Chapter 3- Earthquakes Flashcards
Define earthquake.
A series of seismic waves that shake the ground and buildings
What cause earthquakes?
When 2 plates collide slide past each other or separate.
Pressure builds between the plates and forces the rock to break
What happens during an earthquake?
Surface of crust may shake or move up to several metres
Name the place within the crust where the rock breaks and the earthquake begins sending out shockwaves or seismic waves
Focus
What is the epicentre?
Place on the surface directly above focus
Where most severe tremors occur
What is a fault or fault line?
A crack in the earths surface
What usually happens after an earthquake?
Aftershocks
What are seismic waves?
Vibrations sent out by earthquake
How are seismic waves measured?
Seismographs
What is the force of an earthquake measured on?
The richter scale
Name a killer earthquake and give the details.
Sumatra
2004
230,000 deaths
9.0 on richter scale
Name the immediate effects of earthquakes.
Displacement of the earth
Collapse of buildings
Deaths of people in buildings or form falling debris
Describe follow on effects of earthquakes.
Breaking of gas mains -> cause fires that destroy buildings
Destruction of communication systems -> more difficult to help
Spread of disease eg cholera and typhoid caused by dirty water
Destruction of local economy as factories and communications links are destroyed
Name a recent earthquake.
Give details.
Haiti
12 jan 2010
222,570 deaths
7.0 richter scale
