TY  - BOOK
AU  - Loke,M.H.
AU  - Barker,R.D.
TI  - Rapid least-squares inversion of apparent resistivity pseudosections by a quasi-Newton method
KW  - COMPUTER SIMULATION
KW  - ELECTRIC CONDUCTIVITY OF SOLIDS
KW  - INVERSE KINEMATICS
KW  - ITERATIVE METHODS
KW  - LEAST SQUARES APPROXIMATIONS
KW  - MATHEMATICAL MODELS
KW  - MICROCOMPUTERS
KW  - PARTIAL DIFFERENTIAL EQUATIONS
KW  - RESPONSE TIME (COMPUTER SYSTEMS)
KW  - SPURIOUS SIGNAL NOISE
KW  - SURFACE PROPERTIES
N2  - A fast inversion technique for the interpretation of data from resistivity tomography surveys has been developed for operation on a microcomputer. This technique is based on the smoothness-constrained least-squares method and it produces a two-dimensional subsurface model from the apparent resistivity pseudosection. In the first iteration, a homogeneous earth model is used as the starting model for which the apparent resistivity partial derivative values can be calculated analytically. For subsequent iterations, a quasi-Newton method is used to estimate the partial derivatives which reduces the computer time and memory space required by about eight and twelve times, respectively, compared to the conventional least-squares method. Tests with a variety of computer models and data from field surveys show that this technique is insensitive to random noise and converges rapidly. This technique takes about one minute to invert a single data set on an 80486DX microcomputer
UR  - https://drive.google.com/file/d/1Kq5OWDoLK0l9DNCrnl0Gq3jR5hTKtL4w/view?usp=drivesdk
ER  -