The Richter and Mercalli Scale
Refers to AQA A2 Geography
Plate Techtonics and Assosiated Hazards
- Created by: Bethany
- Created on: 01-04-14 17:01
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- The Richter and Mercalli Scale
- THE RICHTER SCALE
- A LOGARITHMIC Scale
- This means that an event measured a 7 on the scale is TEN TIMES GREATER than one measuring 6 on the scale.
- Energy release is proportional to magnitude.
- For eact unit increase on the scale, energy released increases approx. 30 times.
- Past earthquakes on the scale
- Largest ever measured on scale was Great Chilean Earthquake of 1960, which measured 9.5.
- Largest ever recorded UK earthquake was 4.8 on the scale, large for the UK but small compared to Haiti Earthquake, for example, with a magnitude of 7.0.
- A LOGARITHMIC Scale
- THE MERCALLI SCALE
- Considers both the intensity of an event AND its impact.
- Level I would be equivelent to two on the the Richter Scale. Detected by seismometers but felt by very few, if any. No damage caused.
- Comparisons to Richter scale would depend on the location of the earthquake, hence influencing its impacts.
- The top level is Level XII. This represents total destruction with the ground seen to shake. This would be equivlent to approx 8.5 on the Richter Scale.
- Comparisons to Richter scale would depend on the location of the earthquake, hence influencing its impacts.
- Level I would be equivelent to two on the the Richter Scale. Detected by seismometers but felt by very few, if any. No damage caused.
- Considers both the intensity of an event AND its impact.
- WHICH IS BETTER?
- Problems with the Mercalli Scale.
- No use in an uninhabited area such as a desert where there is little human damage
- Statements such as resembling heavy traffic only apply if a person has felt heavy traffic, or what they feel is heavy traffic, which may differ if they live in a rural area.
- Impacts vary in different areas, so may be multiple values for the same earthquake.
- Somewhat SPECULATIVE
- Problems with the Richter Scale
- Doesn't take into account amount of damage; an earthquake which may cause collosal damage in one place would cause little damage in an uninhabited area.
- Judgement
- The Richter Scale allows easy comparisons of earthquakes which are not speculative regardless of location, and is a mathematical calculation, not a rough category.
- Problems with the Mercalli Scale.
- THE RICHTER SCALE
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