During the last decades the number of seismic stations has increased dramatically. The ISC has been cooperating together with the United States Geological Survey, National Earthquake Information Center (NEIC), in its capacity as World Data Center A for Seismology, the International Data Center for the Comprehensive Nuclear Test Ban Treaty (CTBT/IDC) in Austria, the Incorporated Research Institutions for Seismology (IRIS) Data Center in Seattle, Washington, and the Federation of Digital Seismograph Networks (FDSN), indexing and cataloging these stations.