EARTHQUAKE
VOCABULARY
COMPARISON
Unit 11
P Wave & S Wave
P Wave

Compress and expand
in the ground
S Wave

Vibrate from side to
side AND up and
down
Seismograph & Seismogram
Seismograph
A device that record
ground movement
caused by seismic
waves as they move
through earth
Seismogram
The record of an
earthquakes seismic
waves produce by an
seismograph
Stress & Tension
Stress
A force that acts on
rock to change its
shape or volume
Can be compression,
tension or shearing
Tension
Stress that stretches
rock so that it becomes
thinner in the middle
Mercalli Scale, Richter Scale and
Moment Magnitude Scales
Mercalli scale
Rates
earthquakes
according to
intensity and
how much
damage they
cause at a
particular
place.
Richter scale
Rates
earthquakes
based on the
size of its
seismic
waves.
Moment magnitude scale
Rates earthquakes
by estimating the
total energy
related by an
earthquake
Focus & Epicenter
Focus
The point beneath
earth’s surface where
rock breaks under
stress and causes an
earthquake
Epicenter
The point on Earth’s
surface directly above
an earthquake’s focus
Anticline & Syncline
Anticline
An upward fold in rock
formed by
compression
Syncline
A downward fold in
rock formed by
compression
Hanging Wall & Foot wall
Hanging wall
The block of rock that
forms the upper half
of a fault
Hanging
wall slopes
in
Footwall
The block of rock that
forms the lower half of
a fault
Footwall
slopes out