Integrated magnetic, gravity, and GPR surveys to locate the probable source of hydrocarbon contamination in Sharm El-Sheikh area, south Sinai, Egypt Mona Morsy a , Mohamed Rashed a, b, ⁎ a Geology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt b Faculty of Earth Sciences, King Abdulaziz University, Jeddah, Saudi Arabia abstract article info Article history: Received 4 September 2012 Accepted 5 November 2012 Available online 17 November 2012 Keywords: Magnetic Gravity GPR Contamination Tank Pipe Sharm El-Sheikh waters were suddenly hit by hydrocarbon spills which created a serious threat to the pros- perous tourism industry in and around the city. Analysis of soil samples, water samples, and seabed samples collected in and around the contaminated bay area showed anomalous levels of hydrocarbons. An integrated geophysical investigation, using magnetic, gravity, and ground penetrating radar geophysical tools, was conducted in the headland overlooking the contaminated bay in order to delineate the possible subsurface source of contamination. The results of the geophysical investigations revealed three underground manmade reinforced concrete tanks and a complicated network of buried steel pipes in addition to other unidentified buried objects. The depths and dimensions of the discovered objects were determined. Geophysical investi- gations also revealed the presence of a north–south oblique slip fault running through the eastern part of the studied area. Excavations, conducted later on, confirmed the presence of one of the tanks delineated by the geophysical surveys. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Sharm El-Sheikh City, a famous Egyptian resort on the Red Sea, is known for its fascinating beaches transparent water, and pristine reef life. The city also forms a cornerstone in the Egyptian tourism indus- try and attracts millions of national and international tourists every year. In 1999, Sharm El-Sheikh area was devastated by a sudden leak- age of huge amounts of hydrocarbons into the sea. The spills were concentrated in and around Sharm El-Maya Bay and caused huge damage to the tourism activities in and around the contaminated area (Fig. 1). Although the spills were contained and instant remedial actions were taken, the source of the spills was not appropriately investigated and remains a controversial issue until today. Some stud- ies, conducted immediately after the incident, concluded that the spill was caused by the inappropriate dismantling of an old power plant and its surface fuel storage tanks (Cairo University Report, 2001; Suez Canal University Report, 1999). This power plant was located on the shoe-shaped headland defining the southwestern border of the bay and was dismantled a few months before the spill incident. Other stud- ies, however, suggested that oil contamination could be attributed to spilled crude oil, dumped oil wastes, and leaked fuel from boats (Khattab et al., 2006). Some researchers stated that the source of oil pol- luting the waters of the bay is buried under the southern headland and that the area is still under a threat from a persistent source of oil con- tamination (Morsy et al., 2010). Although previous studies did not agree on the source of the pol- lution, they all agreed on the presence of high levels of hydrocarbon contamination in the area. Chemical analyses conducted on samples collected from the surface soil of the southern headland, and from the seawater and seabed sediments of Sharm El-Maya Bay showed anomalously high levels of hydrocarbon contamination (Khattab et al., 2006; Morsy et al., 2010). The aim of the present study is to examine the hypothesis stating that the contamination source is buried under the southern headland and to identify the nature, location, and distribution of the sources of contamination in the area using appropriate geophysical tools such as magnetic, gravity, and ground penetrating radar techniques. Magnetic techniques are efficient tools to investigate shallow arti- ficial buried objects such as tanks, drums, and pipes and they are used frequently in environmental, engineering, and archaeological investiga- tions (e.g. Jordanova et al., 2008; Mathe and Leveque, 2003; Simpson et al., 2009). The gravity method, however, is usually used as an assistant tool that is capable of differentiating between natural soil and buried manmade objects having different densities (e.g. Batayneh et al., 2007; El-Behiry and Hanafy, 2000; Hickey and McGrath, 2003). Ground Penetrating Radar (GPR) is the most commonly used technique in envi- ronmental and engineering investigations and has been increasingly used to successfully detect buried manmade objects in recent years (e.g. Allred and Redman, 2010; Peters et al., 1995; Porsani and Sauck, 2007; Zeng and McMechan, 1997). Journal of Applied Geophysics 88 (2013) 131–138 ⁎ Corresponding author at: Faculty of Earth Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. E-mail address: rashedmohamed@gmail.com (M. Rashed). 0926-9851/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jappgeo.2012.11.003 Contents lists available at SciVerse ScienceDirect Journal of Applied Geophysics journal homepage: www.elsevier.com/locate/jappgeo