Alternatively to the digital MBAS system the analog version of a borehole geophone string (MBAS-A) is available on the market.
The instrument can be used for S-wave borehole tomography or downhole surveying. It consists of up to eight geophone stations each equipped with a tri-axial sensor. The string is fully water proof and can be used to receive P- and S-waves in dry or water filled boreholes. Please take detailed technical information from the product sheet.
We will release our new P-wave sparker borehole source and digital hydrophone string soon.
The borehole source SBS1000 Magnum is designed for P-wave tomography between boreholes up to 1000 m depth. The source consists of three parts housing the complete high-voltage power supply for charging up to about 3 KV. The source can be connected to a GO-4 cable head and a standard logging unit (4-conductor cable). The unit is powered from surface by means of a 230 VAC power supply.
The hydrophone string BHC1000 is a fully digitized borehole receiver unit running on 4-conductor cable. The system consists of max. 24 hydrophones moulded to a multicore cable. A digitization unit is placed on top of the string and can be connected to the standard 4-conductor cable. At surface a control unit is connected to the logging winch and directly to laptop.
The 78th EAGE Conference & Exhibition 2017 is the largest and most comprehensive multi-disciplinary geoscience event in the world. The event includes a large conference – in total over 1,000 technical oral and poster presentations – and a technical exhibition presenting the latest developments in geophysics, geology and reservoir/petroleum engineering.
Come and visit us at BOOTH#781 to find our latest seismic borehole technology demonstrated.
The German Geophysical Society (DGG) organizes a scientific conference every year. This conference is a forum for the presentation of works from all areas of geophysics with the focus on current researches.
Come and visit us at the Geotomographie booth.
SAGEEP is internationally recognised as a leading conference on the practical application of shallow geophysics.
Come and visit us at BOOTH#1
Listen to our talk given by Thomas Fechner:
Structure delineation using S-wave reflection seismic and borehole tomography to support ground water modelling.
Medicines Sans Frontiers provides medical assistance to people in need and to alleviate their suffering when local health structures no longer work due to natural hazards or human-induced crises. It is a private international organization. Most of the employees are doctors and nurses, but also representatives of many other professions. They help people regardless of their ethnic origin and religious or political convictions.
The seal "Innovation through Research" has been awarded to Geotomographie by the Stifterverband/Germany. The Stifterverband honors researching organizations for their special communal and societal responsibility with the quality seal. The Stifterverband focuses its efforts primarily on the fields of education, science and innovation. To date, it is the only organisation in Germany to engage in holistic work in all three areas, with projects that build on one another with synergistic effect.
12. - 15. June
79th EAGE Conference & Exhibition 2017
Paris Expo Porte de Versailles, Paris (France)
19. - 23. March
SAGEEP (Symposium on the Application of Geophysics to Engineering and Environmental Problems)
Denver Marriott Denver City Center, Denver (USA)
27. - 30. March
University Potsdam, Potsdam (Deutschland)
3. - 7. September
Near Surface Geoscience (23rd European Meeting of Environmental and Engineering Geophysics)
Clarion Hotel & Congress Malmö Live, Malmö (Schweden)
9. - 12. October
International Conference of Engineering Geophysics (ICEG)
Conference Auditorium of the Crescent Building, Al Ain (UAE)
19. - 20. January
10. Kolloquium „Bauen in Boden und Fels“
Technische Akademie Esslingen, Ostfildern (Germany)
14. - 17. March
Universität Münster, Münster (Germany)
30. May - 2. June
78th EAGE Conference & Exhibition 2016
Reed Messe, Wien (Austria)
24. - 27. June
7th International Conference on Environmental and Engineering Geophysics
Institute of Geology and Geophysics - Chines Academy of Science, Beijing (China)
5. - 9. September
ISC’15 (5th International conference on geotechnical and geophysical site characterization)
Jupiters Hotel, Gold Coast, Queensland (Australien)
5. - 8. October
Piacenzaexpo, Piacenza (Italy)
16. - 21. October
SEG (Society of Exploration Geophysicists) - Annual Meeting
Kay Bailey Hutchison Convention Center, Dallas (USA)
2016: T. Fechner, J. v. Ketelhodt and Z. Lin
Geophysical methods are able to fill the gap between boreholes and to provide a measure of the spatial continuity of structures. Borehole seismic tomography promises the highest resolution when applied at a local scale of a few tens of meters. Currently, almost exclusively P-wave tomography is employed in geotechnical oriented tomographic surveys. However, from the geotechnical perspective, the benefit of P-wave tomography is rather limited. It is the S-wave structure of the ground which is crucial to derive geotechnical relevant parameters, such as shear strength or other elastic moduli. Up to now, only little effort has been made to develop the borehole S-wave crosshole tomographic method. S-wave tomography has some clear advantages compared to conventional P-wave tomography, such as a better spatial resolution and a higher sensitivity to material changes. Furthermore, S-waves are only slightly influenced by the ground water table and S-waves passing this zone are not much affected by ray bending compared to P-waves. Within this paper we present first results of a newly developed S-wave tomography system and field results from different test sites.
2016: T. Fechner, H. Kolb, A. Patzelt
Subsidence of pavement and infrastructure of a gas plant located on an island in the Middle East were observed. Several parts of the industrial plant were built on highly weathered sandstone and limestone or backfilled areas which are pretty inhomogeneous. The results are loosening zones and cavities in the subsurface. A combination of ground-penetrating radar (GPR), electrical resistivity tomography (ERT) as well as surface wave seismic (MASW) were used to benefit from their individual resolution, depth penetration and advantages to investigate the underground.
2015: T. Fechner, S. I. Ehosioke, S. Mackens, L. Karl and D. Tweeton
Seismic borehole tomography is a standard method and is routinely used for the detection of karstic phenomena and the delineation of geological structures. Seismic tomography is believed to be the seismic method promising highest accuracy and reliability. However, data quality has a significant influence on the accuracy of a travel time pick. Tomographic inversion results are presented where the signal-to-noise ratio of the first arrival times is considered as a data quality measure during tomographic inversion. This new data quality weighting scheme is supposed to provide more reliable inversion results. Information about the reliability of the tomogram provided along with the seismic tomogram may support the geophysicist interpretation.
2015: S. Mackens, T. Fechner, N. I. C. Rios, D. Tweeton, J. C. Galindo Guerreros and E. Niederleithinger
Jet grouting is a geotechnical method of ground improvement to increase shear strength and stiffness of soils. Typical geometries of grouted soil are panels or columns. The final diameter of grouted columns can be predicted only vaguely and an in situ control often impossible, especially under complex site conditions. Therefore, borehole seismic measurements (crosshole, downhole and tomography) were tested as a quality control to verify the extent of the column and to monitor the influence of the jet grout injection on the soil over time. The acquired seismic data show clear traveltime differences which allow the determination of the specific column depth and diameter.
2015: S. Mackens, L. Karl, T. Fechner and D. Tweeton
In seismic borehole tomography, the interpretation of the results is commonly limited to the comparison of the velocity map, the ray coverage, and the global root-mean-square RMS residual. However, the quality of the seismic data has a significant influence on the accuracy of the arrival time picking, but is generally not considered in the inversion. An inversion procedure is presented taking into account the data quality based on the signal-to-noise ratio which is used to weight the traveltime residuals in each iteration step. This implementation also calculates the spatial distribution of the data quality and the distribution of the residual remaining at the end of the inversion, which are used to support the evaluation of a velocity map.
2011: L. Karl, T. Fechner, M. Schevenels, S. Francois and G. Degrande
Effective and reliable methods to survey and monitor the structure of earth-fill dams recently became pressing in terms of the increasing number of flood events in central Europe. Among geophysical techniques, dam imaging using electrical resistivity methods is applied in most cases. Ground-penetrating radar is occasionally used to search for subsurface facilities. This paper focuses on seismic methods, in particular the multichannel analysis of the surface waves (MASW) method to determine dynamic soil properties and identify dyke and dam structures. In this paper the influences of the dyke’s topography on the test results are studied by means of a numerical analysis. Typical cross-sections are modelled using 2.5D finite and boundary elements. The results of models taking the topography into account are compared with models neglecting the topography. The differences are evaluated on the level of the dispersion curves and for one cross-section on the level of the S-wave velocity. They were found to be insignificant for dykes with a width-to-height ratio larger than four. Test results of a testing campaign obtained at two test sites on dykes are selected and compared to the results of borehole logs and cone penetration tests. A remarkable relation between the S-wave velocity and the consistency of the clay sealing was found at one site and valuable information on the composition of the dyke body and base could be obtained.