Deep Shear Wave Velocity Profiles from Surface Wave Measurements in the Mississippi Embayment

2007 ◽  
Vol 23 (4) ◽  
pp. 791-808 ◽  
Author(s):  
Brent L. Rosenblad ◽  
Jianhua Li ◽  
Farn-Yuh Menq ◽  
Kenneth H. Stokoe
Keyword(s):  
Surface Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Site Response ◽  
Source Surface ◽  
Mississippi Embayment ◽  
Near Surface ◽  
Wave Measurements ◽  
Central United States

Shear wave velocity ( VS) profiles to depths of approximately 200 m were developed from active-source surface wave velocity measurements in the Mississippi Embayment region of the Central United States. Soil deposits in this region are hundreds of meters thick, but are poorly characterized at depths below 60 m. Measurements were performed at five locations in Arkansas and Tennessee with a maximum distance between sites of approximately 130 km. The median VS profile calculated from the five profiles is in good agreement with a generic reference VS profile for the Mississippi Embayment that has been used in recent site response studies. The near-surface VS profiles at the five sites were remarkably consistent with average shear wave velocities in the top 30 m ( VS30), varying by less than 10%. Increasing variability between the VS profiles was observed at greater depths. The variability between VS profiles was shown to be correlated with changes in lithology at two of the sites where nearby lithologic information was available.

Development of Deep Shear Wave Velocity Profiles with Estimates of Uncertainty in the Complex Interbedded Geology of Christchurch, New Zealand

2018 ◽  
Vol 34 (2) ◽  
pp. 639-672 ◽  
Author(s):  
David Teague ◽  
Brady Cox ◽  
Brendon Bradley ◽  
Liam Wotherspoon
Keyword(s):  
New Zealand ◽  
Surface Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Site Response ◽  
Epistemic Uncertainty ◽  
Data Uncertainty ◽  
Source Surface ◽  
Dispersion Data

Deep (+500-m) shear wave velocity ( V S) profiles were developed at 14 sites throughout Christchurch, New Zealand, using a combination of active-and passive-source surface wave testing. The geology of Christchurch is complex and presents several challenges for surface wave testing. Specifically, the complex interlayering of relatively stiff gravels with soft sands, silts, and clays makes (1) the interpretation of experimental dispersion data ambiguous and (2) complicates the determination of appropriate inversion-layering parameterizations. In order to address the first issue, dispersion data uncertainty was quantified and several mode interpretations were considered during inversion. To address the second issue, 155 geotechnical boreholes and 199 geologic well logs in the vicinity of the test sites were used to guide the choice of layering parameterizations such that geologically realistic V S profiles were obtained via surface wave inversion. At each site, a suite of 1,000 V S profiles representing the combined effects of epistemic uncertainty and apparent aleatory variability in V S was obtained. These V S profiles are available on the DesignSafe-CI web site ( https://doi.org/10.17603/DS21D4D ) and are intended to aid in future seismic site response analyses.

Near-surface shear-wave velocity estimation based on surface-wave inversion

2016 ◽  
Vol 35 (11) ◽  
pp. 940-945 ◽  
Author(s):  
Peiming Li ◽  
Kui Zhang ◽  
Yimeng Zhang ◽  
Zhihui Yan
Keyword(s):  
Surface Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Velocity Estimation ◽  
Surface Shear ◽  
Near Surface ◽  
Wave Inversion ◽  
Surface Shear Wave

Rapid Post-Earthquake Microtremor Measurements for Site Amplification and Shear Wave Velocity Profiling in Kathmandu, Nepal

2017 ◽  
Vol 33 (1_suppl) ◽  
pp. 55-72 ◽  
Author(s):  
Sheri Molnar ◽  
John Onwuemeka ◽  
Sujan Raj Adhikari
Keyword(s):  
Surface Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Joint Inversion ◽  
Ambient Vibration ◽  
Site Classification ◽  
Source Surface ◽  
Individual Measurement ◽  
Site Period

This paper presents application of microtremor (ambient vibration) and surface wave field techniques for post-earthquake geotechnical reconnaissance purposes in Kathmandu, Nepal. Horizontal-to-vertical spectral ratios (HVSR) are computed from microtremor recordings at 16 individual measurement locations to obtain an estimate of fundamental frequency (site period) of the subsurface soils. A combination of active- and passive-source surface wave array testing was accomplished at five key sites including Kathmandu's Durbar Square and Airport. Joint inversion of each site's higher frequency dispersion and lower frequency HVSR data sets provides an estimate of subsurface material stiffness [i.e., shear wave velocity ( V S) depth profiles]. Direct comparison of our V S profiling at Kathmandu Durbar Square and that accomplished by downhole V S and/or standard penetration testing (SPT) profiling yield similar results. Classification of the five sites based on average V S, site period, and/or basin depth is presented. There is little differentiation in these site classification designations amongst the five sites, which does not capture significant differences in observed earthquake damage.

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