Wave

a mechanism of energy transfer through a medium. The origin of the wave is vibrating particles, which store and release energy while their mean position remains constant as it is only the wave that travels. Waves can be classified as being either LONGITUDINAL WAVES, e.g. sound, or TRANSVERSE WAVES, e.g., light, depending on the direction of their vibrations. There is a basic wave equation that related the wavelength (λ), frequency(f), and speed (c) of the wave as c = fλ. All forms of waves have the following properties: diffraction; interference; reflection and refraction. ELECTROMAGNETIC WAVES have all of these properties but differ from ordinary waves, such as water waves, in that they can travel through a vacuum, e.g. outer space.

Taken from Dictionary of Science

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A wave is a disturbance that propagates through space and time, usually with transference of energy. A mechanical wave is a wave that propagates or travels through a medium due to the restoring forces it produces upon deformation. There also exist waves capable of traveling through a vacuum, including electromagnetic radiation and probably gravitational radiation. Waves travel and transfer energy from one point to another, often with no permanent displacement of the particles of the medium (that is, with little or no associated mass transport); they consist instead of oscillations or vibrations around almost fixed locations.

Taken from Wikipedia

Earthquake

the often violent movement of the earth along a fault or fault zone due to tectonic upheaval caused by the sudden release of stress that has built up over some time. The focus is the point at which the earthquake originates within the earth and earthquakes are classified by depth of focus: shallow -- less than 70 km; intermediate -- 70-300 km; deep -- more than 300 km. Attempts to predict earthquakes rely upon measurement of stress increases, but can so far be related only to an increasing risk of activity.

Taken from Dictionary of Science