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APPENDIX A GLOBAL NETWORK DATA A-l Map showing distribution of WHSSN stations. A-2 Map showing distribution of GDSN, IDA, and RSTN stations. A-3 WWSSN data services. A-4 Objectives and funding options in Earthquake Prediction and Hazard Mitigation: Options for USGS and NSF Programs (NSF l976), under the Global Seismology Sub-Element of the Fundamental Earthquake Studies Element. A-5 Funding history for Global Seismology Branch, USGS. Total funds include, in addition to direct program funds, funding received from other agencies and program elements. FY l983 numbers are projected. A-6 Summary of global network options and possible consequences. A-7 Statement in support of analog WWSSN data. 3l

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34 EXHIBIT A-3 WWSSN data services. An essential part of the WWSSN from its inception was the microfilming of the original records and the provision of high-quality film copies. Since its beginning in l96l, more than 5 million original records have been copied and 60 million copies supplied to users. Currently, there are several hundred requests per year for seismogram microfilm. The network had an intended size of l25 stations and still operates with about ll0 stations. Originally, the seismograms were filmed on specially designed 70-mm panoramic cameras at 8X reduction. In l978 filming was changed to put 24 images (4 days of normal operation) on a single l05-mm microfiche at 32X reduction. Standing orders of the whole network have been provided to eight institutions (Lamont-Doherty Geophysical Observatory; Institute of Geological Sciences, Edinburgh, U.K.; University of Tokyo; California Institute of Technology; Massachusetts Institute of Technology; USGS/Menlo Park; USGS/Golden; NGSDC/CIRES), and substantial parts of the network have been supplied to five institutions (University of Texas/Galveston; Cornell University; University of Otago (New England); Los Alamos National Laboratory; USGS/Albuquerque). The network is augmented by copies of the visible records from the HGLP (l), ASRO (4), and SRO (l2) networks, from the Canadian network on 35-mm film since l966, from the People's Republic of China l7-station national network on 70-mm since l980, and for large- magnitude or seismologically important earthquakes from several hundred additional stations including those of the USSR under the International Data Exchange. The system is operating primarily with contract labor and with about 8 weeks being required for the cycle from receipt of original records to supplying copies to users. Fifty percent of the network data is generally available for distribution within 8 months after the recording interval. In general the archival film copy is made at NOAA expense with the cost of copy being borne by the user. Present costs to users are $0.80 per fiche, but this will undoubtedly increase as contract costs rise.

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35 EXHIBIT A-4 Objectives and funding options in Earthquake Prediction and Hazard Mitigation: Options for USGS and NSF Programs (NSF, l976), under the Global Seismology Sub-Element of the Fundamental Earthquake Studies Element. Global Seismology—Collect and disseminate seismological data from around the world. l. Operate the World-wide Standardized Seismograph Network (WWSSN) and reestablish a maintenance program for the stations that lapsed several years ago. 2. Operate the data acquisition and processing capability of the National Earthquake Information Service, including use of satellite telecommunications, issuance of new seismicity maps, and routine computation of the parameters of the earthquake mechanism. 3. Upgrade about half of the WWSSN and establish the capability to produce integrated tapes of digital seismic data. 4. Acquire and operate a ten-station array of transportable broadband seismographs for global seismic studies. 5. Operate an integrated digital network consisting of high-gain long-period stations, Seismological Research Observatories, and the upgraded WWSSN stations called for in activity 3, and produce integrated tapes of digital seismic data. 6. Acquire, install, and operate l0 ocean-bottom seismographs. Present and Proposed Funding Options Element: l. Fundamental Earthquake Studies Option A will allow a stable, minimally sufficient, operation of the WWSSN and operation of the data acquisition and processing capability of the National Earthquake Information Service (NEIS) in FY l978-l980, a very limited start in upgrading a few of the WWSSN stations in FY l979, and the incorporation of the

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36 FY 76 FY 77 FY l978 FY l979 FY l980 Sub Element Act. Req. a. The Earth- quake Process NSF l.l l.6 2.3 2.6 3.4 2.6 3.0 3.6 3.0 3.3 3.8 b. The Impli- cations of Plate Tectonics for Earth- quake Hazard Reduction NSF l.5 l.9 2.4 2.7 4.l 2.7 3.0 4.0 3.0 3.3 3.9 c. Global Seismology USGS l.9 l.7 2.3 2.6 3.2 2.5 3.l 3.6 3.4 3.6 4.0 TOTAL 4?5 iT2 TTo 7.9 l0.7 TTi 9.l ll.2 9.4 l0.2 ll.7 (Amounts are in millions of dollars) existing high-gain long-period stations and Seismic Research Observatories into an expanded WWSSN in FY l980. Option B will allow a partial reestablishment of the maintenance program that lapsed several years ago and the upgrading of about half of the WWSSN stations to produce integrated types of digital seismic data by the end of FY l980. Option C allows the acquisition and operation of a l0-station array of broadband seismographs for global seismic studies.

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38 EXHIBIT A-6 Summary of global network options and possible consequences. The following options are those considered by the USGS in its deliberations for the FY l983 budget, and offered to the Committee on Seismology for its comments and recommendations on behalf of the scientific community. They are an excellent example of the options that have been considered in recent years and that have given rise to this workshop: l. Terminate all USGS support for the WWSSN. It may be assumed with certainty that the network will cease to function if the USGS withdraws support. Most of the foreign stations are located in developing or under- developed countries that do not have the hard currencies needed to purchase operating supplies even though the annual costs of supplies are small. Even more important, all of the stations, whether they have adequate funding or not, depend upon the USGS Albuquerque Seismological Laboratory as the only source of replacement parts and components, which are no longer manufactured by private industry. Thus a decision to withdraw support would mean the demise of the WWSSN within l or 2 years. Of course, the data exchange, which is the purpose of the entire program, would end abruptly. 2. Seek support for the WWSSN from the stations and/or foreign governments. Based on past experience, we are not optimistic that such an appeal would produce results of substance. Many WWSSN stations continue to operate only because of traditional obligations to global seismic data exchange engendered by the network. However, it is doubtful that this goodwill will extend to sup- porting with their internal funds what in many cases is considered obsolete equipment in comparison with other, more modern stations serving their national needs. In this competition for funds, WWSSN stations are bound to deteriorate and finally terminate operations. Another concern is the apparent incongruity between the con- siderable funds being expended on the Digital WWSSN upgrade and other new programs and a plea on our part for several thousand dollars in support funds from a host country. Such a plea might also send out unintentional signals that the WWSSN has lost or is losing its importance to the worldwide seismological community.

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39 3. Terminate photographic supplies to all U.S. WWSSN stations. Termination of supplies to 2l U.S. stations would result in an annual saving of about $70,000. Although international obligations will be met, our national needs will not, since many U.S. stations will be forced to terminate operations. 4. Reduce trace spacing from l0 mm to 5 mm on all WWSSN long-period components. The reduction in requirements for photographic paper would result in an annual saving of about $75,000. Present fiche format is arranged to line up all six components for each day in one column for the ease of users. There would be a slight inconvenience to users in that in the new recording pitch long-period data would appear only in the first and third column. The degradation of data will in some instances be unacceptable to users. 5. Replace WWSSN photographic paper recording by rectilinear recording on heat sensitive paper. This change in the WWSSN recording medium would result in an annual saving of about $335,000. Operationally, the change would result in less losses due to developing errors and light intensity problems and in more uniform microfiche images. The total one-time cost for procurement and installation of heated pen assemblies would be about $l,400,000. 6. Eliminate WWSSN short-period horizontal recordings. The reduction in requirements for photographic paper would result in an annual saving of about $l00,000. Loss of short-period horizontal data would seriously curtail current studies of the earth's anisotropic properties and of the regional discrimination problem. 7. Terminate all USGS support for the GDSN. A capital investment of more than $l0,000,000 would be lost. An opportunity to establish a resource of great potential will be irrevocably lost to seismology for many years in the foreseeable future. Principal advantages of GDSN data are the wide dynamic range, bandwidth, resolution, and the ease and speed with which large amounts of data can be processed. Without these data it will not be possible quickly to test and verify recent and future advances in theoretical seismology by comparing synthetic waveforms and spectra against large volumes of high- quality digital data. The routine use of many digital processing techniques, until recently impeded by the lack of resolution in analog recording, will not be possible without digitally recorded data.

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40 8. Support a Global Seismograph Network (GSN) that combines the GDSN and WWSSN stations. Given this choice, three options are open to the USGS: (a) reduced support for the WHSSN in favor of the digital stations, (b) reduced support of the digital stations in favor of the analog stations, and (c) redirection of funds from other elements of the Earthquake Hazards Reduction Program within the USGS to the support of the global networks.

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4l EXHIBIT A-7 Statement in support of analog WWSSN data. The WWSSN has been by far the most productive general- purpose network of seismograph stations ever operated. The instruments now consist of moving coil pendulums coupled with recording galvanometers. Free periods are l and 0.75 s, respectively, for the short-period instru- ments and l5 and l00 s for the long-period. However, the cost of photographic paper to record three components of short-period and three components of long-period motion at some l00 stations amounts to about $300,000 annually. This expense can reasonably be questioned since the under- lying technology here is about 25 years old. Thus we see pressures for the option of reducing the analog WWSSN system. Let us examine the underlying WWSSN issues in three parts, the first two being amenable to scientific discussion and the last, more nebulous. Analog or Digital Recording? Digital recording will supplant analog. The present advantages of analog have largely to do with merits that can be maintained as the transfer to digital recording is accomplished. Thus digital now offers nothing like film chip distribution nor the archiving that is so easily done with analog. This last point is very serious. We have the example of LASA digital data—of which very little remain. In the year 2000 or beyond, let us imagine that we wish to look back on the previous decades and apply new theories as we study some of the seismic activity preceding a great Alaska earthquake that might have occurred in, say, l990. The archive will be essential. We should not underestimate the present advantages of well-written paper records. As one looks over the sheet, there is an enormous amount of detail in a compressed format contributing to a sense of where one is, with respect to noise levels, across a quite wide frequency band (for WWSSN long periods) and a substantial dynamic range. The trained eye can absorb this information rapidly. Although accepting the merits of properly written digital equivalents (absence of overlapping

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42 traces, lack of human error in digitizing, suitability for data analysis), there is a considerable loss in going from analog to digital facsimilies of LP WWSSN at one sample per second. Global Coverage There are now about l00 more stations in the WWSSN than in the GDSN. Many seismologists claim that without that extent of global coverage, we would go back into the dark ages of seismology. This point of view applies not only to those studying tectonics and regional problems, but also to those studying the upper 700 km of the mantle. The many structures proposed differ from one another because of the earth's lateral variability. The problems of inverting seismic data from too few stations have a history as long as that of the science itself. For many scientific purposes, the main pressure should be on expanding coverage rather than improving technology. Thus the many special problems associated with Alaska, and comparisons with the coverage by standard stations in Canada (about 34), indicate about six to eight more Alaskan stations are necessary. Work is required to improve South American stations. They sometimes do not submit data for days on which South American earthquakes occur. Of course, island stations in the world's oceans are critical. Work Habits of Analog Users, As Compared to Those of Digital Users This is the nonscientific part of the issue, but it must be addressed because opinions are strongly held. In many cases, seismology is not applied as a "stand alone" science. Rather, it has links to materials science, structural geology, gravity, heat flow, geo- magnetism, and remote sensing. Those scientists who wish to proceed on a broad front with data from various disciplines will typically not now make what they perceive to be a heavy investment in digital hardware (tape drives, plotting devices, etc.), nor take the time to master a digital facility if offered. This remark obviously does not apply to those close to discrimination/ verification problems, or to those in exploration/ prospecting. In those fields, a digital revolution has already been accomplished and is appropriate.

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43 For the broader view of seismology, consider a couple of examples. A recent review of geophysical and geologic evidence strongly suggests the Makran region of Pakistan and Iran is now an active subduction zone and probably has been during most of the Cenozoic. Oceanic portions of the Arabian plate currently subduct northward toward Eurasia with a relative motion of about 5 cm/year. The Makran region consists of a nearly complete trench-arc system; however, some of its tectonic features are somewhat atypical. For example, an abundant supply of sediments seems to lead to a shallow dip for the sub- ducted Arabian plate, and it does not permit a bathymetric trench to develop; the accretionary prism is very wide, and a large part of it is subaerially exposed rather than being submarine; only moderate seismicity occurs in the shallow-dipping thrust zone; at subcrustal depths the dipping seismic zone has a weak and sporadic expression to depths of only 80 km and is not documented at larger depths; the volcanic arc is poorly developed with large spacing (about l00 km) between its major Quaternary volcanic centers; the trench-volcano gap measures 500 +_ l00 km, more than twice the width of a typical trench- volcano gap. Despite these peculiarities, geologic, geophysical, and plate tectonic data suggest an active plate boundary with ongoing subduction beneath the Makran region. It is a rapidly accreting continental margin, large portions of which are still underlain by a mobile oceanic basement. This work in Asian tectonics, which made major uses of WWSSN data, would not in practice have reached the same insights if only the sparser GDSN data had been available. To say whether that is important or not is a value judgment. Consider another example: In the proceedings volume of the last Ewing Symposium—Earthquake Prediction, An International Review (American Geophysical Union, l98l), edited by David W. Simpson and Paul G. Richards—about one quarter of the papers used data coming in large part from the WWSSN. Furthermore, except in a couple of cases, the future research anticipated by these papers would still use such a data base. It is healthy that some seismologists are driven to diversity in the direction of other earth sciences, and some to diversity in the direction of signal-processing and information theory. The present merits of film-chip distribution are recognized by all seismologists, and something like this widespread distribution system for

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44 visible records should be maintained even with a digital data base. This is stated in Global Earthquake Monitoring (NRC, l977a, pages 3l, 42) and in the report of the Panel on Data Problems in Seismology (NRC, in preparation).