Seismological Research Requirements for a Comprehensive Test-Ban Monitoring System (1995) / Chapter Skim
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4 DISTRIBUTION OF ISMS DATA WITHIN THE UNITED STATES
4 DISTRIBUTION OF ISMS DATA WITHIN THE UNITED STATES
Pages 33-52
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From page 33... ...
We consider the mechanisms and infrastructure required for providing broad access to the ISMS seismic data for multiple-use applications, including nuclear test monitoring, earthquake monitoring, and research efforts that support these monitoring functions. The design of the CTBT monitoring system has significant implications for the future of nuclear monitoring in the United States and for the structure of seismic monitoring and research on a wide variety of topics of vital interest to the United States.
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From page 34... ...
The seismic data used for past and present nuclear monitoring purposes, many of which are now unclassified, are not accessible for scientific research and thus fail to achieve their maximum impact in both the nuclear monitoring and earthquake monitoring communities. The pane!
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From page 35... ...
, which collects, archives, and distributes seismic data from a global array of permanent stations, temporary regional networks, and portable instrumentation. IRIS has also received funding through the DOD explicitly for data acquisition and research related to nuclear monitoring efforts.
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From page 36... ...
Modeling broadband seismograms identifies characteristics of earth structure, like the heterogeneity of the crust, that influence the signals from a surreptitious nuclear test. For seismograms recorded at regional distances of from ~ 00-1,200 km, which involve complex reverberations in the shallow crust, the relative amplitudes of different arrivals as a function of frequency are among the strongest diagnostics of the source type (e.g., OTA, ~ 9881.
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From page 37... ...
This has prompted the development of the fRIS-DMS archive of continuous broadband seismic data, which has the ability to service individually tailored data requests. With the role that frequency dependence of waveform energy and path effects play in discriminating nuclear explosion signals from quarry blasts and earthquakes, availability of archives of waveforms from previous regional events is also as critical for nuclear monitoring.
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From page 38... ...
In addition, the parameter data produced by the operations of the ISMS will be important for preparation of event bulletins, which is discussed next. Seismological Event Bulletins Both nuclear monitoring and earthquake monitoring involve the preparation of bulletins of events.
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From page 39... ...
to have a threshold detection capability in the magnitude Parke below 3 for parts of Eurasia and North America, above magnitude 3.4 in some continental areas of the southern hemisphere, and above magnitude 3.8 in parts of the southern oceans. From these detections, plus additional data that may be requested from auxiliary stations as deemed necessary to improve location estimates, the ISMS-IDC will obtain automated event locations that will be reviewed and, if necessary, corrected by an analyst.
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From page 40... ...
A comprehensive global seismicity bulletin that emphasizes completeness and accuracy of location rather than speed of publication would improve CTBT monitoring by: · providing location estimates generally superior to those of the REB, thus supporting evaluation of the REB and the preparation of guidance on how to improve it; · locating events not included in the REB, thus allowing an evaluation of the REB threshold in different regions; · providing an archive of accurate event locations useful for prompt interpretation of new seismic locations in the REB as they accumulate; · supporting special studies of seismicity in different regions of Earth that may be of CTBT concern; · improving our knowledge of earth structure and hence improving the accuracy of event location by the REB; and . aiding in regional characterization and in the resolution of ambiguous events.
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From page 41... ...
For CTBT monitoring purposes, information about quarry blasts is of great importance, and the REB will include many such sources. It will be a major task ofthe national verification activity to identify quarry blasts and to ensure that none of the explosions are nuclear tests.
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From page 42... ...
The combined user community should attempt to integrate all international seismic data acquisition, archiving, distribution, and bulletin preparation efforts in a way that benefits all of the potential users of seismic data and strengthens monitoring capabilities in both the short and Tong term. The pane} concludes that efficient integration of the ISMS and ISMS-NDC with existing facilities for earthquake monitoring and distribution of data to the seismic research community can provide benefits to the nuclear test and earthquake monitoring communities and to the research efforts that support them.
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From page 43... ...
This will require coordination between operators of the auxiliary stations and the nuclear monitoring community, which will be investing in these stations, to ensure that on-demand access is available and that the data satisfy the operational requirements for the auxiliary network. Historically, many ofthe seismic data collected by the United States for nuclear monitoring have not been accessible to the scientific community, even though the data were unclassified.
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From page 44... ...
The pane! recommends that the ·SMS and nuclear monitoring communities adopt a clear commitment to provide ready access to all seismic data collected by the ·SMS, and that language to this effect be inserted into the Protocol to the Tread The ISMS-IDC will provide to the I:SMS-NDCs data that will directly service national nuclear monitoring applications and other activities.
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From page 45... ...
In addition, there is concern that the responsibility for data distribution could be subordinated to the nuclear monitoring operations, making data access difficult in practice. Procedures for minimizing the data distribution burden of the TSMS-NDC are discussed in the next section.
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From page 46... ...
These will involve an international process associated with the treaty negotiation itself, a national process, different in each country, that defines the responsibilities of operational agencies (such as AFTAC and the USGS in the United States) , and a broader seismological context involving organizations doing seismology that have no formal responsibility to report to the ISMS or to the nuclear monitoring agency.
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From page 47... ...
Since the prototype ISMS-NDC explicitly involves interagency coordination between AFTAC and the USGS on data collection, it should be straightforward to coordinate on data distribution arid multiple utilization of ISMS data. The continuous three-component broadband data from the primary stations are certainly of interest to earthquake monitoring groups, such as the USGS and tsunami warning systems, near real-time access to selected stations is necessary for these earthquake monitoring applications.
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From page 48... ...
The pane! recommends that the U.S ISMS-NDC make the segmented auxiliary station broadband data that it acquires available in near real time to the earthquake monitoring agencies; the data should be archived at the IRIS-DMS Since many ofthe ISMS broadband stations are currently operated by members ofthe FDSN, which has data distribution agreements with IRIS, it should be politically straightforward to incorporate both the continuous primary and segmented auxiliary data from these stations into the {RIS-DMS.
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From page 49... ...
auxiliary stations should be shared by the nuclear monitoring, earthquake monitoring, and basic research agencies. The most technically and financially difficult data access issue involves the short-period primary array data, which have immense storage requirements and pose major challenges for maintaining a filthy accessible on-line database.
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From page 50... ...
Here the major concerns are to minimize impact on the nuclear monitoring function and to protect the security of classified data bases at the TSMS-NDC. Having the ISMS-NDC service multiple user requests for the array data would require extensive software development and would require seismic data users to become familiar with a new data access system (in addition to the {RIS-DMS, USGS, and university data centers)
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From page 51... ...
recommends that the seismic event parameter information (arrival times and /'ypocentral parametersJ and final bulletin from the ISMS be made available to the earthquake monitoring agencies rapidly via file ISMS-NDC. These parameter data should include event locations and phase information as well as other event parameters determined by the IDC.
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From page 52... ...
Such a structure will ensure that there is no deleterious effect on the nuclear monitoring operation while enabling optimal multiple use of the data. This integrated approach, involving open access to all unclassified seismic data, offers the first opportunity to work toward a rational U.S.
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