ALBERT

Description: A new ground-motion prediction equation (GMPE) model for central and eastern North America (CENA) is presented. The Graizer 2016 (G-16) model is based on the Next Generation Attenuation-East (NGA-East) database for this horizontal peak ground acceleration and 5% damped pseudospectral acceleration RotD50 component ( Goulet et al. , 2014 ). The CENA database is not sufficient for creating purely empirical GMPE with recordings covering mostly a range of moment magnitudes M 〈6.0 and a limited number of near-fault recordings. The functional forms of the G-16 model are derived from filters representing a particular physical phenomenon affecting the seismic-wave radiation from the source, following the approach developed by Graizer and Kalkan (2007 , 2009 , and 2011 ) for active tectonic environment. Main changes in the functional forms for CENA relative to the western United States model ( Graizer and Kalkan, 2015 ) are a shift of maximum frequency of the acceleration response spectrum (RS) toward higher frequencies and an increase in RS amplitudes at high frequencies. The developed site correction is based on multiple runs of representative V S 30 profiles through SHAKE-type equivalent-linear codes. Site amplifications are calculated relative to the hard-rock definition used in nuclear industry ( V S =2800 m/s). The number of model predictors is limited to a few measurable parameters such as moment magnitude M , closest distance to fault rupture plane R rup , V S 30 , and anelastic attenuation factor Q 0 . Incorporating Q 0 as an input parameter allows adjustments based on the regional crustal properties. The model is applicable for the stable continental regions and covers the following range: 4.0≤ M ≤8.5, 0≤ R rup ≤1000 km, 450≤ V S 30 ≤2800 m/s, and frequencies 0.1≤ f ≤100 Hz.

Description: We present a revised ground-motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration (PGA) and 5% damped pseudospectral acceleration (PSA) response ordinates of the horizontal component of randomly oriented ground motions to be used for seismic-hazard analyses and engineering applications. This GMPE is derived from the expanded Next Generation Attenuation (NGA)-West 1 database (see Data and Resources ; Chiou et al. , 2008 ). The revised model includes an anelastic attenuation term as a function of quality factor ( Q 0 ) to capture regional differences in far-source (beyond 150 km) attenuation, and a new frequency-dependent sedimentary-basin scaling term as a function of depth to the 1.5 km/s shear-wave velocity isosurface to improve ground-motion predictions at sites located on deep sedimentary basins. The new Graizer–Kalkan 2015 (GK15) model, developed to be simple, is applicable for the western United States and other similar shallow crustal continental regions in active tectonic environments for earthquakes with moment magnitudes ( M ) 5.0–8.0, distances 0–250 km, average shear-wave velocities in the upper 30 m ( V S 30 ) 200–1300 m/s, and spectral periods ( T ) 0.01–5 s. Our aleatory variability model captures interevent (between-event) variability, which decreases with magnitude and increases with distance. The mixed-effect residuals analysis reveals that the GK15 has no trend with respect to the independent predictor parameters. Compared to our 2007–2009 GMPE, the PGA values are very similar, whereas spectral ordinates predicted are larger at T 〈0.2 s and they are smaller at longer periods.

Description: We present a revised ground-motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration (PGA) and 5% damped pseudospectral acceleration (PSA) response ordinates of the horizontal component of randomly oriented ground motions to be used for seismic-hazard analyses and engineering applications. This GMPE is derived from the expanded Next Generation Attenuation (NGA)-West 1 database (see Data and Resources ; Chiou et al. , 2008 ). The revised model includes an anelastic attenuation term as a function of quality factor ( Q 0 ) to capture regional differences in far-source (beyond 150 km) attenuation, and a new frequency-dependent sedimentary-basin scaling term as a function of depth to the 1.5 km/s shear-wave velocity isosurface to improve ground-motion predictions at sites located on deep sedimentary basins. The new Graizer–Kalkan 2015 (GK15) model, developed to be simple, is applicable for the western United States and other similar shallow crustal continental regions in active tectonic environments for earthquakes with moment magnitudes ( M ) 5.0–8.0, distances 0–250 km, average shear-wave velocities in the upper 30 m ( V S 30 ) 200–1300 m/s, and spectral periods ( T ) 0.01–5 s. Our aleatory variability model captures interevent (between-event) variability, which decreases with magnitude and increases with distance. The mixed-effect residuals analysis reveals that the GK15 has no trend with respect to the independent predictor parameters. Compared to our 2007–2009 GMPE, the PGA values are very similar, whereas spectral ordinates predicted are larger at T 〈0.2 s and they are smaller at longer periods.

Description: This article introduces new ground-motion prediction equations (GMPE) for central and eastern North America that represents an alternative, more physically justified approach to ground-motion attenuation modeling than my previous Graizer (2016) G-16 model. The new model has a bilinear slope of ~ R –1 within 70 km from the fault (confirmed by empirical data) with a slope of ~ R –0.5 at larger distances corresponding to the geometrical spreading of body and surface waves. This new (G-16v2) model is based on the Next Generation Attenuation (NGA)-East database for the horizontal peak ground acceleration and 5% damped pseudospectral acceleration RotD50 component ( Goulet et al. , 2014 ) and also on comparisons with western United States data and ground-motion simulations. Based on data, I estimated the average slope of the distance attenuation within the 50–70 km distance from the fault to be ~–1.0 at most of the frequencies supporting regular geometrical spreading of body waves. Multiple inversions are performed to estimate apparent (combination of intrinsic and scattering) attenuation of response spectral acceleration (SA) amplitudes from the NGA-East database for incorporation into the GMPE. These estimates demonstrate a difference between classical seismological Q ( f ) and the above-mentioned attenuation factor that I recommend calling Q SA ( f ). Based on residuals, I adjusted previously developed site correction ( Graizer, 2016 ) that was based on multiple runs of representative V S 30 (time-averaged shear-wave velocity in the upper 30 m of the geological material) profiles through SHAKE-type equivalent-linear codes. Site amplifications are calculated relative to the hard-rock definition used in nuclear industry ( V S =2800 m/s). These improvements resulted in a modest reduction in total ( ) and within-event ( ) logarithmic standard deviations in the new G-16v2 relative to G-16 model. The number of model predictors is limited to a few measurable parameters: moment magnitude M , closest distance to fault rupture plane R rup , V S 30 , and apparent attenuation factor Q SA ( f ). The model is applicable for the stable continental regions and covers the following range: 4.0≤ M ≤8.5, 0≤ R rup ≤1000 km, 450≤ V S 30 ≤2800 m/s, and frequencies 0.1≤ f ≤100 Hz.