Seismographic Networks Problems and Outlook for the 1980s: Report (1983) / Chapter Skim
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APPENDIX A: GLOBAL NETWORK DATA
APPENDIX A: GLOBAL NETWORK DATA
Pages 31-44
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From page 31... ...
, under the Global Seismology Sub-Element of the Fundamental Earthquake Studies Element. A-5 Funding history for Global Seismology Branch, USGS.
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From page 33... ...
33 C o it)
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From page 34... ...
, 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 largemagnitude or seismologically important earthquakes from several hundred additional stations including those of the USSR under the International Data Exchange.
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From page 35... ...
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)
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From page 36... ...
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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From page 37... |
From page 38... ...
Another concern is the apparent incongruity between the considerable 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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From page 39... ...
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 highquality digital data.
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From page 40... ...
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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From page 41... ...
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)
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From page 42... ...
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.
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From page 43... ...
For example, an abundant supply of sediments seems to lead to a shallow dip for the subducted 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 trenchvolcano gap.
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From page 44... ...
44 visible records should be maintained even with a digital data base. This is stated in Global Earthquake Monitoring (NRC, l977a, pages 3l, 42)
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