#### Filter Results:

#### Publication Year

1987

2014

#### Publication Type

#### Co-author

#### Publication Venue

#### Key Phrases

Learn More

We present a general method for estimating the location of small, well-separated scatterers in a randomly inhomogeneous environment using an active sensor array. The main features of this method are (i) an arrival time analysis of the echo received from the scatterers, (ii) a singular value decomposition of the array response matrix in the frequency domain,… (More)

- James G Berryman
- 1990

Reconstruction of acoustic, seismic, or electromagnetic wave speed distribution from rst arrival traveltime data is the goal of traveltime tomography. The reconstruction problem is nonlinear, because the ray paths that should be used for tomographic backprojection techniques can depend strongly on the unknown wave speeds. In our analysis, Fermat's principle… (More)

- James G Berryman
- 1989

{ Methods are developed for design of linear tomographic reconstruction algorithms with speciied properties. Assuming a starting model with constant slowness, an algorithm with the following properties is found: (1) The optimum constant for the starting model is determined automatically. (2) The weighted least-squares error between the predicted and… (More)

- P. A. Berge, J. G. Berryman, B. P. Bonner, J. J. Roberts, D. Wildenschild
- 1997

Introduction The purpose of this project is to develop a computer code for joint inversion of seismic and electrical data, to improve underground imaging for site characterization and remediation monitoring. The computer code developed in this project will invert geophysical data to obtain direct estimates of porosity and saturation underground, rather than… (More)

- James G Berryman
- 2007

Fermat's principle shows that a deenite convex set of feasible slowness models { depending only on the traveltime data { exists for the fully nonlinear traveltime inversion problem. In a new iterative reconstruction algorithm, the minimum number of nonfeasible ray paths is used as a gure of merit to determine the optimum size of the model correction at each… (More)

Analytical expressions for three P-wave attenuation mechanisms in sedimentary rocks are given a unified theoretical framework. Two of the models concern wave-induced flow due to heterogeneity in the elastic moduli at " mesoscopic " scales (scales greater than grain sizes but smaller than wavelengths). In the first model, the heterogeneity is due to… (More)

- James G Berryman
- 1991

When an inverse problem can be formulated so the data are minima of one of the variational problems of mathematical physics, feasibility constraints can be found for the nonlinear inversion problem. These constraints guarantee that optimal solutions of the inverse problem lie in the convex feasible region of the model space. Furthermore, points on the… (More)

Phenomenological equations (with coeecients to be determined by speciied experiments) for the poroelastic behavior of a dual porosity medium are formulated and the coeecients in these linear equations are identiied. The generalization from the single porosity case increases the number of independent coeecients for volume deformation from three to six for an… (More)

- James G Berryman
- 1992

Three single-scattering approximations for coeecients in Biot's equations of poroelasticity are considered: the average T-matrix approximation (ATA), the coherent potential approximation (CPA), and the diierential eeective medium (DEM). The scattering coeecients used here are exact results obtained previously for scattering from a spherical inclusion of one… (More)

- James G Berryman
- 1992

General eeective-stress rules are derived for various physical properties of inhomogeneous porous rocks. Some rigorous relations arising in the analysis show that the uid (pore) pressure p f is least eeective at counteracting the changes caused by connning pressure for the solid (grain) volume; p f is more eeective for the total (solid plus pore) volume; p… (More)