scholarly journals Site-Response Models for Charleston, South Carolina, and Vicinity Developed from Shallow Geotechnical Investigations

2006 ◽  
Vol 96 (2) ◽  
pp. 467-489 ◽  
Author(s):  
M. C. Chapman
Keyword(s):  
South Carolina ◽  
Site Response ◽  
Response Models ◽  
Geotechnical Investigations

Taiwan-Specific Model for VS30 Prediction Considering Between-Proxy Correlations

2018 ◽  
Vol 34 (4) ◽  
pp. 1973-1993 ◽  
Author(s):  
On Lei Annie Kwok ◽  
Jonathan P. Stewart ◽  
Dong Youp Kwak ◽  
Pang-Li Sun
Keyword(s):  
Ground Motion ◽  
Prediction Models ◽  
Site Response ◽  
Specific Model ◽  
Weighted Mean ◽  
Response Models ◽  
Database File ◽  
A Site ◽  
Gradient Effects ◽  
Model Weighting

Ergodic site response models are generally conditional on the time-averaged shear wave velocity in the upper 30 m ( V S30). Ground motion databases contain many recordings from Taiwan, and because of site characterization efforts, 56% of recording sites have V S30 derived from measurements. We develop proxy-based V S30 prediction models, one application of which is for the remaining 44% of Taiwan sites. Our approach, which can be suitable for other regions, differs from previous studies in which proxies are based on detailed geologic categories and possible within-category topographic gradient effects. Instead, we use three broad, age-based geologic categories, and for the youngest category of Holocene and Quaternary undivided sediments, we propose models conditioned on gradient and elevation. We also adapt a geomorphic terrain-based method, thus providing two V S30-prediction models. We describe a model weighting scheme that combines the models in consideration of their relative dispersions and correlation, producing a weighted mean and standard deviation natural-log V S30. Included as an electronic supplement is a profile database file and a site database with site parameters for Taiwan ground motion stations.

Nonlinear shear stress reduction factor (rd) for assessment of liquefaction potential in Christchurch Central Business District

2014 ◽  
Vol 47 (1) ◽  
pp. 1-14
Author(s):  
James N. Dismuke
Keyword(s):  
Shear Stress ◽  
Stress Reduction ◽  
Site Response ◽  
Ground Motions ◽  
Limit State ◽  
Central Business District ◽  
Reduction Factor ◽  
Response Models ◽  
Business District ◽  
Nonlinear Shear

Simplified procedures for evaluating liquefaction triggering potential use the nonlinear shear stress reduction factor, rd, to estimate the peak earthquake-induced cyclic shear stress within the soil strata. Previous studies have derived rd by considering the response of representative ground profiles subjected to input ground motions with a range of ground motion characteristics. In this study, site–specific rd for serviceability limit state (SLS) and ultimate limit state (ULS) design ground motions are developed using site response models of the Christchurch Central Business District (CBD). The site response models are generated for typical geologic conditions of Christchurch CBD with shear wave velocity, Vs, profiles developed from the results of multichannel analysis of surface waves (MASW) surveys conducted across Christchurch CBD. A total of 528 simulations were conducted using 1D nonlinear time domain site response analyses using a suite of input ground motions that are representative of controlling ground motion scenarios for seismic hazard of Christchurch. The results of the ground response analyses are used to determine Christchurch CBD-specific rd relationships for liquefaction triggering assessments. The proposed relationships provide a better estimate of the cyclic stress ratios induced below Christchurch CBD when subjected to design SLS and ULS ground motions as compared to typical practice using generic liquefaction assessment methodologies.

scholarly journals Site Effects in Structural Response Predictions of Inelastic SDOF Oscillators

2012 ◽  
Vol 28 (3) ◽  
pp. 859-883 ◽  
Author(s):  
Dominic Assimaki ◽  
Wei Li ◽  
Michalis Fragiadakis
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Structural Response ◽  
Attenuation Relations ◽  
Period Range ◽  
Response Models ◽  
Linear Elastic ◽  
Ground Motion Variability ◽  
Inelastic Displacement Ratio ◽  
Input Motion

We study how the inelastic structural response predicted via synthetic seismograms is affected by the selection of site response models in ground motion simulations. We first generate synthetics for multiple scenarios and site conditions in Southern California using attenuation relations, site specific linear, vis-coelastic and nonlinear analyses, and estimate the ground motion variability that results from the soil model selection. We next use bilinear single degree-of-freedom oscillators to demonstrate how this variability propagates to the inelastic structural response predictions. Results show high bias and scatter of the inelastic displacement ratio predicted using the empirical and linear elastic site response models relative to the nonlinear, for periods close to the fundamental period of the site. For the synthetic motions and sites used, we derive empirical correlations between the amount of bias and period range where it manifests, and selected input motion and site parameters.

Evaluating Proxy-Based Site Response in Israel

2020 ◽  
Vol 110 (6) ◽  
pp. 2953-2966
Author(s):  
Almog Baram ◽  
Gony Yagoda-Biran ◽  
Ronnie Kamai
Keyword(s):  
Site Response ◽  
Model Performance ◽  
Velocity Profiles ◽  
Large Database ◽  
Response Models ◽  
Alternative Site ◽  
Depth Effects

ABSTRACT Three alternative site-response models are developed, using two complementing predictors, accounting for both stiffness and depth effects. The analysis is based on a large database of velocity profiles and their associated calculated amplifications with respect to the local generic rock profile. The frequency of peak amplification—fpeak—is chosen to supplement VS30, after considering the predictability of eight different site proxies. The suggested models are continuous in terms of spectral periods as well as in terms of their predictor parameters—VS30 and fpeak. Model performance is evaluated in terms of the reduction in variability. For example, for a spectral period of T=0.5  s, using either one of the suggested models reduces the amplification variability from 0.4 to 0.18, whereas using VS30 alone reduces it only to 0.24. This improvement suggests that the addition of fpeak is a significant improvement in the midperiod range.

scholarly journals Fundamental Resonant Frequencies Derived from Shallow Sediment Properties for the Charleston, South Carolina Area

2021 ◽  
Author(s):  
William Dale Schermerhorn
Keyword(s):  
South Carolina ◽  
Surface Deformation ◽  
Site Response ◽  
Atlantic Coastal Plain ◽  
Published Data ◽  
State University ◽  
Surface Wave Dispersion ◽  
Soil Thickness ◽  
Near Surface ◽  
Reflection Data

Large historic earthquakes, low velocity near surface sediments, a poor understanding of earthquake sources, and a growing population base for the Charleston, South Carolina area suggest robust site response and active fault maps are needed. A Boise State University team acquired 14 km of new surface-based seismic data to obtain surface wave dispersion curves and reflection images for the southern isoseismal region of the 1886 earthquake. From these data, I generate shear wave velocity (Vs)-depth profiles through a grid search approach. I integrate my results with other published data to develop a soil thickness and high frequency fundamental resonance maps for the Charleston region. From the reflection data, I identify faults that may be Quaternary active, as they are co-located with surface deformation features observed in 1886. The Boise State University rapid seismic land streamer acquisition system produces robust dispersion and reflection data that may be applicable for other areas within the Atlantic Coastal Plain, where shallow high impedance boundaries and faults that offset Tertiary strata are common.

Evaluation of Uncertainties in Site Response Analysis of Deep Soil Profiles in South Carolina Coastal Plain

2021 ◽  
Author(s):  
Siwadol Dejphumee ◽  
Inthuorn Sasanakul
Keyword(s):  
South Carolina ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Coastal Plain ◽  
Amplification Factor ◽  
Site Response ◽  
Velocity Profiles ◽  
The South ◽  
Deep Soil

ABSTRACT The South Carolina Coastal Plain consists of deep soil sediments over basement bedrock. The depth of basement bedrock varies from being present at the surface to a depth of more than 1200 m at the southern tip of the state. A large variation exists in the thickness of the sediment, which impacts the seismic site response analyses of the Coastal Plain, particularly in areas where the availability of deep shear-wave velocity profiles is limited. This study evaluates the impact of variations in the shear-wave velocity profiles for two sites in the South Carolina Coastal Plain. The shear-wave velocity profiles were measured using different geophysical methods, including a combined multichannel analysis of surface waves and microtremor array measurement (MASW-MAM) method and P–S suspension logging. The equivalent-linear site response analyses were conducted by applying a synthetic earthquake motion at the depth of the B–C boundary (a depth of competent rock in which the shear-wave velocity is 760 m/s). The results are presented in terms of the amplification factor and its standard deviation. Results show that the average shear-wave velocity at the first 30 m (VS30), the shear-wave velocity contrast at the interface of the base layer and the B–C boundary, and the depth to the B–C boundary have a significant impact on the amplification factor and its variability, particularly for the amplification factor at periods higher than 0.1 s. The MASW-MAM method provided significantly lower VS30 values than the P–S suspension logging method at one of the two sites. Consequently, an additional peak in the amplification factor was observed for the site that had a low VS30, and the corresponding period was close to the resonant period of the loose, surface deposit.

scholarly journals Recent Advances in the Modelling of Earthquake Hazard in Australia: Part 1 - Source, Attenuation and Site Response Models

2003 ◽  
Vol 2003 (2) ◽  
pp. 1-1 ◽  
Author(s):  
Trevor Dhu ◽  
Trevor Jones ◽  
Cvetan Sinadinovski ◽  
Andrew Jones ◽  
David Robinson ◽  
...  
Keyword(s):  
Site Response ◽  
Earthquake Hazard ◽  
Response Models ◽  
Recent Advances

scholarly journals Acreage Planting Decision Analysis of South Carolina Tomatoes: Nerlovian Versus Just Risk Model

1986 ◽  
Vol 18 (2) ◽  
pp. 65-72 ◽  
Author(s):  
T. T. Fu ◽  
S. M. Fletcher ◽  
J. E. Epperson
Keyword(s):  
South Carolina ◽  
Decision Analysis ◽  
Structural Model ◽  
Risk Model ◽  
Response Behavior ◽  
Response Models ◽  
Supply Response ◽  
Risk Effect ◽  
Market Instability

AbstractFactors which explain supply response behavior of South Carolina tomato growers were determined. Two well known supply response models were used for comparison: the Nerlovian structural model and the Just risk model. The Just risk model reflected the significance of the risk effect in both stable and unstable periods. An evaluation of forecasting power between the two models was indeterminate. Growers are apparently willing to invest in more information with increased market instability because growers were influenced by the Florida winter price of tomatoes in planting decisions during the period of instability.

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