What is inside here?
Process of Investigation:
Teams of Seismologists
develop a model of earth’s
interior which is to
compared to one
developed by teams of
theoreticians.
Theoreticians
Seismologist
Hypothesis: the simplest
solution to the question
“What is beneath our feet”
is a homogeneous Earth,
or one comprised entirely
of rock
Seismologist
Your task is to help test this hypothesis by analyzing a set
of seismograms from a real earthquake to determine how
long it takes for the seismic waves released from an
earthquake to arrive at various points on Earth’s surface.
Theoreticians
Your task is to help test this hypothesis by creating a model
of the Earth, using the known velocity of seismic waves in
rock ~ 11km/s to predict how long it should take seismic
waves to reach various distances around Earth.
Earth’s surface
Center of the Earth
Right
Left
o
180
Scale model of a homogeneous Earth
140°
Seismologists
Theoreticians
REPLACE WITH YOUR OWN DATA
Sample set shown
How does this anomaly
in the data translate
back to Earth?
Measure the geocentric angle from the epicenter to the
anomaly in the data (108 degrees for example).
Use your ruler to connect the epicenter to the mark you just
drew on Earth’s surface.
Next, repeat this procedure to the bottom of the circle
Like a tree making a shadow, something is blocking the
energy. Can we tell what it is?
Cut out this shape from you model
Lay the cut out from Earth A on top of Earth B and trace
along its edges (indicated with orange)
Next, rotate the cut out and continue to trace its edges