Contribution of Seismic and Magnetic Data for the Prevention of Geotechnical Risks Related to Building Cracking in Agadez Region (North Niger)
- 1 Department of Fundamental Sciences, University of Agadez, Agadez, Niger
- 2 Department of Fossil Energy, University of Agadez, Agadez, Niger
Abstract
This study tries to highlight the role of magnetic and seismic data in the prevention of building cracking, which constitutes a geotechnical risk in Agadez City. This city is built on the faulted and fractured sandstone formations of the “Agadez Sandstones Formations”, which were deposited in unconformity on the basement of the Aïr Mountain. This study focuses on the prevention of geotechnical damages related to building cracking in the Agadez region through geophysical methods, which are well known for investigating tectonic structures and their directions on the surface and subsurface. A methodological approach integrated the seismic and magnetic data interpretation combined with field measurement on the cracked building and its underlying substratum, represented by Agadez sandstones and basement. The extraction of seismic lineaments from the West African seismic map showed the seismic directions oriented NW-SE (N135˚ to N160˚), passing through the studied area. The structural interpretation of the magnetic map shows that the Agadez region is also affected by the subsurface lineaments mainly oriented in NW-SE (N135˚) directions, which are similar to the identified seismic lineaments in the same zone. A structural study carried out on the Agadez sandstones and the underlying basement showed that faults and fractures oriented N120˚ to N165˚ affect both the basement of the Aïr Mountains and the sandstone formations on which the city of Agadez is built. These observations showed that building cracking in the Agadez region has a higher propagation tendency according to the directions ranging from NW-SE (N135˚) to NNW-SSE (N165˚). Therefore, the building’s cracking has a stronger propagation component according to these mean directions that are not recommended for building. To prevent and reduce the risks related to building cracking in Agadez region, it is highly recommended to build in the minor directions of cracking propagation, which correspond to NE and SW directions.
- Souley, B.I., Sani, A., Maïga, A.W.D. and Konaté, M. (2022) Geotechnical Risk Assessment and Geological Origin of Building Fracturation in Agadez City (North Niger). Journal of Environmental & Earth Sciences , 4, 33-44. https://doi.org/10.30564/jees.v4i2.4697
- Bonnier (1989) Agadez Sandstones Nappes. Ministry of Hydraulic-DRE, Project NER/86/001.
- Tauzin, P. (1981) Geological Context of Uranium Ore Deposit in Eastern Edge of Tim Mersoï Sedimentary Basin. Intern. Report Minatome, 15.
- Sani, A., Konaté, M., Karimou, D.H. and Wollenberg, P. (2020) Polyphasic Tectonic History of the N70˚ DASA Graben (Northern, Niger). Global Journal of Earth and Environmental Science , 5, 58-72. https://doi.org/10.31248/gjees2020.075
- Wahab, D.M.A. (2017) Location Map of Seismic Focus on the African Continent. OTICE Department, HANEA.
- Wagani, I., Maman, S.B. and Alhassane, I. (2019) Structural study of Akola Uranium Ore Deposit and Geotechnical Risk Related to the Extracting Method in the Cominak, Niger. Revue Ivoirienne des Sciences et Technologie , 34, 230-246.
- Liu, B., Zhang, G., Mao, F., Liu, J., Cheng, D. and Lü, M. (2017) The Petroleum System of the Tenere Basin: Oil Geochemistry from the SH-1 Wildcat Well in Eastern Niger. Petroleum Geoscience , 23, 427-439. https://doi.org/10.1144/petgeo2015-067
- PRDSM (2005) Aeromagnetic Cartography of Aïr Mountains. Ministry of Mines and Industrial Development, 55.
- Ball, E. (1980) An Example of Very Consistent Brittle Deformation over a Wide Intracontinental Area: The Late Pan-African Fracture System of the Tuareg and Nigerian Shield. Tectonophysics , 61, 363-379. https://doi.org/10.1016/0040-1951(80)90240-1
- Liégeois, J.P., Latouche, L., Boughrara, M., Navez, J. and Guiraud, M. (2003) The LATEA Metacraton (Central Hoggar, Tuareg Shield, Algeria): Behaviour of an Old Passive Margin during the Pan-African Orogeny. Journal of African Earth Sciences , 37, 161-190. https://doi.org/10.1016/j.jafrearsci.2003.05.004
- Aissa, D. and Marignac, C. (2017) Controls on Gold Deposits in Hoggar, Tuareg Shield (Southern Algeria). Journal of African Earth Sciences , 127, 136-145. https://doi.org/10.1016/j.jafrearsci.2016.09.002
- Liégeois, J.P., Black, R., Navez, J. and Latouche, L. (1994) Early and Late Pan-African Orogenies in the Aïr Assembly of Terranes (Tuareg Shield, Niger). Precambrian Research , 67, 59-88. https://doi.org/10.1016/0301-9268(94)90005-1