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In the fields of chemical graph theory, molecular topology, and mathematical chemistry, a topological index, also known as a connectivity index, is a type of a molecular descriptor that is calculated based on the molecular graph of a chemical compound. Topological indices are numerical parameters of a graph which characterize its topology and are usually graph invariant. Topological indices are used for example in the development of quantitative structure-activity relationships (QSARs) in which the biological activity or other properties of molecules are correlated with their chemical structure | https://huggingface.co/datasets/fmars/wiki_stem |
Thermal physics is the combined study of thermodynamics, statistical mechanics, and kinetic theory of gases. This umbrella-subject is typically designed for physics students and functions to provide a general introduction to each of three core heat-related subjects. Other authors, however, define thermal physics loosely as a summation of only thermodynamics and statistical mechanics | https://huggingface.co/datasets/fmars/wiki_stem |
The Wolfram Demonstrations Project is an organized, open-source collection of small (or medium-sized) interactive programmes called Demonstrations, which are meant to visually and interactively represent ideas from a range of fields. It is hosted by Wolfram Research, whose stated goal is to bring computational exploration to a large population. At its launch, it contained 1300 demonstrations but has grown to over 10,000 | https://huggingface.co/datasets/fmars/wiki_stem |
WolframAlpha ( WUULf-rəm-) is an answer engine developed by Wolfram Research. It answers factual queries by computing answers from externally sourced data. WolframAlpha was released on May 18, 2009, and is based on Wolfram's earlier product Wolfram Mathematica, a technical computing platform | https://huggingface.co/datasets/fmars/wiki_stem |
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. Geophysicists, who usually study geophysics, physics, or one of the earth sciences at the graduate level, complete investigations across a wide range of scientific disciplines. The term geophysics classically refers to solid earth applications: Earth's shape; its gravitational, magnetic fields, and electromagnetic fields ; its internal structure and composition; its dynamics and their surface expression in plate tectonics, the generation of magmas, volcanism and rock formation | https://huggingface.co/datasets/fmars/wiki_stem |
The following outline is provided as an overview of and topical guide to geophysics:
Geophysics – the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and composition; its dynamics and their surface expression in plate tectonics, the generation of magmas, volcanism and rock formation. However, modern geophysics organizations have a broader definition that includes the hydrological cycle including snow and ice; fluid dynamics of the oceans and the atmosphere; electricity and magnetism in the ionosphere and magnetosphere and solar-terrestrial relations; and analogous problems associated with the Moon and other planets | https://huggingface.co/datasets/fmars/wiki_stem |
The Adams–Williamson equation, named after Leason H. Adams and E. D | https://huggingface.co/datasets/fmars/wiki_stem |
In reflection seismology, the anelastic attenuation factor, often expressed as seismic quality factor or Q (which is inversely proportional to attenuation factor), quantifies the effects of anelastic attenuation on the seismic wavelet caused by fluid movement and grain boundary friction. As a seismic wave propagates through a medium, the elastic energy associated with the wave is gradually absorbed by the medium, eventually ending up as heat energy. This is known as absorption (or anelastic attenuation) and will eventually cause the total disappearance of the seismic wave | https://huggingface.co/datasets/fmars/wiki_stem |
In the natural sciences, especially in atmospheric and Earth sciences involving applied statistics, an anomaly is a persisting deviation in a physical quantity from its expected value, e. g. , the systematic difference between a measurement and a trend or a model prediction | https://huggingface.co/datasets/fmars/wiki_stem |
The Azimi Q models used Mathematical Q models to explain how the earth responds to seismic waves. Because these models satisfies the Krämers-Krönig relations they should be preferable to the Kolsky model in seismic inverse Q filtering.
Azimi's first model
Azimi's first model (1968), which he proposed together with Strick (1967) has the attenuation proportional to |w|1−γ and is:
α
(
w
)
=
a
1
|
w
|
1
−
γ
(
1 | https://huggingface.co/datasets/fmars/wiki_stem |
Bottom simulating reflectors (BSRs) are, on seismic reflection profiles, shallow seismic reflection events, characterized by their reflection geometry similar to seafloor bathymetry.
. They have, however, the opposite reflection polarity to the seabed reflection, and frequently intersect the primary reflections | https://huggingface.co/datasets/fmars/wiki_stem |
In geodesy and geophysics, the Bouguer anomaly (named after Pierre Bouguer) is a gravity anomaly, corrected for the height at which it is measured and the attraction of terrain. The height correction alone gives a free-air gravity anomaly.
Definition
The Bouguer anomaly
g
B
{\displaystyle g_{B}}
defined as:
Here,
g
F
{\displaystyle g_{F}}
is the free-air gravity anomaly | https://huggingface.co/datasets/fmars/wiki_stem |
Computational geophysics is the field of study that uses any type of numerical computations to generate and analyze models of complex geophysical systems. It can be considered an extension, or sub-field, of both computational physics and geophysics. In recent years, computational power, data availability, and modelling capabilities have all improved exponentially, making computational geophysics a more populated discipline | https://huggingface.co/datasets/fmars/wiki_stem |
During seismic exploration, P-waves (also known as primary or compressive waves) penetrate down into the earth. Due to mode conversion, a P-wave can reflect upwards as an S-wave (also known as a secondary, shear or transverse wave) when it hits an interface (e. g | https://huggingface.co/datasets/fmars/wiki_stem |
A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel tube, called a core drill. The hole made for the core sample is called the "core hole" | https://huggingface.co/datasets/fmars/wiki_stem |
The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron–nickel outer core, at a depth of 2,891 km (1,796 mi) below Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of the core | https://huggingface.co/datasets/fmars/wiki_stem |
The Deep Earth Carbon Degassing (DECADE) project is an initiative to unite scientists around the world to make tangible advances towards quantifying the amount of carbon outgassed from the Earth's deep interior (core, mantle, crust) into the surface environment (e. g. biosphere, hydrosphere, cryosphere, atmosphere) through naturally occurring processes | https://huggingface.co/datasets/fmars/wiki_stem |
A diamond anvil cell (DAC) is a high-pressure device used in geology, engineering, and materials science experiments. It enables the compression of a small (sub-millimeter-sized) piece of material to extreme pressures, typically up to around 100–200 gigapascals, although it is possible to achieve pressures up to 770 gigapascals (7,700,000 bars or 7. 7 million atmospheres) | https://huggingface.co/datasets/fmars/wiki_stem |
Earth tide (also known as solid Earth tide, crustal tide, body tide, bodily tide or land tide) is the displacement of the solid earth's surface caused by the gravity of the Moon and Sun. Its main component has meter-level amplitude at periods of about 12 hours and longer. The largest body tide constituents are semi-diurnal, but there are also significant diurnal, semi-annual, and fortnightly contributions | https://huggingface.co/datasets/fmars/wiki_stem |
Episodic tremor and slip (ETS) is a seismological phenomenon observed in some subduction zones that is characterized by non-earthquake seismic rumbling, or tremor, and slow slip along the plate interface. Slow slip events are distinguished from earthquakes by their propagation speed and focus. In slow slip events, there is an apparent reversal of crustal motion, although the fault motion remains consistent with the direction of subduction | https://huggingface.co/datasets/fmars/wiki_stem |
The interaction between erosion and tectonics has been a topic of debate since the early 1990s. While the tectonic effects on surface processes such as erosion have long been recognized (for example, river formation as a result of tectonic uplift), the opposite (erosional effects on tectonic activity) has only recently been addressed. The primary questions surrounding this topic are what types of interactions exist between erosion and tectonics and what are the implications of these interactions | https://huggingface.co/datasets/fmars/wiki_stem |
Exploration geophysics is an applied branch of geophysics and economic geology, which uses physical methods at the surface of the Earth, such as seismic, gravitational, magnetic, electrical and electromagnetic, to measure the physical properties of the subsurface, along with the anomalies in those properties. It is most often used to detect or infer the presence and position of economically useful geological deposits, such as ore minerals; fossil fuels and other hydrocarbons; geothermal reservoirs; and groundwater reservoirs. It can also be used to detect the presence of unexploded ordnance | https://huggingface.co/datasets/fmars/wiki_stem |
Figure of the Earth is a term of art in geodesy that refers to the size and shape used to model Earth. The size and shape it refers to depend on context, including the precision needed for the model. A sphere is a well-known historical approximation of the figure of the Earth that is satisfactory for many purposes | https://huggingface.co/datasets/fmars/wiki_stem |
A Fraser Filter, named after Douglas Fraser, is typically used in geophysics when displaying VLF data. It is effectively the first derivative of the data.
If
f
(
i
)
=
f
i
{\displaystyle f(i)=f_{i}}
represents the collected data then
a
v
e
r
a
g
e
12
=
f
1
+
f
2
2
{\displaystyle average_{12}={\frac {f_{1}+f_{2}}{2}}}
is the average of two values | https://huggingface.co/datasets/fmars/wiki_stem |
Gas-rich meteorites are meteorites with high levels of primordial gases, such as helium, neon, argon, krypton, xenon and sometimes other elements. Though these gases are present "in virtually all meteorites," the Fayetteville meteorite has ~2,000,000 x10−8 ccSTP/g helium, or ~2% helium by volume equivalent. In comparison, background level is a few ppm | https://huggingface.co/datasets/fmars/wiki_stem |
The Gassmann equation, first described by Fritz Gassmann, is used in geophysics and its relations are receiving more attention as seismic data are increasingly used for reservoir monitoring. The Gassmann equation is the most common way of performing a fluid substitution model from one known parameter.
Procedure
These formulations are from Avseth et al | https://huggingface.co/datasets/fmars/wiki_stem |
A geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged (not to be confused with geographic north and geographic south). The Earth's field has alternated between periods of normal polarity, in which the predominant direction of the field was the same as the present direction, and reverse polarity, in which it was the opposite. These periods are called chrons | https://huggingface.co/datasets/fmars/wiki_stem |
Geomathematics (also: mathematical geosciences, mathematical geology, mathematical geophysics) is the application of mathematical methods to solve problems in geosciences, including geology and geophysics, and particularly geodynamics and seismology.
Applications
Geophysical fluid dynamics
Geophysical fluid dynamics develops the theory of fluid dynamics for the atmosphere, ocean and Earth's interior. Applications include geodynamics and the theory of the geodynamo | https://huggingface.co/datasets/fmars/wiki_stem |
Geophysical fluid dynamics, in its broadest meaning, refers to the fluid dynamics of naturally occurring flows, such as lava flows, oceans, and planetary atmospheres, on Earth and other planets. Two physical features that are common to many of the phenomena studied in geophysical fluid dynamics are rotation of the fluid due to the planetary rotation and stratification (layering). The applications of geophysical fluid dynamics do not generally include the circulation of the mantle, which is the subject of geodynamics, or fluid phenomena in the magnetosphere | https://huggingface.co/datasets/fmars/wiki_stem |
Geophysical imaging (also known as geophysical tomography) is a minimally destructive geophysical technique that investigates the subsurface of a terrestrial planet. Geophysical imaging is a noninvasive imaging technique with a high parametrical and spatio-temporal resolution. Geophysical imaging has evolved over the last 30 years due to advances in computing power and speed | https://huggingface.co/datasets/fmars/wiki_stem |
Geophysical signal analysis is concerned with the detection and a subsequent processing of signals. Any signal which is varying conveys valuable information. Hence to understand the information embedded in such signals, we need to 'detect' and 'extract data' from such quantities | https://huggingface.co/datasets/fmars/wiki_stem |
There are several conflicting usages of geosphere, variously defined. It may be taken as the collective name for the lithosphere, the hydrosphere, the cryosphere, and the atmosphere. The different collectives of the geosphere are able to exchange different mass and/or energy fluxes (the measurable amount of change) | https://huggingface.co/datasets/fmars/wiki_stem |
The Hayford ellipsoid is a geodetic reference ellipsoid, named after the US geodesist John Fillmore Hayford (1868–1925), which was introduced in 1910. The Hayford ellipsoid was also referred to as the International ellipsoid 1924 after it had been adopted by the International Union of Geodesy and Geophysics IUGG in 1924, and was recommended for use all over the world. Many countries retained their previous ellipsoids | https://huggingface.co/datasets/fmars/wiki_stem |
The historical development of geophysics has been motivated by two factors. One of these is the research curiosity of humankind related to planet Earth and its several components, its events and its problems. The second is economical usage of Earth's resources (ore deposits, petroleum, water resources, etc | https://huggingface.co/datasets/fmars/wiki_stem |
The Hybrid Coordinate Ocean Model (HyCOM) is an open-source ocean general circulation modeling system. HyCOM is a primitive equation type of ocean general circulation model. The vertical levels of this modeling system are slightly different than other models, because the vertical coordinates remain isopycnic in the open stratified ocean, smoothly transitioning to z-level coordinates in the weakly stratified upper-ocean mixed layer, to terrain-following sigma coordinates in shallow water regions, and back to z-level coordinates in very shallow water | https://huggingface.co/datasets/fmars/wiki_stem |
Hydrogeophysics is a cross-disciplinary area of research that uses geophysics to determine parameters (characteristics; measurements of limitations or boundaries) and monitor processes for hydrological studies of matters such as water resources, contamination, and ecological studies. The field uses knowledge and researchers from geology, hydrology, physics, geophysics, engineering, statistics, and rock physics. It uses geophysics to provide quantitative information about hydrogeological parameters, using minimally invasive methods | https://huggingface.co/datasets/fmars/wiki_stem |
Inertial waves, also known as inertial oscillations, are a type of mechanical wave possible in rotating fluids. Unlike surface gravity waves commonly seen at the beach or in the bathtub, inertial waves flow through the interior of the fluid, not at the surface. Like any other kind of wave, an inertial wave is caused by a restoring force and characterized by its wavelength and frequency | https://huggingface.co/datasets/fmars/wiki_stem |
Isotope geochemistry is an aspect of geology based upon the study of natural variations in the relative abundances of isotopes of various elements. Variations in isotopic abundance are measured by isotope ratio mass spectrometry, and can reveal information about the ages and origins of rock, air or water bodies, or processes of mixing between them.
Stable isotope geochemistry is largely concerned with isotopic variations arising from mass-dependent isotope fractionation, whereas radiogenic isotope geochemistry is concerned with the products of natural radioactivity | https://huggingface.co/datasets/fmars/wiki_stem |
Large low-shear-velocity provinces, LLSVPs, also called LLVPs or superplumes, are characteristic structures of parts of the lowermost mantle (the region surrounding the outer core) of Earth. These provinces are characterized by slow shear wave velocities and were discovered by seismic tomography of deep Earth. There are two main provinces: the African LLSVP and the Pacific LLSVP | https://huggingface.co/datasets/fmars/wiki_stem |
A magnetic anomaly detector (MAD) is an instrument used to detect minute variations in the Earth's magnetic field. The term refers specifically to magnetometers used by military forces to detect submarines (a mass of ferromagnetic material creates a detectable disturbance in the magnetic field); military MAD equipment is a descendant of geomagnetic survey or aeromagnetic survey instruments used to search for minerals by detecting their disturbance of the normal earth-field.
History
Geoexploration by measuring and studying variations in the Earth's magnetic field has been conducted by scientists since 1843 | https://huggingface.co/datasets/fmars/wiki_stem |
Mantle oxidation state (redox state) applies the concept of oxidation state in chemistry to the study of the Earth's mantle. The chemical concept of oxidation state mainly refers to the valence state of one element, while mantle oxidation state provides the degree of decreasing of increasing valence states of all polyvalent elements in mantle materials confined in a closed system. The mantle oxidation state is controlled by oxygen fugacity and can be benchmarked by specific groups of redox buffers | https://huggingface.co/datasets/fmars/wiki_stem |
Marine geophysics is the scientific discipline that employs methods of geophysics to study the world's ocean basins and continental margins, particularly the solid earth beneath the ocean. It shares objectives with marine geology, which uses sedimentological, paleontological, and geochemical methods. Marine geophysical data analyses led to the theories of seafloor spreading and plate tectonics | https://huggingface.co/datasets/fmars/wiki_stem |
In astronomy, astrophysics and geophysics, a mass concentration (or mascon) is a region of a planet's or moon's crust that contains a large positive gravity anomaly. In general, the word "mascon" can be used as a noun to refer to an excess distribution of mass on or beneath the surface of an astronomical body (compared to some suitable average), such as is found around Hawaii on Earth. However, this term is most often used to describe a geologic structure that has a positive gravitational anomaly associated with a feature (e | https://huggingface.co/datasets/fmars/wiki_stem |
In physics and mechanics, mass distribution is the spatial distribution of mass within a solid body. In principle, it is relevant also for gases or liquids, but on Earth their mass distribution is almost homogeneous.
Astronomy
In astronomy mass distribution has decisive influence on the development e | https://huggingface.co/datasets/fmars/wiki_stem |
Mathematical Q models provide a model of the earth's response to seismic waves. In reflection seismology, the anelastic attenuation factor, often expressed as seismic quality factor or Q, which is inversely proportional to attenuation factor, quantifies the effects of anelastic attenuation on the seismic wavelet caused by fluid movement and grain boundary friction. When a plane wave propagates through a homogeneous viscoelastic medium, the effects of amplitude attenuation and velocity dispersion may be combined conveniently into the single dimensionless parameter, Q | https://huggingface.co/datasets/fmars/wiki_stem |
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples "bolides" | https://huggingface.co/datasets/fmars/wiki_stem |
A micrometeorite is a micrometeoroid that has survived entry through the Earth's atmosphere. Usually found on Earth's surface, micrometeorites differ from meteorites in that they are smaller in size, more abundant, and different in composition. The IAU officially defines meteorites as 30 micrometers to 1 meter; micrometeorites are the small end of the range (~submillimeter) | https://huggingface.co/datasets/fmars/wiki_stem |
A Miyake event is a powerful burst of cosmic rays. The origin and cause of these increases in cosmic ray activity is currently unknown. The outbreaks are marked in particular by the increase in the radioactive carbon isotope 14C in tree rings, meaning the events can be dendrochronologically dated | https://huggingface.co/datasets/fmars/wiki_stem |
The moment magnitude scale (MMS; denoted explicitly with Mw or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori | https://huggingface.co/datasets/fmars/wiki_stem |
In rock physics and petrophysics, the mudrock line, also called Castagna's equation or Castagna's relation, is an empirical linear relation between seismic P-wave velocity and S-wave velocity in brine-saturated siliciclastic rocks (i. e. sandstones and shales) | https://huggingface.co/datasets/fmars/wiki_stem |
Multidimensional seismic data processing forms a major component of seismic profiling, a technique used in geophysical exploration. The technique itself has various applications, including mapping ocean floors, determining the structure of sediments, mapping subsurface currents and hydrocarbon exploration. Since geophysical data obtained in such techniques is a function of both space and time, multidimensional signal processing techniques may be better suited for processing such data | https://huggingface.co/datasets/fmars/wiki_stem |
Near-surface geophysics is the use of geophysical methods to investigate small-scale features in the shallow (tens of meters) subsurface. It is closely related to applied geophysics or exploration geophysics. Methods used include seismic refraction and reflection, gravity, magnetic, electric, and electromagnetic methods | https://huggingface.co/datasets/fmars/wiki_stem |
A one-way wave equation is a first-order partial differential equation describing one wave traveling in a direction defined by the vector wave velocity. It contrasts with the second-order two-way wave equation describing a standing wavefield resulting from superposition of two waves in opposite directions. In the one-dimensional case, the one-way wave equation allows wave propagation to be calculated without the mathematical complication of solving a 2nd order differential equation | https://huggingface.co/datasets/fmars/wiki_stem |
Pressure is force magnitude applied over an area. Overburden pressure is a geology term that denotes the pressure caused by the weight of the overlying layers of material at a specific depth under the earth's surface. Overburden pressure is also called lithostatic pressure, or vertical stress | https://huggingface.co/datasets/fmars/wiki_stem |
Pore pressure gradient is a dimensional petrophysical term used by drilling engineers and mud engineers during the design of drilling programs for drilling (constructing) oil and gas wells into the earth. It is the pressure gradient inside the pore space of the rock column from the surface of the ground down to the total depth (TD), as compared to the pressure gradient of seawater in deep water.
Whereas in "pure math," the gradient of a scalar function expressed by the math notation grad(f) may not have physical units associated with it; in drilling engineering the pore pressure gradient is usually expressed in API-type International Association of Drilling Contractors (IADC) physical units of measurement, namely "psi per foot | https://huggingface.co/datasets/fmars/wiki_stem |
Refraction microtremor (ReMi) is a surface-performed geophysical survey developed by Dr. John Louie (and others) based on previously existing principles of evaluating surface waves and in particular Rayleigh waves. The refraction microtremor technology was developed at the University of Nevada and is owned by the State of Nevada | https://huggingface.co/datasets/fmars/wiki_stem |
In the oil and gas industry, reservoir modeling involves the construction of a computer model of a petroleum reservoir, for the purposes of improving estimation of reserves and making decisions regarding the development of the field, predicting future production, placing additional wells and evaluating alternative reservoir management scenarios.
A reservoir model represents the physical space of the reservoir by an array of discrete cells, delineated by a grid which may be regular or irregular. The array of cells is usually three-dimensional, although 1D and 2D models are sometimes used | https://huggingface.co/datasets/fmars/wiki_stem |
Rock magnetism is the study of the magnetic properties of rocks, sediments and soils. The field arose out of the need in paleomagnetism to understand how rocks record the Earth's magnetic field. This remanence is carried by minerals, particularly certain strongly magnetic minerals like magnetite (the main source of magnetism in lodestone) | https://huggingface.co/datasets/fmars/wiki_stem |
Scientific drilling into the Earth is a way for scientists to probe the Earth's sediments, crust, and upper mantle. In addition to rock samples, drilling technology can unearth samples of connate fluids and of the subsurface biosphere, mostly microbial life, preserved in drilled samples. Scientific drilling is carried out on land by the International Continental Scientific Drilling Program (ICDP) and at sea by the Integrated Ocean Drilling Program (IODP) | https://huggingface.co/datasets/fmars/wiki_stem |
The SEG-Y (sometimes SEG Y) file format is one of several standards developed by the Society of Exploration Geophysicists (SEG) for storing geophysical data. It is an open standard, and is controlled by the SEG Technical Standards Committee, a non-profit organization.
History
The format was originally developed in 1973 to store single-line seismic reflection digital data on magnetic tapes | https://huggingface.co/datasets/fmars/wiki_stem |
Seismic anisotropy is the directional dependence of the velocity of seismic waves in a medium (rock) within the Earth.
Description
A material is said to be anisotropic if the value of one or more of its properties varies with direction. Anisotropy differs from the property called heterogeneity in that anisotropy is the variation in values with direction at a point while heterogeneity is the variation in values between two or more points | https://huggingface.co/datasets/fmars/wiki_stem |
Seismic inverse Q filtering is a data processing technology for enhancing the resolution of reflection seismology images. Q is the anelastic attenuation factor or the seismic quality factor, a measure of the energy loss as the seismic wave moves.
Basics
Seismic inverse Q-filtering employs a wave propagation reversal procedure that compensates for energy absorption and corrects wavelet distortion due to velocity dispersion | https://huggingface.co/datasets/fmars/wiki_stem |
In geophysics (primarily in oil-and-gas exploration/development), seismic inversion is the process of transforming seismic reflection data into a quantitative rock-property description of a reservoir. Seismic inversion may be pre- or post-stack, deterministic, random or geostatistical; it typically includes other reservoir measurements such as well logs and cores.
Introduction
Geophysicists routinely perform seismic surveys to gather information about the geology of an oil or gas field | https://huggingface.co/datasets/fmars/wiki_stem |
Seismic migration is the process by which seismic events are geometrically re-located in either space or time to the location the event occurred in the subsurface rather than the location that it was recorded at the surface, thereby creating a more accurate image of the subsurface. This process is necessary to overcome the limitations of geophysical methods imposed by areas of complex geology, such as: faults, salt bodies, folding, etc. Migration moves dipping reflectors to their true subsurface positions and collapses diffractions, resulting in a migrated image that typically has an increased spatial resolution and resolves areas of complex geology much better than non-migrated images | https://huggingface.co/datasets/fmars/wiki_stem |
Seismic refraction is a geophysical principle governed by Snell's Law of refraction. The seismic refraction method utilizes the refraction of seismic waves by rock or soil layers to characterize the subsurface geologic conditions and geologic structure.
Seismic refraction is exploited in engineering geology, geotechnical engineering and exploration geophysics | https://huggingface.co/datasets/fmars/wiki_stem |
Seismic stratigraphy is a method for studying sedimentary rock in the deep subsurface based on seismic data acquisition.
History
The term Seismic stratigraphy was introduced in 1977 by Vail as an integrated stratigraphic and sedimentologic technique to interpret seismic reflection data for stratigraphic correlation and to predict depositional environments and lithology. This technique was initially employed for petroleum exploration and subsequently evolved into sequence stratigraphy by academic institutes | https://huggingface.co/datasets/fmars/wiki_stem |
Seismic wide-angle reflection and refraction is a technique used in geophysical investigations of Earth's crust and upper mantle. It allows the development of a detailed model of seismic velocities beneath Earth's surface well beyond the reach of exploration boreholes. The velocities can then be used, often in combination with the interpretation of standard seismic reflection data and gravity data, to interpret the geology of the subsurface | https://huggingface.co/datasets/fmars/wiki_stem |
The seismoelectrical method (which is different from the electroseismic physical principle) is based on the generation of electromagnetic fields in soils and rocks by seismic waves. This technique is still under development and in the future it may have applications like detecting and characterizing fluids in the underground by their electrical properties, among others, usually related to fluids (porosity, transmissivity, physical properties).
Operation
When a seismic wave encounters an interface, it creates a charge separation at the interface forming an electric dipole | https://huggingface.co/datasets/fmars/wiki_stem |
Shale Gouge Ratio (typically abbreviated to SGR) is a mathematical algorithm that aims to predict the fault rock types for simple fault zones developed in sedimentary sequences dominated by sandstone and shale.
The parameter is widely used in the oil and gas exploration and production industries to enable quantitative predictions to be made regarding the hydrodynamic behavior of faults.
Definition
At any point on a fault surface, the shale gouge ratio is equal to the net shale/clay content of the rocks that have slipped past that point | https://huggingface.co/datasets/fmars/wiki_stem |
Shear velocity, also called friction velocity, is a form by which a shear stress may be re-written in units of velocity. It is useful as a method in fluid mechanics to compare true velocities, such as the velocity of a flow in a stream, to a velocity that relates shear between layers of flow.
Shear velocity is used to describe shear-related motion in moving fluids | https://huggingface.co/datasets/fmars/wiki_stem |
Space climate is the long-term variation in solar activity within the heliosphere, including the solar wind, the Interplanetary magnetic field (IMF), and their effects in the near-Earth environment, including the magnetosphere of Earth and the ionosphere, the upper and lower atmosphere, climate, and other related systems. The scientific study of space climate is an interdisciplinary field of space physics, solar physics, heliophysics, and geophysics. It is thus conceptually related to terrestrial climatology, and its effects on the atmosphere of Earth are considered in climate science | https://huggingface.co/datasets/fmars/wiki_stem |
Spectral noise logging (SNL) is an acoustic noise measuring technique used in oil and gas wells for well integrity analysis, identification of production and injection intervals and hydrodynamic characterisation of the reservoir. SNL records acoustic noise generated by fluid or gas flow through the reservoir or leaks in downhole well components.
Development history
Noise logging tools have been used in the petroleum industry for several decades | https://huggingface.co/datasets/fmars/wiki_stem |
Cryptosaurus (meaning "hidden lizard") is a dubious genus of dinosaur known from a partial femur from the Late Jurassic of England. The sole species is Cryptosaurus eumerus.
The femur was found by the geologist Lucas Ewbank and donated by him to the Woodwardian Museum at Cambridge in 1869 | https://huggingface.co/datasets/fmars/wiki_stem |
Diclonius (meaning "double sprout") is a genus of dinosaur from the Late Cretaceous. It was a hadrosaur based solely on teeth. Its fossils were found in the Judith River Formation of Montana, northern US | https://huggingface.co/datasets/fmars/wiki_stem |
Dinodocus (meaning "terrible beam") is a genus of sauropod dinosaur, named by Richard Owen in 1884. The name is now usually considered a nomen dubium. The only species, D | https://huggingface.co/datasets/fmars/wiki_stem |
Discosaurus is an extinct genus of Cretaceous plesiosaur first discovered in Alabama by Joseph Leidy. It was argued to be the same animal as Elasmosaurus.
See also
Timeline of plesiosaur researchList of plesiosaurs
References
http://www | https://huggingface.co/datasets/fmars/wiki_stem |
Dryptosauroides (meaning "similar in form to Dryptosaurus") is the name given to a dubious genus of dinosaur from the Late Cretaceous. It was a large theropod, possibly belonging to the Abelisauroidea. It has been estimated as 10 meters (33 feet) long and 1 | https://huggingface.co/datasets/fmars/wiki_stem |
Epanterias is a dubious genus of theropod dinosaur from the Kimmeridgian-Tithonian age Upper Jurassic upper Morrison Formation of Garden Park, Colorado. It was described by Edward Drinker Cope in 1878. The type species is Epanterias amplexus | https://huggingface.co/datasets/fmars/wiki_stem |
Eucercosaurus (meaning "good-tailed lizard") is the name given to a genus of ornithopod dinosaur from the Albian stage of the Early Cretaceous. It was an ornithopod discovered in the Cambridge Greensand of England and is known from 19 centra, 3 sacrals, 4 dorsals and 12 caudals, and a neural arch found near Trumpington, Cambridgeshire. The type species, E | https://huggingface.co/datasets/fmars/wiki_stem |
Fabrosaurus ( FAB-rə-SOR-əs) is an dubious extinct genus of ornithischian dinosaur that lived during the Early Jurassic during the Hettangian to Sinemurian stages 199 - 189 mya. It was originally placed within the now obsolete family Fabrosauridae (now considered basal Ornithischia). Fabrosaurus was named and described by paleontologist Leonard Ginsburg in 1964 based on the holotype specimen, a partial jawbone with three teeth | https://huggingface.co/datasets/fmars/wiki_stem |
Gongbusaurus is a genus of ornithischian, perhaps ornithopod, dinosaur that lived between about 160 and 157 million years ago, in the Late Jurassic period. A small herbivore, it is very poorly known. Two species have been assigned to it, but as the original name is based on teeth, there is no concrete evidence to connect the two species | https://huggingface.co/datasets/fmars/wiki_stem |
Halitherium is an extinct dugongid sea cow that arose in the late Eocene, then became extinct during the early Oligocene. Its fossils are common in European shales. Inside its flippers were finger bones that did not stick out | https://huggingface.co/datasets/fmars/wiki_stem |
Heptasteornis is the name given to a potentially dubious genus of alvarezsaurid dinosaur from the Late Cretaceous. The type (and only known) species is Heptasteornis andrewsi, described as a presumed gigantic prehistoric owl in 1975. It was previously included in Elopteryx nopcsai and indeed the holotypes of both were believed to be from the same individual as they were discovered, and initially were assigned the same specimen number | https://huggingface.co/datasets/fmars/wiki_stem |
Heterosuchus is an extinct genus of crocodylomorph that may have been a eusuchian. It is known only from neck and back vertebrae recovered from Early Cretaceous-age rocks of the Hastings Beds (Wealden Group) of Hastings, Sussex. These vertebrae are procoelous (ball-and-socket articulation with the socket in front and the ball on the back of individual vertebrae), which is a trait of eusuchians | https://huggingface.co/datasets/fmars/wiki_stem |
Hierosaurus (meaning "sacred lizard") is an extinct genus of nodosaurid ankylosaur which lived during the Late Cretaceous 87 to 82 million years ago. Its fossils were found in the Smoky Hill Chalk Member of the Niobrara Formation, in western Kansas, which would have been near the middle of the Western Interior Sea during the Late Cretaceous. It was a nodosaurid, an ankylosaur without a clubbed tail | https://huggingface.co/datasets/fmars/wiki_stem |
Iliosuchus (meaning "crocodile hipped") is a genus of theropod dinosaur known from Bathonian–age (168. 3 – 166. 1 mya) rocks of England | https://huggingface.co/datasets/fmars/wiki_stem |
Iuticosaurus (meaning "Jute lizard") is a genus of titanosaur sauropod dinosaur from the Early Cretaceous of the Isle of Wight. Two species have been named: I. valdensis and I | https://huggingface.co/datasets/fmars/wiki_stem |
Laosaurus (meaning "stone or fossil lizard") is a genus of neornithischian dinosaur. The type species, Laosaurus celer, was first described by O. C | https://huggingface.co/datasets/fmars/wiki_stem |
Liaoxiornis is a dubious genus of enantiornithine bird. The only named species is Liaoxiornis delicatus, described by Hou and Chen in 1999. Because the species was named for a hatchling specimen, it cannot be matched with adult specimens, and so it is impossible to determine which, if any, birds from the same rocks represent adults of this species | https://huggingface.co/datasets/fmars/wiki_stem |
Marmarospondylus ("marble [reference to the Forest Marble Formation] vertebra") is a dubious genus of sauropod dinosaur from Middle Jurassic deposits in the English Midlands.
The type species, Marmarospondylus robustus, was described by Richard Owen as a species of the Late Jurassic genus Bothriospondylus in 1875. The holotype, NHMUK R | https://huggingface.co/datasets/fmars/wiki_stem |
Omosaurus is a dubious genus of extinct crurotarsan reptile, possibly a phytosaur, from the Late Triassic (Carnian) of North Carolina. Only scant remains are known, which makes Omosaurus hard to classify. The type, and only species, Omosaurus perplexus, was named and described in 1856 by Joseph Leidy | https://huggingface.co/datasets/fmars/wiki_stem |
Otischalkia is an extinct genus of archosauromoph from late Triassic (late Carnian stage) deposits of Howard County, Texas, US It is known from the holotype TMM 31025-263, left humerus and from the referred specimens TMM 31025-262, TMM 31025-266, TMM 31025-264, TMM 31185-92 and TMM 31185-93. It was found in the Lower Dockum Group near the abandoned settlement of Otis Chalk. It was first named by Adrian P | https://huggingface.co/datasets/fmars/wiki_stem |
Palaeopteryx (meaning "ancient wing") is an extinct genus of dubious paravian theropod dinosaur from the Morrison Formation of Colorado. The type species is P. thomsoni | https://huggingface.co/datasets/fmars/wiki_stem |
Palaeospinax is an extinct genus of shark which lived from the Early Triassic to the end of the Eocene epoch. Although several species have been described, the genus is considered nomen dubium because the type-specimen of the type species, Palaeospinax priscus, lacks appropriate diagnostic characters to define the genus. Other species originally described as Synechodus were transferred to the genus Palidiplospinax | https://huggingface.co/datasets/fmars/wiki_stem |
"Patricosaurus" (meaning "paternal lizard") is the name given to a dubious and chimeric genus of reptile from the Early Cretaceous. It is based on a femur and sacrum from two animals: the femur from a large lepidosaur, and the sacrum from an archosaur (Barrett and Evans, 2002), both specimens are known from the Cambridge Greensand. The type species, Patricosaurus merocratus, was described by Harry Seeley in 1887, and was originally thought to have been a lizard | https://huggingface.co/datasets/fmars/wiki_stem |
Polyodontosaurus (meaning "many-toothed lizard") is a potentially dubious genus of troodontid dinosaur named in 1932 by Charles W. Gilmore for a left dentary from the Dinosaur Park Formation. It had been considered a synonym of Stenonychosaurus or Troodon for a significant time, before being declared a nomen dubium | https://huggingface.co/datasets/fmars/wiki_stem |
Priodontognathus (meaning "saw tooth jaw") was a genus of ankylosaurian dinosaur possibly from the Oxfordian-age Upper Jurassic Lower Calcareous Grit of Yorkshire, England. It is a dubious genus based on a maxilla, and has been erroneously mixed up with iguanodonts and stegosaurs.
History and taxonomy
English paleontologist Harry Govier Seeley, who described the genus, first mentioned the holotype (SMC B53408), a maxilla or upper jaw bone, in 1869 | https://huggingface.co/datasets/fmars/wiki_stem |
Proacrodon is a dubious genus of extinct mammal from South America. Its type species is Proacrodon transformatus. The only known specimen, a lower premolar or molar, is now lost, and its affinities are unknown | https://huggingface.co/datasets/fmars/wiki_stem |
Protoavis (meaning "first bird") is a problematic taxon known from fragmentary remains from Late Triassic Norian stage deposits near Post, Texas. The animal's true classification has been the subject of much controversy, and there are many different interpretations of what the taxon actually is. When it was first described, the fossils were described as being from a primitive bird which, if the identification is valid, would push back avian origins some 60-75 million years | https://huggingface.co/datasets/fmars/wiki_stem |
Scaldicetus is an extinct genus of highly predatory macroraptorial sperm whale. Although widely used for a number of extinct physeterids with primitive dental morphology consisting of enameled teeth, Scaldicetus as generally recognized appears to be a wastebasket taxon filled with more-or-less unrelated primitive sperm whales.
Taxonomy
Scaldicetus is known from the Miocene to Pleistocene deposits of Western Europe, the U | https://huggingface.co/datasets/fmars/wiki_stem |
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