{"thcode":2,"term":{"code":2054,"name":"sub-bottom profiling","parent":1045,"scope":"Methods of imaging the structure of sediments below the sea floor  or lakebed using ship-borne or towed sensors with a variety of sound sources."},"uf":[{"name":"boomer profiling","usewith":false},{"name":"chirp profiling","usewith":false},{"name":"multi-channel seismic profiling","usewith":false},{"name":"multichannel seismic profiling","usewith":false},{"name":"single channel seismic profiling","usewith":false},{"name":"sparker profiling","usewith":false},{"name":"subbottom profiling","usewith":false}],"bt":[{"code":1045,"name":"seismic reflection methods","parent":1042,"scope":"Geophysical technique to study the subsurface of the earth using sound waves induced by explosives, vibrating devices, or percussive equipment.  The reflections of the sound waves from the boundaries of different rocks are measured."},{"code":1042,"name":"seismic methods","parent":375,"scope":"Procedures used to record and study earthquakes or earth vibrations including those that are artificially induced."},{"code":375,"name":"field inventory and monitoring","parent":376,"scope":"Repeated observation or sampling at a site, on a scheduled or event basis, for study and analysis.  In general, this category excludes sampling programs in which materials are obtained in the field and brought back to a laboratory for study and analysis."},{"code":376,"name":"field methods","parent":734,"scope":"Research procedures and instrumental means to measure, collect data and samples, and observe in the natural areas where the materials, phenomena, structures, or species being studied occur."},{"code":734,"name":"methods","parent":1,"scope":"Techniques, methods, procedures, or strategies for research, management, collection, or analysis of scientific information in USGS."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[],"rt":[{"code":2081,"name":"profiles","parent":235,"scope":"Observations or calculations given for a series of depths, at or near the same horizontal position."},{"code":1047,"name":"seismic refraction methods","parent":1042,"scope":"Geophysical technique to study the subsurface of the earth by generating compressional waves by means of hammering or explosive methods. The variations in velocity of the waves traveling through rocks or geological layers are measured."}]}