Estimating Model Parameters from Self-Potential Anomaly of 2D Inclined Sheet Using Whale Optimization Algorithm: Applications to Mineral Exploration and Tracing Shear Zones     

Gobashy  Mohamed  Abdelazeem  Maha  Abdrabou  Mohamed  Khalil  Mohamed H. 《Natural Resources Research》2020,29(1):499-519

The use of spontaneous potential (SP) anomalies is well known in the geophysical literatures because of its effectiveness and significance in solving many complex problems in mineral exploration. The inverse problem of self-potential data interpretation is generally ill-posed and nonlinear. Methods based on derivative analysis usually fail to reach the optimal solution (global minimum) and trapped in a local minimum. A new simple heuristic solution to SP anomalies due to 2D inclined sheet of infinite horizontal length is investigated in this study to solve these problems. This method is based on utilizing whale optimization algorithm (WOA) as an effective heuristic solution to the inverse problem of self-potential field due to a 2D inclined sheet. In this context, the WOA was applied first to synthetic example, where the effect of the random noise was examined and the method revealed good results using proper MATLAB code. The technique was then applied on several real field profiles from different localities aiming to determine the parameters of mineralized zones or the associated shear zones. The inversion parameters revealed that WOA detected accurately the unknown parameters and showed a good validation when compared with the published inversion methods.

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Seismic microzonation of Marsa Alam, Egypt using inversion HVSR of microtremor observations   总被引：1，自引：0，他引：1  

Sherif El-Hady  Elsayed Abdel-Azeem Fergany  Adel Othman  Gad ElKareem Abdrabou Mohamed 《Journal of Seismology》2012,16(1):55-66

An attempt was made to estimate seismic microzonation in Marsa Alam city, Egypt based on the analysis of seismic microtremor observations. Observations were carried out at 140 sites in the study region. Analysis and processing of microtremor were divided into two steps; the first one is to measure the horizontal-to-vertical spectral ratios (HVSR) for each site and picked predominant frequency and its amplitude for each site. The second step is to measure the average shear wave velocity in the upper 30 m (Vs30) of subsoil using inversion of HVSR technique. The results show well matching of theoretical HVSR and observed HVSR for body waves in all sites. The Vs30 parameter was used to classify subsoil into classes of soil properties converted to the slandered European soil code (Eurocode-8 (2002)) as follows; Vs < 180(class D), 180 ≤ Vs < 360 (class C), 360 ≤ Vs < 800 (class B) and Vs ≥ 800 m/s (class A). Our study exhibits that most of Marsa Alam city were covered by B and C classes with small portions of class D close to the shoreline and class A at the northeastern part of the region. The developed classification soil map of the study area was correlated with the distribution of the predominant frequency in view of the surface geology and given a good matching. The results of this study will be useful for planning the Marsa Alam region to be the future tourist dream for Egypt. The method used in assessment of seismic microzonation in Marsa Alam city could be the fast and inexpensive technique to measure the Vs30 based on the HVSR of microtremor and would be applied in many other areas in Egypt.  相似文献