Integrated Geophysical Studies for tracing the Northern Extension of the Subsurface Spillway Fault, Aswan, Egypt

The main object of this study is to trace the northern extension of the subsurface Spillway fault, Aswan, Egypt. To achieve this, we used two geophysical techniques, magnetic and passive seismic surface wave. Magnetic data provides insights into subsurface structures, basement depth and structural trends. While passive seismic surface wave technique (frequency-wavenumber) uses seismic surface waves (Rayleigh wave) to map the subsurface allowing for the evaluation the fault depth. This method relies on data collected from a sensor array that captures wave field information in order to obtain shear wave velocity models. In the current study, 10 microtremor arrays have been conducted north of Ben Ban solar plant location (north of Aswan city), in order to construct 2D profile for tracing the subsurface faults. The obtained results show graben fault, in which areas has low shear wave velocity value (350 m/s) confined between high shear wave velocity (1100 m/s) areas. Also, a detailed land magnetic survey has been carried out for the total component of the geomagnetic field using two overhauser magnetometers. The necessary corrections concerning daily variation, the regional gradient and time variations have been applied. Then, the total magnetic intensity anomaly map (TMI) has been constructed and transformed to the reduced to the pole magnetic map (RTP). The reduction-to-pole magnetic anomaly maps was used to obtain regional extensions of this subsurface structure. Regional–residual separation is carried out using the power spectrum. Also, Edge detection techniques are applied to delineate the structure and hidden anomalies various edge detection techniques including the tilt angle derivative, its total horizontal derivative, and 3D-Euler Deconvolution are applied to delineate the boundaries of these sources. The Euler solutions were superimposed on the tilt angle derivative map, revealing a strong correlation between the techniques, confirming their effectiveness in mapping the area's structural framework. The analysis indicates that the study area is influenced by multiple structural trends. Depth estimation was conducted using multiple approaches, yielding consistent results. The derived depths to the top of basement sources range from 300 to approximately 2500 meters. We can conclude that the obtained graben fault could be considered as an extension of the spillway fault

KEYWORDS
Land magnetic, frequency-wavenumber, Spillway fault, Euler Deconvolution, Edge detection and Spectral analysis.