Question

Earthquakes are essentially sound waves traveling through the earth. They are called seismic waves. Because the earth is solid, it can support both longitudinal and transverse seismic waves. These travel at different speeds. The speed of longitudinal waves, called P waves, is . Transverse waves, called S waves, travel at a slower . A seismograph records the two waves from a distant earthquake.

If the S wave arrives 2.0 min after the P wave, how far away was the earthquake? You can assume that the waves travel in straight lines, although actual seismic waves follow more complex routes.

Answer 1

Vs and Vp were not given?

d = Vs t
d = Vp(t-120 seconds)
so
Vs t = Vp(t-120)
t (Vp-Vs)=120
t = 120/(Vp-Vs)
and
d = Vs t = 120 Vs / (Vp-Vs)