Amplification of strong ground motions at Heathcote Valley during the 2010–2011 Canterbury earthquakes: Observation and 1D site response analysis

Jeong, Seokho; Bradley, Brendon

doi:10.1016/j.soildyn.2017.06.004

Cited by 16 publications

(10 citation statements)

References 22 publications

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“…Figure A.1 in Supplemental Appendix A illustrates shear wave velocity ( V S ) profiles of the 20 sites based on site investigation results from Wotherspoon et al (2014), Deschenes et al (2018), and Jeong and Bradley (2017a). Wotherspoon et al (2014) also performed detailed site investigations at most of the sites, including surface wave testing (using active and passive methods), cone penetration tests (CPTs), standard penetration tests (SPTs), and laboratory index tests.…”

Section: Earthquakes and Sites Consideredmentioning

confidence: 99%

“… a + δ S 2 S ) from all three analysis methods for four sites. Figure 8a shows the results for HVSC, which consistently produced exceptionally strong ground shaking throughout the Canterbury Earthquake Sequence (Bradley, 2015; Jeong and Bradley, 2017a). This is evident from the large underprediction at T < 1 s when site effects are not considered (i.e.…”

Section: Systematic Prediction Residualsmentioning

confidence: 99%

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Modeling nonlinear site effects in physics-based ground motion simulations of the 2010–2011 Canterbury earthquake sequence

2020

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This study examines the performance of nonlinear total stress one-dimensional (1D) wave propagation site response analysis for modeling site effects in physics-based ground motion simulations of the 2010–2011 Canterbury, New Zealand earthquake sequence. This approach explicitly models three-dimensional (3D) ground motion phenomena at the regional scale, and detailed site effects at the local scale. The approach is compared with a more commonly used empirical VS30-based method of computing site amplification for simulated ground motions, as well as prediction via an empirical ground motion model. Site-specific ground response analysis is performed at 20 strong motion stations in Christchurch for 11 earthquakes with 4.7≤ MW≤7.1. When compared with the VS30-based approach, the wave propagation analysis reduces both overall model bias and uncertainty in site-to-site residuals at the fundamental period, and significantly reduces systematic residuals for soft or “atypical” sites that exhibit strong site amplification. The comparable performance in ground motion prediction between the physics-based simulation method and empirical ground motion models suggests the former is a viable approach for generating site-specific ground motions for geotechnical and structural response history analyses.

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Section: Earthquakes and Sites Consideredmentioning

confidence: 99%

Section: Systematic Prediction Residualsmentioning

confidence: 99%

Modeling nonlinear site effects in physics-based ground motion simulations of the 2010–2011 Canterbury earthquake sequence

2020

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“…We acknowledge that the actual wave velocity of the rock would be a lot more variable For all materials, the Poisson's ratios are assumed as ν = 0.25, and the ground water was not considered. Table 1 summarizes the key parameters used in the simulations, and the detailed information on the geophysical investigations can be found in Jeong and Bradley, (2016).…”

Section: Model Descriptionmentioning

confidence: 99%

“…To investigate the role of 2D site effects, we compared the HVSC/LPCC spectral ratios of 2D and 1D simulations as shown in Figure 14, where the 1D simulations are performed using the velocity profile evaluated at the location of the station HVSC (Jeong and Bradley, 2016). In both 1D and 2D spectral ratios, the fundamental frequencies and the corresponding peak amplitudes are quite similar.…”

Section: D Vs 1d Simulation At Hvscmentioning

confidence: 99%

“…ement analysis, to examine the role of shallow geological conditions on the surface ground motions at Heathcote Valley. Fifteen seismic cone penetration tests (sCPT) and 26 singlesensor ambient vibration tests are conducted to characterize the shear wave velocity and the thickness of sedimentary soils.Figure 7andTable 1summarize the results of the aforementioned site-characterization study; the details are summarized in(Jeong and Bradley, 2016).Figure 7shows fence diagrams of the cross-sections of 3D shear wave velocity model of Heathcote Valley based on the geophysical tests, in which the cross section considered in the 2D analyses is marked as 'N75E'.…”

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confidence: 99%

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Amplification of Strong Ground Motions at Heathcote Valley during the 2010–2011 Canterbury Earthquakes: The Role of 2D Nonlinear Site Response

Jeong

Bradley

2017

Bulletin of the Seismological Society of America

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This article presents a quantitative case study on the site amplification effect observed at Heathcote Valley, New Zealand, during the 2010-2011 Canterbury earthquake sequence for 10 events that produced notable ground acceleration amplitudes up to 1.4g and 2.2g in the horizontal and vertical directions, respectively. We performed finite element analyses of the dynamic response of the valley, accounting for the realistic basin geometry and the soil non-linear response. The site-specific simulations performed significantly better than both empirical ground motion models and physics based regional-scale ground motion simulations (which empirically accounts for the site effects), reducing the spectral acceleration prediction bias by a factor of two in short vibration periods. However, our validation exercise demonstrated that it was necessary to quantify the level of uncertainty in the estimated bedrock motion using multiple recorded events, to understand how much the simplistic model can over-or underestimate the ground motion intensities. Inferences from the analyses suggest that the Rayleigh waves generated near the basin edge contributed significantly to the observed high frequency (f>3Hz) amplification, in addition to the amplification caused by the strong soil-rock impedance contrast at the site fundamental frequency. Models with and without considering soil non-linear response illustrate, as expected, that the linear elastic assumption severely overestimates ground motions in high frequencies for strong earthquakes, especially when the contribution of basin edge-generated Rayleigh waves becomes significant. Our analyses also demonstrate that the effect of pressure-dependent soil velocities on the high frequency ground motions is as significant as the amplification caused by the basin edge-generated Rayleigh waves. Author Comments: Please note that there is a bug in the 'biblatex' package installed on the LaTeX build system, which puts a strange comma between the name and the year. For example, it creates "Bradley, (2015)" instead of the intended "Bradley (2015)" Suggested Reviewers: Opposed Reviewers: Response to Reviewers: I will upload the response to reviewer as a pdf file. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation Manuscript Click here to download Manuscript Jeong_HeathcoteValley_BSSA_2016.tex strong soil-rock impedance contrast at the site fundamental frequency. Models with and without considering soil non-linear response illustrate, as expected, that the linear elastic assumption severely overestimates ground motions in high frequencies for strong earthquakes, especially when the contribution of basin edge-generated Rayleigh waves becomes significant. Our analyses also demonstrate that the effect of pressuredependent soil velocities on the high frequency ground motions is as significant as the amplification caused by the basin edge-generated Rayleigh waves.

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Prediction and Modeling for Local Site Amplification Effect of Ground Motion: Exploring Optimized Machine Learning Approaches

Meng

Zhao

Liu

et al. 2022

Pure Appl. Geophys.

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Amplification of strong ground motions at Heathcote Valley during the 2010–2011 Canterbury earthquakes: Observation and 1D site response analysis

Cited by 16 publications

References 22 publications

Modeling nonlinear site effects in physics-based ground motion simulations of the 2010–2011 Canterbury earthquake sequence

Modeling nonlinear site effects in physics-based ground motion simulations of the 2010–2011 Canterbury earthquake sequence

Amplification of Strong Ground Motions at Heathcote Valley during the 2010–2011 Canterbury Earthquakes: The Role of 2D Nonlinear Site Response

Prediction and Modeling for Local Site Amplification Effect of Ground Motion: Exploring Optimized Machine Learning Approaches

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