The components were funded by the National Science Foundation and were constructed, operated, and maintained as a collaborative effort with UNAVCO, the Incorporated Research Institutions for Seismology (IRIS), and Stanford University, with contributions from several other national and international organizations.
A major goal of USArray was to collect detailed seismic images of the North American lithosphere.
[1][2][3] USArray consists of four "observatories": The Transportable Array (TA) was a network of 400 high-quality broadband seismographs on temporary sites that marched across the conterminous United States.
The density of the TA network — typical station spacing of about 70 km — provided a level of resolution not previously available in many parts of the country and provided finer details of the lithosphere under parts of North America.
The Flexible Array was a pool of portable seismic instruments available for short-term high-density observations of particular areas of interest.