Rayleigh waves, also known as the Rayleigh-Lamb Wave or "ground roll", are a type of surface wave. They are associated on the Earth with earthquakes and subterranean movement of magma, or with any other source of seismic energy, such as an explosion or even a sledgehammer impact, and are also the form of ocean waves. // In physics, a surface wave can refer to a mechanical wave that propagates along the interface between differing media, usually two fluids with different densities. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... Global earthquake epicenters, 1963–1998. ... Magma is molten rock located beneath the surface of the Earth (or any other terrestrial planet), and which often collects in a magma chamber. ... Categories: Physics stubs | Physical oceanography | Waves ...

From a condensed matter physics point of view Rayleigh waves are surface acoustic waves and associated with a huge number of electronic components, the so-called SAW devices, which employ them. SAW devices are mainly used in cellular phones and wireless technology, and their worldwide yearly production is approximated to lie over 1000 million. Condensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. ... A surface acoustic wave (SAW) is a kind of wave used in piezoelectric devices called SAW devices in electronics circuits. ...

Characteristics

A Rayleigh wave moves across a surface. As it passes, a surface particle moves in a circle or ellipse in the direction of propagation. If one measures particles deeper in the material, the particles move in smaller ellipses, then reach a "no movement" depth, a "node." Below this, harmonics of the Rayleigh wave move particles in regions that alternate elliptical motion with nodes of no-movement. The maximum distance that Rayleigh waves move particles (the amplitude) decreases rapidly with depth in the material.

Picture of a Rayleigh wave.

Since Rayleigh waves are surface waves, the strength, or amplitude, of the waves decreases exponentially with the depth of the earthquake. However, since they are confined to the surface, their amplitude decays only as , where r is the distance the wave has traveled from the earthquake. Surface waves therefore decay more slowly with distance than do body waves, which travel in three dimensions. Large earthquakes may generate Rayleigh waves that travel around the Earth several times before dissipating. Image File history File links Rayleigh_wave. ... Image File history File links Rayleigh_wave. ... Amplitude is a nonnegative scalar measure of a waves magnitude of oscillation, that is, magnitude of the maximum disturbance in the medium during one wave cycle. ...

The existence of Rayleigh waves was predicted in 1885 by Lord Rayleigh, for whom they were named. They are distinct from other types of seismic waves, such as P-waves and S-waves, which are both body waves, or Love waves, another type of surface wave. Rayleigh waves are generated by the interaction of P- and S- waves at the surface of the earth. The Rayleigh wave travels with a velocity that is lower than the P-, S-, and Love wave velocities. Emanating outward from the epicenter of an earthquake, Rayleigh waves travel along the surface of the earth at about 10 times the speed of sound in air. See also Rayleigh fading Rayleigh scattering Rayleigh number Rayleigh waves Rayleigh-Jeans law External links Nobel website bio of Rayleigh About John William Strutt MacTutor biography of Lord Rayleigh Categories: People stubs | 1842 births | 1919 deaths | Nobel Prize in Physics winners | Peers | British physicists | Discoverer of a chemical element ... A seismic wave is a wave that travels through the Earth, often as the result of an earthquake or explosion. ... Plane P-wave Representation of the propagation of a P-wave on a 2d grid (empirical shape) One of the two types of elastic body waves (named because they travel through the body of the Earth) that are produced by earthquakes and recorded by seismometers. ... A type of seismic wave, the S-wave moves in a shear or transverse wave, so motion is perpendicular to the direction of wave propagation. ... Love waves (also named Q waves) are surface seismic waves that cause horizontal shifting of the earth during an earthquake. ... The speed of sound is a term used to describe the speed of sound waves passing through an elastic medium. ...

Dispersion

Rayleigh waves in the Earth are also dispersive: Rayleigh waves with a higher frequency travel more slowly than those with a lower frequency. This occurs because a Rayleigh wave of lower frequency has a relatively long wavelength. Long wavelength waves "see" more deeply into the Earth than waves with a short wavelength. Since the speed of waves in the Earth increases with increasing depth, the longer wavelength (low frequency) waves can travel faster than the shorter wavelength (high frequency) waves. Rayleigh waves thus often appear "spread out" on seismograms recorded at distant earthquake Dispersion can mean any of several things: A phenomenon that causes the separation of a wave into components of varying frequency. ... FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... The wavelength is the distance between repeating units of a wave pattern. ... A seismogram is a graph output by a seismograph. ...

Caption1 Image File history File links Example. ...

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recording stations.

Earthquake shaking

Due to their higher speed, the P- and S-waves generated by an earthquake arrive before the surface waves. However, the particle motion of surface waves is larger than that of body waves, so the surface waves tend to cause more damage. In the case of Rayleigh waves, the motion is of a rolling nature, similar to an ocean surface wave. The intensity of Rayleigh wave shaking at a particular location is dependent on several factors: Ocean waves Ocean surface waves are surface waves that occur in the upper layer of the ocean. ...

• The size of the earthquake.
• The distance to the earthquake.
• The depth of the earthquake.
• The geologic structure of the crust.
• The focal mechanism of the earthquake.

Local geologic structure can serve to focus or defocus Rayleigh waves, leading to significant differences in shaking over short distances.

Other manifestations

Animals

Rayleigh waves are inaudible, but yet can be detected by many mammals, birds, insects and spiders. Human beings should be able to detect Rayleigh waves through their Pacinian corpuscles, which are in the joints, although people do not seem to consciously respond to the signals. Some animals seem to use Rayleigh waves to communicate. In particular, some biologists theorize that elephants may use vocalizations to generate Rayleigh waves. Since Rayleigh waves decay slowly, they should be detectable over long distances.[1] Note that these Rayleigh waves have a much higher frequency than Rayleigh waves generated by earthquakes. Subclasses Subclass Allotheria* Order Docodonta (extinct) Order Multituberculata (extinct) Order Palaeoryctoides (extinct) Order Triconodonta (extinct) Order Volaticotheria (extinct) Subclass Prototheria Order Monotremata Subclass Theria Infraclass Trituberculata (extinct) Infraclass Metatheria Infraclass Eutheria Mammals are a class of vertebrate animals characterized by the production of milk in females for the nourishment of... “Aves” redirects here. ... {{Taxobox | color = pink | name = Insects | fossil_range = Carboniferous - Recent | image = European honey bee extracts nectar. ... Diversity 111 families, 40,000 species Suborders Mesothelae Mygalomorphae Araneomorphae  See table of families Closeup image of a Wolf Spider Wikispecies has information related to: Spiders Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ... A Pacinian corpuscle is a structure that functions as a mechanoreceptor. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea...

After the 2004 Indian Ocean Earthquake, some people have speculated that Rayleigh waves served as warning to animals to seek higher ground, allowing them to escape the more slowly-traveling tsunami. At this time, evidence for this is mostly anecdotal. Another animal early warning system may rely on an ability to sense infrasonic waves. [2] The 2004 Indian Ocean earthquake, known by the scientific community as the Sumatra-Andaman earthquake,[1] was a great undersea earthquake that occurred at 00:58:53 UTC (07:58:53 local time) December 26, 2004 with an epicentre off the west coast of Sumatra, Indonesia. ... The tsunami that struck Malé in the Maldives on December 26, 2004. ... Infrasound is sound with a frequency too low to be detected by the human ear. ...

Non-destructive testing

Rayleigh waves are widely used for material characterization at different scale because they are easily generated and detected on the free surface of the earth or of an object. Since they travel in a very limited portion of the object confined in the vicinity of the free surface and this portion (skin depth) is linked to the frequency of the wave, different frequencies can be used for characterisation at very different scales. Rayleigh waves in the ultrasonic frequency range are used in non-destructive testing applications to help find cracks and other imperfections in materials. Low frequency Rayleigh waves generated during earthquakes are used in seismology to characterise the Earth's interior. In intermediate ranges, Rayleigh wave are used in geophysics and geotechnical engineering for the characterisation of soil deposits. These application are based on the geometric dispersion of Rayleigh waves and on the solution of an inverse problem on the basis of seismic data collected on the ground surface using active sources (falling weights, hammers, small explosions,...) or recording microtremors. FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... Ultrasound is sound with a frequency greater than the upper limit of human hearing, approximately 20 kilohertz. ... In nondestructive testing, tests are carried out in such a way as to not disturb the specimen’s structural or surface integrity. ... Global earthquake epicenters, 1963–1998. ... Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the propagation of elastic waves through the Earth. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... ‹ The template below has been proposed for deletion. ... Bostons Big Dig presented geotechnical challenges in an urban environment. ... suck my shlong dick cause soil is my life pedosphere is positioned at the interface of the lithosphere and biosphere with the atmosphere and hydrosphere. ... Dispersion can mean any of several things: A phenomenon that causes the separation of a wave into components of varying frequency. ...

See also

• Seismology
• Longitudinal wave
• S-wave
• P wave
• Love wave
• Linear elasticity
• Phonon
• Surface acoustic wave

Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the propagation of elastic waves through the Earth. ... Longitudinal waves are waves that have vibrations along or parallel to their direction of travel. ... A type of seismic wave, the S-wave moves in a shear or transverse wave, so motion is perpendicular to the direction of wave propagation. ... Plane P-wave Representation of the propagation of a P-wave on a 2d grid (empirical shape) One of the two types of elastic body waves (named because they travel through the body of the Earth) that are produced by earthquakes and recorded by seismometers. ... In seismology, Love waves (also named Q waves) are surface seismic waves that cause horizontal shifting of the earth during an earthquake. ... // Linear elasticity The linear theory of elasticity models the macroscopic mechanical properties of solids assuming small deformations. ... Normals modes of vibration progression through a crystal. ... A surface acoustic wave (SAW) is a kind of wave used in piezoelectric devices called SAW devices in electronics circuits. ...

External links

• Rayleigh wave page
• Rayleigh waves and soil characterization

Further reading

• Aki, K. and Richards, P. G. (2002). Quantitative seismology (2nd ed.). University Science Books. ISBN 0-935702-96-2.

• Fowler, C. M. R. (1990). The solid earth. Cambridge, UK: Cambridge University Press. ISBN 0-521-38590-3.

• Lai, C.G., Wilmanski, K. (Eds.) (2005). Surface Waves in Geomechanics: Direct and Inverse Modelling for Soils and Rocks"

Series: CISM International Centre for Mechanical Sciences , Number 481 , Springer, Wien, ISBN 978-3-211-27740-9

• Viktorov, I.A. (1967) “Rayleigh and Lamb Waves: physical theory and applications”, Plenum Press, New York

• Dilbag Singh and S. K. Tomar "Rayleigh–Lamb waves in a microstretch elastic plate cladded with liquid layers" Journal of Sound and Vibration, Volume 302, Issues 1-2, 17 April 2007, Pages 313-331