ORIGINAL PAPER Conceptual model and numerical simulation of the hydrothermal system in Hammam Faraun hot spring, Sinai Peninsula, Egypt Mohamed Abdel Zaher & Sachio Ehara & Gad El-Qady Received: 22 May 2009 / Accepted: 29 September 2009 / Published online: 26 January 2010 # Saudi Society for Geosciences 2010 Abstract The tectonic position of Egypt in the northeastern corner of the African continent suggests that it may possess significant geothermal resources, especially along its east- ern margin. The most of the thermal springs in Egypt are located along the shores of Gulf of Suez and Red Sea. These springs are probably tectonic or nonvolcanic origin associated with the opening of the Red Sea—Gulf of Suez rifts, where the eastern shore of the Gulf of Suez is characterized by superficial thermal manifestations includ- ing a cluster of hot springs with varied temperatures. Hammam Faraun area consists of the hottest spring in Egypt where the water temperature is 70°C. Conceptual as well as numerical models were made on the Hammam Faraun hot spring based on geological, geochemical, and geophysical data. The models show that the heat source of the hot spring is probably derived from high heat flow and deep water circulation controlled by faults associated with the opening of the Red Sea and Gulf of Suez rifts. Keywords Hot springs . Hammam Faraun . Conceptual model . Numerical model . Red Sea . Gulf of Suez Introduction There is a clear correlation between the principal areas of current geothermal development and the seismically active boundaries of the moving segments of lithosphere defined by the plate tectonic models of the earth. It would therefore seem logical to concentrate the search for new geothermal resources along the plate boundaries. The location of Egypt in the northeastern corner of African plate which bounded to the east by what has been interpreted as a median spread- ing center in the Red Sea (Mckenzie et al. 1970) reflects that this area is an important candidate for geothermal develop- ment. Recently, geophysical techniques have been applied intensively in geothermal studies especially in area around Gulf of Suez and Red Sea. These studies show that the most important geothermal resources in Egypt are located on the eastern and western sides of Gulf of Suez, and the hottest one is Hammam Faraun hot spring (Fig. 1). The aim of this study is to construct conceptual model of the hydro- thermal system in Hammam Faraun area depending on geological, geochemical, and geophysical data. The features of the conceptual model were reproduced by numerical modeling in order to match the subsurface temperatures and heat flow data in this area. Geologic regime The Red Sea and Gulf of Suez occupy part of a large rift valley in the continental crust which was initiated during the late Oligocene to early Miocene by the NE–SW separation of the African and Arabian plates (Patton et al. 1994). This break in the crust is part of a complex rift system that includes the East African Rift System (Said 1962). During this rifting, many faulted tilted blocks were M. A. Zaher : S. Ehara Laboratory of Geothermics, Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan M. A. Zaher (*) : G. El-Qady National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Cairo, Egypt e-mail: mohamed-zaher@mine.kyushu-u.ac.jp Arab J Geosci (2011) 4:161–170 DOI 10.1007/s12517-009-0109-2