Contents of 8.3 How do we know ... how to determine velocities of seismic waves in rocks?

Laboratory experiments relate seismic-wave velocities to different rock types, over ranges temperatures and pressures comparable to those in Earth's interior.
Seismic waves move more slowly in unconsolidated sediment than through sedimentary rock, and even faster through igneous and metamorphic rocks. Within igneous rocks, felsic rocks transmit waves more slowly than mafic, and ultramafic are the most rapid of all.

8.3 How do we know ... how to determine velocities of seismic waves in rocks?