Extending ground-motion prediction equations for spectral accelerations to higher response frequencies

Abstract

Ground-motion prediction equations (GMPEs) for spectral accelerations have traditionally focused on the range of response periods most closely associated with the dynamic characteristics of buildings. Providing predictions only in this period range (from 0.1 to 2 or 3 s) has also accommodated the assumed limitations on the usable period range resulting from the processing of accelerograms. There are, however, engineering applications for which estimates of spectral ordinates are required at shorter response periods. Recent work has demonstrated that high-frequency spectral ordinates are relatively insensitive to record processing, contrary to previous assumptions. In the light of this finding, additional regressions are performed to extend a recent pan-European GMPE to higher response frequencies. This model and others that also include coefficients for spectral ordinates at several high response frequencies are used to explore options for interpolating coefficients for equations that do not provide good coverage in this range. The challenges and uncertainties associated with such interpolations are discussed. The paper concludes that a set of standard response frequencies could be usefully established for future GMPEs.

Near‐source ground motion in the M7.8 Gaziantep (Turkey) earthquake

“…Among them, the shear‐wave velocity in the upper 30 m, or $${V_{s30}}$$, is available for eighty‐eight stations: sixteen stations have $${V_{s30}} > 750m/s$$, fifty have $${V_{s30}} < 360m/s$$ and twenty‐two stations have $$360\;m/s \le {V_{s30}} \le 750m/s$$. The records from the last group have been compared with expectations of the ground motion model of Akkar et al., cited earlier (considering the corrected parameters), 6,18 which uses $${R_{jb}}$$ as distance metric and distinguishes soil amplification for each of the three $${V_{s30}}$$ ranges given previously.…”

Review article: Deterministic seismic hazard assessment of the area comprised between west Gulf of Cádiz and east Alboran Sea

“…Although the degree of relative importance or weighting of each GMPE has been adjusted, considering that they apply equally over the entire extent of the ASCR, according to the values observed at points (control cities) in emerged territory. For AKBO10 in particular, the coefficients of Bommer et al (2012) have been incorporated, and the distance applied in CAFA08 is limited to 15 km below, in accordance with the recommendations made by GEM-OQ in its inventory of GMPEs. The magnitude of the seismic intensity Y used in all selected GMPE models is the PGA.…”

“…The BOAT08 model (Boore and Atkinson, 2008) has an uncertainty in Ln(Y) of = 0.564, with Y in g, is valid for the entire magnitude range, uses the Joyner-Boore RJB distance in its formulation, recommended when the fault geometry is unknown, for focal depths between 2 km and 31 km, and a formulation parameterised according to the focal rupture mechanism (reverse, normal, or rupture-tear). The AKBO10 model (Akkar and Bommer, 2010) has been used in its updated rock version (Bommer et al, 2012), as recommended by GEM-OQ (Giardini et al, 2013;Woessner et al, 2015), to obtain log(Y), with the PGA in cm/s 2 , considering a formulation in three categories according to the failure mechanism, using the RJB distance and uncertainties 1 = 0.2610 (intra-event) and 2 = 0.0994 (inter-event). The CAFA08 model (Cauzzi and Faccioli, 2008) provides log(Y) where Y is in m/s 2 , with an uncertainty of = 0.344 for the horizontal PGA, taking a reference shear wave velocity in the upper 30 m (Vs30) of 800 m/s, corresponding to soil type A, according to Eurocode-8 and the RJB distance modified with the depth to the source.…”

Approximate Bayesian network formulation for the rapid loss assessment of real-world infrastructure systems

“…The mean annual rate λ 0 has been adjusted by the ratio of the selected area (i.e., the one within 100 km of the infrastructure) on the total area of the seismogenic zone. A spatially correlated ground motion field is generated over the area of interest by using the GMPE by Akkar and Bommer [21], as extended by Bommer et al [22] to periods below 0.05 s. Local site amplifications are also accounted for by the GMPE, through the specification of Eurocode 8 soil classes for the vulnerable sites. Given the illustrative character of the application, only one limit state is considered for the vulnerable edges, so that the corresponding BN nodes are binary.…”