The Mohr circle, most commonly met in the analysis of mechanical stress, is used to depict magnetotelluric impedance information, taking the real and quadrature parts of magnetotelluric tensors separately. The magnetotelluric concepts of two-dimensionality, three-dimensionality, skew and anisotropy are then all given quantitative expression on a diagram, as are various magnetotelluric invariant...

The results of application of multichannel Kalman filtering to reduction of uncorrelated noise in magnetotelluric recordings are discussed in this article. Magnetotelluric method of Earth structure recognition is shortly presented together with the its most popular measurement method called the remote reference method. The basic theory of nonstationar, discrete Kalman filter and its implementat...

The magnetotelluric method has improved significantly in recent years and is being used in hydrocarbon exploration in regions where seismic exploration is difficult. This includes areas where highvelocity carbonates and volcanic rocks are present in the near surface, overthrust belts, and in subsalt imaging. Magnetotelluric exploration was used in the Rocky Mountain Foothills in 2002 to determi...

The method of Hybrid Adaptive Filtering (HAF) aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing t...

S U M M A R Y Robust magnetotelluric response function estimators are now in standard use in electromagnetic induction research. Properly devised and applied, these have the ability to reduce the influence of unusual data (outliers) in the response (electric field) variables, but are often not sensitive to exceptional predictor (magnetic field) data, which are termed leverage points. A bounded ...

Conductivity models beneath the Nanga Parbat Haramosh Massif (NPHM) derived from magnetotelluric soundings reveal that there is no widespread, interconnected, conductive aqueous fluid to minimum depths of 40 km below sea level. Given the continuing tectonic denudation, young granitic and migmatitic bodies indicating partial melt at shallow crustal depths, and active seismicity, this result is s...

This note presents a brief synopsis of analysis of magnetotelluric data for model dimensionality and strike and its application to the data used in the main paper. Magnetotelluric (MT) data begin as time series of horizontal magnetic (H) and electric (E) fields collected at Earth's surface. After cross-correlation of the field components in orthogonal measurement directions (x,y), the frequency...

We review and describe the electromagnetic transmitters and receivers used to carry out magnetotelluric and controlled source soundings in the marine environment. Academic studies using marine electromagnetic methods started in the 1970s but during the last decade these methods have been used extensively by the offshore hydrocarbon exploration industry. The principal sensors (magnetometers and ...

When we study and process magnetotelluric data, the earth’s interior structure is usually equated with isotropic medium in the existing approaches. When the underground structure is complex, there is serious resistivity anisotropy in macroscopic view, and then the traditional processing and interpretation methods often produce wrong results. For that we must establish the study method based on ...

The paper discusses the complex, agent-oriented hierarchic memetic strategy (HMS) dedicated to solving inverse parametric problems. The strategy goes beyond the idea of two-phase global optimization algorithms. The global search performed by a tree of dependent demes is dynamically alternated with local, steepest descent searches. The strategy offers exceptionally low computational costs, mainl...