Resistivity surveys application for detection of shallow caves in a case example from Western Iraq

Subject Areas : Geophysics

Ali  Abed ¹ (Department of Applied Geology, College of Science, Anbar University, Ramadi, Iraq.)
Kamal  Ali ² (Department of Applied Geology, College of Science, Anbar University, Ramadi, Iraq.)
Asama  Al-Hadithy ³ (Department of Applied Geology, College of Science, Anbar University, Ramadi, Iraq.)

Received: 2021-07-23 Accepted : 2021-10-29 Published : 2021-10-29

Keywords: Iraq, Haditha, Dipole-dipole array, cavity, 2-D and 3-D imaging technique,

Abstract :

The 2-D and 3-D imaging resistivity techniques were used in the current study to determine the shallow subsurface caves in the Haditha region, western Iraq. The 2-D resistivity imaging has been applied at five locations. The dipole-dipole arrangement was selected with an electrode spacing of 2 m. The inverted models show the anomalous resistivity variation between the background rocks and the voids. Which showed shallow cavities at 1 to 6 m depth, whereas some of them are extending to a depth of 23 m. The unconformity layer between Anah and Euphrates formations is the lowest cohesive than the rocks beneath and above it. Providing the best area for the caves to be formed resulted from dissolving its rocks by leaking rainwater and groundwater. The 3-D resistivity imaging technique was selected near some visible caves by collating seven 2D imaging lines in mapping the subsurface extent of such cavities. 3D imaging draws a sub-surface image in presence of 3D inhomogeneity such as caves. The horizontal slices of 3D models show up these caves with anomalous high resistivity at 0-0.80 m, 0.80-1.72 m, 1.72-2.78 m, and 2.78-3.99 m depths. It also shows a group of small caves, such as the sink-hole canals that connect the main cave to the surface. Both 2-D and 3-D resistivity models have marked a very similar spread of subsurface caves in the study area and show some caves, in the upper part of the unconformity layer. The large values of RMS error for models, attributed to the presence of large homogeneities in the study area. Such heterogeneities are mainly caused by a large variation in the subsurface resistivity of the rocks surrounding the caves and the large spread of shallow caves.

References:

1. Abed AM (2013) Comparison between 2D imaging survey and traditional electrode arrays in delineating subsurface cavities in Haditha-Hit area (W. Iraq), Ph. D. Thesis (Unpublished), University of Baghdad, College of Science 7(3):166-75


2. Abed AM, Al-Zubedi AS, and Abdulrazzaq ZT (2020) Detected of gypsum soil layer by using 2d and 3d electrical resistivity imaging techniques in University of Anbar, Iraq, Iraqi Geological Journal 53 (2C):134-144.


3. Abed AM, Thabit JM, AL-Menshed FH (2021) An Attempt to Image Um El-Adam Cavity Structure in the Karst Terrain at Hit Area, Western Iraq, Iraqi Geological Journal 54 (1A), 44-54.


4. Al-Ane JM (1993) Detection subsurface cavities by using the electrical resistivity method in Hamam A-Alel area. Journal of the Geological Society Iraq 26:13–26,


5. Al-Hetty SO, Al-jibouri AS, Abed AM (2021) Description of the Karst Phenomena Spreading Along Stratified Sequence in the Western Desert of Iraq, Iraqi Geological Journal 54 (1B), 94-101.


6. Al-Zoubi AS, Abueladas AE, Al-Rzouq RI, Camerlynck C, Akkawi E, Ezarsky M, Abu-Hamattch ZSH, Ali W, Al Rawashdeh S (2007) Use of 2D multi electrodes resistivity imaging for sinkholes hazard assessment along the Eastern part of the Dead Sea, Jordan. American Journal of Environmental Sciences 3:230–234.


7. Aizebeokhai AP, Oyeyemi KD (2014) Application of geoelectrical resistivity imaging and VLF-EM for subsurface characterization in a sedimentary terrain, Southwestern Nigeria. Arabian Journal of Geosciences8: 4083-4099.


8. Bentley LR, Gharibi M (2004) Two- and three-dimensional electrical resistivity imaging at a heterogeneous remediation site. Geophysics 69:674–680.


9. Busby JP (2000) The effectiveness of azimuthal apparent resistivity measurements as a method for determining fracture strike orientations. Geophysical Prospecting 48:677–695.


10. Chambers JE, Kuras O, Meldrum PI, Ogilvy RD, Hollands J (2006) Electrical resistivity tomography applied to geologic, hydrogeologic, and engineering investigations at a former waste-disposal site. Geophysics 71(6): B231–B239.


11. Chambers JE, Wilkinson PB, Wardrop D, Hameed A, Hill I, Jeffrey C, Loke, MH, Meldrum PI, Kuras O, Cave M, Gunn DA (2012) Bedrock detection beneath river terrace deposits using three-dimensional electrical resistivity tomography. Geomorphology 177–178:17–2520.


12. Dahlin T, Loke MH (1997) Quasi-3D resistivity imaging: mapping of 3D structures using two-dimensional dc resistivity techniques, 3rd Mtg., Environ. Eng. Geophysics. Assn., Expanded Abstracts, pp 143–146.


13. Dahlin T, Bernstone C, Loke MH (2002) A 3-D resistivity investigation of a contaminated site at Lernacken, Sweden. Geophysics 67(6):1692–1700.


14. Dutta NP, Rose RN, Saikia BC (1970) Detection of solution channels in limestone by electrical resistivity method. Geophysical Prospecting 28: 405–407.


15. Elawadi E, El-Qady G, Salem A, and Ushijma (2001) Detection of cavities using pole-dipole resistivity technique. Memoirs of the Facility of Engineering, Kyushu University 61(4):101-112.


16. Loke MH, Dahlin T (2010) Methods to reduce banding effects in 3-D resistivity inversion. In: Proceedings of the 16th European Meeting of Environmental and Engineering Geophysics, 6–8 Sep 2010, Zurich, Switzerland, A16.


17. Loke MH, Barker RD (1996) Practical techniques for 3D resistivity surveys and data inversion. Geophysical Prospecting 44:499–524.


18. Loke MH (2020) Tutorial: 2-D and 3D Electrical Imaging Surveys, Malaysia. http://www.geotomosoft.com/


19. Massoud U, Qady G, Metwaly, Santos F (2009) Delineation of a shallow subsurface structure by azimuthal resistivity sounding and joint inversion of VES-TEM data: case study near lake Qaroun, El Fayoum, Egypt. Pure and applied geophysics 166:701–719.


20. McDowell PW (1979) Geophysical mapping of water-filled fracture zones in rocks. International Association of Engineering Geology 19:258–264.


21. Obiadi II, Onwuemesi AG, Anike OL, Obiadi CM, Ajaegwu NE, Anakwuba EK, Akpunonu EO, Ezim EO (2012) Imaging subsurface fracture characteristics using 2D electrical resistivity tomography. International Journal of Engineering Science 1:103–110.


22. Rucker DF, Levitt MT, Greenwood WJ (2009) Three-dimensional electrical resistivity model of a nuclear waste disposal site. Journal of Applied Geophysics 69(3-4): 150–164.


23. Salman AM, Abed AM, Thabit JM (2020a) Comparison between Dipole-dipole and Pole-dipole arrays delineation of Subsurface Weak Zones Using 2D ElectricalImaging Technique in Al-AnbarUniversity, Western Iraq, Iraqi Journal of Science 61 (3): 567-576.


24. Salman AM, Thabit JM, Abed AM (2020b) Application of the Electrical Resistivity Method for Site Investigation in the University of Anbar, Ar-Ramadi City, Western Iraq, Iraqi Journal of Science 61(6): 1345-1352.


25. Sissakian V, Salih SM (1994) The Geology of Ramadi, Area. Map-NA- 38-9 (GM-18) Scale 125000, GEOSURV. UnpublishedInternal Report.


26. Sissakian V, Ibrahim E, Ibrahimand F, AL-Ali N (2005) Explanatory of Geological Hazard Map of Iraq 1st Edition, (Scale 1:1000000) D. Geol. Surv. (GEOSURV) Min. Invest, Baghdad.


27. White RMS, Collins S, Denne R, Hee R, Brown P (2001) A new survey design for 3D IP modeling at Copper hill. Exploration Geophysics 32(4):152–155.


28. Yang X, Lagmanson N (2006) Comparison of 2D and 3D electrical resistivity imaging methods. Symposium on the Application of Geophysics to Engineering and Environmental Problems Proceedings: 585–594.


29. Yilmaz S (2011) A case study of the application of electric resistivity imaging for investigation of a landslide at the highway. International Journal of Physical Sciences 6:5843–5849.