Two- and three-dimensional ground-penetrating radar surveys across a medieval choir: a case study in archaeology

Abstract

Excavations around the Prediger Church in Zurich (Switzerland) for a building project prompted interest in the region beneath the choir, which dates from the thirteenth century. To supplement archaeological information on the church, the hidden remains beneath the choir were investigated with ground-penetrating radar (GPR). An initial coarse GPR survey with shielded highfrequency antennae mapped the locations and dimensions of buried walls beneath the choir. The choir was determined to be rectangular and an altar was discovered. The rectangular ground plan of the historic choir is typical for a Cistercian church. To resolve the exact dimensions of structures, migration of the data was required. The most important parameter for this process is the velocity model of the ground, which was determined by different methods: constant velocity migration tests of the GPR data, common mid-point analyses, time-domain reflectometry in drill holes and network analyser measurements on samples. A second GPR survey with a very fine grid was carried out over a small area to test the resolution capabilities of this method. A threedimensional display of semi-automatic selected interfaces allowed the identification of single rocks. Such detail provided an insight into the construction and the state of destruction or preservation of the walls.

An Iterative Approach to Ground Penetrating Radar at the Maya Site of Pacbitun, Belize

“…There are numerous commonly employed geophysical techniques for archaeological prospection in ancient, complex, urban sites, which describes the site core area of Pacbitun, including electric resistivity tomography or imaging (ERT/ERI) [10][11][12][13], geomagnetic mapping (GM), frequency domain electromagnetic methods (FDEM) [14][15][16][17][18][19], and GPR or georadar [17,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. A GPR and GM survey was deemed most appropriate for exploring two plaza areas which needed to be completed in six days.…”

The shrine of Edward the Confessor: a study in multi‐frequency GPR investigation

“…The antennas used were almost invariably at the low‐frequency end of the spectrum thus favouring depth penetration at the potential expense of target definition and there was a higher usage of 2D data sets than of time slices extracted from 3D data. One notable exception was the detailed work carried out by Leckebusch (2000) in detecting the buried remains of a 13 th century church using complementary orthogonal surveys and 3D data. More recently there has been a growing interest in improved definition of the image of buried substructures and the detection of smaller features resulting in the creation of denser data sets as well as greater use of horizontal time slices as an effective mapping tool (e.g., Piro et al 2003; Linford 2004; Utsi 2006; Novo et al 2010; Udphuay et al 2010).…”

3-D high-resolution multi-channel radar investigation of a Roman village in Northern Italy

“…A good overview was given by Owen (1995). This technique has a limited depth of penetration and involves relatively complicated processing and interpretation methods, but is very appealing for mapping buried archaeological structures (Goodman et al, 1995;Pipan et al, 1999;Leckebusch, 2000;Piro et al, 2001;Seren et al, 2006) because of its 3-D imaging capability. Various authors have described recent attempts to increase field productivity (Lehmann and Green, 1999), including the use of multi-channel devices (Birken et al, 2002(Birken et al, , 2005Leckebusch, 2005b;Gustafsson and Alkarp, 2007) and high accuracy positioning systems (Young and Lord, 2002;Leckebusch, 2005a).…”