United States National Data Center

Overview

In an April 1994 letter, the Assistant Secretary of Defense for Atomic Energy (ASD/AE) assigned AFTAC the responsibility to develop and operate the US National Data Center (US NDC). These responsibilities were reaffirmed in a 22 May 1996 letter signed by the Air Force Chief of Staff. The US NDC will provide the US the capability to receive, process, archive, and report events of interest in monitoring the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The US NDC became officially operational on 17 December 1999 with Phase 1 of the US NDC processing system. The AFTAC Distributed Subsurface Network (ADSN) Data Acquisition System (DAS) and Data Acquisition Management (DAM) functions will be retained and integrated into the US NDC DAS. The Phase 1 US NDC has the ability to acquire, process, and archive continuous seismic and hydroacoustic data collected by sensors that are part of the USAEDS or US International Monitoring System (IMS) networks as well as acquire, archive, and store all continuous IMS station data. The US NDC currently serves as the data distribution point for all US government users and other authorized US users of IMS data, as designated by US National Authorities.

Seismic Network

AFTAC operates and maintains the current United States Atomic Energy Detection System (USAEDS) and installs additional seismic arrays to support national objectives. The US will also acquire additional US seismic stations through new seismic array installations and through the Comprehensive Nuclear-Test-Ban Treaty (CTBT). A major upgrade of all seismic systems will begin in 2001 and continue through 2005 with the installation of the Seismic Data Acquisition System (SDAS). Integration of Other USAEDS Techniques. The infrasound and radionuclide techniques will be part of the US NDC for monitoring and reporting purposes. These systems will provide data to and receive data from the US NDC. However, the processing of radionuclide data will be performed on systems managed independently of the US NDC.

Comprehensive Nuclear-Test-Ban Treaty (CTBT)

The US NDC also 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 will be composed of a worldwide network of monitoring stations that will 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 will be 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. The network, as planned, will consist of the following types and numbers of systems:

Primary Seismic: 50 stations, 5 of which will be US/IMS sites;
Auxiliary Seismic: 120 stations, 12 of which will be US/IMS sites;
Nuclear Debris Collection and Analysis: 80 stations, 11 of which will be US/IMS sites;
Hydroacoustic: 11 stations, 2 of which will be US/IMS sites;
Infrasound: 60 stations, 8 of which will be US/IMS sites.

The United States is involved not only through its planned 38 obligatory station commitment to the treaty, but through assistance to foreign stations in helping install and maintain stations through the IMS network. The figures below show the US involvement in treaty stations (both US contribution and bi-lateral agreements).

US INVOLVEMENT IN TREATY STATIONS

Primary Seismic 38%
19 of 50

Hydroacoustic 27%
3 of 11

Infrasound 13%
8 of 60

Radionuclide 13%
11 of 80

Auxiliary Seismic 10%
12 of 120

International Data Center (IDC)

The IDC will be the international repository for all treaty-monitored data. It will accept all data via a VSAT link through the GCI at the station, provide access to this data to all CTBT signatories, and provide services to all treaty signatories so they can fulfill their national verification functions. Data sent to the IDC will be collected, archived, processed, and provided to treaty signatories on a routine basis. The IDC will also serve as the communications hub for the international monitoring network.

Communications

The US NDC receives data by direct links through an independent communications network from individual stations worldwide. The US NDC also receives additional data directly from the IDC through the GCI link between the IDC and US NDC. The drawing below exemplifies the North American network as it feeds data into the Center. The GCI is the long haul communications system of the PTS. Its purpose is to retrieve IMS data for the IDC from stations and/or NDCs. It will also distribute raw IMS data and IDC products to States Parties.

Data Storage at the US NDC

IMS data recorded at the US NDC is kept on-line for 180 days. After 180 days, the IMS data is kept in off-line archives. All on-line IMS data are available for US customers for 180 days via AutoDRM (Automatic Data Request Manager). Special requests for older data can be sent to datamanager@aftac.gov

Future of the US NDC

As the US NDC matures, it will continue transitioning to a user-friendly environment that will ensure customer access to a wide variety of products. The status of seismic and hydroacoustic stations are currently available, with infrasonic and radionuclide stations to be added in the near future. The system is becoming more automated, with goals of self-monitoring and automatic switchover to redundant systems at a station. Future troubleshooting capabilities will allow worldwide access by technicians to technical manuals and the ability to access remote troubleshooting procedures. Phase 2 will consist of two major builds during FY01-04, each encompassing planned upgrades, enhancements, and tuning of software algorhithms. Beginning in the fourth quarter of FY02, the US NDC will be capable of handling and archiving data from the expanded seismic and hydroacoustic station network, and be able to incorporate infrasonic data. The US NDC will continue improving its cutting edge technology to provide customers with the most time-sensitive detailed products available in its efforts to support the national and international communities.

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