Tomography from seismic profiles

Firbas, Petr

doi:10.1007/978-94-009-3899-1_8

Cited by 16 publications

(10 citation statements)

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“…Methods for the inversion of crustal refraction/wide-angle reflection traveltimes in 2-D media have been developed by Spence (1984), Huang, Spencer & Green (1986), Firbas (1987) and Lutter, Nowack & Braile (1990). These methods employ ray tracing algorithms that were originally designed for forward modelling only.…”

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confidence: 99%

Seismic traveltime inversion for 2-D crustal velocity structure

Zelt¹,

Smith²

1992

Geophysical Journal International

1,388

1,456

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A method of seismic traveltime inversion for simultaneous determination of 2-D velocity and interface structure is presented that is applicable to any type of body-wave seismic data. The advantage of inversion, as opposed to trial-and-error forward modelling, is that it provides estimates of model parameter resolution, uncertainty and non-uniqueness, and an assurance that the data have been fit according to a specified norm. In addition, the time required to interpret data is significantly reduced. The inversion scheme is iterative and is based on a model parametrization and a method of ray tracing suited to the forward step of an inverse approach. The number and position of velocity and boundary nodes can be adapted to the shot-receiver geometry and subsurface ray coverage, and to the complexity of the near-surface. The model parametrization also allows ancillary amplitude information to be used to constrain model features not adequately resolved by the traveltime data alone. The method of ray tracing uses an efficient numerical solution of the ray tracing equations, an automatic determination of take-off angles, and a simulation of smooth layer boundaries that yields more stable inversion results. The partial derivatives of traveltime with respect to velocity and the depth of boundary nodes are calculated analytically during ray tracing and a damped least-squares technique is used to determine the updated parameter values, both velocities and boundary depths simultaneously. The stopping criteria and optimum number of velocity and boundary nodes are based on the trade-off between RMS traveltime residual and parameter resolution, as well as the ability to trace rays to all observations. Methods for estimating spatial resolution and absolute parameter uncertainty are presented. An example using synthetic data demonstrates the algorithm's accuracy, rapid convergence and sensitivity to realistic noise levels. An inversion of refraction and wide-angle reflection traveltimes from the 1986 IRIS-PASSCAL Nevada, USA (Basin and Range province) seismic experiment illustrates the methodology and practical considerations necessary for handling real data. A comparison of our final 2-D velocity model with results from studies using other 1-D and 2-D forward and inverse methods serves as a check on the validity of the inversion scheme and provides estimates of parameter uncertainties that account for the bias introduced by the modelling approach and the interpreter.

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mentioning

confidence: 99%

Seismic traveltime inversion for 2-D crustal velocity structure

Zelt¹,

Smith²

1992

Geophysical Journal International

1,388

1,456

View full text Add to dashboard Cite

show abstract

“…Methods for the inversion of crustal refraction/wide-angle reflection traveltimes in 2D media have been developed by Spence et al (1984), Huang et al (1986), Firbas (1987), and Lutter et al (1990). These methods employ ray-tracing algorithms that were originally designed for forward modeling only, which limits the effectiveness of the approaches since forward modeling algorithms should be suited c Figure 3 The observed seismic data and corresponding synthetic responses computed for the model derived using ray-trace inversion show typical shot points.…”

Section: Forward Modeling and Inversion Of Firstarrival Traveltime Datamentioning

confidence: 99%

Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic Sediments Using Ray-Trace Inversion of First-Arrival Seismic Data and Elastic Finite-Difference Full-Wave Modeling Along Sinor–Valod Profile of Deccan Syneclise, India

Talukdar

Behera

2018

Pure Appl. Geophys.

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Abstract-Imaging below the basalt for hydrocarbon exploration is a global problem because of poor penetration and significant loss of seismic energy due to scattering, attenuation, absorption and mode-conversion when the seismic waves encounter a highly heterogeneous and rugose basalt layer. The conventional (short offset) seismic data acquisition, processing and modeling techniques adopted by the oil industry generally fails to image hydrocarbon-bearing sub-trappean Mesozoic sediments hidden below the basalt and is considered as a serious problem for hydrocarbon exploration in the world. To overcome this difficulty of sub-basalt imaging, we have generated dense synthetic seismic data with the help of elastic finite-difference full-wave modeling using staggered-grid scheme for the model derived from ray-trace inversion using sparse wide-angle seismic data acquired along Sinor-Valod profile in the Deccan Volcanic Province of India. The full-wave synthetic seismic data generated have been processed and imaged using conventional seismic data processing technique with Kirchhoff pre-stack time and depth migrations. The seismic image obtained correlates with all the structural features of the model obtained through ray-trace inversion of wide-angle seismic data, validating the effectiveness of robust elastic finite-difference full-wave modeling approach for imaging below thick basalts. Using the full-wave modeling also allows us to decipher smallscale heterogeneities imposed in the model as a measure of the rugose basalt interfaces, which could not be dealt with ray-trace inversion. Furthermore, we were able to accurately image thin lowvelocity hydrocarbon-bearing Mesozoic sediments sandwiched between and hidden below two thick sequences of high-velocity basalt layers lying above the basement.

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“…In order to overcome the above-mentioned defects of trial-and-error forward modelling, some researchers (Spence, 1984;Huang, et al, 1986;Firbas, 1987;Lutter, et al, 1990) have developed methods for the inversion of seismic wide-angle reflection and refraction traveltimes. As these methods directly employ parameterization and ray tracing algorithms that were originally designed for forward modeling only, they meet with the troubles of poor stability and low efficiency.…”

Section: Introductionmentioning

confidence: 99%

2-D crustal structure of Changbaishan-Tianchi volcanic region determined by seismic traveltime inversion

2002

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2-D velocity structure and tectonics of the crust and upper mantle is revealed by inversion of seismic refraction and wide-angle reflection traveltimes acquired along the profile L~ in the Changbaishan-Tianchi volcanic region. It is used in this study that seismic traveltime inversion for simultaneous determination of 2-D velocity and interface structure of the crust and upper mantle. The result shows that, under Changbaishan-Tiancbi crater, there exists a low-velocity body in the shape of an inverted triangle, and the crustal reflecting boundaries and Moho all become lower by a varying margin of 2-6 km, forming a crustal root which is assumed to be the Changbaishan-Tianchi volcanic system. Finally, we make a comparison between our 2-D velocity model and the result from the studies by using trial-and-error forward modeling with SEIS83.

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Tomography from seismic profiles

Cited by 16 publications

References 0 publications

Seismic traveltime inversion for 2-D crustal velocity structure

Seismic traveltime inversion for 2-D crustal velocity structure

Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic Sediments Using Ray-Trace Inversion of First-Arrival Seismic Data and Elastic Finite-Difference Full-Wave Modeling Along Sinor–Valod Profile of Deccan Syneclise, India

2-D crustal structure of Changbaishan-Tianchi volcanic region determined by seismic traveltime inversion

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