MULTI-DIMENSIONAL SMOOTHED AND LAYERED INVERSION OF DC-RESISTIVITY AND SHALLOW SEISMIC REFRACTION DATA AT THE NEW RAS GHARIB CITY, RED SEA COAST, EGYPT

Abstract

The purpose of the present thesis is mainly devoted to study the multi-dimensional smoothed and layered inversion, which is applied on DC-resistivity and shallow seismic refraction data at the new RasGharib city. In applied geophysics, the data as a result of the earth are measured. This is what might be called a 'forward problem': a model is given and the data are calculated. The forward (or direct) problem is always uniquely solvable. It is often the other way around: data have been measured and we wish to derive a plausible (smoothed or layered) earth model that is consistent with the data, what may be described as 'inverse problem'. 'Inversion theory' is concerned with the problem of making physical interfaces (i.e. layer boundaries) from the measured data. That study introduces a theoretical background about those theories in details at chapter 2. That study is concerned with applying the inversion theory at the electrical resistivity data which is represented by 1-D 'VES' and 2-D 'Wenner profiles' data. It aims at this part to produce the 'smoothed models' that obtain the gradation of the electrical resistivity, and the 'layered models' that illustrate the real geologic layers with those thicknesses and resistivities, It is found to be five layers and reached to depth nearly 250 m. The other important item in this research is studying the sensitivity of the models that expresses those realities. Also this work is applied on shallow seismic refraction data, so a primary conventional study of the depth determination and velocity calculations are applied on the three measured profiles, it is found to be three layers and reached to a depth nearly 40 m.Thenother advanced study is applied by assuming that the third layer is subjected to the 'diving wave' theory.