MTpy-v2: A Python Toolbox for working with Magnetotelluric (MT) Data

Description

mtpy provides tools for working with magnetotelluric (MT) data. MTpy-v2 is an updated version of mtpy. Many things have changed under the hood and usage is different from mtpy v1. The main difference is that there is a central data type that can hold transfer functions and then read/write to your modeling program, plot, and analyze your data. No longer will you need a directory of EDI files and then read them in everytime you want to do something. You only need to build a project once and save it to an MTH5 file and you are ready to go. All metadata uses mt-metadata.

Functionality

• Read/write transfer function files (EDI, EMTFXML, J-file, Z-file, AVG-file) using mt-metadata
• Read/write MTH5 files for full surveys/project in a single file
• Utility functions for GIS

Plotting

• Single transfer function
  • apparent resistivity and phase
  • induction vectors
  • phase tensors
  • strike
  • depth of investigation
• Survey of transfer functions
  • station map
  • phase tensor and induction vector map and pseudosection
  • apparent resistivity and phase maps and pseudosections
  • depth of investigation map

Processing

• Read/write files for time series processing
  • BIRRP
  • Aurora

Modeling

• Read/Write files for modeling programs
  • ModEM
  • Occam 1D and 2D
  • Mare2DEM (?)
  • Pek 1D and 2D

What's been Updated in version 2

The main updates in mtpy-v2 are:

• Remove dependence on EDI files, can be any type of transfer function file
  • Supports (or will support) to/from:
    • EDI (most common format)
    • ZMM (Egberts EMTF output)
    • JFILE (BIRRP output)
    • EMTFXML (Kelbert's format)
    • AVG (Zonge output)
• Uses mt-metadata to read and write transfer function files where the transfer function data are stored in an xarray
• The workflow is more centralized by introducing MTCollection and MTData objects which are the databases to hold a collection of transfer functions and manipulate them
  • Includes plotting methods, to/from data file types for modeling, rotations, interpolations, static shifts, etc.
  • Can store a collection as an MTH5 using mth5

Quick Example

Typically MT data are collected as surveys and each station produces a single transfer function. These are provided in various formats like EDI, EMTF XML, etc.

One benefit of mtpy-v2 is reading all these in only needs to be done once and places them in a single MTH5 file.

from pathlib import Path
from mtpy import MTCollection

transfer_function_path = Path("/home/survey_00/transfer_functions")

# write directly to an MTH5 file and close when finished loading TFs
with MTCollection() as mc:
    mc.open_collection(transfer_function_path.joinpath("tf_collection.h5"))
    mc.add_tf(
        mc.make_file_list(
            transfer_function_path,
            file_types=["edi", "xml", "j", "zmm", "zss", "avg"],
        )
    )
 

Now when you want to access your data again, you just need to open a single file.

mc = MTCollection()
mc.open_collection(r"/home/survey_00/transfer_functions/tf_collection.h5")

# plot station locations
station_locations = mc.plot_stations()

How to Cite

If you use this software in a scientific publication, we'd very much appreciate if you could cite the following papers:

• Kirkby, A.L., Zhang, F., Peacock, J., Hassan, R., Duan, J., 2019. The MTPy software package for magnetotelluric data analysis and visualisation. Journal of Open Source Software, 4(37), 1358. https://doi.org/10.21105/joss.01358

• Krieger, L., and Peacock, J., 2014. MTpy: A Python toolbox for magnetotellurics. Computers and Geosciences, 72, p167-175. https://doi.org/10.1016/j.cageo.2014.07.013

Contacts

| Jared Peacock | peacock.jared@gmail.com

| Alison Kirkby | alkirkby@gmail.com

System Requirements

• Python 3.8+

License

MTpy is licensed under the MIT license

The license agreement is contained in the repository and should be kept together with the code.

History

2.0.0 (2022-10-20)

• major changes under the hood.
  • Now using mt_metadata to read/write transfer function files
  • Now using mth5 to store the transfer functions
  • Introduced MT, MTCollection, and MTData such that operations are more centralized. Now most methods can be called from MT and MTData
  • Removing older modules and group specific modules
  • Added GitActions for testing
  • Updating tests (still lots of work to do)
  • Updated documentation to upload to ReadTheDocs