The GSN provides funding to two Network Operators:
U.S. Geological Survey's Albuquerque Seismological Laboratory (~2/3 of the GSN)
The USGS partnership on the GSN is very valuable and successful. Through this partnership, IRIS has funded the installations, upgrades and major capital improvements of the USGS portion of the GSN (~90 stations) while the USGS has taken responsibility for the operations and maintenance of the network. In addition, the USGS has funded the installation, and O&M of the Caribbean seismic network (9 stations), a network affiliate to the GSN.
Project IDA (International Deployment of Accelerometers), operated by the Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego (~1/3 of the GSN)
Project IDA is funded by IRIS for the installation, upgrades, operations and maintenance of the IDA portion of the GSN (~40 stations). IRIS DMS also funds the IDA Data Collection Center. Check out what's new at project IDA.
In addition, GSN coordinates and collaborates with many other Network Operators, nationally and internationally, including:
AFTAC: (Arrays ILAR, NVAR, PDAR, and TXAR and Stations LBTB and VNDA) Air Force Technical Applications Center, Patrick Air Force Base, Florida
Berkeley: (Station CMB) Berkeley Seismological Laboratory, Department of Earth and Planetary Sciences, University of California, Berkeley
Caltech: (Station PASC) Caltech Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology
GEOSCOPE: (Stations KIP and TRIS). The French GEOSCOPE program of the Institut de Physique du globe de Paris.
NIED: National Research Institute for Earth Science and Disaster Prevention, Japan
As well as several other national and international networks.