Earthquakes Flashcards
What is an earthquake caused by
A sudden movement between the plates
What is an earthquake
When the ground shakes suddenly because a piece of the earths crust has moved
The movement of the earths crust produces what
Very strong shockwaves that travel out from the centre of the crust just like a stone being thrown into a pond
Where do the shockwaves spread out from
The focus
What is the focus
The point where the earth-quake starts
Near the focus the waves are what
Stronger and more damage occurs
What is he epicentre
The point on the earths surface immediately above the focus
Shockwaves or seismic waves are recorded on what
A graph called a seismograph
The strength of an earthquake is measured on what
The richtor scale
What is the richtor scale
A 9 point scale and at each point the strength of the earthquake is 10 times greater than the one before. At point 9 on the scale, the ground can open up
What does the richtor scale measure
Measures energy released from an earthquake, where as the Mercalli scale measures intensity
Give two short term effects of earthquakes
Landslides may occur and tsunamis may cause flooding in coastal areas
People may be killed or injured. Homes may be destroyed. Transport and communication links may be disrupted. Water pipes may burst and water supplies may be contaminated
Give two long term effects of earthquakes
Shops and businesses may be destroyed. The damage to transport and and communication links can make trade difficult and businesses may take a long time to recover from this
The cost of rebuilding a settlement is high and could take years. Investment in the area may be focused only on repairing the damage caused by the earthquake. Income could be lost
How can the earthquake hazard be reduced in the future
We can’t prevent natural earthquakes from occurring but we can significantly mitigate their effects by identifying hazards, building safer structures and providing education on earthquake safety. By preparing for natural earthquakes we can also reduce the risk from human induced earthquakes