Gassmann's Equation
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Gassmann's Equation
Gassmann's equations are a set of two equations describing the isotropic elastic constants of an ensemble consisting of an isotropic, homogeneous porous medium with a fully connected pore space, saturated by a compressible fluid at pressure equilibrium. First published in German by Fritz Gassmann, the original work was only later translated in English long after the adoption of the equations in standard geophysical practice. Gassmann's equations remain the most common way of performing fluid substitution—predicting the elastic behaviour of a porous medium under a different saturant to the one measured. Procedure These formulations are from Avseth ''et al.'' (2006). Given an initial set of velocities and densities, V_^, V_^, and \rho ^ corresponding to a rock with an initial set of fluids, you can compute the velocities and densities of the rock with another set of fluid. Often these velocities are measured from well logs, but might also come from a theoretical model. Step 1 ...
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Fritz Gassmann
Fritz Gassmann (1899–1990) was a Swiss mathematician and geophysicist. Life His Ph.D. advisors at ETH Zurich were George Pólya and Hermann Weyl. He was a geophysics professor at the ETH Zurich. Legacy Gassmann is the eponym for the Gassmann triple and Gassmann's equation. Selected publications *Gassmann, Fritz (1951). Über die Elastizität poröser Medien. ''Viertel. Naturforsch. Ges. Zürich'', 96, 1 – 23. (English translation available as pdhere. * * References * *Gerald L. Alexanderson Gerald Lee Alexanderson (1933–2020) was an American mathematician. He was the Michael & Elizabeth Valeriote Professor of Science at Santa Clara University, and in 1997–1998 was president of the Mathematical Association of America. He was also ..."The Random Walks of George Pólya".Mathematical Association of America, 1999. 303pp. . External linksETH Zurich Webpage1951 ...
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Gary M
Gary may refer to: *Gary (given name), a common masculine given name, including a list of people and fictional characters with the name *Gary, Indiana, the largest city named Gary Places ;Iran *Gary, Iran, Sistan and Baluchestan Province ;United States *Gary (Tampa), Florida * Gary, Maryland *Gary, Minnesota *Gary, South Dakota *Gary, West Virginia *Gary – New Duluth, a neighborhood in Duluth, Minnesota *Gary Air Force Base, San Marcos, Texas * Gary City, Texas Ships * USS ''Gary'' (DE-61), a destroyer escort launched in 1943 * USS ''Gary'' (CL-147), scheduled to be a light cruiser, but canceled prior to construction in 1945 * USS ''Gary'' (FFG-51), a frigate, commissioned in 1984 * USS ''Thomas J. Gary'' (DE-326), a destroyer escort commissioned in 1943 People and fictional characters * Gary (surname), including a list of people with the name *Gary (rapper), South Korean rapper and entertainer * Gary (Argentine singer), Argentine singer of cuarteto songs Other uses *'' Gar ...
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Diagenesis
Diagenesis () is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. In the early stages, the transformation of poorly consolidated sediments into sedimentary rock (lithification) is simply accompanied by a reduction in porosity and water expulsion (clay sediments), while their main mineralogical assemblages remain unaltered. As the rock is carried deeper by further deposition above, its organic content is progressively transformed into kerogens and bitumens. The process of diagenesis excludes surface alteration (weathering) and deep metamorphism. There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwater, rock porosity, permeability, ...
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Biot Theory
The British Indian Ocean Territory (BIOT) is an Overseas Territory of the United Kingdom situated in the Indian Ocean, halfway between Tanzania and Indonesia. The territory comprises the seven atolls of the Chagos Archipelago with over 1,000 individual islandsmany very smallamounting to a total land area of . The largest and most southerly island is Diego Garcia, , the site of a Joint Military Facility of the United Kingdom and the United States. The only inhabitants are British and United States military personnel, and associated contractors, who collectively number around 3,000 (2018 figures). The forced removal of Chagossians from the Chagos Archipelago occurred between 1968 and 1973. The Chagossians, then numbering about 2,000 people, were expelled by the UK government to Mauritius and Seychelles in order to construct the military base. Today, the exiled Chagossians are still trying to return, saying that the forced expulsion and dispossession was unlawful, but the ...
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Seismic
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes such as explosions. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time is called a seismogram. A seismologist is a scientist who does research in seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus (c. 585 BCE), Anaximenes of Miletus (c. 550 BCE), Aristotle (c. 340 BCE), and Zhan ...
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Acoustics
Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an Acoustical engineering, acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries. Hearing (sense), Hearing is one of the most crucial means of survival in the animal world and speech is one of the most distinctive characteristics of human development and culture. Accordingly, the science of acoustics spreads across many facets of human society—music, medicine, architecture, industrial production, warfare and more. Likewise, animal species such as songbirds and frogs use sound and hearing as a key element of mating rituals or for marking territories. Art, ...
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Acoustic Dispersion
Acoustic dispersion is the phenomenon of a sound wave separating into its component frequencies as it passes through a material. The phase velocity of the sound wave is viewed as a function of frequency. Hence, separation of component frequencies is measured by the rate of change in phase velocities as the radiated waves pass through a given medium. Broadband transmission method A widely used technique for determining acoustic dispersion is a broadband transmission method. This technique was originally introduced in 1978 and has been employed to study the dispersion properties of metal (1978), epoxy resin (1986), paper materials (1993), and ultra-sound contrast agent (1998). In 1990 and 1993 this method confirmed the Kramers–Kronig relation for acoustic waves. Application of this method requires the measurements of a reference velocity to obtain values for the acoustic dispersion. This is accomplished by determining (usually) the speed of the sound in water, the thickness o ...
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