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.
Application of Electrical Resistivity Imaging and Land Surveying in the Analysis of Underground Construction Impact on the Warsaw Scarp
Abstract The paper presents the analysis of the II Underground Line construction’s impact on the Warsaw Scarp with the use of the electrical resistivity imaging (ERI, also known as the electrical resistivity tomography) and further total station position measurements.The underground passes under the scarp perpendicular in the area of Dynasy Street 6, in Down-town district.The electrical resistivity imaging was performed for recognition of the geological structure and a potential land slide surface or zone.The gradient system was used during the prospection. In these analyses, the longitudinal section was 40 m long, and the depth of survey amounted to 6 m. In the case of the 200 m long transverse section, the resulted depth of survey was 30 m.The geophysical image of the longitudinal section,does not contain loosening soil zones,which could indicates lip surface.Next, total station measurements, which were tied to the archival geodetic observations’ results, were carried out. The aim of the measurements was to verify the activity of the horizontal and vertical displacements. The TBM excavation process led to summary vertical displacements up to approx. 24 mm and horizontal displacements amounting to approx. 13 mm. To sum up, the current land surveys reveals minor under ground line’ s construction impact on the scarp displacement. Nevertheless, the sensitive urban environment requires further monitoring, especially that the operation loads can result in displacement rate change.
Snowstreamer: an efficient tool in seismic acquisition
The concept of pulling a complete seismic receiver array over land, instead of manually planting each geophone and connecting them to cables, is attractive both from a practical and economical point of view. Geophysical Service Inc. used this concept to collect seismic reflection data on the sea ice in Arctic North America in the 1970s (Einarsson et al.1977). A fairy detailed description of their system exists but no report of the performance was ever published.