GeoTools MTGeotools MT is a comprehensive package of all the software tools you need to process, model, and interpret your magnetotelluric (MT), Audio-frequency MT (AMT), and Controlled Source AMT (CSAMT) data. Geotools MT supports both the explorationists and the research geophysicist. Geotools MT provides the tools you need to:
The flexible Geotools MT framework incorporates all the most commonly used publicly-available codes for forward (1D, 2D, 3D) and inverse (1D, 2D) modeling. The tools in the Database Manager facilitate organization of data, freeing the interpreter or researcher to concentrate on results. The Interactive MT Processing module permits simultaneous viewing of multiple data displays to aid the geophysicist who interactively processes and edits data. There are many options for customizing displays and viewing data throughout Geotools MT, but a carefully-selected set of defaults allows the production geophysicist quick and easy routes through routine processing and interpretation steps; while for the researcher or student there is a comprehensive array of data views and modeling options
Geotools MT - Features
Plots & Processing
The Interactive MT module is often the most-used module in Geotools MT. It includes a flexible viewing system which lets the user to view and compare data from a set of over 500 pre-defined plots. One can customize the appearance of any plot or create your own. Available plot types include XY plots, contoured sections, 1D soundings, stitched 1D soundings, impedance polar diagrams, profile plots, and contours of parameters plotted as a function of frequency and rotation. Over 400 quantities may be plotted including rho, phase, tipper, impedances, coherencies, signal parameters, and 1D or 2D models.
You can compute MT parameters from spectra or impedances based on any type of reference and rotation. Tools then allow the interpreter to mark frequencies as inactive, swap modes, manipulate fit curves, and assign mode (TE/TM) identifications. All of these tools can be applied interactively to individual sites or in batch mode to a group of sites. When a change is made to data, all plots are automatically updated to reflect the change.
1-D MT Modeling
Geotools MT's 1D modeling module incorporates a large selection of tools for both forward and inverse modeling. Its choice of popular modeling algorithms include the Marquardt, Occam, and Fischer inversion and Bostick transform. The user may choose between distinct layer earth models and smoothly varying resistivity structure, and results may be viewed for individual sites or as stitched sections for lines of sites.
Tools in the 1D module allow the interpreter to interactively investigate the effects of variation of model layer thickness, resistivity, and depth; and the effects of static shifts between model and data. Additional tools available in the 1D module include forward modeling for sensitivity analysis; scratch model storage for saving a selection of alternate models for a site; and an auxiliary window option for flexibility in viewing data and models.
2-D MT Modeling
Geotools MT's 2D modeling module combines a selection of the most useful and wished for algorithms for 2D forward and inverse modeling, with a graphical interface which facilitates model entry and viewing of results. 2D modeling codes available in Geotools MT include PW2D forward (Dr. Philip Wannamaker), Occam inversion (Drs. Catherine DeGroot Hedlin and Steve Constable), and Rapid Relaxation Inversion-RRI (Drs. Torquil Smith and John Booker). Also available is a very fast Pseudo-Occam inversion which computes simultaneous 1D inversions of a line of sites while applying 2D smoothing.
Options for easy model / data entry include: a) projection of any depth section, such as a stitched 1D section; b) a polygon editor for model construction; c) projection of any X or Y 3D model slice; and d) painting of resistivity structure via a color palette. Additional features available are an ability to impose fixed structural constraints (Occam); a shared file structure between PW2D, RLM2DI, and Occam, so that one may alternate inversion and 2D forward modeling to verify results; tools for modeling topography and sea-water (PW2D); and a module for viewing results and comparing computed model sites to field data.
Geotools MT provides 3D forward modeling capability. The Geotools MT graphical user interface facilitates a visual construction of the model and provides an array of flexible options for viewing results. The model earth is represented by a mesh like a "stack of bricks" which are assigned electrical resistivity values via a color palette with which the user "paints" the bricks.
Tools which facilitate model painting include flood fill for rapid painting of an area, and an option for copying from one model slice to another. Only the core 3D model is painted; Geotools MT automatically constructs 2D boundary models. The three-window graphical user interface permits views of a model slice in X, Y, or Z, while a cube icon tracks the currently viewed slice. In a separate window, one may step through all slices in the currently selected direction. The user may view model results for any surface element, or retrieve a line of surface sites along a vertical slice. Such model sites may be viewed and manipulated by any of the tools in the Interactive Processing Module
Map & Database Module
The Geotools Map Module allows the interpreter to create a map display of site locations, data, models, and sections. These can be combined with a basemap, topography contours, and other elements to create a complete spatial picture of a survey area.
Items which be displayed on the map include individual sites, sets, or lines of sites; 2D and 3D views including montage plots of sections; induction vectors; wells; overlays containing user-defined lines, areas, symbols, and text; and contours of any Geotools MT data record at a specified frequency or depth.
The user may toggle between lat/long and UTM scales, choose scale bars, and scale ticks and labels. There are options for creating a topography contour or a basemap file with rivers, roads, and other for creating a topography contour or a basemap file with rivers, roads, and other surface features. Your Geotools MT CD-ROM contains the World Data bank (WDB) version 2 public domain data set; and 1:2000000 scale DLG maps from the USGS. Geotools MT can create basemaps for any area of the world based on the WDB data set, and create base maps for the United States from the DLG files.
The completed map can be saved for later display, using the same "save view" option that is available for displays throughout Geotools MT.