Information identified as archived on the Web is for reference, research or recordkeeping purposes. It has not been altered or updated after the date of archiving. Web pages that are archived on the Web are not subject to the Government of Canada Web Standards. As per the Communications Policy of the Government of Canada, you can request alternate formats by contacting us.
Earthquake strength is measured in two ways: magnitude
is a measure of the energy released
at the earthquake source. But how do scientists measure this?
A network of sensors
, called seismometers
, is used to record earthquakes.
An earthquake’s magnitude is calculated based on the ground motion
recorded by each seismometer and the distance
of that seismometer from the earthquake.
For each unit of increase in magnitude, the amount of ground motion increases
by a factor of 10.
This means that the amount of ground motion for a magnitude 6
earthquake is 10 times greater
than for a magnitude 5…
…and 100 times greater
than for a magnitude 4
represents the strength of shaking we feel
. It depends not only on the magnitude of the earthquake but also our distance
from the epicentre...
…and whether we are in a building
The underlying geology
also affects intensity. People on soft soils
usually experience longer
and greater shaking
than those on bedrock
or stiff soils
Back to main article
= energy released at the source. Intensity
= strength of shaking that we feel.
ISSN 1927-0275 = Dimensions (Ottawa. Online)