<descriptor thcode="61"><thesaurus thcode="61" name="Marine Realms Information Bank (MRIB) keywords" scope="Theme keywords from the former Marine Realms Information Bank, focusing on characteristics of coasts and oceans, processes acting on them, and human concerns about them." creator="U.S. Geological Survey" rights="Public domain" date="2016-09-07" codetype="number" prefix="mrib" tblname="mrib" nonpref="mribnp" relterm="mribrt" root_code="1" contact="aallwardt"><category><term thcode="25" code="27" name="types" parent="26" scope="Terms are types of things rather than named instances"/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="27" name="types" parent="26" scope="Terms are types of things rather than named instances"/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/></category><altlabel><altlabel>MRIB keywords</altlabel><altlabel>MRIB keywords</altlabel><altlabel>Marine Realms Information Bank keywords</altlabel><altlabel>Marine Realms Information Bank keywords</altlabel></altlabel></thesaurus><term thcode="61" code="400" name="field observation" parent="398" scope="scientific investigation of physical or biological features and processes in a natural setting."/><uf><usefor name="field methods"/></uf><bt><term thcode="61" code="398" name="research method" parent="1"/><term thcode="61" code="1" name="Marine Realms Information Bank (MRIB) keyword categories"/></bt><nt><term thcode="61" code="417" name="Global Positioning System (GPS) observations" parent="400" scope="the use of satellite signals from the Global Positioning System to determine the precise location of a terrestrial receiver."/><term thcode="61" code="401" name="acoustic methods" parent="400" scope=" measurement of sound propagation in a given medium (such as water) for ranging or acoustical studies."/><term thcode="61" code="447" name="altimetry" parent="400" scope="used for all instruments and techniques that determine altitude, either directly or remotely, including (but not limited to) pressure altimeters, radar altimeters, GPS, and LIDAR."/><term thcode="61" code="405" name="biological observations" parent="400" scope="scientific investigation of organisms in a natural setting."/><term thcode="61" code="408" name="chemical tracer studies" parent="400" scope="the introduction of an easily detected substance into a natural physical or biological system for the purpose of documenting its movement (or other changes) with time."/><term thcode="61" code="409" name="controlled burn experiments" parent="400" scope="prescribed burning of selected tracts of land to understand the behavior of wildfires or to preempt large wildfires."/><term thcode="61" code="410" name="diving" parent="400" scope="used for all methods of direct underwater observation by humans."/><term thcode="61" code="411" name="electrical resistivity measurements" parent="400" scope="borehole measurements to characterize in situ earth materials and pore fluids by their resistance to the flow of electrical currents."/><term thcode="61" code="412" name="electromagnetic conductivity measurements" parent="400" scope="used for shallow underground imaging techniques based on variations in the electrical conductance of earth materials."/><term thcode="61" code="413" name="excavation" parent="400" scope="exposing underground earth materials and structures for inspection, typically by trenching."/><term thcode="61" code="414" name="fossil collecting and description" parent="400" scope="the removal and documentation of fossils from any natural setting, typically for additional study in the laboratory."/><term thcode="61" code="415" name="gamma ray logging" parent="400" scope="measurements of natural gamma radiation emitted by the earth materials in a borehole."/><term thcode="61" code="448" name="geodetic measurements" parent="400" scope="field studies of the Earth's shape, dimensions, and gravitational field."/><term thcode="61" code="416" name="geotechnical measurements" parent="400" scope="the use of standardized field tests to determine the engineering properties of earth materials."/><term thcode="61" code="418" name="gravimetry" parent="400" scope="measurement of the gravitational field at specific locations, yielding data that can be analyzed for a variety of scientific purposes."/><term thcode="61" code="419" name="heat flow observations" parent="400" scope="measurement of the dissipation of internal heat at the Earth's surface."/><term thcode="61" code="420" name="hydraulic conductivity observations" parent="400" scope="measurements to quantify the ability of fluids to move through porous earth materials."/><term thcode="61" code="421" name="hydrologic observations" parent="400" scope="used broadly for observations of atmospheric, surface, and subsurface water."/><term thcode="61" code="426" name="magnetic field observations" parent="400" scope="measurement of the Earth's magnetic field at a specific location; often used to detect magnetic anomalies that reflect the nature and distribution of subsurface earth materials."/><term thcode="61" code="427" name="mapping" parent="400" scope="in addition to traditional cartographic methods, this term is used for all field activities that document spatial relationships of scientific interest."/><term thcode="61" code="430" name="meteorological observations" parent="400" scope="field observations of weather conditions, including but not limited to temperature, humidity, atmospheric pressure, wind, and precipitation."/><term thcode="61" code="437" name="oceanographic observations" parent="400" scope="used for field observations related to all aspects of oceanography: physical, chemical, and biological; may also be used for field studies of freshwater bodies that use oceanographic techniques."/><term thcode="61" code="445" name="photography" parent="400" scope="limited to photography for scientific purposes."/><term thcode="61" code="449" name="remote sensing" parent="400" scope="generally used for the acquisition of images or other data from aircraft or satellites; also used for ground-based systems for collecting data at a distance."/><term thcode="61" code="462" name="sampling" parent="400" scope="used for the collection of physical samples and also images that document physical conditions."/><term thcode="61" code="478" name="seismic methods" parent="400" scope="the study of naturally occurring or artificially induced seismic waves, generally for one of two purposes: 1) understanding the nature and cause of seismic activity (e.g., earthquakes), or 2) understanding the properties of the earth materials through which the seismic waves have passed."/><term thcode="61" code="481" name="seismographic measurements" parent="400" scope="the measurement of transient ground motion attributed to seismic waves."/><term thcode="61" code="482" name="stratigraphic characterization and correlation" parent="400" scope="field observation of sedimentary rock strata at two or more locations, with the goal of establishing their physical continuity or temporal equivalence."/><term thcode="61" code="483" name="underwater vehicle observations" parent="400" scope="direct observation of underwater features using submersibles (manned or remotely operated)."/><term thcode="61" code="484" name="video observation" parent="400" scope="video documentation of natural features and processes."/></nt></descriptor>