Earthquake Time
Travel Graphs
How to Use the Earthquake Travel Time Graph
TRAVEL TIME or DISTANCE from
EPICENTER (Given one, find the other)
Ex 1: A seismic station is 3000
kilometers from the epicenter of an
earthquake. How long will it take P
waves from this earthquake to
reach the
seismic station?
We know the
distance
(3000km)
We’re trying to
find the time it
will
take P waves to
travel this
distance.
Ex 2.
It takes P waves 7:20 (7 minutes and 20
seconds) to travel from an earthquake
epicenter to a seismic station. How long will
it take S waves from the same
earthquake to reach the seismic station?
What do we know?
What are we trying to find?
Another type of
question involves the
“difference in travel
time between P
waves and S waves”.
Ex 3. P waves arrive at
a seismic station
4:30 before
the arrival of S waves
from the same
earthquake. How far
from the epicenter
is the seismic station?
Ex 4. You
determined that
P & S waves
arrived at a
seismic station 6
minutes
apart.
How far from the
epicenter
is the seismic
station?
Ex 5. A seismic
station is 4000km
from the
epicenter
of an earthquake.
P waves arrive
at the station at
2:48:00 PM. At
what
time did the
earthquake
occur?
Ex 6. P waves
arrive
at a seismic station
at 4:22:10 AM.
S waves from the
same earthquake
arrive at 4:28:50
AM. What is the
time
of origin of the
earthquake?