Seismic Surface-Wave Tomography of Waste Sites

Long, Leland Timothy

doi:10.2172/834607

Cited by 3 publications

(2 citation statements)

References 3 publications

(4 reference statements)

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“…Although the ray path is velocity dependent, meaning that traveltime inversion is a non-linear problem, deviations of the paths from a straight line will either be of the same order as the dimension of the blocks or will be less than a quarter of the wavelength (Long 2000). On the one hand, deviations smaller than the block size will not introduce significant errors and, on the other, deviations smaller than a quarter wavelength are within the limits of image resolution.…”

Section: T H E I N V E R S I O N a L G O R I T H Mmentioning

confidence: 99%

A 3D algorithm based on the combined inversion of Rayleigh and Love waves for imaging and monitoring of shallow structures

2017

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S U M M A R YIn recent years, there has been increasing interest in the study of seismic noise interferometry as it can provide a complementary approach to active source or earthquake-based methods for imaging and continuous monitoring the shallow structure of the Earth. This meaningful information is extracted from wavefields propagating between those receiver positions at which seismic noise was recorded. Until recently, noise-based imaging relied mostly on Rayleigh waves. However, considering similar wavelengths, a combined use of Rayleigh and Love wave tomography can succeed in retrieving velocity heterogeneities at depth due to their different sensitivity kernels. Here, we present a novel one-step algorithm for simultaneously inverting Rayleigh and Love wave dispersion data aiming at identifying and describing complex 3-D velocity structures. The algorithm may help to accurately and efficiently map the shear wave velocities and the Poisson ratio of the surficial soil layers. In the high-frequency range, the scattered part of the correlation functions stabilizes sufficiently fast to provide a reliable estimate of the velocity structure not only for imaging purposes but also allows for changes in the medium properties to be monitored. Such monitoring can be achieved with a high spatial resolution in 3-D and with a time resolution as small as a few hours. In this paper, we describe a recent array experiment in a volcanic environment in Solfatara (Italy) and we show that this novel approach has identified strong velocity variations at the interface between liquids and gas-dominated reservoirs, allowing localizing a region which is highly dynamic due to the interaction between the deep convection and its surroundings.

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Section: T H E I N V E R S I O N a L G O R I T H Mmentioning

confidence: 99%

A 3D algorithm based on the combined inversion of Rayleigh and Love waves for imaging and monitoring of shallow structures

2017

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“…seismic reflection (Strepo et al, 2001;Adams and Herridge, 1998), P-wave traveltimes tomography (Azaria et al, 2003) and the spectral analysis of surface waves (SASW; Long, 1997). Each technique, already used as a stand-alone geophysical method, considers a different wave component in the processing and, consequently, should provide complementary information concerning the site lithology.…”

Section: Introductionmentioning

confidence: 99%

A seismic multi-approach method for characterizing contaminated sites

Grandjean¹

2006

Journal of Applied Geophysics

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3D Near-surface Velocity Model Building by Integrating Surface, Borehole Seismic, and Well-logging Data in a Small-scale Testbed

Lee,

Pyun,

Chung

et al. 2023

JEEG

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This study aims to build a 3D velocity model for investigating and evaluating underground contaminants flowing through groundwater pathways. To accomplish this goal, we performed seismic exploration at a test site with fractured rock layers within a depth of 100 m. The acquired seismic data was then used to construct a three-dimensional (3D) P-wave velocity model of the test site. Although comprehensive geophysical exploration may be useful for investigating the near-surface structure, this paper focuses only on constructing a P-wave velocity model using the seismic method. The primary information of the model consists of extracted velocities from a two-dimensional surface, borehole first-arrival traveltime tomography results, and full waveform sonic log data. Since the test site has the spatial restriction of the survey line, we intended to improve the geological structure analysis results using various quantitative and qualitative analysis methods. First, to increase the reliability of velocity information, we performed a traveltime analysis on the zero vertical interval (ZVI) gather from the borehole seismic data. Then, we identified the qualitative information of the fracture zone's location by analyzing the amplitude variation of the ZVI gather. Moreover, we extracted structural information using the common reflection point gather from the borehole seismic data to supplement the obtained lithological information. However, the information for constructing a 3D P-wave velocity model was still insufficient due to the spatial constraints of the survey line and the limited depth of the borehole seismic survey. We filled this gap using the radial basis function interpolation method. We could verify the completed 3D P-wave velocity model by comparing it with core log data. Overall, the integrated interpretation of the final velocity model and the analysis results could provide a probable pathway that indicates hydraulic connectivity.

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Seismic Surface-Wave Tomography of Waste Sites

Cited by 3 publications

References 3 publications

A 3D algorithm based on the combined inversion of Rayleigh and Love waves for imaging and monitoring of shallow structures

A 3D algorithm based on the combined inversion of Rayleigh and Love waves for imaging and monitoring of shallow structures

A seismic multi-approach method for characterizing contaminated sites

3D Near-surface Velocity Model Building by Integrating Surface, Borehole Seismic, and Well-logging Data in a Small-scale Testbed

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