Sensitivity of PSHA results to ground motion prediction relations and logic-tree weights

Epistemic uncertainty in ground motion prediction relations is recognized as an important factor to be considered in probabilistic seismic hazard analysis (PSHA), together with the aleatory variability that is incorporated directly into the hazard calculations through integration across the log-normal scatter in the ground motion relations. The epistemic uncertainty, which is revealed by the differences in median values of ground motion parameters obtained from relations derived for different regions, is accounted for by the inclusion of two or more ground motion prediction relations in a logic-tree formalism. The sensitivity of the hazard results to the relative weights assigned to the branches of the logic-tree, is explored through hazard analyses for two sites in Europe, in areas of high and moderate seismicity, respectively. The analyses reveal a strong influence of the ground motion models on the results of PSHA, particularly for low annual exceedance frequencies (long return periods) and higher confidence levels. The results also show, however, that as soon as four or more relations are included in the logic-tree, the relative weights, unless strongly biased towards one or two relations, do not significantly affect the hazard. The selection of appropriate prediction relations to include in the analysis, therefore, has a greater impact than the expert judgment applied in assigning relative weights to the branches of the logic-tree.

[1]  John Douglas,et al.  How accurate can strong ground motion attenuation relations be , 2001 .

[2]  Conrad Lindholm,et al.  Long-period ground-motions for large European earthquakes, 1905–1992, and comparisons with stochastic predictions , 2003 .

[3]  Robert J. Budnitz,et al.  Recommendations for probabilistic seismic hazard analysis: Guidance on uncertainty and use of experts , 1997 .

[4]  J. Bommer,et al.  PREDICTION OF HORIZONTAL RESPONSE SPECTRA IN EUROPE , 1996 .

[5]  Matthew Free,et al.  SURFACE-WAVE MAGNITUDE CALIBRATION FOR EUROPEAN REGION EARTHQUAKES , 1997 .

[6]  J. Bommer,et al.  Style-of-Faulting in Ground-Motion Prediction Equations , 2003 .

[7]  Gail M. Atkinson,et al.  Some Comparisons Between Recent Ground- Motion Relations , 1997 .

[8]  Julian J. Bommer,et al.  Criteria for Selecting and Adjusting Ground-Motion Models for Specific Target Regions: Application to Central Europe and Rock Sites , 2006 .

[9]  S. Kramer.  Geotechnical Earthquake Engineering , 1996 .

[10]  N. Abrahamson,et al.  Empirical Response Spectral Attenuation Relations for Shallow Crustal Earthquakes , 1997 .

[11]  F. Cotton,et al.  NEW EMPIRICAL RESPONSE SPECTRAL ATTENUATION LAWS FOR MODERATE EUROPEAN EARTHQUAKES , 2003 .

[12]  W. B. Joyner,et al.  Equations for Estimating Horizontal Response Spectra and Peak Acceleration from Western North American Earthquakes: A Summary of Recent Work , 1997 .

[13]  N. Abrahamson,et al.  On the Use of Logic Trees for Ground-Motion Prediction Equations in Seismic-Hazard Analysis , 2005 .

[14]  N. Abrahamson,et al.  Magnitude-dependent variance of peak ground acceleration , 1995, Bulletin of the Seismological Society of America.

[15]  N. Abrahamson,et al.  Composite Ground-Motion Models and Logic Trees: Methodology, Sensitivities, and Uncertainties , 2005 .

[16]  C. Cornell.  Engineering seismic risk analysis , 1968 .

[17]  Fabrice Cotton,et al.  SEISMIC DESIGN REGULATION CODES: CONTRIBUTION OF K-NET DATA TO SITE EFFECT EVALUATION , 2001 .

[18]  F. Sabetta,et al.  Estimation of response spectra and simulation of nonstationary earthquake ground motions , 1996, Bulletin of the Seismological Society of America.

[19]  J. Douglas.  Earthquake ground motion estimation using strong-motion records: a review of equations for the estimation of peak ground acceleration and response spectral ordinates , 2003 .

[20]  K. Campbell.  PREDICTION OF STRONG GROUND MOTION USING THE HYBRID EMPIRICAL METHOD AND ITS USE IN THE DEVELOPMENT OF GROUND-MOTION (ATTENUATION) RELATIONS IN EASTERN NORTH AMERICA , 2003 .

[21]  F. Scherbaum,et al.  On the Use of Response Spectral-Reference Data for the Selection and Ranking of Ground-Motion Models for Seismic-Hazard Analysis in Regions of Moderate Seismicity: The Case of Rock Motion , 2004 .

[22]  Julian J. Bommer,et al.  The Challenge of Defining Upper Bounds on Earthquake Ground Motions , 2004 .

[23]  Y. Fukushima,et al.  Scaling relations for strong ground motion prediction models with M2 terms , 1996, Bulletin of the Seismological Society of America.

[24]  D. Wells,et al.  New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement , 1994, Bulletin of the Seismological Society of America.

[25]  F. Scherbaum,et al.  On the Conversion of Source-to-Site Distance Measures for Extended Earthquake Source Models , 2004 .

[26]  L. Reiter.  Earthquake Hazard Analysis: Issues and Insights , 1991 .

[27]  R. L. Wesson,et al.  USGS National Seismic Hazard Maps , 2000 .

[28]  G. R. Toro,et al.  Model of Strong Ground Motions from Earthquakes in Central and Eastern North America: Best Estimates and Uncertainties , 1997 .

[29]  David M. Boore,et al.  SEA99: A Revised Ground-Motion Prediction Relation for Use in Extensional Tectonic Regimes , 2005 .

[30]  Timothy J. Sullivan,et al.  Probabilistic Seismic Hazard Analyses for Ground Motions and Fault Displacement at Yucca Mountain, Nevada , 2001 .