HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Citation Map Services Email this article to a friend Related articles in Bulletin of the Seismological Society of America Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bommer, J. J. Articles by Abrahamson, N. A. Search for Related Content GeoRef GeoRef Citation

Reply to "Comment on ‘Why Do Modern Probabilistic Seismic-Hazard Analyses Often Lead to Increased Hazard Estimates?’ by Julian J. Bommer and Norman A. Abrahamson" by Zhenming Wang and Mai Zhou

Department of Civil and Environmental Engineering, Imperial College London, South Kensington campus, London SW7 2AZ, United Kingdom j.bommer@imperial.ac.uk

Norman A. Abrahamson

Geosciences Department, Pacific Gas and Electricity Co., San Francisco, CA 94177

The first 20% of the full text of this article appears below.

As with previous discussions submitted by the lead author of this comment (Wang, 2005), Wang and Zhou (2007) are not really commenting directly on the contents of our review article (Bommer and Abrahamson, 2006) but are using the opportunity to present a fundamental objection to probabilistic seismic-hazard analysis (PSHA). However, because the objective of our article was to clarify a fundamental aspect of PSHA that is frequently handled incorrectly in current practice, we welcome the opportunity to also respond to the arguments put forward in this comment. These arguments against the basic formulation of PSHA are likely to appear in print somewhere at some point, and we believe it is useful to explain why they are erroneous.

Before addressing the core argument of Wang and Zhou (2007), it may be useful to clarify the issue of the dependence of the ground-motion variability on magnitude and distance. Most ground-motion prediction (attenuation) equations produced up until about 10 years ago modeled the variability as being homoscedastic, which simply means that the standard deviation () of the lognormal residuals is constant for all values of magnitude and distance. The variation of with magnitude—called heteroscedastic variability—is discussed by Youngs et al. (1995) and has been found in many strong-motion prediction equations (e.g., Abrahamson and Silva, 1997; Campbell, 1997; Campbell and Bozorgnia, 2003; Ambraseys et al., 2005; Akkar and Bommer, 2007a). Whether or not the apparent dependence of on magnitude is genuine or an . . . [Full Text of this Article]

Related articles in Bulletin of the Seismological Society of America:

Why Do Modern Probabilistic Seismic-Hazard Analyses Often Lead to Increased Hazard Estimates?

Julian J. Bommer and Norman A. Abrahamson
Bulletin of the Seismological Society of America 2006 96: 1967-1977. [Abstract] [Full Text]  

Comment on "Why Do Modern Probabilistic Seismic-Hazard Analyses Often Lead to Increased Hazard Estimates?" by Julian J. Bommer and Norman A. Abrahamson

Zhenming Wang and Mai Zhou
Bulletin of the Seismological Society of America 2007 97: 2212-2214. [Extract] [Full Text]