Vol.:(0123456789) 1 3 Environmental Earth Sciences (2019) 78:563 https://doi.org/10.1007/s12665-019-8572-x ORIGINAL ARTICLE Detection of karst features using ground‑penetrating radar: a case study from the western limestone plateau, Assiut, Egypt M. O. Ebraheem 1  · H. A. Ibrahim 2 Received: 27 September 2018 / Accepted: 2 September 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Ground-penetrating radar (GPR) techniques have been progressively developed to investigate several types of subsurface sedimentary features particularly in the upper zone of carbonate rocks. Most of common subsurface sedimentary hetero- geneities such as karst in the western carbonate plateau of Assiut were formed by natural processes. Detection of the karst is very important to face up the expected socio-economical pressure, resulting from the dense population around the Nile Valley and important for the cement industry. These heterogeneities represent anomalies or departures from the surround- ing or “background” geologic conditions which make them easier to detect by GPR. All the GPR profles are made using an antenna 200 MHz. The 400 MHz antenna is used only to get more details on one of the detected abnormal zones. A series of the 3D model cross-section with variable depths in addition to 3D modules for the karst is constructed to ascertain the exist- ence and the characteristics of these features. The careful analysis of the upper part of constructed GPR cross-section in the area is implemented by a digital three-dimensional model. It is believed that the examined area which having low-contrast variable-depth heterogeneities (karst features) may give a satisfactory outcome only by 3D simulation. This study indicates signifcant potential for the presence of karst in diferent locations and depths. Keywords Ground-penetrating radar · Three dimensional · Karst · Western limestone plateau, Assiut Introduction Karst rocks in Egypt cover a large area in the western lime- stone plateaus created during ancient wet periods (Sweeting 1972; Halliday 2003; Bakalowicz 2005). This phenomenon is a geomorphological feature that was formed in soluble rocks and/or sediments (e.g. limestone) by widening exist- ing fractures or cavities through the dissolution activities. These activities form sinkholes and represent subsidence hazards (Kruse et al. 2006; Youssef et al. 2016). More than 10 years ago, the carbonate plateau west of Assiut, as a part of the major western plateau in Egypt, was looked at as an area for the establishment of new urban communities, agricultural and industrial projects to solve the problem of the overcrowding population on both sides of the Nile Val- ley. This plateau is characterized by the presence of diferent karst features either on or below the surface. Most of this karst is inflled by cemented fint, red soil and limestone chips which seem as pockets and anomalies materials in limestone (Fig. 1a) (CSVD 2007). These anomalies materi- als have much reduced the quality and compatibility of the limestone as essential raw material for the cement factory inserted in the area. Also, the identifying of this karst is criti- cal for optimally laying out and designing foundations for urban projects associated with economic growth. Recently, detection of diferent sedimentary features such as sinkholes, cavities, and karst by geophysical methods is very important for solving many environmental problems. Some of these applied techniques are: seismic refection and refraction (Miller and Steeples 1991), gravimetry (Kauf- mann and Romanov 2009), ground-penetrating radar (Noui- oua et al. 2013), magnetic susceptibility diference (Balkaya et al. 2012), and electric resistivity tomography (Redhaounia et al. 2016), or a combination of them (Carbonel et al. 2014). The most important applications of GPR for solving many * H. A. Ibrahim ibraibraibra@yahoo.com M. O. Ebraheem hlmoef98@gmail.com 1 Geology Department, Faculty of Science, New Valley University, El-Kharga 72512, New Valley, Egypt 2 Geology Department, Faculty of Science, Assiut University, Assiut, Egypt