{"thcode":2,"term":{"code":531,"name":"hazards","parent":1174,"scope":"Potential dangers from both natural processes (e.g., earthquakes, floods, and climate change) and human impacts on the environment."},"uf":[{"name":"catastrophes","usewith":false},{"name":"coastal hazards","usewith":{"code":1799,"name":"coastal processes","parent":101,"scope":"Processes unique to coastal areas including longshore transport, beach erosion, storm surge, shoreline change, delta formation, barrier island migration, beach stabilization by vegetation"}},{"name":"disasters","usewith":false},{"name":"earthquake hazards","usewith":{"code":304,"name":"earthquakes","parent":451,"scope":"Ground shaking caused by the sudden release of accumulated strain by an abrupt shift of rock along a fracture in the earth or by volcanic or magmatic activity, or other sudden stress changes in the earth."}},{"name":"emergency management resources","usewith":false},{"name":"environmental hazards","usewith":false},{"name":"geologic hazards","usewith":false},{"name":"harmful algal blooms","usewith":{"code":30,"name":"algal blooms","parent":310,"scope":"Exceptional growth of algae and cyanobacteria in lakes, rivers or oceans due to excessive nutrients or climatic conditions."}},{"name":"ocean hazards","usewith":{"code":816,"name":"ocean processes","parent":101,"scope":"Recurrent natural changes that are physical, biological, or chemical, actively affecting the seas and oceans."}}],"bt":[{"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":[],"rt":[{"code":30,"name":"algal blooms","parent":310,"scope":"Exceptional growth of algae and cyanobacteria in lakes, rivers or oceans due to excessive nutrients or climatic conditions."},{"code":769,"name":"contamination and pollution","parent":1174,"scope":"Introduction of harmful substances into the environment by human action or natural processes."},{"code":246,"name":"desertification","parent":168,"scope":"The alteration of arable land to dry, barren land due to prolonged drought or the deleterious effects of human intervention including overgrazing, overpopulation, or destructive agricultural practices."},{"code":284,"name":"droughts","parent":63,"scope":"Extended periods of moisture deficit over a sizeable area sufficient to have an adverse effect on vegetation, animals, or man."},{"code":304,"name":"earthquakes","parent":451,"scope":"Ground shaking caused by the sudden release of accumulated strain by an abrupt shift of rock along a fracture in the earth or by volcanic or magmatic activity, or other sudden stress changes in the earth."},{"code":320,"name":"ecotoxicology","parent":650,"scope":"Scientific study of causes, dispersal, and effects of contaminants on the environment."},{"code":384,"name":"fires","parent":101,"scope":"Combustion, marked by flames or intense heat, in natural settings, often ignited by lightning or human activities.  For fires set as part of natural resource management, use 'controlled fires'."},{"code":398,"name":"floods","parent":1667,"scope":"Relatively high water that overflows the natural or artificial banks of a stream or coastal area that submerges land not normally below water level."},{"code":548,"name":"human impacts","parent":1174,"scope":"The effects, intentional or unintentional, beneficial or harmful, direct or indirect, which human activities have upon the environment and living things."},{"code":1718,"name":"impact cratering","parent":101,"scope":"Impact of extraterrestrial objects such as asteroids, comets, and meteorites on Earth."},{"code":639,"name":"landslides","parent":1736,"scope":"Downslope movement of rock, soil, or artificial fill under the influences of gravity."},{"code":661,"name":"liquefaction","parent":2284,"scope":"Physical process which can occur during an earthquake.  Clay-free soil deposits (primarily sands and silts)temporarily lose strength and behave as viscuous fluids, resulting in ground failure."},{"code":1721,"name":"magnetic storms","parent":451,"scope":"A period of time during which the earth's magnetic field varies rapidly.  During magnetic storms, satellite electronics can be damaged through the build up and subsequent discharge of static electric charges and astronauts and high-altitude pilots can be subjected to increased levels of radiation."},{"code":750,"name":"mining hazards","parent":548,"scope":"Dangerous conditions which result from the extraction of naturally occurring mineral deposits.  Includes tunnel collapses, fires, and explosions."},{"code":1687,"name":"scour","parent":1667,"scope":"Erosion of sediment in a stream bed, often occurring at manmade structures such as bridge supports."},{"code":1075,"name":"social sciences","parent":1019,"scope":"Sciences concerned with the structure and interrelationships of human societies, human institutions and organizations, and human culture over time."},{"code":1102,"name":"storms","parent":63,"scope":"Atmospheric disturbances with winds of unusual force or direction. Accompanied by rain, snow, hail, or sleet, and often by thunder and lightning."},{"code":1195,"name":"tsunamis","parent":822,"scope":"Sea waves generated by submarine earthquakes, volcanic eruptions, or landslides, which are generally imperceptible in deep water but may be very destructive when striking the shoreline."},{"code":1286,"name":"volcanic activity","parent":451,"scope":"Episodes during which gases, ash, and lava (molten rock) escape from vents in the earth's crust, accompanied by minor tremors."}]}