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Seismic Refraction processing and interpretation using GRM

  • Designed for Windows 9x, NT® and XP® 
  • Protected with convenient USB key
  • Supports most seismic formats
  • Automatic first break picking
  • Manual first break picking by keyboard or mouse with amplified display
  • Automatic assignment of arrivals to layers with manual override
  • Access to arrival assignments and first break picks from GRM interpretation window
  • Presentation graphics with velocity color fill and arc plots for consistency checks
  • Documentation consists of a detailed Windows Help and a PowerPoint tutorial


IXRefraX is the successor to GREMIX and FIRSTPIX, our DOS based seismic refraction data processing and interpretation system. It combines the features of both packages in one integrated system and adds bold and powerful new ideas and features!

New is the simple 2-D forward and inverse modeling. This is designed mostly to automate the GRM interpretation by providing a means of assigning arrivals to layers and determining X-Y values and reciprocal times (where data cannot estimate them). However, the forward and inverse modeling can be used to interpret data sets which lack the redundancy required for GRM interpretation. 

Data Import – RAW Shot Record Trace Data

  • Shot data formats for SEG-1, SEG-2 and SEG-Y formats are auto-detected.

  • There is virtually no limit on number of shots that can be imported to a profile.

  • Data can be appended so historical data can be combined with modern data.

  • ASCII file import of tabulated travel time curves is also available.

IXRefraX™ screen showing a shot record with amplified window near first break pick.

First Break Picking

  • Reads first breaks from files on import or auto-picks as the files are imported.

  • Arrow and page keys are used to move cursor or use mouse to position cursor.

  • Amplified trace section displayed in window on top of trace display.

  • Click mouse or press space bar to pick break.


IXRefrax™ Shot header editor can save, open move or generate geometry of spread.

Shot and geophone spread geometry is read from shot record files as available. Geometry can be created simply and easily and then saved for further use. Addition and multiplication functions allow for shifting and manipulating of existing spread geometries.

Travel time curves can be automatically interpreted using slope-intercept methods.

It is useful to have some information about the earth structure to construct a starting model for the 2-D inversion. Automatic slope-intercept interpretation allows for quick estimates in cases where the earth is relatively flat. Knowledge of ground truth is also useful to have.

Starting with a model which is flat or mimics the topography, inversion methods develop a result that fits the data closely enough to assign arrivals automatically.

Once a general idea of the velocities and depths is conceived, this is used to generate a starting model which is perfected by inversion to get a reasonable fit to the data. The resulting model is then used to assign arrivals to layers and estimate reciprocal times for shot pairs which do not have valid estimates from the data values themselves. 

Model screen showing ray paths from sources to receivers

The simple 2-D model can generate ray paths to illustrate the sampling of the subsurface by the rays which give rise to the travel time data. The forward and inverse modeling can be used to interpret data which lack the redundancy required for GRM interpretation.

The GRM interpretation is automatically generated and the individual segments are presented to the user for perusal, editing, masking and evaluation

Each shot position is used to build as large a shot record as possible using all data recorded from that shot position. These are combined in forward-reverse pairs to generate segments which are then interpreted using GRM and presented for evaluation by the user. Segments can be masked (rejected for use in the combined section), the reciprocal time can be edited, arrivals can be reassigned and even the first breaks for the shots used in generating the segments can be repicked.

Once the GRM interpretation for all shot pairs is compiled, inconsistencies among interpretations for different segments can be investigated, even back to the first break picks on the original shot records.

Once the data has been examined and edited by the user, the GRM interpretation can be regenerated. 

Interpreted depth section showing color fill of velocity and arcs for consistency.

  Eventually, the segments are combined into a single cross section. Colors can be used to denote velocities and arcs can be drawn to illustrate the consistency (or lack thereof) in the interpretation.

Data and Depth section view showing error bars on depth estimates.

Error bars are calculated when interpreted GRM segments are averaged and presented on the graphical display in the depth

 and elevation sections. 



Elevation section showing color coded velocities.

The user has control over the color coding of the velocities so that each section is colored in the same way for comparison.

XYZ file output showing map and profile coordinates with velocities, depths, elevations and time-depths.

ASCII file output of interpreted GRM results can be generated in an XYZ format for importation into third-party software. User has control over output of map and/or station coordinate output, as well as control over output of velocity, depth, elevation and/or time-depth values.



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