GEOLOGY

Detailed explanation-1: -It forces the ground to move backwards and forwards as it is compressed and expanded. The S-wave (secondary or shear wave) follows more slowly, with a swaying, rolling motion that shakes the ground back and forth perpendicular to the direction of the wave.

Detailed explanation-2: -P waves, or primary waves, arrive first while S waves, or secondary waves, arrive second. Both waves cause the ground to shake when an earthquake occurs. S waves cause more intense shaking than P waves and are typically much more destructive.

Detailed explanation-3: -S waves shake the ground in a shearing, or crosswise, motion that is perpendicular to the direction of travel. These are the shake waves that move the ground up and down or from side to side.

Detailed explanation-4: -The motion of secondary waves is perpendicular to the direction of the wave travel, similar to the motion of vigorously shaking a rope (SF Fig. 7.1 B).

Detailed explanation-5: -Seismic waves cause intense shaking at the Earth surface that can cause buildings and roads to collapse.