Tectonic hazards: Earthquakes
- Created by: Laurenskye
- Created on: 06-05-16 20:03
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- Tectonic Hazards: Earthquakes
- Causes
- Caused by sudden movement within the earth
- Could be caused along a fault line or by the upwelling of magma during a volcanic eruption.
- The movement is the result of the release of stress in the rocks that builds up over a period of time.
- This causes shocks or seismic waves
- The point at which the pressure is released is called the focus.
- This is the centre of the earthquake. The point at the earth's surface above is called the epicentre.
- Caused by sudden movement within the earth
- Effects
- Ground Shaking
- Landslides, rock and snow avalanches
- Occur in mountainous areas when slopes are weakened by strong shaking.
- Tsunamis
- Seismic waves occur beneath the sea.
- Liquefaction
- Shock waves cause groundwater to rise to the surface turning soft ground to mud causing buildings to collapse
- Measuring earthquakes
- Magnitutude
- Measured by the richter scale and given the value between the number 1 and 10
- Intensity
- Measures the degree of shaking of the ground and records the level of damage. Mercalli developed a 12-point scale for measuring the intensity of earthquakes which uses the observations of witnesses to the earthquake
- Magnitutude
- What affects the amount of Damage
- Distance away from the epicentre
- The type of material that a building rests on.
- The designs of buildings
- Predictions
- Sensitive instruments measure earth movements and the stress building up in rocks
- Foreshocks help scientists to predict the chances of a major shock following
- Recent earthquakes can be plotted to show if a major earthquake can be expected
- Preparation
- Earthquake-proof buildigs
- Risk of fires from severed power lines and ruptured gas lines, when buildings are constructed they should be constructed with flexible pipes.
- Stronger buildings
- Education
- Government and media can provide guidance to prepare them.
- Emergency services
- Governments must make sure supplies are available and the emergency are prepared for a possible earthquake
- Good communication with earthquake monitoring
- Earthquake-proof buildigs
- Causes
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