Begin the Interactivity portion of the Earthquake Animation by picking the location of seismometers in three cities of your choice. Each of these seismometers produced a seismogram of the earthquake. Open each location's seismogram, and drag the green line to mark the moment of the arrival of the S-waves. This is recorded in seconds as your S–P value. The S-P value is a measure of the difference in time between the:. a. arrival of the shear body waves and the compressional body waves.

b. shear surface waves and the compressional body waves.

c. arrival of the secondary waves and the primary waves.

d. arrival of the secondary waves and the surface waves.

e arrival of the primary waves and the surface waves.