GCSE Geography - Hazards

what is a natural hazard

Extreme natural event that disrupts human activities or extreme damage to property and may result in loss of life

what are the results of physical processes

Earthquakes, volcanoes

Plate tectonics theory

• the core heats up the magma in the mantle

• the hot maga is less dense than its surroundings, so it rises upwards

• when it reaches the top, it cools

• it becomes more dense, and therefore sinks back down to the bottom

• it is heated up again, and the cycle continues

• the plates, which lie on top are pushes and pulled by the convection currents in the magma

continental and oceanic crust characteristics

continental - makes up land, old, less dense, thick

oceanic - makes up the ocean floor, younger, dense, thin

what was the huge supercontinent called

pangaea

where do tectonic hazards occur the most

• west of north and south america

• the ring of fire, which is in the pacific ocean

why do eqarthquakes occur

when the plates move, they can get stuck, the pressure builds up until it is released suddenly and it sends out a huge amount of energy

why do volcano erruptions occur

when the magma from the magma chamber builds up and slowly feeds the volcano, this magma slowly pushes to the surface and erupts. the hotspot I where it erupts

→ ← what plate margin is this

destructive, the plates move towards eachother

← → what plate margin is this

constructive, plates move away from eachother

what plate margic is it when they move past eachother

conservative, plates move alongside eachother