A5070584300- Geophysical and Geoelectrical Methods
- Geophysical Methods and Applications
- Geomagnetism and Paleomagnetism Studies
- Seismic Waves and Analysis
- Geological and Geophysical Studies
- Seismic Imaging and Inversion Techniques
- Planetary Science and Exploration
- Earthquake Detection and Analysis
- Geochemistry and Geologic Mapping
- High-pressure geophysics and materials
- earthquake and tectonic studies
- Astro and Planetary Science
- Geological and Geochemical Analysis
- Underwater Acoustics Research
- Geophysics and Gravity Measurements
- Geology and Paleoclimatology Research
- Space Science and Extraterrestrial Life
- Scientific Research and Discoveries
- Hydrocarbon exploration and reservoir analysis
- NMR spectroscopy and applications
- Methane Hydrates and Related Phenomena
- Non-Destructive Testing Techniques
- Underwater Vehicles and Communication Systems
- Solar and Space Plasma Dynamics
- Geothermal Energy Systems and Applications
Centre National de la Recherche Scientifique
2006-2024
Institut Universitaire Européen de la Mer
2014-2024
Université de Bretagne Occidentale
2012-2024
Geo-Ocean
2019-2023
Ifremer
2022
Neurobiologie de l'Olfaction et Modélisation en Imagerie
2020
Analyse, Géométrie et Modélisation
2019
The University of Tokyo
2006
Laboratoire de Planétologie et Géosciences
2006
Université Sorbonne Nouvelle
2001
Abstract It has long been proposed that water incorporation in olivine dramatic effects on the upper mantle properties, affecting large‐scale geodynamics, and triggering high electrical conductivity. But laboratory‐based laws of conductivity predict contrasting water, precluding interpretation geophysical data term hydration. We review experimental measurements hydrous conclude most are consistent when errors samples contents considered. report a new law calibrated largest database oriented...
The magnetotelluric component of the Mantle Electromagnetic and Tomography (MELT) Experiment measured electrical resistivity structure mantle beneath fast-spreading southern East Pacific Rise (EPR). data reveal an asymmetric structure, with lower to west ridge. uppermost 100 kilometers immediately east ridge is consistent a dry olivine indicating depleted melt volatiles. resistivities are low-melt fraction (about 1 2 percent interconnected melt) distributed over broad region extending depths...
Three‐dimensional modeling of data from 31 vertical electrical and 24 magnetotelluric soundings collected in the Baringo‐Bogoria Basin (central Kenya Rift Valley) shows a thick succession well‐defined tectonostratigraphic units beneath Recent deposits Marigat‐Loboi Plain. They include top to bottom, sedimentary basin, ∼1.5 km thick, controlled by N‐S N140° structural trends, homogeneous resistive layer related bottom overlying conductive structure, which cannot be clearly correlated with...
In April‐June 1989, seafloor magnetotelluric data across and along the leading edge of Tahiti hotspot were obtained. The response functions found to be strongly influenced by bathymetric island effects, a new procedure for modeling removing this distortion using thin sheet approach combined with measured water depths is introduced. corrected are consistent two‐dimensional structure. Inversion shows slightly higher conductivity (relative reference site located away from hotspot) down 130 km...
A deep magnetotelluric sounding in the French Alps provided a vertical electrical conductivity profile between ∼200–1000 km. Two prominent features are observed. First, depth range 400–800 km is smaller than of pyrolite mantle obtained from laboratory results for normal geotherm. Second, data do not require to change throughout transition zone (410–660 km). In this part mantle, temperature 350–450 C less explains profile. At 200–400 km, our model favors cold with 1000–1500 ppm water...
A magnetotelluric (MT) transect has been obtained near latitude 45°N from the active Juan de Fuca spreading center, across subduction zone and Cascades volcanic arc, into back arc Deschutes Basin region. This paper presents MT data set describes its major characteristics as they pertain to resistivity of system. In addition, we discuss measurement processing procedures employed well important concerns in interpretation. Broadband audiomagnetotelluric (AMT)/MT soundings (approx. 0.01–500 s...
We describe the scientific purposes and experimental set-up of an international deployment a 3 component broadband seismometer package on ocean floor in Monterey Bay which took place during summer 1997. Highlights this experiment were installation, performed using remotely operated vehicle (ROV), underwater connection different components package, successful retrieval months seismic auxiliary data. Examples recordings teleseisms regional earthquakes are presented background noise...
We conducted geophysical observations on the French Polynesian seafloor in Pacific Ocean from 2009 to 2010 determine mantle structure beneath Society hotspot, which is a region of underlying volcanic activity responsible for forming Islands. The network Tomographic Investigation by ARray Experiment hotspot (TIARES, named after most common flower Tahiti) composed multi-sensor stations that include broadband ocean-bottom seismometers, electro-magnetometers, and differential pressure gauges....
Rifting in a cratonic lithosphere is strongly controlled by several interacting processes including crust/mantle rheology, magmatism, inherited structure and stress regime. In order to better understand how these physical parameters interact, 2 yr long seismological experiment has been carried out the North Tanzanian Divergence (NTD), at southern tip of eastern magmatic branch East African rift, where southward-propagating continental rift its earliest stage. We analyse teleseismic data from...
Despite the tight constraints put by seismology on elastic properties of Earth's lower mantle, its mineralogical composition and thermal state remain poorly known because interpretation seismic measurements suffers from trade‐off between temperature, iron content, composition. In order to overcome this difficulty, we complement data with electromagnetic induction data. The latter are mostly sensitive temperature while densities acoustic speeds constrain mineralogy. A 0.5 log unit increase in...
Electric potential variations have been recorded from November 1995 to February 1996 and continuously since October at 14 measurement points on a one km wide ridge separating two lakes in the French Alps. The levels of vary by several tens meters yearly cycle, inducing stress fluid percolation. At point, unambiguous as large 120 mV are observed over year, linearly correlated with magnitude 2 per meter water level change. This particular point lies edge SP anomaly, which supports presence...
Abstract To obtain the fullest picture of geothermal systems, it is necessary to integrate different types data, for example, surface electromagnetic surveys, lithology, geochemistry, and temperature logs. Here, by joint modeling a multichannel data set we quantify spatial distribution heat transfer through hydrothermally altered, impermeable smectite layer that has developed atop Wairakei‐Tauhara system, New Zealand. Our approach involves first constraining magnetotelluric inversion models...
In geothermal exploration, magnetotelluric (MT) data and inversion models are commonly used to image shallow conductors typically associated with the presence of an electrically conductive clay cap that overlies main reservoir. However, these suffer from nonuniqueness uncertainty, inclusion useful geologic information is still limited. We have developed a Bayesian method integrates electrical resistivity distribution MT surveys borehole methylene blue (MeB) data, indicator content. The MeB...
Abstract The Northern Tanzanian Divergence in the East Africa Rift is arguably best place on Earth to study controls rifting of thick lithosphere. Here, where intersects Craton and Mozambique Belt, relationships between volcanism, faulting, pre‐existing structures lithospheric thickness composition can be observed. In this work, we carry out first lithospheric‐scale 3D magnetotelluric modeling combine results with experimental electrical conductivity petrology models calculate mantle...
The induced magnetic signature at satellite altitude associated with crustal and mantle electrical heterogeneities is examined using five different Earth models. three-dimensional induction problem solved in these models the solar quiet daily variation as an inducing source field. Every model has upper shell representing land–ocean conductivity distribution. have either a homogeneous or heterogeneous containing subduction zones, ridge system conductive blocks. Electromagnetic anomalies,...
Abstract We have conducted a seafloor magnetotelluric survey that images, for the first time, three‐dimensional electrical conductivity structure in upper mantle beneath Society hotspot. A striking feature our model is high‐conductivity anomaly few hundred kilometers diameter, which continuous from lowest part of to depth approximately 50 km below sea level. Using theoretical and experimental results mineral physics, we interpret as evidence melt fraction up 2.2 vol.%, robust regardless...