Southern California Permanent GPS Geodetic Array

Error analysis of daily position estimates and site velocities

Jie Zhang, Yehuda Bock, Hadley Johnson, Peng Fang, Simon Williams, Joachim Genrich, Shimon Wdowinski, Jeff Behr

Research output: Contribution to journalArticle

323 Citations (Scopus)

Abstract

We analyze time series of daily positions estimated from data collected by 10 continuously monitoring Global Positioning System (GPS) sites in southern California during the 19-month period between the June 28, 1992 (Mw=7.3), Landers and January 17, 1994 (Mw=6.7), Northridge earthquakes. Each time series exhibits a linear tectonic signal and significant colored noise. Spectral power at frequencies in the range 5 yr-1 to 0.5 d-1 is dominated by white noise or possibly fractal white noise and is several orders of magnitude higher than what would be expected from random walk noise (in this short-period range) attributed by others to geodetic monument motions. Estimating a single slope for the time series' power spectra suggests fractal white noise processes with spectral indices of about 0.4. Site velocity uncertainties assuming this fractal white noise model are 2-4 times larger than uncertainties obtained assuming a purely white noise model. A combination white noise plus flicker noise (spectral index of 1) model also fits the data and suggests that the velocity uncertainties should be 3-6 times larger than for the white noise model. We cannot adequately distinguish between these two noise models, nor can we rule out the possibility of a random walk signal at the lowest frequencies; these questions await the analysis of longer time series. In any case, reducing the magnitude of low-frequency colored noise is critical and appears to be best accomplished by building sites with deeply anchored and braced monuments. Otherwise, rate uncertainties estimated from continuous GPS measurements may not be improved significantly compared to those estimated from infrequent campaign-mode measurements.

Original languageEnglish (US)
Pages (from-to)18035-18055
Number of pages21
JournalJournal of Geophysical Research C: Oceans
Volume102
Issue numberB8
StatePublished - Aug 10 1997
Externally publishedYes

Fingerprint

Southern California
white noise
Global Positioning System
error analysis
Error analysis
Global positioning system
GPS
Time series
Fractals
estimates
time series
fractals
monument
random walk
Tectonics
Power spectrum
low frequencies
Earthquakes
flicker
Uncertainty

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Earth and Planetary Sciences (miscellaneous)
  • Atmospheric Science
  • Geochemistry and Petrology
  • Geophysics
  • Oceanography
  • Space and Planetary Science
  • Environmental Science(all)
  • Astronomy and Astrophysics

Cite this

Zhang, J., Bock, Y., Johnson, H., Fang, P., Williams, S., Genrich, J., ... Behr, J. (1997). Southern California Permanent GPS Geodetic Array: Error analysis of daily position estimates and site velocities. Journal of Geophysical Research C: Oceans, 102(B8), 18035-18055.

Southern California Permanent GPS Geodetic Array : Error analysis of daily position estimates and site velocities. / Zhang, Jie; Bock, Yehuda; Johnson, Hadley; Fang, Peng; Williams, Simon; Genrich, Joachim; Wdowinski, Shimon; Behr, Jeff.

In: Journal of Geophysical Research C: Oceans, Vol. 102, No. B8, 10.08.1997, p. 18035-18055.

Research output: Contribution to journalArticle

Zhang, J, Bock, Y, Johnson, H, Fang, P, Williams, S, Genrich, J, Wdowinski, S & Behr, J 1997, 'Southern California Permanent GPS Geodetic Array: Error analysis of daily position estimates and site velocities', Journal of Geophysical Research C: Oceans, vol. 102, no. B8, pp. 18035-18055.
Zhang, Jie ; Bock, Yehuda ; Johnson, Hadley ; Fang, Peng ; Williams, Simon ; Genrich, Joachim ; Wdowinski, Shimon ; Behr, Jeff. / Southern California Permanent GPS Geodetic Array : Error analysis of daily position estimates and site velocities. In: Journal of Geophysical Research C: Oceans. 1997 ; Vol. 102, No. B8. pp. 18035-18055.
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