Geophysical Prospecting, 2009, 57, 447–459 doi: 10.1111/j.1365-2478.2008.00747.x Interpretation case study of the Sahl El Qaa area, southern Sinai Peninsula, Egypt Taha Rabeh 1∗† , Jorge Miguel Miranda 2 , Joao Carvalho 3 and Andrei Bocin 4 1 NRIAG, Department of Geophysics, Helwan el Marsad 11425, Egypt, 2 University of Lisbon, CGUL, IDL, Campo Grande, 1749-016 Lisbon, Portugal, 3 Instituto Nacional de Engenharia, Tecnologia e Inovac ¸˜ ao, Estrada da Portela – Zambujal, Alfragide, 2720-461 Amadora, Portugal, and 4 Faculty of Life and Earth Sciences, VU University Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands Received September 2007, revision accepted July 2008 ABSTRACT The study area is located in the Sinai Peninsula, which is considered one of the most promising regions for oil resources. Three different tectonic forces affect the area in the triple junction structures associated with the opening of the Gulf of Suez and the strike slip movement along the Gulf of Aqaba. The main goal of this work is to model the structure of the basement rocks in the study area using magnetic methods. To achieve this, a high-resolution land magnetic survey was acquired and the results were combined with existing seismic reflection data. The magnetic interpretation was carried out using the analytical signal, horizontal gradient, Euler and Werner deconvolution and 3D magnetic modelling methods. We concluded that most of the deduced structures are trending in N–S, N35 ◦ –N45 ◦ west and E–W directions. The Aqaba trend (N15 ◦ –N25 ◦ east) is barely noticeable. The depth to the basement rocks ranges from 1 km to more than 2 km below sea level and these results are in agreement with the available well log data. In addition, interpretation of seismic reflection sections was carried out and compared with overlapping magnetic profiles interpreted using Euler deconvolution. They show that the sedimentary section was affected by the basement tectonics, with faults extending from the basement upwards through the sedimentary cover. These faults constitute good potential structural traps for oil accumulation. INTRODUCTION The study area lies at the southern part of the Sinai Peninsula between latitudes 28 ◦ 30 ′ and 28 ◦ 40 ′ north and longitudes 33 ◦ 17 ′ and 33 ◦ 37 ′ east adjacent to the Gulf of Suez (Fig. 1). This region is considered to be an important area for oil and gas production (Khalil 1998). It also indicates the presence of copper-nickel mineralization (e.g., Sarabit El Khadem Copper Mine). Many studies were performed to understand the sub- surface geological structure of the area. It is considered a part of a Tertiary cratonic rift between north-eastern Africa and the ∗ E-mail: taharabeh@yahoo.com † Now at: University of Lisbon, CGUL, IDL, Campo Grande, 1749- 016 Lisbon, Portugal Arabian Peninsula. The rifting phase essentially ceased during the early-Middle Miocene (18–14 Ma) when continental sep- aration became more oblique due to the dominant movements on the left-lateral transform fault, which extends through the Gulf of Aqaba north-eastwards to the Dead Sea (Patton et al. 1994; USGS 1998). The Gulf of the Suez region has long been recognized as one of the best examples of long-axis segmentation with different dip polarities (Moustafa 1976; Colleta et al. 1988; Moustafa 1993; Bosworth 1994; Patton et al. 1994; McClay et al. 1998). It suggests interaction between extensional tectonics and sed- imentations (Gawthorpe et al. 1997; Gupta et al. 1999; Sharp et al. 2000). The Gulf of Suez area is remarkably non-volcanic with only a few late pre-rift to early syn-rift basic dykes and isolated basaltic features (Bosworth and McClay 2001). Four C  2009 University of Lisbon 447