Twelve broadband magnetotelluric (MT) soundings were performed across the Himalaya of Central Nepal in 1996 order to determine electrical structure crust and its relation geological structures active tectonics. The MT impedance tensors obtained for frequencies between 0.001 500 Hz. 2‐D section, derived from joint inversion TE‐ TM mode after RRI Groom/Bailey decomposition, shows high conductivity foreland basin (∼30 Ω.m) that contrasts with resistive Indian basement (>300 Lesser (>1000...

Previous studies have shown that up to a few per cent porosity filled with saline fluid in the lower crust can explain many of regions with: (1) low electrical resistivities, (2) velocities appear be too for otherwise inferred mafic composition, and (3) strong crustal reflectivity. Several predictions free model are examined this article. A compilation approximately coincident magnetotelluric resistivity refraction seismic velocity data continental is presented test predicted correlation. In...

Electrokinetic effects of water flow during pumping tests have been shown to generate surface Streaming Potential (SP) anomalies several tens mV that are well correlated with the geometry table. It follows SP measurements can be used estimate aquifer hydraulic properties. We developed an inversion scheme for data generated by and found we able conductivity depth thickness aquifer. applied our from Bogoslovsky Ogilvy [1973] a 10 −5 m.s −1 , roughly 28 m electrokinetic coupling coefficient...

Classical interpretation techniques developed primarily for gravity and magnetic data have been adapted to electric self‐potential (SP) data. From a recently wavelet‐based technique potential field interpretation, we propose novel approach the forward inverse modeling of SP anomalies caused by subsurface fluid flow. We use analytic signals wavelets associated with flow potentials. Fluid singularities typical signatures in wavelet‐domain that can be used inversion scheme. For cases where...

Processing and interpretation of magnetotelluric data, recorded as part the LITHOPROBE Southern Cordillera transect studies, across boundary Intermontane Omineca morphogeological belts reveals: (a) high electrical conductivity in middle lower parts crust everywhere, (b) a depth dependency geoelectric strike. The data have been modelled using two different inversion algorithms methods for correcting 'static shifts'. approaches gave similar results: to top conductive layer decreases from 15-17...

Stimulated fluid flow in geothermal reservoirs can produce surface Self‐Potential (SP) anomalies of several mV. A commonly accepted interpretation involves the activation electrokinetic processes. However we not rule out electrochemical or electrothermal processes generated by differences chemical composition and temperature between in‐situ injected fluids. We analyzed relative contribution electrokinetic, potentials to SP observed above Soultz‐sous‐Forêts reservoir while injecting cold...

The Upper Cretaceous Carmacks Group (70.4 ± 2.4 Ma) comprises gently dipping basaltic and andesitic lava flows overlying volcaniclastic deposits of the Intermontane Belt in Whitehorse Trough. sampling area is southern Yukon northern British Columbia; it lies west Tintina – Northern Rocky Mountain Trench fault Teslin Suture Zone east Denali Shakwak fault. Volcanic sections were sampled three regions spread over 300 km, providing first paleomagnetic data from pre-Tertiary volcanic rocks...

The Upper Cretaceous Carmacks Group (70.4 ± 2.4 Ma) comprises gently dipping basaltic and andesitic lava flows overlying volcaniclastic deposits of the Intermontane Belt in Whitehorse Trough. sampling area is southern Yukon northern British Columbia; it lies west Tintina – Northern Rocky Mountain Trench fault Teslin Suture Zone east Denali Shakwak fault. Volcanic sections were sampled three regions spread over 300 km, providing first paleomagnetic data from pre-Tertiary volcanic rocks...

We have observed surface electric potential variations of several mV during a reservoir stimulation experiment run in 2000 at the Soultz-sous-Forêts (France) Hot Dry Rock site that we interpreted as deep electrokinetic processes. Using data from another 2003 same site, show here electrically conducting steel casing makes possible measurement SP anomalies even 5 km above injection zone, but obliterates any information about geometry sources. also slow temporal decay after end interpret large...

We carried out monitoring of surface electric potential variations at the Soultz Hot Dry Rock site (France) during a stimulation experiment where 23 000 m 3 water were injected in granite 5 km depth. have observed long‐period (9–10 days) variation with maximum amplitude ≈5 mV, thanks to conductive well casing. The start this anomalous coincides that injection and its magnitude increases as more is before returning toward original value after shut‐in. interpret an electrokinetic effect which...

Field estimation of the soil water flux has direct application for resource management. Standard methods like tensiometry or time domain reflectometry are often difficult to use because subsurface heterogeneity, whereas noninvasive tools such as electrical resistance tomography, nuclear magnetic resonance, ground penetrating radar limited content. We present an method that provides estimates: streaming potential (SP) monitoring. This cost‐effective tool may help estimate nature flow process...

Geophysical joint inversion requires the setting of a few parameters for optimum performance process. However, there are yet no known detailed procedures selecting various performing inversion. Previous works on electromagnetic (EM) and seismic data have reported parameter applications sets acquired from same dimensional geometry (either in two dimensions or three dimensions) variant geometry. But none has discussed selections methods (for example, 2D travel pseudo-2D frequency-domain EM...

We show that morphologic dating techniques have been applied successfully in arid and semi-arid areas are also suitable for slowly evolving scarps usually found temperate climate environments. attempted two approaches, based on diffusion, to relate the present-day shape of an abandoned terrace riser its age. The first assumes a model scarp degradation diffusive process (the D method). second evaluates state using slope distribution SD method) along topographic profile. By manmade known age,...

ABSTRACT We propose here a new, robust, methodology to estimate the errors on magnetotelluric (MT) impedance tensor. This method is developed with bounded influence remote‐reference processing (BIRRP) code in single site configuration. The error estimated by reinjecting an electric field residual obtained after calculation of tensor into function procedure. show using synthetic examples that calculated our yields more reliable than one from Jackknife statistics. modulus realistic estimates...

We propose here a methodology to build near-surface velocity models by joint inversion of traveltime and high-resolution airborne EM (AEM) data. The resulting resistivity are steered be structurally similar through the inclusion cross-gradient term in objective function. is stable results better-fitting models. model then used compute statics corrections on pre-stack seismic tested method high-quality coincident 3D AEM data from Canada computing three different models: Model 1 tomography...