Seismological Research Letters; May/June 2007; v. 78; no. 3;
p. 369-374; DOI: 10.1785/gssrl.78.3.369
© 2007 Seismological Society of America
Use of ANSS Strong-Motion Data to Analyze Small Local Earthquakes
Kris L. Pankow,
James C. Pechmann, and
Walter J. Arabasz
University of Utah Seismograph Stations
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INTRODUCTION
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Advances in seismometry and recording systems have greatly increased the
range of signals that can be recorded by strong-motion instruments. This
increased range has practical implications for observational weak-motion
seismology, as we demonstrate in this study. Analog strong-motion instruments,
the most common type in use until the 1990s, had an effective bandwidth from
0.1–0.2 Hz to 25–50 Hz and a dynamic range of 40 to 60 dB
(Heaton et al. 1989;
Trifunac and Todorovska 2001).
By contrast, modern 16- and 24-bit digital strong-motion instruments have
bandwidths from DC to 80 Hz (at 200 sps) and a dynamic range of 90 to 135 dB
(Trifunac and Todorovska
2001).
Another advance in strong-motion instrumentation during the past decade or
so has been the development of recorders that can support continuous digital
telemetry of the data. Historically, strong-motion data have been recorded
on-site in a triggered mode. The triggers usually are set to record
potentially damaging ground motions from moderate to large (M > 4)
local earthquakes. These data are used mostly by engineers for structural
design and by seismologists for modeling fault rupture histories. The
continuous telemetry of strong-motion data has been driven primarily by the
need for reliable near-real-time information on potentially damaging ground
shaking (Kanamori et al.
1997). Fortunately, the continuous telemetry also enables the
recording of smaller signals that normally would not trigger the strong-motion
instruments, which means that the full range of signals recorded by the modern
accelerometers and digitizers can be investigated.
With the deployment of the Advanced National Seismic System (ANSS;
USGS 1999) beginning in the
year 2000, the number of modern continuously telemetered strong-motion
instruments throughout the United States has increased greatly. Before ANSS,
the only dense network of such instruments in the United States was . . . [Full Text of this Article]
University of Utah Seismograph Stations
135 South 1460 East, Room 705
Salt Lake City, Utah 84112-0111 USA
pankow@seis.utah.edu
(K. L. P.)
pechmann@seis.utah.edu
(J. C. P.)
arabasz@seis.utah.edu
(W. J. A.)
Copyright © 2009 by Seismological Society of America