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Mapping 3-D mantle electrical conductivity from space: Development of a new 3-D inverse solution based on analysis of matrix Q-responses

English title Mapping 3-D mantle electrical conductivity from space: Development of a new 3-D inverse solution based on analysis of matrix Q-responses
Applicant Kuvshinov Alexey
Number 140711
Funding scheme Project funding
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.06.2012 - 31.05.2015
Approved amount 162'120.00
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Keywords (11)

satellite; mantle; geomagnetic field; adjoint approach; response functions; three-dimensional models ; electromagnetic induction; integral equations; optimization methods; inversion; electrical conductivity

Lay Summary (English)

Lead
Lay summary
The study of lateral variability in physical properties of Earth's mantle using
geophysical methods is a topic of present-day fundamental science. It gives insight into
geodynamic processes such as mantle convection, the fate of subducting slabs and the
origin of continents. Global seismic tomography provides today a variety of
three-dimensional (3-D) mantle velocity models that can be interpreted in terms of
cratonic roots, mantle plumes and slab graveyards. The goal of global electromagnetic
(EM) induction studies is to identify complementary large-scale spatial variations (3-D
structures) in the electrical conductivity of the mantle. This is an important issue since
conductivity reflects the connectivity of constituents such as fluids, partial melt, and
volatiles, while seismology ascertains bulk mechanical properties.
To date only ground-based data from a global network of geomagnetic observatories
have been using to obtain global 3-D images of mantle conductivity. But since the
observatories are sparsely and irregularly distributed with only a few in oceanic regions
and the southern hemisphere, reliable images of 3-D variations of mantle conductivity
in these regions can hardly be obtained with the use of observatory data alone.
However, in contrast to ground-based data, satellite-borne measurements provide
excellent spatial data coverage by dint of their almost polar orbits. With the European
Space Agency multi-satellite mission Swarm (to be launched in 2012), and with the
European-Chinese multi-satellite initiative CGM (planned to be launched in 2016 by
the Chinese Academy of Sciences), the possibility of obtaining trustworthy global
images of 3-D mantle heterogeneities, especially in the regions with poor ground-based
coverage, comes into reach. Moreover, mapping of 3-D electrical conductivity of the
Earth’s mantle has been identified as one of the main scientific objectives both for the
Swarm and CGM constellation missions. But satellite data analysis is much more
challenging compared to observatory data analysis since satellites typically travel with
a speed of 7-8 km/s and thus measure a mixture of temporal and spatial changes of
the geomagnetic field. The forthcoming mission Swarm has initiated efforts to develop
methodologies for recovering 3-D electrical conductivity variations from space. One of
the promising concepts which appeared recently relies on estimation and inversion of
the so-called matrix Q-responses. However, to date this concept exists only as a
theoretical possibility. The main objective of this project is to convert the concept into
an efficient and useful tool. The project is self-contained and it is designed to be
suitable for 3-year study leading to a PhD. The PhD student will be guided by the PI’s
(PD Dr. Alexey Kuvshinov) expertise in the development of inverse and forward
solutions for other, but similar applications. Expected outputs from the project are: (a)
a multi-variate time series analysis code to estimate matrix Q-responses; (b) a novel
and fast 3-D global induction inverse code based on the analysis of these responses; (c) a global 3-D conductivity model of the Earth’s mantle. Both the codes and 3-D model will be made available to be used to achieve the goals of aforementioned multi-satellite geomagnetic missions.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Handling complex source structures in global EM induction studies: From c-responses to new arrays of transfer functions
Püthe Christoph, Kuvshinov Alexey, Olsen Nils (2014), Handling complex source structures in global EM induction studies: From c-responses to new arrays of transfer functions, in Geophysical Journal International, 201(1), 318-328.
Reproducing electric field observations during magnetic storms by means of rigorous 3-D modelling and distortion matrix co-estimation
Püthe Christoph, Manoj Chandrasekharan, Kuvshinov Alexey (2014), Reproducing electric field observations during magnetic storms by means of rigorous 3-D modelling and distortion matrix co-estimation, in Earth, Planets and Space, 66(1), 1.
Determination of the 1-D distribution of electrical conductivity in Earth's mantle from Swarm satellite data
Püthe Christoph, Kuvshinov Alexey (2013), Determination of the 1-D distribution of electrical conductivity in Earth's mantle from Swarm satellite data, in Earth, Planets and Space, 65(11), 1233-1237.
Determination of the 3-D distribution of electrical conductivity in Earth's mantle from Swarm satellite data: Frequency domain approach based on inversion of induced coefficients
Püthe Christoph, Kuvshinov Alexey (2013), Determination of the 3-D distribution of electrical conductivity in Earth's mantle from Swarm satellite data: Frequency domain approach based on inversion of induced coefficients, in Earth, Planets and Space, 65(11), 1247-1256.
Mapping 3-D mantle electrical conductivity from space: A new 3-D inversion scheme based on analysis of matrix Q-responses
Püthe Christoph, Kuvshinov Alexey (2013), Mapping 3-D mantle electrical conductivity from space: A new 3-D inversion scheme based on analysis of matrix Q-responses, in Geophysical Journal International, 197(2), 768-784.
The Swarm satellite constellation application and research facility (SCARF) and Swarm data products
Olsen Nils, Friis-Christensen Eigil, Floberghagen Rune, Alken Patrick, Alken Patrick, Beggan Ciaran D., Chulliat Arnaud, Doornbos Eelco, Da Encarnação João Teixeira, Hamilton Brian, Hulot Gauthier, Van Den Ijssel Jose, Kuvshinov Alexey, Lesur Vincent, Lühr Hermann, Macmillan Susan, Maus Stefan, Noja Max, Olsen Poul Erik H, Park Jaeheung, Plank Gernot, Püthe Christoph, Rauberg Jan, Ritter Patricia, Rother Martin (2013), The Swarm satellite constellation application and research facility (SCARF) and Swarm data products, in Earth, Planets and Space, 65(11), 1189-1200.
Towards quantitative assessment of the hazard from space weather. Global 3-D modellings of the electric field induced by a realistic geomagnetic storm
Püthe Christoph, Kuvshinov Alexey (2013), Towards quantitative assessment of the hazard from space weather. Global 3-D modellings of the electric field induced by a realistic geomagnetic storm, in Earth, Planets and Space, 65(9), 1017-1025.

Collaboration

Group / person Country
Types of collaboration
DTU Space Denmark (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
European Geosciences Union General Assembly 2015 Talk given at a conference A new model of Earth’s radial conductivity structure derived from over 10 years of satellite and observatory magnetic data 12.04.2015 Vienna, Austria Püthe Christoph; Kuvshinov Alexey;
22. EM Induction Workshop Talk given at a conference Beyond the ring current: Handling complex source structures in global EM induction studies 24.08.2014 Weimar, Germany Püthe Christoph; Kuvshinov Alexey;
3rd Swarm Science Meeting Poster Is Global 3-D Electromagnetic Tomography Possible? An Analysis based on Matrix Q-Responses 19.06.2014 Copenhagen, Denmark Kuvshinov Alexey; Püthe Christoph;
European Geosciences Union General Assembly 2014 Poster New transfer functions for probing 3-D mantle conductivity from ground and sea 27.04.2014 Vienna, Austria Kuvshinov Alexey; Püthe Christoph;
ESA Living Planet Symposium 2013 Poster Global 3-D imaging of mantle electrical conductivity from space and ground. Recent developments 09.09.2013 Edinburgh, Great Britain and Northern Ireland Kuvshinov Alexey; Püthe Christoph;
5th International Symposium on Three-Dimensional Electromagnetics Poster Mapping 3-D mantle electrical conductivity from space. Development of a new 3-D inversion scheme based on analysis of matrix Q-responses 07.05.2013 Sapporo, Japan Kuvshinov Alexey; Püthe Christoph;
21st EM Induction Workshop Talk given at a conference 3-D Mapping of Mantle Conductivity from Space based on Inversion of Time Spectra of Induced Coefficients 25.07.2012 Darwin, Australia Püthe Christoph; Kuvshinov Alexey;


Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
Scientifica – Zürcher Wissenschaftstage 01.09.2013 Zürich, Switzerland Püthe Christoph;


Abstract

The study of lateral variability in physical properties of Earth's mantle using geophysical methods is a topic of present-day fundamental science. It gives insight into geodynamic processes such as mantle convection, the fate of subducting slabs and the origin of continents. Global seismic tomography provides today a variety of three-dimensional (3-D) mantle velocity models that can be interpreted in terms of cratonic roots, mantle plumes and slab graveyards. The goal of global electromagnetic (EM) induction studies is to identify complementary large-scale spatial variations (3-D structures) in the electrical conductivity of the mantle. This is an important issue since conductivity reflects the connectivity of constituents such as fluids, partial melt, and volatiles, while seismology ascertains bulk mechanical properties.To date only ground-based data from a global network of geomagnetic observatories have been using to obtain global 3-D images of mantle conductivity. But since the observatories are sparsely and irregularly distributed with only a few in oceanic regions and the southern hemisphere, reliable images of 3-D variations of mantle conductivity in these regions can hardly be obtained with the use of observatory data alone. However, in contrast to ground-based data, satellite-borne measurements provide excellent spatial data coverage by dint of their almost polar orbits. With the European Space Agency multi-satellite mission Swarm (to be launched in 2012), and with the European-Chinese multi-satellite initiative CGM (planned to be launched in 2016 by the Chinese Academy of Sciences), the possibility of obtaining trustworthy global images of 3-D mantle heterogeneities, especially in the regions with poor ground-based coverage, comes into reach. Moreover, mapping of 3-D electrical conductivity of the Earth’s mantle has been identified as one of the main scientific objectives both for the Swarm and CGM constellation missions. But satellite data analysis is much more challenging compared to observatory data analysis since satellites typically travel with a speed of 7-8 km/s and thus measure a mixture of temporal and spatial changes of the geomagnetic field. The forthcoming mission Swarm has initiated efforts to develop methodologies for recovering 3-D electrical conductivity variations from space. One of the promising concepts which appeared recently relies on estimation and inversion of the so-called matrix Q-responses. However, to date this concept exists only as a theoretical possibility. The main objective of this project is to convert the concept into an efficient and useful tool. The project is self-contained and it is designed to be suitable for 3-year study leading to a PhD. The PhD student will be guided by the PI’s (PD Dr. Alexey Kuvshinov) expertise in the development of inverse and forward solutions for other, but similar applications. Expected outputs from the project are: (a) a multi-variate time series analysis code to estimate matrix Q-responses; (b) a novel and fast 3-D global induction inverse code based on the analysis of these responses; (c) a global 3-D conductivity model of the Earth’s mantle. Both the codes and 3-D model will be made available to be used to achieve the goals of aforementioned multi-satellite geomagnetic missions.
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