P waves - a pulse energy that travels quickly through the earth and through liquids
-travels faster than s waves
-after an earthquake it reach the detector first
-compressional waves, travel by particles vibrating parallel to the direction the wave travel
-they force the ground to move backward and forward as they are compressed and expanded
-most importantly, they travel through solids, liquids and gases
S-waves - is a pulse energy that travels slower than a p wave through earth and solids
-move as shear or transverse waves, and force the ground to sway from side to side, in rolling motion that shakes the ground back and forth perpendicular to the direction of the waves
-its movement led to seismologists to conclude that the outer core is liquid
