USArray, managed by IRIS, is a 15-year program to place a dense network of permanent and portable seismographs across the continental United States. These seismographs record the seismic waves released by earthquakes that occur around the world. Seismic waves are indicators of energy disbursement within the earth. By analyzing the records of earthquakes obtained from this dense grid of seismometers, scientists can learn about Earth structure and dynamics and the physical processes controlling earthquakes and volcanoes. The goal of USArray is primarily to gain a better understanding of the structure and evolution of the continental crust, lithosphere, and mantle underneath North America.