GEO PHYSI CAL SUR VEY ( GPR ) IN WEST SAQQARA ( EGYPT ) : PRE LIMI NARY RE MARKS
Ab stract Geo phys i cal in ves ti ga tions in West Saqqara area were part of the ar chae o log i cal field work of the Pol ish-Egyp tian ar chae o log i cal mis sion dur ing the cam paign in 2012. The main pur pose of geo phys i cal prospection us ing the groundpen e trat ing ra dar (GPR) was to de ter mine the lo ca tion of po ten tial un der ground se pul chral struc tures. Dur ing the GPR sur vey, op ti mal depth pen e tra tion was achieved due to dry rocks and mono lithic struc ture of the lime stone pla teau on which the an cient cem e tery was lo cated. Us ing an tenna of 100 MHz, the depth of pen e tra tion was up to 45 m and with an tenna of 250 MHz, up to 15 me ters. Three main groups of ar chae o log i cal struc tures were iden ti fied: sar coph agi and mum mies, burial shafts; mo bile ob jects (solid rock blocks as frag ments of tombs). One of the main goal of the GPR sur vey was to track the route of the west ern part of the Dry Moat, ex pressed by a wide and shal low de pres sion spread ing to wards north-south. The re sults of geo phys i cal in ves ti ga tions sug gest that Saqqara pla teau is an ideal site for us ing GPR sur vey ing tech nol ogy.
Applicability of Ground Penetrating Radar on desert archaeological sites: a case study from the Saqqara necropolis in Egypt
Abstract This paper presents the preliminary results of ground penetrating radar sounding applied at the desert archaeological site in Saqqara (Egypt). The survey was carried out in 2012 within a project realized by Institute of Archaeology, Cardinal Stefan Wyszyński University in Warsaw and the Faculty of Geology, University of Warsaw. One of the key aims of the research was testing the application of ground penetrating radar to non-invasive surveys of desert archaeological sites. Radargrams obtained for area of so called the Dry Moat channel surrounding the Step Pyramid complex have shown the geological structure of its filling. It comprises among others debris-sand conglomerate of diluval origin characterized by a significant content of the clay fraction and clay minerals. Such lithological content strongly attenuate the propagation of EM waves, restricting the depth range of the GPR survey. The conducted geophysical prospection west to the Step Pyramid in Saqqara has confirmed the high applicability of the GPR method in non-invasive studies of vast architectural structures, such as the monumental ditch surrounding the Step Pyramid known as the Dry Moat. It should summarised that high horizontal resolution obtained during GPR survey is a result of local geological structure of the searched area, i.e. strong lithological contrast of the sediments filling the Dry Moat, which, depending on their mineralogical composition
MODIFIED LAND STREAMER CONFIGURATION FOR SHALLOW SEISMIC DATA ACQUISITION
The need to reduce the cost of land-based seismic reflection data collection has inspired researchers to investigate the use of a towed land cable or streamer in a fashion similar to that used in marine work. A set of towed land streamers in an array employing gimbaled geophones could significantly reduce the acquisition time and personnel required to complete shallow 3-D seismic reflection surveys. A primary concern of seismic data collection with a land streamer is the possibility of decreased survey resolution when the gimbaled geophones are poorly coupled with the ground surface. To address this concern we tested a gimbaled geophone streamer on grass, wet sand, asphalt pavement and snow. On each surface type we tested three different streamer configurations. Each configuration uses a separate combination of rubber pads which vary the amount of weight on top of the gimbaled geophones. For each configuration we compared trace data from the gimbaled geophones with data from spiked geophones planted directly alongside. The gimbaled and spiked geophones contain identical internal elements. We found that sand, pavement and snow provide ideal conditions for using gimbaled geophones. In addition, we found variations in the streamer configuration provide noticeable improvement in the traces recorded on grass and sand surfaces.