geophysics
The geophysics is a discipline of geosciences at the same time a branch of physics . It researches the physical properties and processes of the earth's crust and interior ( physics of the solid earth , geophysics in the narrower sense ), but also includes the physics of the oceans ( oceanography ), the atmosphere ( meteorology , aeronomy ) and the planets of the Solar system. She also researches various technical methods for exploring the spheres of the earth. In German university policy, geophysics is assigned to the group of so-called small subjects .
Geophysics is primarily concerned with natural phenomena and processes of the earth and its environment as well as with technical aspects for construction and deposits ( applied geophysics ) and geophysical maps .
Sub-areas
Geophysics can be subdivided into further sub-areas according to different criteria. Depending on the selected criterion, there are different subdivisions, the sub-areas of which may partly overlap. One such criterion for subdivision is the spatial division of the earth into several spheres, which various sub-areas have specialized in exploring:
- The physics of the solid earth , often referred to as "Geophysics in the strict sense" or "General Geophysics". This area is in turn divided into the following sub-disciplines:
- Physical geodesy and gravimetry
- Seismology and the structure of the Earth's interior
- Geodynamics
- Geomagnetism
- Rock physics , see also rock mechanics
- geophysical prospecting
- The hydrology , or physics of the hydrosphere (including the science of hydraulic engineering and water management).
- The meteorology , or physics of the lower atmosphere (especially the troposphere ).
- The aeronomy , or physics of the high atmosphere or high atmosphere (including the ionosphere and magnetosphere ).
- The Planetary Science as a generalization of Geophysics to other planets (where you can view the Geophysics and vice versa as a branch of Planetology).
Alternatively, geophysics can also be broken down according to the research methods used and their application. This subdivision is particularly often applied to the physics of the solid earth, or "general geophysics", with the following three sub-areas:
- The theoretical geophysics deals with the mathematical foundations of Geophysics and their application for simulation of geophysical processes. Some typical topics of theoretical geophysics are fluid mechanics , potential theory , wave equations or geodynamics .
- The experimental geophysics deals with laboratory tests. Often it is about the investigation of material properties under conditions such as those found in the earth's interior. If the examined materials are rocks , this branch of research is also called petrophysics . A typical example would be the determination of the sound conductivity of different rocks under high pressure in a material press . Ultimately, numerical simulation is sometimes assigned to experimental and not theoretical geophysics.
- The Applied Geophysics deals with the exploration of the subsoil with geophysical methods for practical applications. Most important is the exploration for the search for raw materials such as crude oil , water or ores . The identification of suitable final storage sites , the investigation of landfills and other contaminated sites , the investigation of the subsoil and the investigation of the subsoil for purposes of agriculture ( agrogeophysics ) also fall into this area. Ultimately, methods of applied geophysics are also used for academic questions, especially in archeology ( archaeometry ). If geophysical explorations are not carried out from the surface of the earth, but from a borehole, one speaks of borehole geophysics , a further sub-area of applied geophysics. Applied geophysics operates at the interface between natural and engineering sciences .
Since geophysics is primarily concerned with those areas of the earth that are not accessible for direct measurements, remote sensing methods are often used. These usually boil down to measuring a physical field close to the earth's surface in order to then extrapolate it into the depth or altitude areas of interest using mathematical methods. The details of the measurement and evaluation methods used vary greatly depending on the measured variable being investigated (acceleration due to gravity, electric or magnetic field strength, etc.), the observed frequency range and the fundamental field characteristics (potential field, diffusion field or wave field; depending on the underlying differential equations). The field characteristics in particular have a major influence on the evaluation methods that can be used. Therefore some typical geophysical exploration methods are listed here according to the relevant field characteristics:
- Potential method (potential fields, elliptical differential equations)
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Diffusion method (diffusion fields, parabolic differential equations):
- Magnetotellurics (MT, also special forms such as AMT, LMT, RMT)
- Geoelectromagnetics (including transient electromagnetics, TEM for short)
- Very Low Frequency (VLF method for short)
-
Wave method (wave fields, hyperbolic differential equations):
- Seismology and seismics
- GPR (Ground Penetrating Radar, short GPR)
- Special case (radiation):
Professional associations
The global research agendas of geophysics are coordinated within the framework of the IUGG (International Union for Geodesy and Geophysics) and its 7 associations.
The world's largest geophysical society with a focus on academia is the American Geophysical Union (AGU) with over 58,000 members. The largest umbrella organization for applied geophysics, especially the search for raw materials, is the Society of Exploration Geophysicists (SEG) with approx. 28,000 members. The German Geophysical Society (DGG) is the largest German geophysical professional association with around 1,000 members.
courses
Germany
Geophysical courses are not offered at all universities. The focus differs between the individual universities in terms of geophysical departments. Some universities offer geophysics as an independent subject and others offer geophysics as a field of study or focus in the subjects of geosciences or physics (see map). The proportions of geophysical content can differ and can be found out at the respective university. It should be noted that a master's degree in "Geophysics" does not necessarily include more geophysical courses than, for example, B. a master's degree in geosciences specializing in geophysics.
The following universities in Germany offer geophysical courses:
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RWTH Aachen
- B.Sc. Applied geosciences (geophysical modules)
- B.Sc. Georesource management (geophysical modules)
- M.Sc. Applied Geophysics
- M.Sc. Applied geosciences (geophysical elective modules)
- M.Sc. Georesource management (geophysical elective modules)
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Free University of Berlin
- B.Sc. in Geological Sciences (geophysical modules)
- M.Sc. of geological sciences / focus on geophysics
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Technical University Berlin
- B.Sc. Geotechnology / Elective Area Applied Geophysics
- M.Sc. Geotechnology / focus on applied geophysics
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University of Bonn
- B.Sc. earth sciences
- M.Sc. Physics of the Earth and Atmosphere (in cooperation with the University of Cologne )
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Technical University of Braunschweig
- B.Sc. Physics with specialization in geo- and astrophysics
- M.Sc. Physics with specialization in geo- and astrophysics
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University of Bremen
- B.Sc. Geosciences (geophysical modules)
- M.Sc. Geosciences (geophysical modules)
- M.Sc. Marine Geosciences
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Ruhr-University Bochum
- B.Sc. Geosciences (geophysical modules)
- M.Sc. earth sciences
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Johann Wolfgang Goethe University Frankfurt am Main
- B.Sc. earth sciences
- M.Sc. Geosciences / focus on geophysics
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Technological University Bergakademie Freiburg
- B.Sc. Geophysics and Geoinformatics
- M.Sc. geophysics
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Georg-August-University Goettingen
- B.Sc. Physics with a focus on astro- and geophysics
- M.Sc. Physics / research focus on astro- and geophysics
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University of Hamburg
- B.Sc. Geophysics / Oceanography
- M.Sc. geophysics
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Friedrich Schiller University Jena
- B.Sc. Geosciences (geophysical compulsory and elective modules)
- M.Sc. geophysics
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Karlsruher Institute for Technology
- B.Sc. geophysics
- M.Sc. geophysics
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Christian Albrechts University in Kiel
- B.Sc. Physics of the Earth System: Meteorology-Oceanography-Geophysics
- M.Sc. geophysics
- M.Sc. Marine Geosciences
- M.Sc. Climate Physics: Meteorology and Physical Oceanography
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University of Cologne
- B.Sc. Geophysics and meteorology
- M.Sc. Physics of the Earth and Atmosphere (in cooperation with the University of Bonn )
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University of Leipzig
- M.Sc. Earth Sciences: Environmental Dynamics and Geohazards
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Ludwig-Maximilians-University Munich
- B.Sc. Geosciences (specialization geophysics)
- M.Sc. Geophysics
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Westfälische Wilhelms-Universität Münster
- B.Sc. geophysics
- M.Sc. geophysics
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University of Potsdam
- B.Sc. Geosciences (focus on geophysics possible)
- M.Sc. Geosciences / specialization in geophysics
literature
- Hans Berckhemer : Fundamentals of geophysics. Scientific Book Society, Darmstadt 1990, ISBN 3-534-03974-2
- Klaus Knödel, Heinrich Krummel, Gerhard Lange (Ed.): Geophysics. In: Handbook for exploring the subsurface of landfills and contaminated sites ( Federal Institute for Geosciences and Raw Materials ), Springer Verlag, Berlin 2005, ISBN 3-540-22275-8
- William Lowrie: Fundamentals of Geophysics. Cambridge University Press, 2007, ISBN 0-521-67596-0
Web links
- Homepage of the German geophysics students
- German Geophysical Society (DGG)
- AGU American Geophysical Union
- SEG The Society of Exploration Geophysicists
- Geosciences Forum: Geophysics
- Information from the DGG on geophysics Bachelor courses (PDF; 101 kB)
- Information from the DGG on geophysics master's programs (PDF; 120 kB)
References and footnotes
- ↑ Small subjects: Geophysics on the Kleine Fächer portal. Retrieved June 18, 2019 .
- ↑ In physics, too, so-called "Computational Physics" is a special subject between experimental physics and theoretical physics .
- ↑ "General information on studying geophysics" of the German Geophysical Society ( Memento of the original from March 19, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ TU Berlin
- ↑ "Geoscientific Master of Science" (PDF; 12 kB), in which the specialization in geophysics is possible
- ↑ "General information on the Bachelor's degree in Geosciences" ( Memento of the original from June 17, 2013 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. in which the specialization in geophysics is possible
- ↑ "General information on the Geophysics Master's degree" ( Memento of the original from March 24, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.