are type of elastic wave, also called seismic waves, that can travel through gases (as sound waves), solids and liquids, including the Earth. P-waves are produced by earthquakes and recorded by seismographs. The name P-wave stands either for primary wave, as it has the highest velocity and is therefore the first to be recorded, or pressure wave,[1] as it is formed from alternating compressions and rarefactions.In isotropic and homogeneous solids, the polarization of a P-wave is always longitudinal; thus, the particles in the solid have vibrations along or parallel to the travel direction of the wave energy.
S-wave
can also refer to the lowest energy electronic wavefunction in atomic physics; see atomic orbital.A type of seismic wave, the S-wave, secondary wave, or shear wave (sometimes called an elastic S-wave) is one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface waves.The S-wave moves as a shear or transverse wave, so motion is perpendicular to the direction of wave propagation: S-waves are like waves in a rope, as opposed to waves moving through a slinky, the P-wave. The wave moves through elastic media, and the main restoring force comes from shear effects. These waves do not diverge, and they obey the continuity equation for incompressible media
Lithosphere
In the Earth, the lithosphere includes the crust and the uppermost mantle, which constitute the hard and rigid outer layer of the Earth. The lithosphere is underlain by the asthenosphere, the weaker, hotter, and deeper part of the upper mantle. The boundary between the lithosphere and the underlying asthenosphere is defined by a difference in response to stress: the lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while the asthenosphere deforms viscously and accommodates strain through plastic deformation. The lithosphere is broken into tectonic plates. The uppermost part of the lithosphere that chemically reacts to the atmosphere, hydrosphere and biosphere through the soil forming process is called the pedosphere.
Asthenosphere
The asthenosphere is a portion of the upper mantle just below the lithosphere that is involved in plate tectonic movements and isostatic adjustments. In spite of its heat, pressures keep it plastic, and it has a relatively low density. Seismic waves pass relatively slowly through the asthenosphere, compared to the overlying lithospheric mantle, thus it has been called the low-velocity zone (LVZ), although the two are not exactly the same. The lower boundary of the LVZ lies at a depth of 180–220 km,[1] whereas the base of the asthenosphere lies at a depth of about 700 km.[2] This was the observation that originally alerted seismologists to its presence and gave some information about its physical properties, as the speed of seismic waves decreases with decreasing rigidity.Under the thin oceanic plates the asthenosphere is usually much closer to the seafloor surface, and at mid-ocean ridges it rises to within a few kilometers of the ocean floor
Mesosphere
The mesosphere (pronounced /ˈmɛsoʊsfɪər/; from the Greek words mesos = middle and sphaira = ball) is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere. In the mesosphere temperature decreases with increasing height. The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally-occurring place on Earth with temperatures below 130 K. The exact upper and lower boundaries of the mesosphere vary with latitude and with season, but the lower boundary of the mesosphere is usually located at heights of about 50 km above the Earth's surface and the mesopause is usually at heights near 100 km, except at middle and high latitudes in summer where it descends to heights of about 85 km
Outer core
The outer core of the Earth is a liquid layer about 2,266 kilometers thick composed of iron and nickel which lies above the Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath the Earth's surface. The transition between the inner core and outer core is located approximately 5,150 km beneath the Earth's surface.The temperature of the outer core ranges from 4400 °C in the outer regions to 6100 °C near the inner core. Because of its high temperature, modeling work has shown that the outer core is a low viscosity fluid (about ten times the viscosity of liquid metals at the surface) that convects turbulentl.
Inner core
The inner core of the Earth, its innermost hottest part as detected by seismological studies, is a primarily solid sphere about 1,216 km (760 mi) in radius, or about 70% that of the Moon. It is believed to consist of an iron-nickel alloy, and may have a temperature similar to the Sun's surface, approximately 5778 K (5505 °C)
Crust
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle. The crusts of Earth, our Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantles
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle. The crusts of Earth, our Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantles
Mohorovicic discontinuity
The Mohorovičić discontinuity (Croatian pronunciation: [mɔhɔˈrɔvitʃitɕ]) (MOE-HOE-ROE-vee-cheech), usually referred to as the Moho, is the boundary between the Earth's crust and the mantle. Named after the pioneering Croatian seisomologist Andrija Mohorovičić, the Moho separates both oceanic crust and continental crust from underlying mantle. The Moho mostly lies entirely within the lithosphere; only beneath mid-ocean ridges does it define the lithosphere – asthenosphere boundary. The Mohorovičić discontinuity was first identified in 1909 by Mohorovičić, when he observed that seismograms from shallow-focus earthquakes had two sets of P-waves and S-waves, one that followed a direct path near the Earth's surface and the other refracted by a high velocity medium.
The Mohorovičić discontinuity (Croatian pronunciation: [mɔhɔˈrɔvitʃitɕ]) (MOE-HOE-ROE-vee-cheech), usually referred to as the Moho, is the boundary between the Earth's crust and the mantle. Named after the pioneering Croatian seisomologist Andrija Mohorovičić, the Moho separates both oceanic crust and continental crust from underlying mantle. The Moho mostly lies entirely within the lithosphere; only beneath mid-ocean ridges does it define the lithosphere – asthenosphere boundary. The Mohorovičić discontinuity was first identified in 1909 by Mohorovičić, when he observed that seismograms from shallow-focus earthquakes had two sets of P-waves and S-waves, one that followed a direct path near the Earth's surface and the other refracted by a high velocity medium.
Mantle
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core. Earth's mantle is a rocky shell about 2,890 km (1,800 mi) thick[1] that constitutes about 84 percent of Earth's volume.[2] It is predominantly solid and encloses the iron-rich hot core, which occupies about 15 percent of Earth's volume.[2][3] Past episodes of melting and volcanism at the shallower levels of the mantle have produced a thin crust of crystallized melt products near the surface, upon which we live
Core
In group theory, a branch of mathematics, a core is any of certain special normal subgroups of a group. The two most common types are the normal core of a subgroup and the p-core of a group
In group theory, a branch of mathematics, a core is any of certain special normal subgroups of a group. The two most common types are the normal core of a subgroup and the p-core of a group
