Assessing the Nation's Earthquakes The Health and Future of Regional Seismograph Networks (1990) / Chapter Skim
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3. Problems and Constraints
3. Problems and Constraints
Pages 17-24
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From page 17... ...
Many powerful new analytical techniques, developed over the last 10-20 years, require higher-quality data than current regional networks can supply. An overwhelming majority of the more than 1,500 stations in existing regional seismic networks consist of short-period, vertical seismometers that were developed and installed one to two decades ago.
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From page 18... ...
Thus, the instrumentation of regional seismic networks, while 'relatively inexpensive in initial cost per station, ultimately has penalized regional networks in terms of missed research opportunities. Unfortunately, the relatively unsophisticated instrumentation has served to isolate regional network operations from the forefront of the seismological community, which relies on the advanced technology of relatively few stations for state-of-theart analyses.
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From page 19... ...
Dynamic range versus frequency for a typical station of a regional seismic network and a typical strong motion compared with the expected levels of ground motion (acceleration) for seismic waves from earthquakes of differing size and distance (from Heaton et al., 1989~.
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From page 20... ...
Seismologists are not experienced accountants, and hidden expenses such as the cost of facilities, complete personnel costs, benefits, and separately paid telemetry or computer maintenance charges may be unintentionally neglected. Despite their recognized shortcomings, surveys of network operators remain the best source of information about true costs at the individual network level.
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From page 21... ...
Where a network operator has distinguished between the numbers of stations operated and recorded, Figure 4 shows both data points connected with a tie line. The two largest regional seismic networks in the United States are CALNET, a network of 327 stations operated by the USGS in central California (operational costs
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From page 22... ...
Except for two networks whose apparent annual cost is $600,000 or more, the remaining 18 networks characterized in Figure 4 seem to define a pattern marked by annual operational costs of approximately $200,000 to $400,000—despite having numbers of stations ranging from less than 20 to 123. Because capital costs for station hardware are not included in this analysis, the $200,000 to $400,000 cost range appears to reflect a fundamental threshold of operational costs for regional networks of moderate size.
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From page 23... ...
The example above readily shows why annual operational costs for a regional seismic network amount to hundreds of thousands of dollarswhether or not those costs are fully identified. Realistically higher salary levels, greater telemetry costs, greater costs for network maintenance in environments harsher than those in California, and other justifiable factors easily escalate the total costs.
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From page 24... ...
Regional seismic networks are fundamentally wide-area communication networks requiring complex electronics, all-weather remote field installations, telemetry systems for continuous data transmission, elaborate central-recording laboratories with dedicated computers and peripherals for recording and data processing, and welltrained scientists, technicians, and data analysts for efficient and productive operation. The returns for such an investment of manpower and resources have been amply demonstrated in Chapters 1 and 2, and additional benefits to science and society are explored in Chapter 4.
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