Case study: Evaluation of the depth of the slip surface of a landslide

Following the rupture of an water pipeline, a landslide movement occurred in an area classified as highly susceptible to collapse. The event dislocated a retaining wall and created tension cracks in the ground. In order to define the geometry of the materials involved in the movement, a seismic survey was carried out using the technique of seismic refraction tomography and the MASW.

Tension cracks

The site is characterized by flysh with a cover of silty colluvial soils with sand and gravel estimated in a few meters thick. The landslide movement apparently involves only the cover.

The seismic line has been realized transversely to the slope taking advantage of the little space available intersecting the tension fractures. An intergeophonic spacing of 2 meters and 4 energizations outside the line and 3 inside was used.

Seismic refraction profile shown using smartTomo.
Tomography profile

The tomographic profile shows a lateral variation in velocity at the tension fractures, highlighted by the undulation of the isolines at about 10 meters from the beginning of the profile. In depth, it can be assumed that the sliding surface is delimited at a depth of about 8 metres by the speed inversion also highlighted by the representation of the Laplacian gradient (local variation of speed with respect to the surrounding cells).

Profile of the laplacian gradient of a seismic tomographic profile using SmartTomo
Laplacian profile displayed using smartTomo. The representation of gradients is one of the advanced views possible when using SmartTomo.

Download demo

The smartTomo demo version allows the users to perform tomographic processing on a preloaded dataset.
The dataset has been recorded on a landfill site where the limestone rock substrate deepens from right to left. The data has acquired by a 16-bit, 16-channel seismograph made by SARA Electronic Instruments . Six energisations were carried out which allowed to identify the geometry of the filling materials.

Continue reading “Download demo”

Release History

September 2019 – smartTomo 2019.3

See release notes

July 2019 – smartTomo 2019.2

This update covers different aspects of the software. Automatic picking of the first breaks now implements a procedure to suppress the first “crazy” arrivals. Only those that fall within a realistic range of seismic velocity are kept.
Manual picking can now be done by dragging the mouse.
The user can select three different modes of smoothing the results, that allow to give more or less emphasis to the local characteristics.
Axes have been added on all four sides of the tomographic profile for better readability of results.
From this version are available new palettes designed to be homogeneous to perception and accessible to colorblind people.

March 2019 – smartTomo 2019.1

This version introduces signal filtering. The user can choose whether to process the signal manually or to rely on NoRe, the automatic tool of Noise Reduction. Further improvements contained in this release are the saving of custom pallets and isolines and the ability to save the configurations of the geometry of the seismic lines.

October 2018 – smartTomo 2019.0

This version was presented at GeoFluid by our partner Geostudi Astier Srl. Compared to the first version, the whole part of the display of results has been rewritten: starting from this release users can display the isolines of speed and the color palette is customizable.

April 2018 – smartTomo 2018.0

It’s the first commercial version of smartTomo. It implements the basic functions of the topographic problem solver. The algorithm is already parallel and takes full advantage of the potential of multicore systems.

SmartTomo 2019.3 – released

On September 10, 2019 a new version of the smarttomo was released.
This version brings news in the visualization of results and improvements in compatibility with seismic files.
Compatibility with some of SEGY formats has been added.
Now user can set the color of the isolines and the density of the labels to make the results of the processing always readable.

smartTomo seismic tomography profile with white contour lines.
smartTomo profile with green contour line