The development and evolution of United States Geological Survey's scientific research from 1970-Evidence from bibliometrics

The United States Geological Survey has a history of more than 130 years, BS the key to its enduring development is to make the changing needs of the country and society serve as the basis of survival. Quantified analysis of its research papers in GeoRef database since 1970 shows that United States Geological Survey's scientific research experienced a major turning point in 1990. At the beginning of the 1990s, the number of papers began to increase significantly instead of being stagnant, and since then, a complete system of discipline has been formed and the integrity of disciplines has kept stable all the time; the research work has shifted from the resource-based supply type to environment-based demand type; in addition, nine key disciplines which were identified based on the degree of discipline continuity have started a relatively stable development trend since 1990; hydrogeology and environmental geolo-gy perhaps is still the focus in future; the clear shift of research focus can be found through keyword-based hotspot analysis and the development of key disciplines.