Chapters authored
Identification of Gravity Lineaments for Water Resources in the Crystalline Massif of Hoggar (South of Algeria)
The Hoggar is a rock mountain located in the South of Algeria. It is a crystalline massif characterized by granitic substratum with a weak sedimentary cover. The pluviometry is low in this region and is characterized by possibilities of floods of big capacities of water. The infiltration of these important quantities of water remains low because of the insufficiency of systems of retains. The problem in this case is locating the water in weathered zones, beyond 50 m, above granites. The weathered areas could be sometimes aquifer at their base. So, this can be interesting if they rise above intensely fractured rocks and/or suitable geometry of the substratum. The fractured rocks and the suitable geometry of the substratum could be linked to natural reservoirs. The perfect case is that this structure is covered by a rather important thickness of silts to let the infiltration of the water. So, to identify the various juxtaposed structures with different densities and delineate gravity lineaments, faults, and cavities, the gravimetric method was preferred. The aim of this work is integrating all geometric and gravimetric observations, models, and approaches so as to provide consistent and reliable information for making decision regarding the location of drilling.
Part of the book: Gravity
The Use of the 2D and 3D Complex Wavelet and Ridgelet Transforms in Geophysical Prospecting: Case of Potential Fields Data
The complex wavelet and ridgelet transforms are used in the potential field data interpretation for identifying the buried structures responsible for potential field anomalies. Its basis is the use of particular analyzing wavelets belonging to the Poisson semigroup that possess amazing properties regarding potential fields. In fact, the analyzed anomaly displays a conical signature in the wavelet domain and whose apex is pointing out at the causative homogeneous structure. Fundamentally, the interpretation is performed in the upward-continued domain where, the dilation of the wavelet transform is the upward-continuation altitude. This confers on the wavelet transform a considerable advantage: its robustness with respect to noise. The method is also developed to identify the depth, horizontal positions, size, strike direction, dips and shape of elongated 3D structures such as finite-dimensional dykes and faults. For this type of anomaly, the 2D wavelet transform corresponds to the ridgelet transform performed in the Radon domain, where elongated anomalies are recognized by high amplitude signatures. A reminder of the developed theory and applications in the 2D and 3D cases on real case studies are shown.
Part of the book: Wavelet Theory and Modern Applications