Numerical Study of Effect of Ridge-Weathering Thickness Effect on the Ground Motion Amplification

An effective earthquake (Mw 7.9) struck Alaska on 3 November, 2002. This earthquake ruptured 340 km along Susitna Glacier, Denali and Totschunda faults in central Alaska. The peak ground acceleration (PGA) was recorded about 0.32 g at station PS10, which was located 3 km from the fault rupture. The PGA would have recorded a high value, if more instruments had been installed in the region. A numerical study has been conducted to find out the possible ground motion record that could occur at maximum horizontal slip during the Denali earthquake. The current study overcomes the limitation of number of elements to model the Denali fault. These numerical results are compared with observed ground motions. It is observed that the ground motions obtained through numerical analysis are in good agreement with observed ground motions. From numerical results, it is observed that the possible expected PGA is 0.62 g at maximum horizontal slip of Denali fault.

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Near-Surface Seismic Studies To Estimate Potential Earthquake Ground Motion Amplification At A Thick Soil Site In The Ottawa River Valley, Canada

10.3997/2214-4609-pdb.192.ssi_6 ◽

2001 ◽

Author(s):

Beatriz Benjumea ◽

Jim A. Hunter ◽

Susan E. Pullan ◽

Robert A. Burns ◽

Ron L. Good

Keyword(s):

Ground Motion ◽

River Valley ◽

Earthquake Ground Motion ◽

Near Surface ◽

Ground Motion Amplification ◽

Ottawa River ◽

Soil Site

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Physical stratigraphy and geotechnical properties controlling the local seismic response in explosive volcanic settings: the Stracciacappa maar (central Italy)

Bulletin of Engineering Geology and the Environment ◽

10.1007/s10064-020-01925-5 ◽

2020 ◽

Vol 80 (1) ◽

pp. 179-199

Author(s):

M. Moscatelli ◽

G. Vignaroli ◽

A. Pagliaroli ◽

R. Razzano ◽

A. Avalle ◽

...

Keyword(s):

Seismic Response ◽

Ground Motion ◽

Central Italy ◽

Volcanic Event ◽

Ground Motion Amplification ◽

Local Seismic Response ◽

Single Station ◽

Seismic Scenarios ◽

Physical Stratigraphy ◽

Subsoil Model

AbstractNowadays, policies addressed to prevention and mitigation of seismic risk need a consolidated methodology finalised to the assessment of local seismic response in explosive volcanic settings. The quantitative reconstruction of the subsoil model provides a key instrument to understand how the geometry and the internal architecture of outcropping and buried geological units have influence on the propagation of seismic waves. On this regard, we present a multidisciplinary approach in the test area of the Stracciacappa maar (Sabatini Volcanic District, central Italy), with the aim to reconstruct its physical stratigraphy and to discuss how subsoil heterogeneities control the 1D and 2D local seismic response in such a volcanic setting. We first introduce a new multidisciplinary dataset, including geological (fieldwork and log from a 45-m-thick continuous coring borehole), geophysical (electrical resistivity tomographies, single station noise measurements, and 2D passive seismic arrays), and geotechnical (simple shear tests performed on undisturbed samples) approaches. Then, we reconstruct the subsoil model for the Stracciacappa maar in terms of vertical setting and distribution of its mechanical lithotypes, which we investigate for 1D and 2D finite element site response analyses through the application of two different seismic scenarios: a volcanic event and a tectonic event. The numerical modelling documents a significant ground motion amplification (in the 1–1.5 Hz range) revealed for both seismic scenarios, with a maximum within the centre of the maar. The ground motion amplification is related to both 1D and 2D phenomena including lithological heterogeneity within the upper part of the maar section and interaction of direct S-waves with Rayleigh waves generated at edges of the most superficial lithotypes. Finally, we use these insights to associate the expected distribution of ground motion amplification with the physical stratigraphy of an explosive volcanic setting, with insights for seismic microzonation studies and local seismic response assessment in populated environments.

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Numerical assessment of vertical ground motion effects on highway bridges

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2019-0096 ◽

2020 ◽

Vol 47 (7) ◽

pp. 790-800 ◽

Cited By ~ 1

Author(s):

Hadi Aryan ◽

Mehdi Ghassemieh

Keyword(s):

Ground Motion ◽

Numerical Study ◽

Three Dimensional ◽

Vertical Component ◽

Time History ◽

Highway Bridges ◽

Vertical Excitation ◽

Vertical Ground Motion ◽

Field Evidence ◽

Vertical Ground

Field evidence of recent earthquakes shows serious bridge damages due to the direct compression or tension in the columns and some flexural and shear failures caused by the variation in axial force of the columns. These damages could not be produced solely by the horizontal seismic excitations; the vertical component of the earthquake is involved. This paper presents a numerical study highlighting the presence of vertical seismic excitation. Nonlinear time history analyses are conducted on detailed three-dimensional models of multi-span simply supported and multi-span continuous bridges using a suite of representative ground motions. The results showed the significant influence of vertical excitation on the bridge responses. Therefore, it is imperative to include more efficient criteria to upgrade the design codes and extend practical techniques that consider and cope with the structural effects of vertical ground motion along with the horizontal excitations.

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Numerical simulation of ground motion amplification in Modong area, Lushan

Applied Geophysics ◽

10.1007/s11770-019-0776-z ◽

2019 ◽

Vol 16 (3) ◽

pp. 277-290

Author(s):

Chao Han ◽

Jiashun Yu ◽

Wei-Zu Liu ◽

Jian-Long Yuan ◽

Xiao-Bo Fu ◽

...

Keyword(s):

Numerical Simulation ◽

Ground Motion ◽

Ground Motion Amplification

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Influence of Multiple-Support Excitation on Seismic Response of Reinforced Concrete Arch Bridges

Applied Sciences ◽

10.3390/app10010017 ◽

2019 ◽

Vol 10 (1) ◽

pp. 17 ◽

Cited By ~ 3

Author(s):

Marta Savor Novak ◽

Damir Lazarevic ◽

Josip Atalic ◽

Mario Uros

Keyword(s):

Reinforced Concrete ◽

Spatial Variation ◽

Seismic Response ◽

Ground Motion ◽

Seismic Analysis ◽

Numerical Study ◽

Relative Significance ◽

Multiple Support ◽

Arch Bridges ◽

Support Excitation

Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the influence of multiple-support excitation accounting for coherency loss and wave-passage effects on the seismic response of reinforced concrete deck arch bridges of long spans founded on rock sites. Parametric numerical study was conducted using the time-history method, the response spectrum method, and a simplified procedure according to the European seismic standards. Results showed that multiple-support excitation had a detrimental influence on response of almost all analyzed bridges regardless of considered arch span. Both considered spatial variation effects, acting separately or simultaneously, proved to be very important, with their relative significance depending on the response values and arch locations analyzed and seismic records used. Therefore, it is suggested that all spatially variable ground-motion effects are taken into account in seismic analysis of similar bridges.

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