaged, 100s km of sewage pipes destroyed, 10,000 homeless
Nepal earthquake responses
15,000 temporary learning centres, millions on litres of water provided, Facebook safety check
Nepal earthquake basic info
2015, 7.9 Richter Scale, Poor country - not prepared
Nepal earthquake effects
8,000 deaths, 14,500 injured,130k homes destroyed, 28 million homeless
Positives of living near high risk zones
Near minerals, source of tourism, fertile soil, geothermal energy