A Note on the Influence of Site Conditions on Ground Motion Values Observed for the Southeastern Illinois Earthquake of June 10, 1987

1993 ◽  
Vol 64 (2) ◽  
pp. 149-156
Author(s):  
M. Zhang ◽  
R. Street ◽  
J. Harris ◽  
V.P. Drnevich
Keyword(s):  
Ground Motions ◽  
Soil Column ◽  
Quantitative Description ◽  
Response Analysis ◽  
Site Conditions ◽  
Sh Wave ◽  
One Dimensional ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
The One

Abstract Site conditions (i.e., depth to bedrock and intermediate horizons within the soil column, and the shear wave velocities of-the soils and bedrock) have been investigated using and SH-wave velocity data at eight sites in Illinois and Indiana where the June 10, 1987, southeastern Illinois earthquake was recorded on blast monitors. The site effects have been calculated using the site conditions and the one dimensional response analysis program WAVES (Hart and Wilson, 1989), and it was found that the site conditions caused the peak particle accelerations to be amplified by a factor of 2.7 to 4.8. It is suggested that the records of ground motions obtained at sites not on rock be considered inadequate for usage at other sites unless accompanied by a quantitative description of the site conditions.

Evaluation of One-Dimensional Multi-Directional Site Response Analyses Using Geotechnical Downhole Array Data in California and Japan

2018 ◽  
Vol 34 (1) ◽  
pp. 349-376 ◽  
Author(s):  
Gangjin Li ◽  
Ramin Motamed ◽  
Stephen Dickenson
Keyword(s):  
Site Response ◽  
Ground Motions ◽  
Soil Column ◽  
Response Analysis ◽  
Engineering Practice ◽  
Backbone Curve ◽  
One Dimensional ◽  
Strain Behavior ◽  
Linear Elastic ◽  
Downhole Array

This study presents a comprehensive investigation of one-dimensional (1-D) site response analysis (SRA) to predict the dynamic response of soil deposits under earthquake loading utilizing the recordings at selected borehole arrays. Seven instrumented downhole arrays in California and Japan were studied using 41 recorded ground motions that cover a broad range of intensities. The arrays were initially assessed in terms of effectiveness of 1-D SRA using taxonomy screening. Furthermore, LS-DYNA, an advanced Finite Element (FE) program, was employed to develop the 1-D soil column models for the SRA of these arrays. The soil stress-strain behavior was characterized with three different models including one linear elastic and two nonlinear backbone curve formulations. All predictions were compared to the measured ground motions to quantify the model biases and uncertainties. Lastly, the practical limitations of 1-D SRA models considered herein are identified, and recommendations are provided to assess the usefulness of the predictions in engineering practice.

The Dynamics Model Analysis of Drying Process in Gelcasting Method

2014 ◽  
Vol 1025-1026 ◽  
pp. 366-371
Author(s):  
Xiao Long Zhang ◽  
Bo Li ◽  
Jun Xian Ye ◽  
Ji Zhou
Keyword(s):  
Qualitative Analysis ◽  
Dynamic Model ◽  
Quantitative Description ◽  
Drying Shrinkage ◽  
Evaporation Process ◽  
Drying Process ◽  
Dynamics Model ◽  
One Dimensional ◽  
Ceramic Components ◽  
The One

<span><span lang="DE">Gelcasting is a widely<br />used method for manufacturing ceramic components. Currently the research on drying process is limited to qualitative analysis for drying process. In order to reveal the mechanism of the gelcast bisque’s drying process, the one-dimensional dynamics model for drying process has been formulated, based on the microscopic quantitative description of the evaporation process and mass transferring process through the gelcast bisque. Then the model has been modified with the consideration of the capillarity effect and the bisque’s drying shrinkage influence. By comparing with the experimental results the one-dimensional dynamic model of drying process can be proved to accurately describe the bisque’s drying process.</span>

scholarly journals Smooth Crustal Velocity Models Cause a Depletion of High-Frequency Ground Motions on Soil in 2D Dynamic Rupture Simulations

2021 ◽  
Author(s):  
Yihe Huang
Keyword(s):  
Shear Wave ◽  
High Frequency ◽  
Ground Motions ◽  
Velocity Model ◽  
Dynamic Rupture ◽  
Ground Acceleration ◽  
Velocity Models ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Crustal Velocity

ABSTRACT A depletion of high-frequency ground motions on soil sites has been observed in recent large earthquakes and is often attributed to a nonlinear soil response. Here, I show that the reduced amplitudes of high-frequency horizontal-to-vertical spectral ratios (HVSRs) on soil can also be caused by a smooth crustal velocity model with low shear-wave velocities underneath soil sites. I calculate near-fault ground motions using both 2D dynamic rupture simulations and point-source models for both rock and soil sites. The 1D velocity models used in the simulations are derived from empirical relationships between seismic wave velocities and depths in northern California. The simulations for soil sites feature lower shear-wave velocities and thus larger Poisson’s ratios at shallow depths than those for rock sites. The lower shear-wave velocities cause slower shallow rupture and smaller shallow slip, but both soil and rock simulations have similar rupture speeds and slip for the rest of the fault. However, the simulated near-fault ground motions on soil and rock sites have distinct features. Compared to ground motions on rock, horizontal ground acceleration on soil is only amplified at low frequencies, whereas vertical ground acceleration is deamplified for the whole frequency range. Thus, the HVSRs on soil exhibit a depletion of high-frequency energy. The comparison between smooth and layered velocity models demonstrates that the smoothness of the velocity model plays a critical role in the contrasting behaviors of HVSRs on soil and rock for different rupture styles and velocity profiles. The results reveal the significant role of shallow crustal velocity structure in the generation of high-frequency ground motions on soil sites.

Relative Differences between Nonlinear and Equivalent-Linear 1-D Site Response Analyses

2016 ◽  
Vol 32 (3) ◽  
pp. 1845-1865 ◽  
Author(s):  
Byungmin Kim ◽  
Youssef M. A. Hashash ◽  
Jonathan P. Stewart ◽  
Ellen M. Rathje ◽  
Joseph A. Harmon ◽  
...  
Keyword(s):  
Peak Velocity ◽  
Site Response ◽  
Practical Significance ◽  
Response Analysis ◽  
Site Conditions ◽  
One Dimensional ◽  
Equivalent Linear ◽  
Stable Continental Regions ◽  
Input Motion ◽  
Relative Differences

This study investigates the conditions for which one-dimensional (1-D) nonlinear (NL) site response analysis results are distinct from equivalent-linear (EL) results and provides guidance for predicting when differences are large enough to be of practical significance. Relative differences in spectral accelerations and Fourier amplitudes computed from NL and EL analyses are assessed for a range of site conditions and for suites of input motions appropriate for active crustal and stable continental regions. Among several considered parameters, EL/NL differences are most clearly dependent on shear strain index ( I γ), defined as the ratio of input motion peak velocity to time-averaged shear-wave velocity in the top 30 m of the soil profile. For small I γ (generally under 0.03%), EL and NL results are practically identical, whereas at larger strains, differences can be significant for frequencies >0.3 Hz. Frequency-dependent I γ values are recommended for conditions above which NL analyses are preferred to EL.

ULTRASONIC SHEAR‐WAVE VELOCITIES IN ROCKS SUBJECTED TO SIMULATED OVERBURDEN PRESSURE

Geophysics ◽  
1962 ◽  
Vol 27 (5) ◽  
pp. 590-598 ◽  
Author(s):  
M. S. King ◽  
I. Fatt
Keyword(s):  
Shear Wave ◽  
High Pressures ◽  
Applied Pressure ◽  
Ultrasonic Energy ◽  
Overburden Pressure ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Ultrasonic Equipment ◽  
The One ◽  
Ultrasonic Shear

Ultrasonic equipment has been developed to measure shear‐wave velocities in small rock samples at hydrostatic pressures up to 2,400 psi. Under certain optimum conditions dilatational wave velocities can also be determined. The method employs a beam of ultrasonic energy passing through a liquid in which a quarter‐inch‐thick parallel‐sided sample of rock is rotated. From the laws of classical optics for the refraction and reflection of waves at boundaries between dissimilar media and the known velocity of sound in the liquid, the velocities in the sample may be calculated from a record of ultrasonic energy transmitted through the sample as a function of angle between the sample and the ultrasonic beam. Results obtained with this apparatus from samples of materials for which the velocity of waves has been published show good agreement with the latter. The variation of the velocity of shear waves in dry rocks with applied hydrostatic pressures up to 2,400 psi have been measured for seven sandstones, a chalk, and a limestone. The shear‐wave velocities were found to increase with an increase of the applied pressure. For five of the sandstones the increase in velocity at high pressures approached the one‐sixth power of the applied hydrostatic pressure predicted theoretically for a sphere pack model.

scholarly journals The Cospectrum of Stress-Carrying Turbulence in the Presence of Surface Gravity Waves

2018 ◽  
Vol 48 (1) ◽  
pp. 29-44 ◽  
Author(s):  
John Trowbridge ◽  
Malcolm Scully ◽  
Christopher R. Sherwood
Keyword(s):  
Spatial Structure ◽  
Gravity Waves ◽  
Reynolds Shear Stress ◽  
Field Measurements ◽  
Surface Gravity ◽  
One Dimensional ◽  
Surface Gravity Waves ◽  
Wave Velocities ◽  
Boundary Layer Turbulence ◽  
The One

AbstractThe cospectrum of the horizontal and vertical turbulent velocity fluctuations, an essential tool for understanding measurements of the turbulent Reynolds shear stress, often departs in the ocean from the shape that has been established in the atmospheric surface layer. Here, we test the hypothesis that this departure is caused by advection of standard boundary layer turbulence by the random oscillatory velocities produced by surface gravity waves. The test is based on a model with two elements. The first is a representation of the spatial structure of the turbulence, guided by rapid distortion theory, and consistent with the one-dimensional cospectra that have been measured in the atmosphere. The second model element is a map of the spatial structure of the turbulence to the temporal fluctuations measured at fixed sensors, assuming advection of frozen turbulence by the velocities associated with surface waves. The model is adapted to removal of the wave velocities from the turbulent fluctuations using spatial filtering. The model is tested against previously published laboratory measurements under wave-free conditions and two new sets of measurements near the seafloor in the coastal ocean in the presence of waves. Although quantitative discrepancies exist, the model captures the dominant features of the laboratory and field measurements, suggesting that the underlying model physics are sound.

LysimeterGEO for modelling soil-vegetation-atmosphere 1D system in the Critical Zone

2021 ◽  
Author(s):  
Concetta D'Amato ◽  
Niccolò Tubini ◽  
Riccardo Rigon
Keyword(s):  
Water Stress ◽  
Soil Column ◽  
Critical Zone ◽  
Stress Factor ◽  
Richards Equation ◽  
Travel Times ◽  
One Dimensional ◽  
Solute Fluxes ◽  
The One ◽  
Non Linear System

&lt;p&gt;Measuring and modelling of water and solute fluxes in the Critical Zone across soil-vegetation-atmosphere system is nowadays a very important challenge because of the complexity of both soil and plants. Considering the one-dimensional problem, we implement a virtual lysimeter model, LysimeterGEO, in which we coupled infiltration and evapotranspiration by using stress factor (Jarvis, 1976; Ball et al., 1987), with which we can compute effective evapotranspiration and remove it from Richards&amp;#8217; equation balance (Casulli and Zanolli, 2010).&lt;/p&gt;&lt;p&gt;As regards the IT implementation, LysimeterGEO is a system of components built upon the Object Modelling System v3 (OMS3). The infiltration component of the virtual lysimeter is WHETGEO 1D - Water, Heat and Transport in GEOframe (Tubini N. 2021), which solves the mass and energy balance for the one-dimensional case. The mass balance is represented by the Richards equation and the non-linear system is solved using the nested Newton algorithm (Casulli and Zanolli, 2010). Evapotranspiration flows are instead estimated using the GEOframe-Prospero model (Bottazzi M. 2020) which estimates the effective transpiration through the equilibrium temperature of the canopy as a function of the stomatal conductance. Finally, the transpiration is calculated starting from the method of Schymanski and Or (2017) and modified by including the dependence on the transpiring surface, the model of conductance of the stomata, as well as the conservation of mass. In LysimeterGEO the interaction between infiltration and evapotranspiration is made possible by BrokerGEO component (D&amp;#8217;Amato C. 2021), which computes the water stress factor for vegetation by using Jarvis or Ball-Berry model. BrokerGEO computes the water stress factor considering the water content information by WHETGEO in each control volumes of the soil column discretization. Moreover, it computes a representative water stress factor for the whole column of soil for the evapotranspiration component. Finally, the density root distribution is considered to remove water into the soil used for evapotranspiration flows.&lt;/p&gt;&lt;p&gt;The modelling of water and solute fluxes across soil-vegetation-atmosphere is made possible by implementation of travel times of waters within vegetation, the growing of the roots and in general the growing of the plants. The idea of a joint infiltration-evapotranspiration model allows us to investigate also problems related to radical growth and the different effect of roots on vegetation. Furthermore, the implementation of travel times on a vegetation scale allows a careful analysis of the behaviour of the same as the soil moisture conditions vary.&lt;/p&gt;

scholarly journals Does the One-Dimensional Assumption Hold for Site Response Analysis? A Study of Seismic Site Responses and Implication for Ground Motion Assessment Using KiK-Net Strong-Motion Data

2019 ◽  
Vol 35 (2) ◽  
pp. 883-905 ◽  
Author(s):  
Marco Pilz ◽  
Fabrice Cotton
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Site Response ◽  
Three Dimensional ◽  
Strong Motion ◽  
Site Response Analysis ◽  
Response Analysis ◽  
One Dimensional ◽  
Ground Motion Variability ◽  
The One

The one-dimensional (1-D) approach is still the dominant method to incorporate site effects in engineering applications. To bridge the 1-D to multidimensional site response analysis, we develop quantitative criteria and a reproducible method to identify KiK-net sites with significant deviations from 1-D behavior. We found that 158 out of 354 show two-dimensional (2-D) and three-dimensional (3-D) effects, extending the resonance toward shorter periods at which 2-D or 3-D site effects exceed those of the classic 1-D configurations and imposing an additional amplification to that caused by the impedance contrast alone. Such 2-D and 3-D effects go along with a large within-station ground motion variability. Remarkably, these effects are found to be more pronounced for small impedance contrasts. While it is hardly possible to identify common features in ground motion behavior for stations with similar topography typologies, it is not over-conservative to apply a safety factor to account for 2-D and 3-D site effects in ground motion modeling.

Implications of the Mw9.0 Tohoku-Oki Earthquake for Ground Motion Scaling with Source, Path, and Site Parameters

2013 ◽  
Vol 29 (1_suppl) ◽  
pp. 1-21 ◽  
Author(s):  
Jonathan P. Stewart ◽  
Saburoh Midorikawa ◽  
Robert W. Graves ◽  
Khatareh Khodaverdi ◽  
Tadahiro Kishida ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Site Amplification ◽  
Low Frequencies ◽  
High Frequencies ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Active Tectonic ◽  
Motion Scaling ◽  
Ground Motion Scaling

The Mw9.0 Tohoku-oki Japan earthquake produced approximately 2,000 ground motion recordings. We consider 1,238 three-component accelerograms corrected with component-specific low-cut filters. The recordings have rupture distances between 44 km and 1,000 km, time-averaged shear wave velocities of VS30 = 90 m/s to 1,900 m/s, and usable response spectral periods of 0.01 sec to >10 sec. The data support the notion that the increase of ground motions with magnitude saturates at large magnitudes. High-frequency ground motions demonstrate faster attenuation with distance in backarc than in forearc regions, which is only captured by one of the four considered ground motion prediction equations for subduction earthquakes. Recordings within 100 km of the fault are used to estimate event terms, which are generally positive (indicating model underprediction) at short periods and zero or negative (overprediction) at long periods. We find site amplification to scale minimally with VS30 at high frequencies, in contrast with other active tectonic regions, but to scale strongly with VS30 at low frequencies.

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