The role of electromagnetic induction in development planning: the case of the Grands Philambins enigma

Spatial planning aims at constantly improving the distribution of people and activities within available space, especially near cities on ancient agricultural or industrial areas. However, a proper schedule development work necessitates assessment, as precisely possible, difficulties that would be encountered in terms geotechnical abilities terrain hazards resulting from previous use. In Grands Philambins site, three different geophysical techniques were combined: multi-depth resistivity; magnetic gradiometry; electromagnetic induction. The aim this study was to map, few days with high measurement densities, all properties evidence metallic features. acquired data compared prior documentation, mainly aerial photos since middle 20th century. structure is complex, junction geological formations composed limestones marls proportions, which characterized by survey. It also exhibits features, among an enigmatic 70 m diameter radially striped disc object, identified non-ferrous corresponding antenna earthed socket. This case illustrates relevance use induction measurements land studies method can map independent underground identify