Story: Earthquakes

Primary and secondary waves (1st of 2)

The P-wave (primary or pressure wave) is a pulse of energy that travels quickly through the earth and through liquids. 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.

About this item

Te Ara – The Encyclopedia of New Zealand

This item has been provided for private study purposes (such as school projects, family and local history research) and any published reproduction (print or electronic) may infringe copyright law. It is the responsibility of the user of any material to obtain clearance from the copyright holder.

How to cite this page:

Eileen McSaveney. 'Earthquakes - What causes earthquakes?', Te Ara - the Encyclopedia of New Zealand, updated 9-Jul-13
URL: http://www.TeAra.govt.nz/en/interactive/4403/primary-and-secondary-waves