We investigate a new algorithm for computing regularized solutions of the 2-D magnetotelluric inverse problem. The algorithm employs a nonlinear conjugate gradients (NLCG) scheme to minimize an objective function that penalizes data residuals and second spatial derivatives of resistivity. We compare this algorithm theoretically and numerically to two previous algorithms for constructing such “m...

since hydrocarbon sources have an important role in development of industry and technology, exploration of them has been lionized by human. the seismic reflection method is one of the most applicable investigative methods to identify the hydrocarbon reservoirs, but in some cases this method does not work well because of geology conditions and wave attenuation in depth. thus, some exploration me...

We provide a framework for preconditioning nonlinear three-dimensional electromagnetic inverse scattering problems using nonlinear conjugate gradient (NLCG) and limited memory (LM) quasi-Newton methods. Key to our approach is the use of an approximate adjoint method that allows for an economical approximation of the Hessian that is updated at each inversion iteration. Using this approximate Hes...

Introduction Compressed Sensing (CS) theory [1] allows one to use the sparsity of images in a transform domain (e.g. wavelets) effectively to enable image reconstruction with sub-Nyquist sampled data. While CS methodologies present several potential benefits for medical imaging applications (e.g. reduced scan times, higher resolution imaging, etc.), their successful implementation on clinical s...

MT2DInvMatlab is an open-source MATLAB software package for two-dimensional (2D) inversion of magnetotelluric (MT) data; it is written in mixed languages of MATLAB and FORTRAN. MT2DInvMatlab uses the finite element method (FEM) to compute 2D MTmodel responses, and smoothness-constrained least-squares inversion with a spatially variable regularization parameter algorithm to stabilize the inversi...

This research was conducted to determine the structure and depth of reservoir using remote sensing as an initial survey assess geological alignment direction, employing ALOS PALSAR radar imagery. Subsequently, further surveys were magnetotelluric gravity methods analyze geothermal reservoir. The data processed Phoenix software, where transformed from time domain frequency Fourier transformation...

The inversion is the Non-Linear Conjugate Gradient (NLCG) algorithm of Rodi and Mackie (2001). This seeks to efficiently find a model that minimizes the objective function) P(τ χ S 2 m + = where ∑ = = N 1 i 2 i 2 i 2 σ r χ is the sum of the squared data residuals weighted by their variances and P(m) is a structure penalty function. At each choice of trade-off parameter τ, the resulting model m ...

Abstract Cubadak area was located in depression zone of great Sumatra fault which affected by normal faults. Geothermal this characterized the appearance hot springs type chloride-bicarbonate on Cubadak, Sawah Mudik and Talu. The manifestation temperature is about 37,1° - 74,8° C. This study purpose to recontruct model subsurface geothermal system based MT data. Model 1-D processed apply Bostic...