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The Air Force Technical Applications Center (AFTAC) is home to the United States National Data Center (US NDC). AFTAC provides national authorities quality technical analysis to monitor Comprehensive Nuclear-Test-Ban Treaty compliance.

Comprehensive Nuclear-Test-Ban Treaty (CTBT)

The US NDC receives data from stations that support the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The treaty is administered by a Provisional Technical Secretariat (PTS) located in Vienna, Austria. The PTS oversees both the International Monitoring System (IMS) and an International Data Center (IDC). The IMS is composed of networks of seismic (primary and auxiliary), infrasound, hydroacoustic, and radionuclide sensors and the Global Communications Infrastructure (GCI). The IDC is responsible for receiving data from the IMS and making data products available to the States Parties. The IMS is composed of a worldwide network of monitoring stations that feed data to the IDC. These stations are owned, controlled, and operated by the states hosting or otherwise taking responsibility for the stations in accordance with the treaty protocol. The PTS is responsible for supervising and coordinating the operations of the stations, according to a series of internationally approved operations manuals for each technique. Incorporation of US stations into the IMS is dependent on congressional approval and continued funding.

International Data Center (IDC)

The IDC is the international repository for all treaty-monitored data. It accepts all data via a VSAT link through the GCI at the station, provides access to this data to all CTBT signatories, and provides services to all treaty signatories so they can fulfill their national verification functions. Data sent to the IDC is collected, archived, processed, and provided to treaty signatories on a routine basis. The IDC also serves as the communications hub for the international monitoring network. The US NDC receives continuous data feeds from the IDC for all US-IMS stations and hydroacoustic stations. These data are analyzed and archived indefinitely for future analysis and to fulfill requests from national authorities and the scientific community.


The US NDC receives additional data directly from the IDC through the GCI link between the IDC and US NDC. The GCI is the long-haul communications system of the IDC. Its purpose is to retrieve IMS data for the IDC from stations and/or NDCs. It also distributes raw IMS data and IDC products to treaty signatory countries.

Data Storage at the US NDC

All seismic, infrasonic and hydroacoustic data and reports received at the US NDC are archived to disk and remain online indefinitely. Distribution of seismic data to the public is accomplished through the Incorporated Research Institutions for Seismology (IRIS).