Umumnya, variasi kerapatan tidaklah terlalu besar, dengan demikian kecepatan gelombang hampir sepenuhnya bergantung pada nilai k dan μ.
Of these density shows the least variation so the velocity is mostly controlled by k and μ
==Lihat pula==
Almost all the information we have on the structure of the Earth's deep interior is derived from observations of the travel times, [[Reflection (physics)|reflection]]s, [[refraction]]s and phase transitions of seismic body waves, or [[normal modes]]. Body waves travel through the fluid layers of the [[Earth#Interior|Earth's interior]], but P-waves are refracted slightly when they pass through the transition between the semisolid [[mantle (geology)|mantle]] and the liquid [[Earth#The core|outer core]]. As a result, there is a P-wave "shadow zone" between 104° and 140°, where the initial P-waves are not registered on [[seismometer]]s. In contrast, "S" waves do not travel through liquids, rather, they are attenuated.
▲{{cite web|url=http://earthquake.usgs.gov/image_glossary/shadow_zone.html|work=U.S. Geological Survey"|title="Photo Glossary of Earthquakes"|accessdate=October 10|accessyear=2005}}
==External links==
*[http://www.eas.purdue.edu/~braile/edumod/waves/WaveDemo.htm Purdue's catalog of animated illustrations of seismic waves]
'''Gelombang P''' adalah [[gelombang]] yang arah simpangannya searah dengan arah rambatannya. Sebagai contoh adalah sebuah [[pegas]], bila kita beri gaya dorong maka pegas akan merambatkan [[energi]] dengan cara merapat dan perengangkan pegas, dan searah dengan arah rambatannya.
