Seismic wave amplification: Basin geometry vs soil layering

Semblat, Jean‐François; Kham, Marc; Parara, E.; Bard, Pierre Yves; Pitilakis, Kyriazis; Makra, Konstantia; Raptakis, Dimitrios

doi:10.1016/j.soildyn.2004.11.003

Cited by 161 publications

(77 citation statements)

References 22 publications

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“…The orientation of the ridges relative to such shaking pattern may result in different resonance behaviour of the ridges (as known to occur for sedimentary basins, e.g. Rial et al, 1992;Semblat et al, 2005) and shown by Bouchon (1973). Segments orientated at one azimuth may experience amplification of shaking and in contrast, the other ridge-system at different azimuths may experience relative damping or less forcing.…”

Section: (Iv) Shaking Pattern Relative To Azimuthmentioning

confidence: 98%

Assessment of submarine slope failures off Vancouver Island, British Columbia

Riedel

Naegeli²,

Côté

2016

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Multibeam bathymetric data acquired off Vancouver Island across the accretionary prism of the Cascadia subduction zone reveal a prominent segmentation of the deformation front with dominant azimuths of the ridges at ~120° and ~150° and abundant submarine landslides. Both these ridge-orientations are oblique to the direction of subduction (~45°). Ridges at a strike of ~120° show dominantly rectangular-shaped failure head-scarps and intact blocks of sediments within the failed sediment mass, whereas ridges with an azimuth of ~150° show curved head-scarps and incoherent debris in the failure mass. We propose that this systematic change in failure-style is related to the underlying thrust fault system producing steeper and taller ridges for azimuths around 150°, but less steep and tall ridges at 120°. Thus, debris-flow style failure is simply a result of higher kinetic forcing of the down-sliding sediment mass: more mixing and destruction of the coherent blocks for taller and steeper ridges, and blocks of intact sediment for gentle slopes and less elevated ridges. A segmentation of the deformation front and ridge alignment into two dominant azimuths could be a result of: a) complex interaction and competing forces from overall slab-pull (45°), b) re-activated faults orientated almost N-S (~175°) on the oceanic plate and overlying sediment cover (reflected in the magnetic stripes and abyssal plain strike-slip faulting), and c) relative orientation of the back-stop off Vancouver Island and accreted terranes (at ~127° following the coastline between Nootka Island and Port Renfrew). Extensional faulting is observed only at ridges with debris-flow style failure, which also are the ridges with larger height and steeper slopes. These extensional faults may be the result of over-steepening of the ridges and collapse of the sediment pile that can no longer withstand its own weight due to limited internal shear strength.

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Section: (Iv) Shaking Pattern Relative To Azimuthmentioning

confidence: 98%

Assessment of submarine slope failures off Vancouver Island, British Columbia

Riedel

Naegeli²,

Côté

2016

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“…For example, Semblat et al (2005) study the influence of the complexity of the media geometry when computing the 2-D Volvi basin response in Greece. Guidotti et al (2011) assess the role of basin geometry and kinematic seismic source in 3-D ground motion simulation of the 2011 February 22 M w 6.2 Christchurch earthquake.…”

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confidence: 99%

Influence of a sedimentary basin infilling description on the 2-D P–SV wave propagation using linear and non-linear constitutive models

Gelis¹,

Bonilla

2014

Geophysical Journal International

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S U M M A R YNumerical modelling is a useful tool to understand the role of different parameters (site geometry, impedance contrast, material properties, constitutive model, input motion) governing site effects. We focus here on the 2-D P-SV seismic wave propagation in a simple-shaped asymmetric model. We consider two ways of describing the sedimentary infilling properties: the basin is either composed of distinct homogeneous geological layers or is described through properties progressively changing as a function of depth (smooth model). In order to study the wave propagation in the two basins with similar soil properties, P and S velocities of the layered basin are deduced from the smooth basin ones, making both models compatible in a kinematic point of view. P and S velocities globally increase with depth. Following EPRI, non-linear properties are considered as constant in layers for the two basins. We assess the influence of the model choice on the wave propagation while taking into account linear and non-linear constitutive models. We test the influence of the input motion by propagating two different input motions, the first being a simple impulsive one and the second a real complex accelerogram. We find that transfer functions computed in each basin are quite similar irrespective of the soil constitutive behaviour and the input motion. Moreover, we show that the maximum shear strain spatial distribution depends on the input motion frequency content and maximum values depend on the input motion strength and complexity. Maximum shear strains are generally higher for superficial layers than for deeper ones. We show that the highest shear strain values are located above discontinuities, where velocities are lower and the soil is more non-linear than in the underlying layer, regardless of the input motion. Indeed, in a layered basin, the shear strain is higher above interfaces for all the soil constitutive models that were used. In the smooth visco-elastoplastic model, a kind of layering appears, absent in a viscoelastic model, due to the different non-linear properties in each layer. Moreover, no matter what the model structure and the input motion used, maximum shear strain levels are higher in the visco-elastoplastic soil than in the viscoelastic one. Such a numerical study helps to understand the non-linearity location and therefore the consequences of a model choice when performing a site-specific study.

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“…In the surface layer, surface waves are formed. Many authors have studied the phenomenon of propagation and amplification of seismic waves in soils (Driad-Lebeau et al 2009;Semblat et al 2000Semblat et al , 2005. Surface waves have the greatest impact on surface structures, particularly their horizontal components.…”

Section: Assumed Kinematic Loads and Dynamic Analysismentioning

confidence: 99%

Experimental and numerical analysis of an industrial RC tower

Tatara

Pachla

Kuboń

2016

Bull Earthquake Eng

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This study presents the results of analyses performed using a dynamic 3D model of a RC skip tower located at a coal mine in Poland. Kinematic excitation was based on acceleration records of a mining tremor (underground mining activity) and an earthquake. Although Poland is not a particularly active seismic region, there are regional seismic phenomena associated with mineral exploitation. These vibrations, generally connected with human activity, are so-called paraseismic events. Whilst mining-related surface vibrations show some similarities with natural earthquakes, there are also some differences. Dynamic calculations were performed in the time domain. Analysis of the results refers to the distribution of stresses and displacements which were compared to the limit values. An additional goal of the study was to examine the possibility of loss of structural stability and the risk of collapse. The reason for making the analysis was the fact that kinematic excitations of high structures had not been taken into account in the design procedure. Using actual recorded surface vibrations caused by rock burst and earthquake as kinematics loads allowed a comparison of the dynamic responses of the structure with two different seismic events.

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Seismic wave amplification: Basin geometry vs soil layering

Cited by 161 publications

References 22 publications

Assessment of submarine slope failures off Vancouver Island, British Columbia

Assessment of submarine slope failures off Vancouver Island, British Columbia

Influence of a sedimentary basin infilling description on the 2-D P–SV wave propagation using linear and non-linear constitutive models

Experimental and numerical analysis of an industrial RC tower

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