Discuss the movement of seismic waves through Earth and along its surface. What will be an ideal response?

---

Surface waves move along Earth’s surface. Like ocean waves, they ripple the free surface
and can sometimes be seen as an undulating wavelike motion in the ground. Surface waves
cause most of the property damage suffered in an earthquake. Body waves are less dramatic,
but they are very useful for analyzing Earth’s interior structure. One kind of wave, the P
wave (or primary wave), is a compressional wave similar in behavior to a sound wave.
Rapidly pushing and pulling a very flexible spring (like a Slinky) generates P waves. The S
wave (or secondary wave) is a shear wave like that seen in a rope shaken side to side. P
waves and S waves are generated simultaneously at the source of an earthquake. P waves
travel through Earth nearly twice as fast as S waves, so P waves arrive first at a distant
seismograph, an instrument that senses and records earthquakes. Liquids are unable to
transmit the side-to-side S waves but do propagate compressional P waves. Solid rock
transmits both kinds of waves. Analysis of the characteristics of seismic waves returning to
Earth’s surface after passage through the interior suggests which parts of the interior are
solid, liquid, or partially melted.