Measuring Earthquakes
Cornell Notes page 127
What is seismology?
• The study of
earthquakes
• An entire branch of
science is devoted
to understanding
earthquakes
What do we use to
measure
earthquakes?
Seismograph
• an instrument that
measures
vibrations in the
ground, and
records the location
and strength of an
earthquake
An alternative seismic instrument…
What is the Richter
Scale?
• Measures the magnitude or
strength of the shock
waves.
• Is measured in steps from one
upward.
• Each successive unit is
ten times more powerful
than the one before.
• A 7.0 on the Richter scale is
1000 times more powerful
than an earthquake
measuring 4.0.
What is the Mercalli
Intensity Scale?
• Measures what is felt by
people and the amount of
damage caused
• Uses roman numerals
• Scale: I- not felt
to XII- total destruction
Scale II
• Felt
indoors
by few
Scale IV
• Felt
indoors
by many,
outdoors
by few
Scale VI
• Felt by all,
indoors
and
outdoors.
Moved
furniture
Scale VIII
• Fright
general alarm
approaches
panic.
Scale XII
• Damage
total practically
all
buildings
damaged
greatly
http://www.abag.ca.gov/bayarea/eqmaps/doc/mmi.html