GPR studies in the Piano di Pezza area of the Ovindoli‐Pezza fault, central Apennines, Italy: Extending palaeoseismic trench investigations with high‐resolution GPR profiling

Abstract

ABSTRACTA high‐resolution 200 MHz frequency GPR profile with 0.1 m station spacing was collected using a Pulse EKKO 100 system, adjacent to a trench site that had been previously excavated and interpreted. The profile intersected the fault scarp on one of the alluvial fans on the northern slope of the Piano di Pezza; this fault scarp was thought to be associated with repeated earthquake activity along the Ovindoli‐Pezza fault. The GPR profile was conducted to evaluate the effectiveness of the technique in radar mapping and in extending the trenching information laterally and in depth in this environment. The work was carried out as part of a wider research programme of GPR profiling along the Ovindoli‐Pezza fault system. The GPR data were processed using Win EKKO radar data processing software and time–depth conversion was facilitated using field‐derived CMP velocity analysis. The results provided a detailed image of the GPR data, which shows a generally high spatial correlation with the mapped fault and 14C‐dated lithologic/pedologic units. Furthermore, the GPR data has provided a framework for estimating the extent of extensional and episodic catastrophic activity along the fault, and has elucidated the geometric relationship between the faulting in response to recent tectonic events.