OPINION - Seismological Research Letters

OPINION
Do Regional Seismic Networks in the U.S. Have a
Future
In October 1997, the U.S. Congress charged the Director of
the U.S. Geological Survey to "provide for an assessment of
regional seismic monitoring networks in the United States"
under Public Law 105-47. While a report is being duly prepared
by the USGS, with broad
input from the seismological com-
munity, some critics may ask, "Do
regional seismic networks (RSN's)
really have a future Or are they just
a dying branch on the evolutionary
tree of observational seismology
Should they functionally be superseded,
say, by a combination of
widely spaced, super-quality broadband
stations and temporary dense
arrays Or organizationally by a
national information outlet" (Few,
if any, would seriously apply these
questions to California, but bear
with me as I attempt a national overview.)
I believe that RSN's are vital elements both for building
a next-generation national seismic system and for directly
serving the 75 million people, including 46 million outside
of California, who live in metropolitan areas in the U.S. at
moderate to high earthquake risk (data from A Plan far
Implementing a Real-time Seismic Hazard Warning System, A
Report to Congress Required by Public Law 105-47, U.S. Geological
Survey, March 1998, Table 1; note that the column
total there is in error). Further, I believe RSN's have a key
role to play in advancing the science of earthquakes.
The RSN's to which I am referring operate continuously
on a scale of hundreds of kilometers in seismically active
parts of the U.S., are generally operated by government
agencies or universities, and have a multipurpose mission
that relates to "earthquake monitoring and rapid emergency
response; scientific research; and the acquisition of information
required for earthquake hazard and risk analyses as well
as for earthquake engineering" (Assessing the Nation's Earthquakes,
National Research Council, 1990). Approximately
two dozen RSN's in the U.S. fit this definition. From a
recent survey by the Council of the National Seismic System
(see http://www.cnss.org/NETS), such RSN's now operate
about 90 percent of an estimated 1,776 stations in the U.S.
with conventional weak-motion seismic instruments
(roughly t ,400 short-period and 150 broad-band) and about
I believe that RSN's are vital
elements both for building a
next-generation national seismic
system and for directly serving
the 75 million people, including
46 million outside of California,
who live in metropolitan areas in
the U.S. at moderate to high
earthquake risk ....
15 percent of the nation's 1,388 stations with strong-motion
recorders.
For clarification, my use of the term RSN's includes both
their physical infrastructure and the organizations that operate
them. The infrastructure, in the form of regional elements
of an evolving national seismic system, provides essential
long-term focus on discrete seismically active parts of the
nation. The network operators provide
sustained attention to problems
of regional and local importance,
and their centers serve as "direct outlets
for public information and for
expert assistance to public policy
makers, planners, designers, and
safety officials" (National Seismic System
Science Plan, U.S. Geol. Survey
Circular 1031, 1989). Often overlooked
is the important role RSN's
play in the graduate education and
training of this country's earthquake
seismologists.
The history of RSN's in the
U.S. can straightforwardly be traced from a proto-Southern
California seismic network of Wood-Anderson seismographs
in the 1920's to the telemetered networks of chiefly shortperiod
instruments that grew significantly in the 1960's and
1970's. The original scientific motivation was clear--systematically
to record and study local earthquakes over broad
regions. By the 1980's, the view of RSN's was that their general
role was "to delineate the time and space distribution of
earthquakes on a fine enough scale to contribute to our scientific
understanding of earthquake occurrence and related
tectonic processes and to provide important baseline data for
engineering investigations ..." (Seismograph Networks: Problems
and Outlook far the 1980'S, National Research Council,
1983).
Through the 1960's and 1970's, RSN's were a logical
extension of observatory seismology, notably in university
settings where there was a rich tradition of seismological science.
By 1980 it was evident to all that advances in seismology
demanded new digital instrumentation for earthquake
science. The university community grasped a unique opportunity
to move forward in 1984 in forming the Incorporated
Research Institutions for Seismology (IRIS). But a fateful
decision was made purposely to exclude RSN's as a program
component as IRIS set out to promote "a national focus for
the development, deployment, and support of modern digital
seismic instrumentation"--for a global seismographic
Seismological Research Letters Volume 69, Number6 November/December 1998 513

network and for array seismic studies of the continental
lithosphere.
One legacy of this action, which still affects earthquake
seismology in the U.S., is the dynamics of what can be called
an IRIS-NSF arena vis-a-vis a USGS-NEHRP arena, In
1984, university RSN'S were left squarely in the latter, and
the majority of them became doubly disadvantaged, first by
years of no-growth or reduced NEHRP funding and second
by NSF program directions and influences on funding that
(a) effectively handicapped attempts by RSN researchers to
get NSF grants for network-related science and (b) generally
precluded help to RSN'S from NSF in improving instrumentation.
Since the mid-1980's, RSN's
have been seriously strained to meet
the simultaneous challenges of modernization
(if not sheer survival),
increased expectations to meet practical
user needs for public safety and
earthquake loss reduction, delivery
of all data into an open information
system for community use, and scientific
research. Present support for
university network seismologists to
perform many basic RSN functions
depends unstably on competition
for research funding, separate from
operational funding. Some may reason
that Darwinian survival of
RSN's is appropriate, but this begs the question of how the
real needs of populations at risk in the affected regions are to
be met. (Recall the 46 million outside of California.)
H. Rishbeth and others, writing in a 1993 article in Eos
on long-term solar-terrestrial monitoring, wrote: "Monitoring
programs are often undervalued because of a false view
that they have little to do with innovative research. In reality,
the data derived from long-term monitoring operations
often add to new scientific results and underpin other
research." In a related vein, R. L. Vogel observed in a recent
1998 issue of Eos that "making data available for interdisciplinary
or future uses has not traditionally been a valued
activity in the scientific community." He goes on to say,
"The information revolution is causing the values of the scientific
community to be assessed." In the July/August 1998
issue of SeisrnologicalResearch Letters, Lowell Whiteside made
the point that "It]he history of science shows that great
breakthroughs occur when new tools are combined with
available data and innovative scientific thinking." What data
will be valuable fifty years from now Fundamental data for
advancing the science of earthquakes surely must include
continuous temporal monitoring of key source zones from
the microearthquake level (below magnitude 3) to the level
of strong motion. Continuity of data, which may become
critical to earthquake forecasting or prediction, cannot be
provided by temporary dense arrays. And widely spaced
broad-band stations cannot yield either a sufficiently low
magnitude threshold of space-time sampling or data needed
Decades of struggling to establish
stable support for national and
regional seismic monitoring, as
well as strong-motion recording,
could be decisively resolved by
persuading Congress to recognize
the fundamental importance of a
national seismic system and to
finance it under a line-item
appropriation.
514 Seismological Research Letters Volume 69, Number6 November/December1998
for advancing our understanding of main-shock ground
motions in extensional and intraplate regions.
The importance of continuously monitoring specific
seismic source zones in detail sensibly varies according to
hazard and risk, but balanced nationwide attention is essential
because risk is markedly increasing in many regions.
Consider Utah's densely populated Wasatch Front area,
where more than three quarters of the state's population and
economy literally sits astride the most active segments of the
Wasatch Fault. Population in this dramatically growing megalopolis
is projected to increase from a 1995 base of 1.6 million
to 2.7 million by 2020 and to 5 million by 2050. Many
other areas warrant similar concern,
such as San Juan, Puerto Rico, and
Las Vegas, Nevada, the fastest growing
metropolis in the U.S.
My experience tells me that--
like politics and history--earthquake
problems are ultimately
"local", and the social dynamics
vary widely. How user needs are
defined and served in California
may not be a desirable or cost-effective
model for Alaska, Montana, or
New England. RSN's have played an
important role historically, especially
in regions of moderate to low
seismicity, in creating public awareness
of earthquake dangers and in marshaling much of the
relevant information to deal with those dangers. This special
attunement to region-specific earthquake problems and
social dynamics leads me to believe that RSN's have a unique
potential in the seismological community to meet long-term
user needs, on a region-by-region basis, for earthquake data,
information (what users want or need to know), and related
services. Anyone who has ever worked in a regional network
center understands that RSN's are where "the rubber hits the
road" when it comes to "societally relevant" earthquake seismology.
Where do we go from here I see at least three possibilities
for major progress in dealing with the issues I have
raised: (1) creation of a next-generation national seismic system,
(2) securing congressional line-item funding for ongoing
operation of such a system, and (3) promoting better
synergy between the USGS-NEHRP arena and the IRIS-
NSF arena.
Since 1993 there has been clear progress in creating
what I will call a first-generation national seismic system by
integrating RSN's with the U.S. National Seismograph Network.
This system is inherently cooperative, muhijurisdictional,
and with resources unevenly spread. In my view, the
challenge is to take a systems engineering approach to create
the physical and informational infrastructure of a new technologically
advanced national seismic system, consisting of
national, regional, and local elements. The process now
underway of writing the report to Congress on seismic mon-

itoring in the U.S. that I referred to in my first paragraph has
brought seismologists and earthquake engineers together in
an unprecedented way to create a vision of such a next-generation
national seismic system. The vision combines integrated
seismographic monitoring on national, regional, and
local scales with strong-motion recording and structuralresponse
monitoring focused on urban areas at risk. It
emphasizes services and information products, including
rapid and timely information for emergency management.
The evolution of real-time earthquake information systems
and the great practical value of rapidly broadcasting maps of
actual ground shaking have created a powerful new flamework
for unifying strong- and weak-motion recording for
emergency management, engineering, and science.
In the report Assessing the Nation's Earthquakes (National
Research Council, 1990), the foremost recommendation was
that "[t]he federal government should establish a more rational,
coordinated, and stable means of support for the seismic
networks of the United States .... "The most effective way to
do this, it seems to me, would be through congressional lineitem
funding for a national seismic system of the type
described above. For decades, the existence of infrastructure
for fine-scale regional monitoring in the U.S. has depended
on the sacrifices and career-long dedication of key individuals.
I do not think this framework is sustainable. Nor do I
think this burden should be perpetuated for future generations
of seismologists. Decades of struggling to establish stable
support for national and regional seismic monitoring, as
well as strong-motion recording, could be decisively resolved
by persuading Congress to recognize the fundamental
importance of a national seismic system and to finance it
under a line-item appropriation.
Finally, what about synergy between the USGS-
NEHRP and IRIS-NSF arenas The seismological commu-
nity is not immune from internal tensions, some of which
are implicit, for example, in Tom Jordan's opinion piece in
the January/February 1997 issue of Seismological Research
Letters, in which he took a balanced look at the value of both
applied and basic science in the study of earthquakes. Perhaps
a timely lesson can be drawn from well known observations
of hemispheric differences--and conflicts--in the
human brain. We know that both sides of the brain process
the same information in different ways, that they are motivated
differently, and that one side tends to seek dominance
and inhibit the other. In art and writing, the solution to dealing
with these tensions between the left-brain and rightbrain
lies in recognizing the special capabilities of each side
and in finessing a complementary division of labor. (See, for
example, Gabriele Lusser Rico's book, Writing the Natural
ItPhy, or Betty Edwards' classic text on Drawing on the Right
Side of the Brain.) In helping the nation deal with its earthquake
problems, are there special capabilities on each side
and possibilities for a complementary division of labor
between the USGS-NEHRP arena and the IRIS-NSF arena
I think any outside observer can readily see them. Can we
Peter Bowen, a contemporary Montana writer,
observed: "The cowboy won't ever be replaced--no mere
machine could ever stand the abuse." Will RSN's be
replaced Part of me rushes to say, "Not soon--for the same
reason as cowboys." Another part of me, seeing the vision of
an evolving national seismic system, adds, "No, RSN's have
a unique role to play--and better things are coming." El
Walter A rabasz
Department of Geology and Geophysics
University of Utah
arabasz@seis.utah.edu
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