Magnetotelluric array data analysis from north-west Fennoscandia

Cherevatova, M.; Jones, Alan G.; Pedersen, Laust B.; Becken, Michael; Biolik, M.; Ebbing, Jörg; Gradmann, Sofie; Gurk, Marcus; Hübert, Juliane; Junge, Andreas; Kamm, Jochen; Korja, T.; Lahti, I.; Löwer, Alexander; Nittinger, C.; Savvaidis, Alexandros; Smirnov, Maxim

doi:10.1016/j.tecto.2014.12.023

Cited by 27 publications

(15 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The MT transfer functions Z and T were calculated using Smirnov's (2003) algorithm MTU2000, which applies amongst other processing, levelling and notch filtering (removing power line signals) to the segmented time series, uses a robust estimation procedure with a high break-down point and has an option for remote reference processing (Gamble et al 1979). MT data from sites in northern Sweden and northern Norway (Cherevatova et al 2015) recorded at the same time as our data were used for remote referencing. In addition, stations recorded simultaneously in our measurement area were also used as remote references, although the distance between the processing station and the remote reference station would be only 500-3000 m in most cases.…”

Section: Mt Data Acquisition P Ro C E S S I N G a N D A N A Ly S I Smentioning

confidence: 99%

A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information

Yan¹,

Juanatey²,

Kalscheuer³

et al. 2016

Geophys. J. Int.

View full text Add to dashboard Cite

Section: Mt Data Acquisition P Ro C E S S I N G a N D A N A Ly S I Smentioning

confidence: 99%

A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information

Yan¹,

Juanatey²,

Kalscheuer³

et al. 2016

Geophys. J. Int.

View full text Add to dashboard Cite

“…Results from the three different processing schemes were averaged to produce the final MT response estimates. The more recent multivariate principal component approach of Smirnov and Egbert (2012) was also used to determine that MT responses free of source field-induced distortion were obtained for the MaSca experiment (Cherevatova et al 2015a). A similar approach was used in a series of papers exploring Svalbard (Beka et al 2015(Beka et al , 2017a to infer high-quality data free of source field-generated distortion were obtained (Smirnov, pers.…”

Section: Source Fieldsmentioning

confidence: 99%

“…More recently, the BEAR (e.g., Korja et al 2002;Varentsov et al 2002) and MaSca (e.g., Cherevatova et al 2015a, b) experiments were focused on resolving crustal and upper mantle lithospheric structure of the Fennoscandian shield, and identifying the lithosphere-asthenosphere boundary. BEAR data collection comprised of 46 long-period MT and 20 geomagnetic depth soundings recording simultaneously (Lahti et al 2005), while the MaSca array included 59 synchronous long-period MT and 220 broad-band MT sites (Cherevatova et al 2015a), deployed using standard terrestrial field practice. The upper crust is in general resistive which is attributed to differing processes: Archaean gneisses in the north; the resistive Svecofennian volcanic belt in the east; and in the south and central zones the entire crust is predominantly resistive intrusive granitoids (Cherevatova et al 2015b).…”

Section: Bear and Masca Array Mt Experiments Fennoscandiamentioning

confidence: 99%

“…Consideration of source effects is required when working in highlatitude warm polar regions, in the northern hemisphere ( Fig. 1) locations such as Alaska (e.g., Fisher et al 2004;Glen et al 2007), northern Canada (e.g., Jones and Spratt 2002;Evans et al 2005;Spratt et al 2014), Scandinavia (e.g., Korja et al 2002;Lahti et al 2005;Sokolova et al 2007;Cherevatova et al 2015a), Svalbard (e.g., Beka et al 2015Beka et al , 2017a, coastal Greenland (e.g., Heincke et al 2015;Hautot and Tarits 2016;Lauritsen et al 2016), Russia (e.g., Bubnov et al 2007), and in the southern hemisphere ( Fig. 1) for those working in the sub-Antarctic islands (e.g., Pedrera et al 2012) where during the summer months the ground is not covered in snow and ice as there is the potential for periods where the source field is a non-plane wave.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the Use of Electromagnetics for Earth Imaging of the Polar Regions

Hill

2019

Surv Geophys

View full text Add to dashboard Cite

The polar regions are host to fundamental unresolved challenges in Earth studies. The nature of these regions necessitates the use of geophysics to address these issues, with electromagnetic and, in particular, magnetotelluric studies finding favour and being applied over a number of different scales. The unique geography and climatic conditions of the polar regions means collecting magnetotelluric data at high latitudes, which presents challenges not typically encountered and may result in significant measurement errors. (1) The very high contact resistance between electrodes and the surficial snow and ice cover (commonly MΩ) can interfere with the electric field measurement. This is overcome by using custom-designed amplifiers placed at the active electrodes to buffer their high impedance contacts.(2) The proximity to the geomagnetic poles requires verification of the fundamental assumption in magnetotellurics that the magnetic source field is a vertically propagating, horizontally polarised plane wave. Behaviour of the polar electro-jet must be assessed to identify increased activity (high energy periods) that create strong current systems and may generate non-planar contributions. (3) The generation of 'blizstatic', localised random electric fields caused by the spin drift of moving charged snow and ice particles that produce significant noise in the electric fields during periods of strong winds. At wind speeds above ~ 10 m s −1 , the effect of the distortion created by the moving snow is broad-band. Station occupation times need to be of sufficient length to ensure data are collected when wind speed is low. (4) Working on glaciated terrain introduces additional safety challenges, e.g., weather, crevasse hazards, etc. Inclusion of a mountaineer in the team, both during the site location planning and onsite operations, allows these hazards to be properly managed. Examples spanning studies covering development and application of novel electromagnetic approaches for the polar regions as well as results from studies addressing a variety of differing geologic questions are presented. Electromagnetic studies focusing on near-surface hydrologic systems, glacial and ice sheet dynamics, as well as large-scale volcanic and tectonic problems are discussed providing an overview of the use of electromagnetic methods to investigate fundamental questions in solid earth studies that have both been completed and are currently ongoing in polar regions.

show abstract

“…Alternatively MT can be used to investigate very deep (100s of km) features, such as the structure of the upper mantle, with the low frequency (i.e. long wavelength) component (Tarits et al, 2004;Ichiki et al, 2006;Meqbel et al, 2014;Vozar et al, 2014;Cherevatova et al, 2015;Kahn et al, 2015;Zhang et al, 2015). In order to see deep features, such as those expected to exist within the mantle, it is necessary to record over long time periods (> 1 month) (Selway, 2014;Selway et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Possible compositional effects on the electrical conductivity of olivine: A preliminary study

Lanati¹

2018

Preprint

View full text Add to dashboard Cite

Abstract:Volatile sensitive probes of the upper mantle, such as magnetotellurics, are being developed to overcome insensitivities in seismic and gravity subsurface mapping as part of an effort to identify the location of deeply buried ore deposits, in addition to more broadly understanding mantle temperature and water contents. An understanding of the conductivity of mantle minerals is an essential prerequisite to the full interpretation of magnetotelluric data. Current proton conduction models for simple mineral systems, such as olivine, show large discrepancies. The material used for these determinations, San Carlos peridotite, is not a single mineral phase and may have compositional variations. This could be one of the origins of these discrepancies. To test this hypothesis, a sample of San Carlos olivine was taken and separated out the mineral components using a combination of electrostatic rock disaggregation, magnetic susceptibility as well as manual separation. The separated fractions were characterised using petrography. Impedance data were collected as a function of temperature and pressure in a multi-anvil press from both the separated olivine material and the original mixture. Comparison of these values with literature data has been made.ii Acknowledgements:I wish to acknowledge the extensive and onerous effort that has gone into this work and the team of people who have taken time from their own work to guide, mentor and advise me. These people not only provided me with an amazing amount of academic help but also showed care and compassion during a personal illness suffered during the course of this thesis.To my supervisors, Associate Professor Simon Clark, Associate Professor Tracy Rushmer, Associate Professor Juan Carlos Afonso, I can never repay the immense amount of time you've given me over the past two years.Simon, I thank you for the guidance and tasks you set for me during the coursework component of this MRes, I do not think I would have anywhere near the grasp of this subject area I currently have without you challenging me. I wish to thank you also for the useful and informative discussion throughout the course of this research project. We may not have always agreed but they certainly helped me to understand how the project was evolving and how impactful and important all aspects of the project can be with a bit more hard work.Tracy, I wish to thank you for meeting with me regularly and helping me through the formalities at the beginning of this year. Your insight specifically into the way which a research project is planned and executed gave me a unique perspective in how I would carry out future work. I want to also thank you for giving me so much time and for the last minute edits that helped me make this thesis much more consistent. This was all while acting as an Associate Dean as well as having other students submitting this year.JC, I want to acknowledge the way you make people think about problems. I truly respect and appreciate the dedication you have to your students and your res...

show abstract

Magnetotelluric array data analysis from north-west Fennoscandia

Cited by 27 publications

References 57 publications

A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information

A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information

On the Use of Electromagnetics for Earth Imaging of the Polar Regions

Possible compositional effects on the electrical conductivity of olivine: A preliminary study

Contact Info

Product

Resources

About