The shakes of the transverse 'S' waves arrive at parts of the Earth
distant from the epicentre as vertical movements of the Earth's
crust. The base and graph paper in this seismometer will move with the ground, but
the heavy mass and connected pen stay still. The resulting trace will therefore
record all vertical movements.
Click on the button to see
how the seismometer responds to an an earthquake. Use the slider to change the magnitude
of the earthquake.
On the next page, we will have a look at some example
seismometer traces.
