Gravimetric evidences of active faults and underground structure of the Cheliff seismogenic basin (Algeria)

• Published in: Journal of African earth sciences (1994) 2014-11, Vol.99 (2), p.363-373
• Main Authors: Abtout, A., Boukerbout, H., Bouyahiaoui, B., Gibert, D.
• Format: Article
• Language: English
• Subjects: Cheliff basin; Continuous wavelet transform 3-D image; Deep structures; Earth Sciences; Faults and contacts; Geophysics; Gravity anomalies; Sciences of the Universe; Structural map
• ISSN: 1464-343X; 1879-1956
• DOI: 10.1016/j.jafrearsci.2014.02.011

•We study gravity anomalies of the seismogenic Cheliff region in Algeria.•We use different processing methods to highlight long and short wavelength.•We use the continuous wavelet transform to identify deep anomalies causative bodies.•We establish the 3-D image of Cheliff basin.•A correlation between geological, seismotectonic data and gravity features is done. The Cheliff basin (ex El Asnam) is known as one of the most seismic active zone in Algeria and the West Mediterranean region. We can cite the El Asnam earthquake which occurred in 10.10.01980 with magnitude of 7.3. It was generated by a thrust fault with NE–SW sinistral component. Until now, there is a little information about existence of deep active faults, which generate this strong activity. The gravity field is an important resource of information on crustal structure. The aim of this work is giving a reliable geometry of the major faults relative to the kinematics of this region. The results obtained from various filtered maps (derivatives, upward continuation) of the gravity data, were used to generate a structural map of the studied area. Whilst the continuous wavelet transform method can help in automatic detection of elongated structures in 3-D, to estimate their strike direction, shape and depth. It gives a 3-D image or a model of the region and confirms the existence of several faults, localized or inferred, from former geological studies.