An empirical method to estimate shear wave velocity of soils in the New Madrid seismic zone

Wei, Bao-Zhu; Pezeshk, Shahram; Chang, T-S; Hall, Ketter; Liu, Huaibao P.

doi:10.1016/0267-7261(96)00014-0

Cited by 14 publications

(4 citation statements)

References 2 publications

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“…At a given frequency, this translates into smaller source sizes. MS in soils may thus signal sources down to millimeter size (Bartake & Singh, 2007;Hu, Hicher, et al, 2018;Sellers et al, 2003;Wei et al, 1996). The high-energy component of MS from granular slopes, filtered through empirical mode decomposition and instantaneous frequencies determination (Hilbert-Huang transform; N. E. Huang et al, 1998), has been associated to interparticle slip and microstructural rearrangements (Hu, Hicher, et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Acoustic Emissions and Microseismicity in Granular Slopes Prior to Failure and Flow‐Like Motion: The Potential for Early Warning

Scaringi

et al. 2018

Geophysical Research Letters

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Rain-triggered landslides in loosely packed granular deposits are highly hazardous because of their sudden failure, flow-like motion, and high mobility. Predicting their initiation and establishing monitoring and early-warning strategies based on the actual mechanisms of failure, rather than on statistical-empirical relations, can be challenging. Experiments on artificial granular slopes revealed a systematic instability-triggering process entailing the internal erosion and seepage-driven transport of small grains. This rearrangement of matter generates acoustic signals and microseismicity detectable prior to any pore water pressures spikes or macroscopic deformations, which are common proxies for slope stability monitoring. Acoustic emissions are more pronounced in loose assemblies, while they are much weaker in densely packed mixtures, which will not exhibit fluid-like motion. Acoustic sensors and accelerometers in support to monitoring networks for flow-like landslides can improve our early warning capabilities, as long as their good performance is confirmed in real-scale applications.Plain Language Summary Some landslides initiated by rainfalls and evolving into very fast and destructive fluid-like movements are hardly predictable because they happen suddenly, with little warning. Traditional monitoring systems might fail to capture precursory signals, and thus, timely alarms cannot always be released. These systems mostly rely on known correlations between the amount and intensity of rainfall and the occurrence of landslides in the past or on the detection of water level and pressure changes by instruments installed within the slopes. However, these changes are often detected late, when the movement is already accelerating dramatically. In our experiments, we found that one of the processes that trigger flow-like landslides in granular soils is the internal erosion of small soil particles transported by water flowing within the slopes. This produces measurable vibrations (microseismicity) and sounds (acoustic emissions) well before water pressure changes and deformation trends can be identified. The performance of real-scale acoustic and seismic monitoring systems is still being verified, but we believe that complementing slopes monitoring with acoustic and seismic sensors can be the winning strategy to provide more timely alarms to evacuate people along the landslide paths and save more lives.

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Section: Introductionmentioning

confidence: 99%

Acoustic Emissions and Microseismicity in Granular Slopes Prior to Failure and Flow‐Like Motion: The Potential for Early Warning

Scaringi

et al. 2018

Geophysical Research Letters

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“…Wills and Silva, 1998) and geotechnical characteristics (e.g. Wei et al, 1996). Actual published measurements of Vs,30 are rare (mainly due to the high cost of surveys) and are only available at individual locations rather than over wide areas.…”

Section: Introductionmentioning

confidence: 99%

Testing the Applicability of Correlations between Topographic Slope and VS30 for Europe

Lemoine¹,

Douglas²,

Cotton³

2012

Bulletin of the Seismological Society of America

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International audienceIn the past few years a series of articles have been published concerning the use of topographic slope from digital elevation models (DEMs) constructed through remote sensing (satellite imaging) to give first-order estimates of National Earthquake Hazards Reduction Program (NEHRP) site classes based on the average shear-wave velocity in the top 30 m, VS30 (Wald and Allen, 2007). We evaluate the potential applicability of these methods taking advantage of a large (706 sites) new database of measured and estimated VS30 values and their topographic slopes for locations in Europe and the Middle East. Novel statistical tests are performed to evaluate the predictive power of the procedure in this region. We evaluate the percentage of sites correctly classified/misclassified for each site class for active and stable regimes. We also analyze the marginal distributions of the input VS30 and slope values and their impact on the VS30-slope correlations and we evaluate whether the method performs better than does chance. We also consider the surface geology of sites and investigate whether differences in geology can help explain why certain sites are poorly classified by the method. Finally, we use the city of Thessaloniki, Greece, as a test case for comparison between the results of a recent microzonation and the site classes predicted by VS30-slope correlations. Our results show that the method does a better job than blind chance for all site classes in active regions, but only for class B (rock) and to a lesser extent class C (stiff soil) sites located in stable areas, although the conclusions for stable areas are based on limited data. We recommend that site classifications based on the VS30-slope correlations proposed by Wald and Allen (2007) be used only for regional or national (and not local or site-specific) first-order studies in active parts of Europe and only in the absence of other more detailed information, excluding sites inside small basins or those with special geological conditions that may affect results (e.g., flat-lying volcanic plateaus, carbonate rocks, continental glaciated terrain, or a coastal location if slope is not calculated using bathymetric data)

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“…day time and meteorological), on different dates (field surveys were performed in 2005, 2006, 2007 and 2008), Table 1 Representative mean values (Ribó 2010) of the total unit weight, t.u.w., and shear-wave velocity, V S , for the defined geotechnical units including their range of variation by estimated bounds or SD, and the source for the V S values, i.e. SPT: penetration resistance, Qu: unconfined compressive strength, and L: literature (Borcherdt and Fumal 2002;Delgado 1997;Hasancebi and Ulusay 2007;Imai and Tonouchi 1982;Wei et al 1996) Bard 2008) were followed for obtaining high quality records. All measurements were conducted with the sensor directly on top of the soil/ground to guarantee a good coupling, avoiding pavement, asphalt or similar that could produce surficial inversions of shear-wave velocity as reported by e.g.…”

Section: Ambient-noise Measurements and Nhv Analysismentioning

confidence: 99%

Site characterization in the Vega Baja, SE Spain, using ambient-noise H/V analysis

Garcı́a-Fernández

Jiménez

2012

Bull Earthquake Eng

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New available geological, geotechnical, and geophysical data and new acquired ambient-noise surveys allowed for a detailed characterization of the soils in the Vega Baja region, located in the Lower Segura River basin, SE of the Iberian Peninsula. Single-station measurements were carried out at 90 sites, mainly over the central area of the basin, checking reproducibility by repeating some measurements under different conditions, on different dates, and through different acquisition systems, following well established standard procedures. The detailed data processing and analysis of the new acquired ambient-noise records provided the identification of multiple peaks in some of the horizontal-to-vertical spectral ratio curves, representing different impedance contrasts at depth that were 1D modelled to characterize the Vega Baja soils in terms of resonant frequencies, average shear-wave velocity, thickness of the different soil units, depth to the engineering bedrock and depth to the rock units when the model includes it. The depth to the engineering bedrock is around 30 m in the central part of the region, reaching maximum values of about 50 m in the north and to the east. Maximum values of the shear-wave velocity averaged over the soil units are close to 200 m/s while that averaged in the top 30 m reach values around 300 m/s south of the river bank. Contour mapping and cross-sections of the obtained model parameters illustrate the soil characteristics over the region, providing relevant information for the generation of representative sets of seismic hazard scenarios at different probability levels in future studies for their application in risk mitigation and emergency planning in the Vega Baja.

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An empirical method to estimate shear wave velocity of soils in the New Madrid seismic zone

Cited by 14 publications

References 2 publications

Acoustic Emissions and Microseismicity in Granular Slopes Prior to Failure and Flow‐Like Motion: The Potential for Early Warning

Acoustic Emissions and Microseismicity in Granular Slopes Prior to Failure and Flow‐Like Motion: The Potential for Early Warning

Testing the Applicability of Correlations between Topographic Slope and VS30 for Europe

Site characterization in the Vega Baja, SE Spain, using ambient-noise H/V analysis

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