Swan

• Analysis of 2-dimensional sections of the ground using multi-shot data obtained by rolling-along the receivers array.
   
• Graphic interface studied to simplify the:
  
  
  • Parameters setting to defines the synthetic model for the inversion in interactive mode.
  • Picking option directly on the spectrum graph to extract the dispersion curve.
  • Editing of the experimental dispersion curve.
     
• Computational algorithms complete, fast and efficient:
  • computation of the FK, FV and FX spectra.
  • several windowing options (boxcar, hamming, hanning, blackman, bartlett, etc.).
  • parameter estimation of the synthetic model of the ground up to 30 layers.
  • control of the main parameters during the automatic inversion process (tolerance on errors and fit, noise level settings).
     
• Export of images in several graphic file formats.
   
• Editing of the experimental dispersion curve.

INFORMATION REQUEST

Download SWAN as FREE DEMO version, or the FULL version (which requires license and USB protection).
The DEMO version only has a few limitations compared to the FULL version: you can not save the processing, the demo expires after 50 hours of operation (so avoiding to leave unnecessarily the program open you can continue to use it for months), you can not change synthetic model of the table manually, and other small limitations. Anyway they are not preventing the evaluation of the software.
(For the old Windows XP operating system is recommended that you download this version of SWAN DEMO and FULL).

Follow these instructions if you have problems installing SWAN.

If problems with the drivers of your USB protection dongle you can try to replace those distributed with SWAN with those of the producer, which could be more up to date. Open the application, uninstall those already on your computer (Uninstall), relaunch the app and install the drivers (KEYLOK 2 USB, Standalone), then insert the USB dongle into your computer, wait a few seconds, and start SWAN.

Download the tutorial (example data with a detailed description of the procedure for the data interpretation).

Finally a few notes on the interpretation of REMI data.

INFORMATION REQUEST

The processing flow of the raw data follows these steps:

• Pre-processing:
  
  
  • Clean-up of signal from noise events and ambient sources.
  • Assembly of virtual arrays, to overcome the limitations on geophones available in site.
  • Spectral analysis, through FFT, of the seismogram obtained, through mathematical tools user selectable.
     
• Extraction (manual or automatic) of the experimental dispersion curve with display in the frequency domain.
   
• Generation of a dispersion curve based on a synthetic model of the ground, through the characterization, of the thickness of each layer, of the velocity of S waves and of P waves.
   
• Inversion of the synthetic model in interactive mode, or automatic (with options to reconstruct or constrain the S waves velocities or the layer thicknesses).

After the processing the value of the parameter Vs30 is calculated, to classify the site according to the design and engineering standards and regulations.

INFORMATION REQUEST

Rix, G.J. and Lai, C.G.
Model-Based Uncertainty in Surface Wave Inversion
Proceedings, GeoCongress 2006, “Geotechnical Engineering in the Information Technology Age”, Atlanta, February 26-March 1, 2006. Paper Reference No. 11904.

Lai C.G., Wilmanski K. (Editors)
Surface Waves in Geomechanics: Direct and Inverse Modeling for Soils and Rocks, CISM Lecture Notes No. 481, CISM-Springer Verlag, pp. 385, ISBN: 3-211-27740-4. CD with software programs for surface wave analysis is included.

Lai, C.G.
“Chapter 3 – Surface Waves in Dissipative Media: Forward and Inverse Modelling” in Surface Waves in Geomechanics: Direct and Inverse Modeling for Soils and Rocks. Edited by C.G. Lai and K. Wilmanski, CISM Lecture Notes Vol. No. 481, Springer-Verlag, pp. 385, October 2005. ISBN: 3-211-27740-4. CD with software programs for surface wave analysis is included.

Rix, G.J.
“Chapter 3 – Near-Surface Site Characterization Using Surface Waves” in Surface Waves in Geomechanics: Direct and Inverse Modeling for Soils and Rocks. Edited by C.G. Lai and K. Wilmanski, CISM Lecture Notes Vol. No. 481, Springer-Verlag, pp. 385, October 2005. ISBN: 3-211-27740-4. CD with software programs for surface wave analysis is included.

Lai, C.G., Foti, S., Rix, G.J.
Propagation of Data Uncertainty in Surface Wave Inversion
Journal of Environmental and Engineering Geophysics, 10(2), pp. 219-228, July 2005.

Lai, C.G., Rix, G.J., Foti, S., Roma, V.
Simultaneous Measurement and Inversion of Surface Wave Dispersion and Attenuation Curves
Soil Dynamics and Earthquake Engineering, Vol. 22, No. 9-12, pp. 923-930, October-December 2002.

Rix, G.J., Lai, C.G., Spang, A.W.
In Situ Measurements of Damping Ratio Using Surface Waves
Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 126, No.5, pp. 472-480, May 2000.

Lai, C.G., Foti, S., Godio, A., Rix, G.J., Sambuelli, L., Socco, V.
Geotechnical Site Characterization Using Geophysical Techniques
Italian Geotechnical Journal, RIG, Special Publication, No.3, pp. 99-118, September 2000, Specialty Panel of 20th Italian National Conference on Geotechnics, Parma, Italy, September 22-25, 1999 (in Italian).

Lai, C.G.
Spectral Analysis of Surface Waves – Active Methods – Technical Recommendations
Italian Geotechnical Journal, RIG, No.4, pp. 201-212. December 2000.

Lai, C.G., Rix, G.J.
Inversion of Multi-Mode Effective Dispersion Curves
Proceedings, 2nd International Symposium on Pre-Failure Deformation Characteristics of Geomaterials, IS Torino 99, Torino, Italy, September 26-29, 1999, Vol. I, pp. 411-418.

Lai, C.G., Rix, G.J.
Simultaneous Inversion of Rayleigh Phase Velocity and Attenuation for Near- Surface Site Characterization
Contract Report prepared for the National Science Foundation under Grant No. CMS-9402358, and the U.S. Geological Survey, Department of Interior, Award No. 1434-95-G-2634, Report No. GIT-CEE/GEO-98-2, July, 1998, pp. 258.

Strobbia, C.
Surface wave methods: acquisition, processing and inversion,
Ph.D. Thesis, Politecnico di Torino, Italy, 2003.

INFORMATION REQUEST