Geological Survey, United States, is a federal agency that conducts studies of public lands and offshore areas. It is part of the U.S. Department of the Interior. Commonly called the USGS, the agency conducts research in geology, geochemistry, geophysics, hydrology, mapmaking, and related sciences. It also studies natural hazards, such as earthquakes and volcanoes, and identifies flood hazard areas. The USGS monitors the quantity, quality, and use of water resources, gathers information on energy and mineral resources, and publishes thousands of technical reports and maps each year. The agency has headquarters in Reston, Virginia, and major facilities in Denver and in Menlo Park, California. The USGS was established in 1879.