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RAYFRACT® Seismic Refraction & Borehole Tomography - Subsurface Seismic Velocity Models for Geotechnical Engineering and Exploration

Our Rayfract® refraction tomography software allows reliable imaging of subsurface velocity structure including faults, strong lateral velocity variation and other velocity anomalies. Our Smooth inversion tomographic method is based on physically meaningful modeling of first break propagation, for P-wave and S-wave surveys. This includes forward modeling of refraction, transmission and diffraction (Lecomte, 2000) and back-projection of traveltime residuals along wave paths, also known as Fresnel volumes (Watanabe, 1999) instead of conventional rays. This increases the numerical robustness of the method. A smooth minimum-structure and artefact-free 1D starting model is determined automatically directly from the seismic traveltime data, by horizontally averaging DeltatV (improved Wiechert-Herglotz) method 1D velocity-depth profiles along the seismic line. This procedure delivers reliable smoothed models even in case of velocity inversions. The starting model is then refined with 2D WET Wavepath Eikonal Traveltime inversion (Schuster, 1993). We use an adapted SIRT algorithm for velocity update of grid cells, when back-projecting traveltime residuals along wavepaths as described by (Schuster, 1993) and (Watanabe, 1999).

WET inversion does not require mapping traveltimes to refractors. Supports many input data formats and extreme topography. Also allows interpretation of traveltimes with layer-based Plus-Minus and Wavefront refraction methods. Map traveltimes to refractors interactively or semi-automatically. Supports Smooth inversion of borehole surveys with constant-velocity starting model, for crosshole, zero-offset VSP, walkaway VSP and uphole refraction surveys. Review our SAGEEP 2010 manual (PowerPoint version, function key help). Allows frequency filtering of traces, with single-pole or Chebyshev-Butterworth filter. Uses multiple CPU cores, for fast parallel forward modeling of traveltimes and back-projection of residuals along wave paths (Fresnel volumes), with SIRT algorithm.

We support import of SEGY and SEG-2 seismic data files, and .HDR batch import of shots. Our XTV inversion models critical refraction of first breaks (intercept-time method) besides diving waves (with DeltatV method) and allows better modeling of low-velocity weathering overburden without a gradient, now both for 1D starting model and for pseudo-2D imaging. XTV inversion output can be used as a starting model for WET inversion. Visit our booth #14 at ARMA Rock Mechanics Symposium in San Francisco.


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WET tomogram with core. Starting model obtained with Delta-t-V method.

View these tutorials, application samples and theoretical publications :

An Evaluation of Methods and Available Software for Seismic Refraction Tomography Analysis (Jacob R. Sheehan et al., Oak Ridge National Laboratory, JEEG March 2005. Compares Rayfract with GeoTomo LLC GeoCT-II and OYO SeisImager)

Determination of rippability (excavatability) characteristics of sub-surface materials, for box culvert construction (Gasch Geophysical Services, Inc. 2013)

Prof. Bob Whiteley compares published interpretations of SAGEEP 2011 blind refraction data with true model

The seismic transmission volume (J.G. Hagedoorn, G. Diephuis EAGE GP 2001. Explains Fresnel volume)

Imaging a fault trace with ERT and SRT (Bavec et al., Geological Survey of Slovenia 2012)

Determination of stratigraphic boundaries with seismic refraction and push probe (Linn Karlsson, Gothenburg University 2011)

Imaging of shale bedrock with SRT and RQD (GEOVision 2010)

Ground Proving Three Seismic Refraction Tomography Programs (Dennis R. Hiltunen et al. 2007, University of Florida. Compares OYO SeisImager and Optim LLC SeisOpt Pro with Rayfract)

Imaging an abandoned mining shaft (GeoExpert AG 2013)

Burton et al. use SRT, ERT and borehole logs to investigate preferential flowpaths for contaminants

Powers and Burton use SRT to investigate the depth to competent bedrock, at a construction site

Ruiz-Villanueva et al. use SRT, Time Domain Reflectometry (TDR) and geotechnical tests for hydrogeomorphic characterization of a shallow landslide

Travelletti et al. use SRT and laser scanning to define the geometry, the kinematics and the failure mechanism of a large landslide

Bedrosian et al. use SRT, ERT, TEM, MT and LiDAR to image structure beneath an earthen dam

Gazdek et al. use SRT to image soil improvement by embedding of gravel cylinder columns (piles)

Prof. Bob Whiteley comments on Mt. Bulga line 00 SAGEEP 2012 interpretation by Dr. Palmer

Smooth inversion with free trial, of synthetic data for thrust fault model. Shows successful imaging of strong lateral velocity variation.

Smooth XTV inversion with free trial, of Jacques Jenny THEORIC2.ASC synthetic data for a layered model. Shows Surfer gridding artefacts.

Smooth inversion with free trial, of Palmer Mt. Bulga data. Shows interactive varying of WET wavepath width, to control non-uniqueness.

Master Thesis Stefan Jansen, Niels Bohr Institute, University of Copenhagen 2010. Evaluates Rayfract with synthetic data.

Comparison of WET tomography with ERT and Nakamura H/V method (Benjumea et al. 2011)

Smooth inversion compared to XTV inversion and Wavefront method, for long profile (Joanneum)

Interpretation of long profile with Smooth inversion, DeltatV inversion, Wavefront refraction and Plus-Minus method (GeoExpert ag)

Smooth inversion of 6 shots into 12 channels (Guyana Goldfields)

Geothermal fault imaging with ERT, SRT and SP ( Lamb et al., Boise State University, AGU 2011)

Interpretation of synthetic and field data with surface wave analysis and Rayfract traveltime tomography, Boiero and Socco, EAGE Geophysical Prospecting Nov 2010.

Integrating Hydrogeological and Geophysical Methods for the Characterization of a Deltaic Aquifer System, Falgas et al. 2011.

Thrust fault modeling and imaging with Surfer 8 and Rayfract 3.19

Import SEG-2 shots into borehole profile database, update header data, Smooth invert (GHD data)

Robert J. Whiteley comments on Mt. Bulga interpretation published by Dr. Palmer

Combine two adjacent cross-hole surveys (3 boreholes) into one tomogram (LNEC data)

Interpretation of First-Arrival Travel Times with Wavepath Eikonal Traveltime inversion and Wavefront method (Rohdewald, SAGEEP 2011)

Tutorial how to build and use your own layer-based starting model

Tutorial showing how to resort borehole traces by common receiver

An analytical raypath approach to the refraction wavefront method (Ali Ak, Geophysical Prospecting November 1990. Compares Wavefront method with Plus-Minus and GRM)

Detecting perched water bodies using surface-seismic time-lapse traveltime tomography (Gaines et al, SEG 2010. Includes velocity error analysis)

Subsurface tunnel detection using electrical resistivity tomography and refraction tomography: a case study (Riddle, Hickey et al., SAGEEP 2010)

Time-lapse seismic measurements on a small earthen embankment during an internal erosion experiment (Hickey et al., SAGEEP 2009)

Seismic measurement for detecting underground high-contrast voids (Hickey et al., SAGEEP 2009)

Interpretation of Jacob Sheehan's Epikarst model

Refraction methodology for groundwater level determination: "Water seismic index" (Gerardo Grelle and Francesco Maria Guadagno, University of Sannio)

Enhanced coastal geotechnics with integrated marine seismic reflection and multi-source, extended array refraction (Robert Whiteley, Matthieu Bardout and Simon Stewart 2010; includes synthetic model with velocity inversion)

Smooth 2D inversion compared to conventional Wavefront interpretation of Palmer Mt. Bulga data set

Building syncline model and forward modeling data described by Derecke Palmer in EAGE Geophysical Prospecting March 2010

Improving interpretation of syncline model

Plume and Lithologic Profiling with Surface Resistivity and Seismic Tomography (David B. Watson et al. 2005, Oak Ridge National Laboratory Tennessee)

Comparison of pseudo-2D Delta-t-V starting model with 1D-gradient starting model, for basement depression (syncline model) described by Derecke Palmer

Is the Optimum XY spacing of the Generalized Reciprocal Method (GRM) constant or variable? Paper presented by Hamdy H. Seisa at 67th Annual Meeting of the German Geophysical Society (DGG), Aachen, March 26-29 2007

Determining depth of blast induced damage in a mine wall (J.A. Singer et al. 2009)

Geophysical characterisation of karstic networks (Roger Guérin et al. 2009, Comptes Rendus Geosciences Volume 341, Issues 10-11)

The Gschliefgraben Landslide (Robert Marschallinger et al. 2009, Austrian Journal of Earth Sciences Vol. 102/2; compares P-wave tomography with GRM)

Refraction Tomography for volume analysis of saturated alluvium (Michael H. Powers and Bethany L. Burton, USGS 2006. Compares GeoTomo LLC GeoCT-II with Rayfract)

Tutorial showing interpretation of 5 shots recorded with 12 channels

Beach subsurface imaging with reflection seismic, WET inversion and MASW (Mark G. Olson, Advanced Geoscience, Inc. 2008)

Geophysical investigation of the Sandalp rock avalanche deposits (Laura V. Socco et al. Journal of Applied Geophysics Jan 2010. Compares resistivity tomography with seismic P-wave tomography, and active and passive surface wave analysis)

Seismic characterization of an Alpine site (L.V. Socco et al. EAGE Near Surface Geophysics Aug 2008. Correlates WET tomography with reflection, surface wave and pseudo-2D shear wave interpretation plus downhole measurement)

Underwater refraction (Robert J. Whiteley and Simon B. Stewart 2008. WET tomography confirmed with onshore boreholes)

WET tomography compared to conventional refraction and magnetic lineaments (Håkan Mattsson, GeoVista AB, SKB report R-07-56 Sep 2007, pages 131-144)

Sub-bottom river imaging with Smooth inversion and constant-velocity starting model (Geotomographie GmbH data)

Active landslide imaging with two crossing lines, different receiver spacing (JOANNEUM RESEARCH data)

Smooth inversion of cross-hole survey, with constant-velocity starting model (International Geophysical Technology S.L. data)

Smooth inversion of Geometrics SeisImager sample file (Geofisica Misure s.n.c. data)

Smooth inversion of Optim LLC SeisOpt® data set (FUGRO WEST data)

2D sections of porosity and water saturation percent from combined resistivity and seismic surveys for hydrogeologic studies (R. Mota and F. Monteiro dos Santos, SEG The Leading Edge June 2006. Simulated Annealing of Res2DInv and Rayfract output)

Sinkhole imaging with Smooth 2D inversion compared with conventional Wavefront interpretation

Velocity imaging through complex near-surface structures by tomography (Xianhuai Zhu, EAGE 64th Conference & Exhibition, Florence 2002. Shows diffraction and scattering of first break energy penetrating thin high-velocity Basalt layer)

Land Streamer Aided Geophysical Studies at Saqqara, Egypt (Carlyle R. Miller et al. JEEG December 2005; HTML)

Client WET interpretations imaging faults, dikes, boulders and stratigraphy (Terra Geosciences 2007)

Refraction seismic theory and application (Jacques Jenny)

Subsurface velocity imaging below street (Zivko Terzic, 2007)

Comparison of shallow refraction interpretation methods for regolith mapping (Robert J. Whiteley and Peter J. Eccleston, ASEG Exploration Geophysics Dec 2006 final draft)

Data interpretation with Rayfract® software (Microsoft PowerPoint slide show)

Comparison of pseudo-2D Delta-t-V starting model with 1D-gradient starting model, for basement depression model as described by Jacob Sheehan

Comparison of 2D WET tomographic imaging with conventional interpretation (Håkan Mattsson, GeoVista AB)

seg2_edit; A Program for Editing and Manipulating SEG-2 Files, by K. J. Ellefsen (USGS Open-File Report)

Tau-p refraction tomography and statics, compared to well stratigraphy and applied to reflection survey (WesternGeco)

Rayfract in Marine Surveys (Zivko Terzic, 2006)

The Plus-Minus Method of Interpreting Refraction Sections (J.G. Hagedoorn 1959, EAGE Geophysical Prospecting, volume 7, pp. 158-182)

Comparison of pseudo 2D Delta-t-V starting model with 1D gradient starting model

Imaging of dynamic Poisson's ratio with fail-safe "Smooth inversion" as implemented for version 2.51

Investigation of a landfill with Refraction, Resistivity and Electromagnetic methods (William E. Doll et al. 2001, Oak Ridge National Laboratory Tennessee; Adobe Acrobat; compares Rayfract with Rimrock Geophysics SIPT-2 software)




More tutorials, application samples and theoretical publications


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