Measuring Earthquakes
Geography: Cambridge International GCSE (2027 Exams), topic 4.3.4
Measuring Earthquakes
The Moment Magnitude scale is used to measure earthquake magnitude. The Mercalli scale measures the damage done by earthquakes.
The Moment Magnitude scale
- The moment magnitude scale measures the magnitude of an earthquake by measuring how much energy it releases.
Logarithmic
- The scale is logarithmic.
- This means that it goes up in tens. So 2 on the scale is 10x stronger than 1, and 3 is 10x stronger than 2.
Magnitude 1-10
- We have never seen an earthquake with a magnitude larger than 9.5.
- Earthquakes with a magnitude of 7 or more often cause a lot of damage and deaths.
The Mercalli scale
- It measures damage done and is scored from I-XII.
- It is recorded in Roman numerals.
- This scale is more likely to hide differences between LIC and HIC countries as it shows damage;
- A much smaller earthquake (in terms of magnitude) could cause total destruction in a poorly built city than in a well-built one with earthquake-proof buildings.
Test yourself on Measuring Earthquakes
What scale is used to measure earthquake magnitude?
Which of these mathematical terms describes the moment magnitude scale?