GEOPHYSICAL ANALYSIS OF A TELL: SUBSURFACE IMAGING USING GPR AND ERT

Several attempts to reconstruct the ancient coastal landscape of northern Haifa Bay, Israel have been attempted over the past decades. The complexity of this land-sea interface in this prominent Levant region requires a multi-disciplinary approach. In this study, we utilized geophysical methods to better understand the geomorphic changes that have changed the human activities and habitation patterns at Tel Akko (mound formed by multiple anthropogenic layers). Urbanization took place at Tel Akko approximately 4,000 years ago based on archaeological, archaeo-botanical remains, and core-based geological studies. These earlier studies have not, to date, been successful at depicting and delimiting the ancient beach/shore zone interface and the potential location of an ancient anchorage site(s) that would have served the prominent ancient port city of Tel Akko.

Multiple Electric Resistivity Tomography (ERT) lines were collected on the tell and localities surrounding the tell. This technique images the subsurface in terms of the physical property of electrical resistivity with surveys indicating that aeolianite (kurkar) underlaying parts of the tell which is highly resistive showing values greater than 80 ohm-m. The saturated, fine-grained materials (silts and clays) at Tel Akko display low resistivities (<15 ohm-m). Ground penetrating radar (GPR) 2D and grids were collected on the lower edges of the tell to try and identify the tell - beach/shore interface as well as possible anchorage sites. A Sensors and Software pulseEKKO PRO 1000 GPR system was utilized to collect the data with 225 MHz and 500 MHz antennae (0.1 m and 0.05 m step size, respectively). Survey collection occurred on the south and west embankments where marine sands are most abundant in the sediment cores taken. Due to the conductive nature of sediment, depths of penetration were limited to less than 3 m but the imagery did indicate possible locations for the tell-beach/shore interface.