earthquakes
A vibration.
vibration
back in forth movement is the anwser
I don't think a "resonant frequency" makes much sense for the Universe. Even a single vibration would never be able to get back and forth, even if it's only through the OBSERVABLE Universe.
sound has properties of loudness and pitch. The loudness of a sound depends on the amplitude of vibration. A speaker making a loud sound moves back and forth more than a speaker making a soft sound. The pitch of a sound depends on the frequency of vibration. A speaker making a high pitched sound like a siren vibrates with a higher frequency than the same speaker making a low pitched sound like thunder
longitudinal vibration
A vibration.
vibration or brownian motion
The back and forth movement of an object is called undulation, more commonly referred to as swaying or rocking. An object's undulation is measured in cycles (e.g. the number of times an object moves back and forth) per unit time. Ex. the undulation of a pendulum (such as in a grandfather clock) is usually measured in cycles per second.
The rapid back and forth of air or other matter is the sounds vibration (vibration is the anwser).
if you mean where they rub sideways against eachother then that is called the transform movement.
vibration
A back-and-forth or reciprocating movement is known as an oscillation. An example would be the motion of a pendulum. Closely related words include flux, undulation, pulsation, cycle, vibration, alternation, and see-saw(ing).
The time required for a single vibration (back and forth motion).
Vibration
Vibration
vibration