{"thcode":2,"term":{"code":1367,"name":"earth material properties","parent":287,"scope":"Physical characteristics of rocks and unconsolidated earth materials such as soils and sediments."},"uf":[],"bt":[{"code":287,"name":"earth characteristics","parent":1174,"scope":"The measurable, definable properties and features of the earth."},{"code":1174,"name":"topics","parent":1,"scope":"Themes, subjects, and concerns for which USGS information resources are relevant."},{"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":[{"code":2276,"name":"acid neutralizing potential","parent":1367,"scope":"Geochemical capacity of earth materials to affect the pH of waters flowing through them."},{"code":1714,"name":"bulk density","parent":1367,"scope":"Overall density of an unconsolidated earth material."},{"code":2290,"name":"electromagnetic reflectance and emissivity","parent":1367,"scope":"Effectiveness of an earth material in reflecting or emitting radiation, varying by wavelength.  Measurements are made over the infrared part of the electromagnetic spectrum in a laboratory to compare with remotely-sensed data obtained by airborne or satellite imaging systems."},{"code":1741,"name":"magnetism","parent":1367,"scope":"Strength and orientation of the permanent magnetic field in a given sample of an earth material"},{"code":1368,"name":"permeability","parent":1367,"scope":"The ability of fluids to pass through an earth material, typically depending on the connectedness of pore space in the material."},{"code":1369,"name":"porosity","parent":1367,"scope":"The proportion of open space in a rock or unconsolidated material."},{"code":1701,"name":"radioactivity","parent":1367,"scope":"Release of subatomic particles from earth materials.  Generally the energy of these particles is used to determine the chemical elements present."},{"code":1712,"name":"resistivity","parent":1367,"scope":"Electrical resistance of materials, often measured in boreholes."},{"code":2027,"name":"soil moisture","parent":1367,"scope":"Water content of soil and other near-surface unconsolidated earth material"},{"code":2028,"name":"soil temperature","parent":1367,"scope":"Temperature and temperature gradients in soil and other near-surface unconsolidated earth materials"}],"rt":[{"code":2279,"name":"thermal maturation","parent":435,"scope":"Chemical alteration of organic material within sediments and sedimentary rocks as a result of heat. Measures of thermal maturation indicate the extent of transformation of detrital organic material into coal and petroleum."}]}