Influence of site response and focal mechanism on the performance of peak ground motion prediction equations for the Greek region

2019 ◽  
Vol 125 ◽  
pp. 105745 ◽  
Author(s):  
Vincenzo Del Gaudio ◽  
Pierpaolo Pierri ◽  
Konstantinos Chousianitis
Author(s):  
Linda Al Atik ◽  
Norman Abrahamson

ABSTRACT Site response in ground-motion prediction equations (GMPEs) is primarily characterized as a function of the time-averaged shear-wave velocity over the top 30 m of the site profile (VS30). Although the use of VS30 as a main site-response predictor parameter is practical, GMPE site adjustments to different target regions or target site conditions require characterization of the GMPE’s rock-site response in terms of host VS profile and host kappa. Regional VS profiles and kappa values have been traditionally used to characterize GMPEs host site conditions. These regional site properties may not reflect the average site response in GMPEs. We present a methodology, based on the quarter-wavelength principles, that allows the derivation of GMPE-compatible host 1D VS profiles and kappa values. This methodology is applied to the Next Generation Attenuation-West2 (NGA-West2) GMPEs to derive GMPE-specific host VS profiles and kappa for western United States (WUS) site conditions with VS30 of 360, 490, 620, 760, and 1100 m/s. This application uses, for input, the GMPEs’ site response in Fourier amplitude spectra domain relative to a reference VS30 of 1000 m/s and requires an assigned VS profile for the reference site condition. The impact of the choice of reference VS profile on the results is not large. Comparisons of the derived GMPE-specific VS profiles for VS30 of 760 m/s show differences in the host VS profiles among the NGA-West2 GMPEs for the same site condition in WUS. Differences are also observed when comparing the derived GMPE-compatible VS profiles with the commonly used profiles for WUS for VS30 of 760 m/s. These differences highlight the importance of using GMPE-compatible VS profiles and kappa in GMPE adjustments and in site-response analyses. Limitations of this approach for soft site conditions are discussed.


IEEE Access ◽  
2017 ◽  
Vol 5 ◽  
pp. 23920-23937
Author(s):  
M. S. Liew ◽  
Kamaluddeen Usman Danyaro ◽  
Mazlina Mohamad ◽  
Lim Eu Shawn ◽  
Aziz Aulov

2021 ◽  
pp. 875529302110039
Author(s):  
Filippos Filippitzis ◽  
Monica D Kohler ◽  
Thomas H Heaton ◽  
Robert W Graves ◽  
Robert W Clayton ◽  
...  

We study ground-motion response in urban Los Angeles during the two largest events (M7.1 and M6.4) of the 2019 Ridgecrest earthquake sequence using recordings from multiple regional seismic networks as well as a subset of 350 stations from the much denser Community Seismic Network. In the first part of our study, we examine the observed response spectral (pseudo) accelerations for a selection of periods of engineering significance (1, 3, 6, and 8 s). Significant ground-motion amplification is present and reproducible between the two events. For the longer periods, coherent spectral acceleration patterns are visible throughout the Los Angeles Basin, while for the shorter periods, the motions are less spatially coherent. However, coherence is still observable at smaller length scales due to the high spatial density of the measurements. Examining possible correlations of the computed response spectral accelerations with basement depth and Vs30, we find the correlations to be stronger for the longer periods. In the second part of the study, we test the performance of two state-of-the-art methods for estimating ground motions for the largest event of the Ridgecrest earthquake sequence, namely three-dimensional (3D) finite-difference simulations and ground motion prediction equations. For the simulations, we are interested in the performance of the two Southern California Earthquake Center 3D community velocity models (CVM-S and CVM-H). For the ground motion prediction equations, we consider four of the 2014 Next Generation Attenuation-West2 Project equations. For some cases, the methods match the observations reasonably well; however, neither approach is able to reproduce the specific locations of the maximum response spectral accelerations or match the details of the observed amplification patterns.


2015 ◽  
Vol 31 (1) ◽  
pp. 19-45 ◽  
Author(s):  
Jonathan P. Stewart ◽  
John Douglas ◽  
Mohammad Javanbarg ◽  
Yousef Bozorgnia ◽  
Norman A. Abrahamson ◽  
...  

Ground motion prediction equations (GMPEs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. From many available GMPEs, we select those models recommended for use in seismic hazard assessments in the Global Earthquake Model. We present a GMPE selection procedure that evaluates multidimensional ground motion trends (e.g., with respect to magnitude, distance, and structural period), examines functional forms, and evaluates published quantitative tests of GMPE performance against independent data. Our recommendations include: four models, based principally on simulations, for stable continental regions; three empirical models for interface and in-slab subduction zone events; and three empirical models for active shallow crustal regions. To approximately incorporate epistemic uncertainties, the selection process accounts for alternate representations of key GMPE attributes, such as the rate of distance attenuation, which are defensible from available data. Recommended models for each domain will change over time as additional GMPEs are developed.


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