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

Our Smooth inversion tomographic method is based on physically realistic modeling of first break propagation for P-wave and S-wave surveys. We forward model refraction, transmission and diffraction (Lecomte, 2000) and back-project traveltime residuals along wave paths also known as Fresnel volumes (Watanabe, 1999) instead of conventional rays. This increases the numerical robustness of the inversion. A smooth minimum-structure and artefact-free 1D starting model is determined automatically directly from the seismic traveltime data by horizontally averaging DeltatV (Wiechert-Herglotz) method 1D velocity-depth profiles along the seismic line. The starting model is then refined with 2D WET Wavepath Eikonal Traveltime inversion (Schuster, 1993). No need to map traveltimes to refractors.

Plot 1.5D refractors obtained with layer-based Plus-Minus and Wavefront refraction methods on 2D WET tomograms. Map traveltimes to refractors interactively or semi-automatically. Automatically convert refractors to layered starting model. Smooth inversion of borehole surveys with constant-velocity starting model for crosshole, zero-offset VSP, walkaway VSP, reverse VSP and VSP constrained refraction surveys. Bidirectional frequency filtering of traces with single-pole or Chebyshev-Butterworth filter. Check your picks for reciprocal traveltime errors in Trace|Offset gather display. Shift picks for all traces of same shot with trigger delay correction. Review our SAGEEP 2010 manual (PowerPoint version, function key help).

Import SEGY and SEG-2 seismic data files and 3rd-party ASCII files using .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. Use Gaussian smoothing as an alternative to uniform smoothing during WET inversion for better resolution. We now support the Conjugate Gradient method for improved imaging of sharp velocity contrasts besides our default Steepest Descent method. Use your layered refraction starting model for WET inversion. Our latest version 3.35 allows multiscale tomography with our new multirun WET inversion.

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WET tomogram with core. Starting model obtained with DeltatV method.

View these tutorials, application samples and theoretical publications :

How to improve your first break picks (PowerPoint 2017; .pdf version)

Imaging of tunnel Excavation Disturbed Zone (EDZ)

Plus-Minus layered refraction vs. 1D-gradient starting model (NGU 2016)

2D characterization of near-surface VP/VS: surface-wave dispersion inversion versus SRT (Pasquet et al. EAGE NSG 2015)

Three dimensional mapping of a buried bedrock valley (Eric B. Avalos, Illinois State University, SEG 2011)

Using refraction seismic velocities to characterize jointing (Palmstrom A., PhD thesis, Oslo University, Norway, 1995)

Comparing conventional layer-based refraction interpretation with 2D SRT (VR Balasubramaniam et al. NIRM, RARE 2016)

Our latest ad shown in EAGE NSG Apr 2017

Using SRT to constrain initial model for MASW (Joana Santos, Univ. Lisboa 2016)

Characterization of a fault system with P-wave SRT, seismic reflection and AMT (Johanna Camacho, Universidad de Granada 2015/2016)

Joint inversion of surface-refraction survey and walkaway-VSP survey

Walkaway VSP survey used to constrain above refraction survey

Blind Test of Methods for Obtaining 2-D Near-Surface Seismic Velocity Models from First-Arrival Traveltimes (Colin Zelt et al., JEEG Sep 2013)

Multiscale tomography for SAGEEP11 blind fault model with version 3.34

Multiscale tomography for basement step model with version 3.34

Häusler et al. image a fault system with ERT, SRT, reflection seismics and gravimetry (Int J Earth Sci 2014)

Quantitative estimation of water storage and residence time in the epikarst with time-lapse SRT (Pierre-Yves Galibert, EAGE GP March 2016)

Site characterisation at the Äspö Hard Rock Laboratory through SRT (Lasheras Maas, Nayeli; Lund University 2015)

SRT for mapping of limestone surface in a tunnel project in Copenhagen (L. C. Bagger et al., Rambøll Danmark May 2016)

Geologic Model of Glacial Outwash in Mclean County, Illinois (Matthew Hartz et al., MDPI Geosciences Feb 2016)

Geophysical and Paleoseismic Investigation of the Cheraw Fault, Southeastern Colorado (Mark Zellman and Dean Ostenaa, ResearchGate Apr 2016)

Application of combined time-lapse SRT and ERT to the analysis of infiltration and dissolution processes in the epikarst of the Causse du Larzac, France (Remi Valois et al., EAGE NSG Feb 2016)

Cross plot analysis on a levee using time lapse SRT and ERT (Leti Wodajo et al., SEDHYD 2015, Reno Nevada)

Water-table depth estimation using SRT (Douglas B. Desper et al., EAGE NSG Oct 2015)

Combining SRT with ERT and surface-wave dispersion to understand bedrock aquifer recharge (Sylvain Pasquet et al., EAGE NSG Aug 2015)

Using WET SRT and Poisson's ratio for near-surface imaging at an archeological site in Greece (Hinojosa-Prieto and Hinzen, EAGE NSG Apr 2015)

Tunnel overburden imaging with multiscale WET tomography

Our latest ad shown in SEG TLE Aug 2015 and EAEG NSG Aug 2015

Our booth at SAGEEP 2014 in Boston MA, U.S.A.

Imaging of buried stream channel in estuary setting with 21 shots into 67 receivers

Layered SRT using 7 shots into 20 receivers

Our SAGEEP 2014 expanded abstract now at library.seg.org

Updated tutorial showing how to convert layer model .CSV to layered .GRD starting model (Fig. 17)

2D Conjugate-Gradient WET inversion, CMP Intercept-Time layered interpretation of synthetic traveltime data

Blind Test of Methods for Obtaining 2-D Near-Surface Seismic Velocity Models from First-Arrival Traveltimes (Colin Zelt et al., JEEG Sep 2013)

Earth flow imaging with SRT and cone penetration tests (Guerriero et al. in Geomorphology Aug 2014)

Sloan et al. use SRT and MASW to detect shallow tunnels (JAG Dec 2013)

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

Our expanded abstract presented at SAGEEP 2014, Boston, MA U.S.A.

Optimized interpretation of SAGEEP 2011 blind data, with Smooth inversion and Plus-Minus method

Kotyrba and Schmidt show combination of SRT and ERT for the detection of abandoned mine workings

Ramboll uses SRT for offshore wind farm planning, with extensive marine streamer survey

Our contribution to forum.detectation.com SRT modeling and interpretation showing 2D WET inversion

Imaging brine zones with SRT and ERT (Thomas Schicht, K-UTEC AG / EAGE First Break Aug 2013)

Comparing MASW with SRT and VSP (Dal Moro, Keller / EAGE NSG 2013)

Reverse VSP survey, 49 shots from two boreholes into 24 receivers (GHD 2013)

Tutorial showing how to build a "basement step" model grid with Surfer, and how to generate and invert synthetic shots for this model

Updated PalmFig9 tutorial, now showing Smooth inversion and layer-based Wavefront interpretation of synthetic shots for syncline model

Interpretation of 7 shots into 24 receivers with Smooth inversion, Plus-Minus and Wavefront layer-based methods (Geo2X 2013)

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

Prof. Bob Whiteley compares published interpretations of SAGEEP 2011 blind 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 SRT and push probe (Linn Karlsson, Gothenburg University 2011)

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

Ground Proving Three SRT 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 with XTV inversion and Wavefront method, for long profile (Joanneum)

Interpretation of long profile with Smooth inversion, DeltatV inversion, Wavefront 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)

PowerPoint presentation of above blind interpretation (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 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 ERT and SRT : 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)

ERT and Seismic Tomography in Identifying Subsurface Cavities (Riddle et al., GeoCanada 2010)

Interpretation of Jacob Sheehan's Epikarst model

Groundwater level determination with SRT : "Water seismic index" (Gerardo Grelle and Francesco Maria Guadagno, University of Sannio)

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

Smooth 2D inversion compared with 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

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)

SRT 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)

WET tomography compared with 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 SRT and statics, compared with well stratigraphy and applied to reflection survey (WesternGeco)

Rayfract in Marine Surveys (Zivko Terzic, 2006)

Plus-Minus Method (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 SRT, ERT 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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