Next Generation Attenuation (NGA) empirical ground motion models : Can they be used in Europe

We are one of five teams developing empirical ground motion models (attenuation relationships) for active shallow crustal regions as part of the PEER Next Generation Attenuation (NGA) Project. Each NGA Developer Team was provided with a common database of worldwide strongmotion recordings but used different data selection criteria, parameters, and functional forms in the development of their models. One of the biggest challenges was to develop a functional form that accounted for the apparent change in magnitude scaling around M 6.5–7.0 that was indicated by several recent large worldwide earthquakes. We selected a trilinear rather than the more traditional quadratic functional form for magnitude scaling to allow more flexibility in modeling magnitude-scaling effects between small and large earthquakes. Parameters included in the model are moment magnitude, closest distance to rupture, buried reverse faulting, normal faulting, sediment depth (both shallow and basin effects), hanging-wall effects, average shear-wave velocity in the top 30 m, and nonlinear soil response as a function of shear-wave velocity and rock PGA. A comparison of our NGA model with a recent attenuation relationship for Europe indicates that our model and likely the other NGA models can be used in this region. The largest discrepancies appear to be due to the use of linear magnitude scaling and linear site factors in the European model. More detailed evaluations will be needed to confirm this preliminary conclusion.

[1]  N. A. Abrahamson,et al.  A stable algorithm for regression analyses using the random effects model , 1992, Bulletin of the Seismological Society of America.

[2]  W. B. Joyner,et al.  ESTIMATION OF RESPONSE SPECTRA AND PEAK ACCELERATIONS FROM WESTERN NORTH AMERICAN EARTHQUAKES: AN INTERIM REPORT PART 2 , 1993 .

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

[4]  Kenneth W. Campbell,et al.  Empirical Near-Source Attenuation Relationships for Horizontal and Vertical Components of Peak Ground Acceleration, Peak Ground Velocity, and Pseudo-Absolute Acceleration Response Spectra , 1997 .

[5]  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 .

[6]  K. Campbell,et al.  Updated Near-Source Ground-Motion (Attenuation) Relations for the Horizontal and Vertical Components of Peak Ground Acceleration and Acceleration Response Spectra , 2003 .

[7]  James N. Brune,et al.  Precarious Rock and Overturned Transformer Evidence for Ground Shaking in the Ms 7.7 Kern County Earthquake: An Analog for Disastrous Shaking from a Major Thrust Fault in the Los Angeles Basin , 2004 .

[8]  J. Douglas,et al.  Equations for the Estimation of Strong Ground Motions from Shallow Crustal Earthquakes Using Data from Europe and the Middle East: Horizontal Peak Ground Acceleration and Spectral Acceleration , 2005 .

[9]  Maurice S. Power,et al.  An Overview of the NGA Project , 2008 .