|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Department of Earth
Sciences
Carleton University
Ottawa, Ontario K1S 5B6, Canada
Is the random variability of ground motions for a single station less than that obtained by regression analyses of ground-motion data recorded over a broad network of sites? This question has important implications for seismic design of critical facilities because of the influence of this variability (commonly referred to as "sigma") on probabilistic seismic-hazard computations at low probabilities. I address this question using ShakeMap data recorded at a group of 21 stations, all in the Los Angeles region, for which the shear-wave velocity in the upper 30 m (V30) is known. Ground-motion prediction equations are derived from a database of site- corrected amplitudes compiled for the group of stations as a whole. The standard deviation of residuals (sigma) for the regression of the entire database is then compared with the standard deviation of residuals at individual stations. Regressions of single-station databases are also performed.
The sigma for an individual station is less than the overall sigma. The results of this study suggest that when computing hazard at a specific site for which the site amplification has been estimated based on either an empirical correction or on V30, the site sigma can be taken as 90% of the corresponding sigma for the applicable ground-motion prediction equation, if the problem under consideration is one of multiple earthquake sources. If hazard from a single source at a fixed azimuth is considered (such as a single fault), the site sigma is 60% of the corresponding sigma for regional ground-motion relations. Further study with additional datasets is warranted to determine whether these results apply to hazard computations in a general sense, beyond the limited range of conditions studied here.
This article has been cited by other articles:
|
|
 |
|
  P. L. Bragato Assessing Regional and Site-Dependent Variability of Ground Motions for ShakeMap Implementation in Italy Bulletin of the Seismological Society of America, October 1, 2009; 99(5): 2950 - 2960. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Beauval, L. Honore, and F. Courboulex Ground-Motion Variability and Implementation of a Probabilistic-Deterministic Hazard Method Bulletin of the Seismological Society of America, October 1, 2009; 99(5): 2992 - 3002. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Wang and T. Takada A Bayesian Framework for Prediction of Seismic Ground Motion Bulletin of the Seismological Society of America, August 1, 2009; 99(4): 2348 - 2364. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Bindi, L. Luzi, and F. Pacor Interevent and Interstation Variability Computed for the Italian Accelerometric Archive (ITACA) Bulletin of the Seismological Society of America, August 1, 2009; 99(4): 2471 - 2488. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. O. Strasser, N. A. Abrahamson, and J. J. Bommer Sigma: Issues, Insights, and Challenges Seismological Research Letters, January 1, 2009; 80(1): 40 - 56. [Full Text] [PDF]
|
|
|
|
|
|
P. L. Bragato Limits for the Improvement of Ground-Motion Relations in Europe and the Middle East by Accounting for Site Effects Bulletin of the Seismological Society of America, August 1, 2008; 98(4): 2061 - 2065. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Causse, F. Cotton, C. Cornou, and P.-Y. Bard Calibrating Median and Uncertainty Estimates for a Practical Use of Empirical Green's Functions Technique Bulletin of the Seismological Society of America, February 1, 2008; 98(1): 344 - 353. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Bommer and N. A. Abrahamson Why Do Modern Probabilistic Seismic-Hazard Analyses Often Lead to Increased Hazard Estimates? Bulletin of the Seismological Society of America, December 1, 2006; 96(6): 1967 - 1977. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
