1. How do we measure
earthquakes?

2. Epicentre and focus video
• Watch it here
• A =
• B =

4. How can we measure
earthquakes?
• There are two ways of measuring
earthquakes;
1. The Richter Scale
2. The Mercalli Scale
How do we measure earthquakes?

6. 1. Richter Scale
• On the Richter Scale, magnitude is expressed in
whole numbers and decimal fractions.
• Although the Richter Scale has no upper limit,
the largest known shocks have had magnitudes
in the 8.8 to 8.9 range.
• It is a logarithmic scale which means that a size
‘6’ on the Richter Scale is 10 times larger than a
size ’5’ and 100 times larger than a size ‘4’.
• Measured using a seismograph or seismogram.
How do we measure earthquakes?

7. How do we measure earthquakes?
A seismograph - video

8. 2. Mercalli Scale
• Based on the effects of an
earthquake.
• The scale goes from 1to 12
How do we measure earthquakes?

9. Have a go at this past question

10. Swap answers and peer assess

11. Earthquake recap:
When will an earthquake cause the most damage?
Powerful earthquake,
causes a lot of damage
Weak earthquake,
Doesn’t cause much
damage
Distance from the
epicentre
The state of preparation
for an earthquake
(country)
Population density
Type of land the area is
built on
Time of the day
Time of the year