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1

Integrated seismic refraction and geoelectric sounding inversion algorithm for systematic evaluation of aquifers

Sircar A.

Acta Geophysica Polonica

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2000

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Vol. 48, nr 3

359-375

EN

This paper present an interesting idea of using seismic sounding data to stabilize the result of geoelectric sounding data. The seismic refraction data is inverted using a new inversion approach called Ray Inversion for Near Surface Estimation. The output of inversion is used to predict the initial guess for resistivity inversion through a database. The resistivity inversion is performed using a global optimization scheme called Evolutionary Programming. The efficacy of the integrated approach is demonstrated on synthetic and field data.

2

Estimation of model parameters from one-dimensional vertical electrical sounding data using evolutionary programming technique

Shahid S., Nath S., Sircar A., Patra H.

Acta Geophysica Polonica

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1999

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Vol. 47, nr 3

335-348

EN

Calculus based algebraic algorithms like Singular Value Decomposition, Ridge Regression, Weighted Ridge Regression, etc. were used in the inversion of resistivity data till late 80's. With the advent of high speed computers having higher disk space and parallel processing environment, several global optimization techniques (simulated evolution, simulated annealing, very fast simulated annealing, etc.) are adapted to solve various inherent problems in the inversion of geophysical data. In the present paper an attempt is made to use Evolutionary Programming (EP) technique for the estimation of layer parameters from one-dimensional Vertical Electrical Sounding (VES) data. The algorithm is coded in FORTRAN 77 and tested on both synthetic and actual field data. The results, compared with those obtained by Singular Value Decomposition and borehole lithology, prove the efficiency and robustness of the EP approach.

3

Cross-hole tomography using simulated annealing technique

Sircar A., Chouhan R. K. S.

Acta Geophysica Polonica

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1998

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Vol. 46, nr 2

161-170

EN

We describe a method of nonlinear inversion of travel-time tomography data based on a global optimisation method called Simulated Annealing (SA). The simulated annealing has recently been found to be computationally efficient in several geophysical parameter estimation problems. The solution is independent of the initial model because local minima are avoided during the process by convenient up-hill down-hill exploration of the model space. Preliminary results using synthetic model show how a moderately complex structure can be obtained by SA.