MTpy: A Python toolbox for magnetotellurics

We present the software package MTpy that allows handling, processing, and imaging of magnetotelluric (MT) data sets. Written in Python, the code is open source, containing sub-packages and modules for various tasks within the standard MT data processing and handling scheme. Besides the independent definition of classes and functions, MTpy provides wrappers and convenience scripts to call standard external data processing and modelling software. In its current state, modules and functions of MTpy work on raw and pre-processed MT data. However, opposite to providing a static compilation of software, we prefer to introduce MTpy as a flexible software toolbox, whose contents can be combined and utilised according to the respective needs of the user. Just as the overall functionality of a mechanical toolbox can be extended by adding new tools, MTpy is a flexible framework, which will be dynamically extended in the future. Furthermore, it can help to unify and extend existing codes and algorithms within the (academic) MT community. In this paper, we introduce the structure and concept of MTpy  . Additionally, we show some examples from an everyday work-flow of MT data processing: the generation of standard EDI data files from raw electric (EE-) and magnetic flux density (B-) field time series as input, the conversion into MiniSEED data format, as well as the generation of a graphical data representation in the form of a Phase Tensor pseudosection.

[1]  Amy Henderson Squilacote The Paraview Guide , 2008 .

[2]  S. Constable,et al.  Occam's inversion to generate smooth, two-dimensional models from magnetotelluric data , 1990 .

[3]  Gaël Varoquaux,et al.  Mayavi: 3D Visualization of Scientific Data , 2010, Computing in Science & Engineering.

[4]  Anna Avdeeva,et al.  Three-dimensional Magnetotelluric Inversion , 2008 .

[5]  A. Martí,et al.  WALDIM: A code for the dimensionality analysis of magnetotelluric data using the rotational invariants of the magnetotelluric tensor , 2009, Comput. Geosci..

[6]  E. R. Niblett,et al.  Variation of electrical conductivity with depth by the magneto-telluric method , 1960 .

[7]  Alan G. Jones,et al.  Geomagnetic induction studies in Scandinavia. III Magnetotelluric observations , 1983 .

[8]  R. Roberts,et al.  Magnetotelluric strike rules , 1987 .

[9]  David E. Wight SEG standard for MT and EMAP data , 1988 .

[10]  Lion Krischer,et al.  ObsPy: A Python Toolbox for Seismology , 2010 .

[11]  James C. Moore Visualizing with VTK , 1998 .

[12]  A. K. Agarwal,et al.  Characterization of the magnetotelluric tensor in terms of its invariants , 2000 .

[13]  William J. Schroeder,et al.  Visualizing with VTK: A Tutorial , 2000, IEEE Computer Graphics and Applications.

[14]  Alan D. Chave,et al.  On electric and magnetic galvanic distortion tensor decompositions , 1994 .

[15]  R. C. Bailey,et al.  Decomposition of magnetotelluric impedance tensors in the presence of local three-dimensional galvanic distortion , 1989 .

[16]  Gary D. Egbert,et al.  Robust multiple‐station magnetotelluric data processing , 1997 .

[17]  Max Moorkamp,et al.  Comment on ‘The magnetotelluric phase tensor’ by T. Grant Caldwell, Hugh M. Bibby and Colin Brown , 2007 .

[18]  Alan D. Chave,et al.  On the robust estimation of power spectra, coherences, and transfer functions , 1987 .

[19]  C. M. Swift,et al.  On determining electrical characteristics of the deep layers of the Earth's crust , 1986 .

[20]  Ute Weckmann,et al.  Images of the magnetotelluric apparent resistivity tensor , 2003 .

[21]  Walter H. F. Smith,et al.  New, improved version of generic mapping tools released , 1998 .

[22]  Alan G. Jones,et al.  On the Equivalence of the "Niblett" and "Bostick" Transformations in the Magnetotelluric Method , 1983 .

[23]  Alan G. Jones,et al.  RESEARCH NOTE: Improving Bahr's invariant parameters using the WAL approach , 2005 .

[24]  Alan D. Chave,et al.  Bounded influence magnetotelluric response function estimation , 2004 .

[25]  L. Cagniard Basic theory of the magneto-telluric method of geophysical prospecting , 1953 .

[26]  Gary D. Egbert,et al.  Computational recipes for electromagnetic inverse problems , 2012 .

[27]  John D. Hunter,et al.  Matplotlib: A 2D Graphics Environment , 2007, Computing in Science & Engineering.

[28]  Yongwimon Lenbury,et al.  Three-dimensional magnetotelluric inversion : data-space method , 2005 .

[29]  Colin Brown,et al.  Determinable and non-determinable parameters of galvanic distortion in magnetotellurics , 2005 .

[30]  W. D. Parkinson The Influence of Continents and Oceans on Geomagnetic Variations , 1962 .

[31]  Gary D. Egbert,et al.  ModEM: A modular system for inversion of electromagnetic geophysical data , 2014, Comput. Geosci..

[32]  H. Bibby,et al.  The magnetotelluric phase tensor , 2004 .

[33]  Alan D. Chave,et al.  Introduction to the magnetotelluric method , 2012 .

[34]  Michel Menvielle,et al.  Analysis of rotational invariants of the magnetotelluric impedance tensor , 1997 .

[35]  Richard C. Aster,et al.  IRIS Seismology Program marks 20 years of discovery , 2005 .

[36]  Shalivahan,et al.  How remote can the far remote reference site for magnetotelluric measurements be , 2002 .