Comparison of Field Data Processing Methods for the Evaluation of Topographic Effects

Wood, Charles D.; Cox, Brady R.

doi:10.1193/111515eqs170m

Cited by 13 publications

(3 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, for complex conditions of topographic surface and buried morphology, the directional effects of the incoming waves may greatly influence the surface ground motion. Taking into account the limitations of the experimental approaches, mainly due to definition of the reference station (Wood and Cox 2016), some authors have highlighted unexpected substantial differences between experimental and numerical approaches in some topographically complex areas. These differences mainly regard the magnitude of the amplification function and the frequency range within which the topographic effects are greatest (Bard 1982; Bard and Tucker 1985;Geli et al 1988;Hartzell et al 1994;Assimaki et al 2005;Assimaki and Jeong 2013;Chávez-García et al 1996;Barani et al 2014;Sánchez-Sesma et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Seismic site effects in the Red Zone of Amatrice hill detected via the mutual sustainment of experimental and computational approaches

Grelle

Gargini

Facciorusso

et al. 2020

Bull Earthquake Eng

View full text Add to dashboard Cite

This paper presents the results of numerical analyses of ground motion in the Red Zone sector of Amatrice hill, violently struck by the 2016-2017 Central Italy seismic sequence. The methodologies used in processing the data to define the numerical model are firstly described. The results obtained from the computational analyses are then presented and discussed by comparing them with experimental data set of weak motion recordings. Computational analyses were performed via both a 2D-numerical FEM model and a pseudothree-dimensional hybrid model (SiSeRHMap) which develops multispectral maps taking into account topographic effects. Starting from available geological data and geophysical measurements, an original and specific subsoil GIS model was developed and utilised to perform the computational analyses. The preliminary map for fundamental periods computed from the subsoil model is in good agreement with the experimental data. A restricted set of weak ground motions acquired from an accelerometric station located in a reference site was used as input for the numerical analyses, while the signals of the corresponding events recorded at the top of the hill were used as targets in the reliability evaluation analysis of the outputs. In the area of Amatrice hill, which is characterized by a complex geological and topographical context, the reliability analysis shows a good performance of the hybrid model compared to the 2D-FEM model in the prediction of seismic response. Agreement generally was also good with regards to the experimental and computational results, both in relation to the amplitude and to the shape of the spectral amplification that change depending on the hill sector. Considering the predictive reliability of the models, a high amplification, due to topographic effects, was observed for the Red Zone by performing a back-simulation of the 24th August 2016 main shock. The analysis results highlight also that the maximum amplification factors, based on the definition of the Housner intensity, occur in the interval of periods 0-0.5 s covering the fundamental period range of the buildings in this area.

show abstract

Section: Introductionmentioning

confidence: 99%

Seismic site effects in the Red Zone of Amatrice hill detected via the mutual sustainment of experimental and computational approaches

Grelle

Gargini

Facciorusso

et al. 2020

Bull Earthquake Eng

View full text Add to dashboard Cite

show abstract

“…Thanks to ground motion recordings and earthquake damage reports from sites characterized by topography, it has long been known that topographic features are an indicator of site effects, but theoretical explanations based on the relief's geometrical characteristics usually underestimated the observed amplification values (Geli et al 1988). The discrepancies between predictions and observations can be ascribed to the absence of adequate reference site in many experimental estimates (Pedersen et al 1994;Wood and Cox 2016) on one hand, and on the other hand, to the adoption of oversimplified models in theoretical estimates. The oversimplification that may cause underestimation of theoretically predicted amplifications typically consists of inadequate two-dimensional (2D) approximation of prominently three-dimensional (3D) topographic features (Paolucci 2002;Luo et al 2020) or in neglecting impedance contrasts in the subsurface structure that possibly concur with topography in forming amplification effects (Graizer 2009;Assimaki and Jeong 2013;Hailemikael et al 2016, to cite a few).…”

Section: Introductionmentioning

confidence: 99%

Investigation of topographic site effects using 3D waveform modelling: amplification, polarization and torsional motions in the case study of Arquata del Tronto (Italy)

Baron

Primofiore

Klin

et al. 2021

Bull Earthquake Eng

View full text Add to dashboard Cite

The combined effect of topography and near-surface heterogeneities on the seismic response is hardly predictable and may lead to an aggravation of the ground motion. We apply physics-based numerical simulations of 3D seismic wave propagation to highlight these effects in the case study of Arquata del Tronto, a municipality in the Apennines that includes a historical village on a hill and a hamlet on the flat terrain of an alluvial basin. The two hamlets suffered different damage during the 2016 seismic sequence in Central Italy. We analyze the linear visco-elastic seismic response for vertically incident plane waves in terms of spectral amplification, polarization and induced torsional motion within the frequency band 1–8 Hz over a 1 km2 square area, with spatial resolution 25 m. To discern the effects of topography from those of the sub-surface structure we iterate the numerical simulations for three different versions of the sub-surface model: one homogeneous, one with a surficial weathering layer and a soil basin and one with a complex internal setting. The numerical results confirm the correlation between topographic curvature and amplification and support a correlation between the induced torsional motion and the topographic slope. On the other hand we find that polarization does not necessarily imply ground motion amplification. In the frequency band above 4 Hz the topography-related effects are mainly aggravated by the presence of the weathering layer, even though they do not exceed the soil-related effects in the flat-topography basin. The geological setting below the weathering layer plays a recognizable role in the topography-related site response only for frequencies below 4 Hz.

show abstract

“…At present, there are three kinds of methods to study the topographic site effects: experimental method (e.g., Tucker et al, 1984;Wood and Cox, 2016;Stolte et al, 2017), analytical and semi-analytical method (e.g., Yuan and Liao, 1996;Paolucci, 2002) and numerical simulation methods (e.g., Boore, 1972;Geli et al, 1988;Hartzell et al, 2017). The standard spectral ratio (SSR) method (Borcherdt, 1970) is the spectral ratio of ground motions between the target station and the adjacent reference station.…”

Section: Introductionmentioning

confidence: 99%

A numerical study of 3D topographic site effects considering wavefield incident direction and geomorphometric parameters

Wang

Tao

et al. 2023

Front. Earth Sci.

View full text Add to dashboard Cite

The topographic site effect plays a vital role in controlling the characteristics of earthquake ground motions. Due to its complexity, the factors affecting topographic amplification have not been fully identified. In this study, 100 ground motion simulations generated by double-couple point sources in the homogeneous linear elastic half-space are performed based on the 3D (three-dimensional) Spectral Element Method, taking the Menyuan area of Qinghai Province, China as a local testbed site. A relationship between incident direction and the strength of topographic amplification has been observed. The horizontal ground motion is affected by the back-azimuth, which is typically chosen to be the direction from seismic station to seismic source measured clockwise from north. Specifically, the east-west PGA (Peak Ground-motion Acceleration) is significantly amplified when back-azimuth is about 90° or 270°, and the north-south PGA is significantly amplified when back-azimuth is around 0° or 180°. The vertical ground motion is affected by the dipping angle, which is the angle from vertical at which an incoming seismic wave arrives. The vertical PGA is strongly amplified when the seismic wave is almost horizontally incident (e.g., dipping angle = 78°). A correlation study between geomorphometric parameters and frequency-dependent topographic amplification indicates that relative elevation and smoothed curvature contain similar information, both of which are closely related to the topographic amplification of horizontal components, but not the vertical component. Our study reveals the influence of source and propagation path on topographic amplification and provides a reference for considering the topographic site effect in real engineering sites.

show abstract

Comparison of Field Data Processing Methods for the Evaluation of Topographic Effects

Cited by 13 publications

References 39 publications

Seismic site effects in the Red Zone of Amatrice hill detected via the mutual sustainment of experimental and computational approaches

Seismic site effects in the Red Zone of Amatrice hill detected via the mutual sustainment of experimental and computational approaches

Investigation of topographic site effects using 3D waveform modelling: amplification, polarization and torsional motions in the case study of Arquata del Tronto (Italy)

A numerical study of 3D topographic site effects considering wavefield incident direction and geomorphometric parameters

Contact Info

Product

Resources

About