Detection and imaging of piping sinkholes by integrated geophysical methods

Abstract

Piping sinkholes may naturally develop in the case of a thick overburden overlying calcareous bedrock.\ud Their detection and imaging is a challenging task for geophysical methods, not only because of the required resolution and depth of penetration, but also because major pitfalls may arise, in such\ud geologically complex areas, from the speculative interpretation of geophysical anomalies as geological features. Data integration from different geophysical methods is essential to remove these\ud interpretation ambiguities, caused by large near-surface gradients and heterogeneities in the soil properties, as well as by oscillations of the water table and anomalous water circulation.\ud We present an investigation procedure consisting of the sequential application and integrated interpretation of Electrical Resistivity Tomography (ERT), Seismic Refraction Tomography (SRT) and Self Potential (SP) measurements for locating and monitoring piping sinkholes with application to a site in Central Italy. This approach is a compromise between resolution and cost-effectiveness, and it is designed to be economically affordable by the private end user.\ud In complex geological scenarios, it is usually not possible to rate a single geophysical technique as superior to all the others in terms of resolution, cost-effectiveness and diagnostic capability. The independent information coming from the different geophysical methods is the key to removing interpretation ambiguity when evaluating the position and the development over time of the piping sinkholes. The application of the proposed investigation procedure allowed us to individuate a small area subject to the formation of a piping sinkhole. The geophysical results were confirmed about one year after the execution of the geophysical measurements, as the site exhibited surface evidence\ud of a piping sinkhole, with the formation of a small pond filled with sulphurous water and gases coming from below

A multidisciplinary approach in sinkhole analysis: The Quinis village case study (NE-Italy)

“…Therefore, integrated geophysical approaches are often reported as well as the calibration/validation with information obtained directly from boreholes (Dobecki and Upchurch, 2006;Cardarelli et al, 2010;Delle Rose and Leucci, 2010;Kaufmann et al, 2011;Margiotta et al, 2012;Pepe et al, 2013;Cardarelli et al, 2014) or trenches (Gutiérrez et al, 2009).…”

Contribution of Full Wave Acoustic Logging to the Detection and Prediction of Karstic Bodies

“…The integration of field data from different geophysical methods is the most suitable approach for imaging karstic structures, detecting cavities, and characterizing the host rock [2]. A combination of high-resolution seismic diffraction, reflection, refraction, continuous vertical electric sounding, ground-penetrating radar (GPR) and microgravity methods was used to study the shallow subsurface at a sinkhole-development site on the shore of the Dead Sea in Israel [3].…”

Assessing subsoil void hazards along a road system using H/V measurements, ERTs and IPTs to support local decision makers

“…The effectiveness of a geophysical method varies with the characteristics of the survey, and only their integration allows for a better data interpretation. Especially in an urban environment, selecting an appropriate geophysical method calls for taking into consideration the trade-off between their advantages, their intrinsic limitations and ambiguities, and their cost-to-time ratio (Piro, Tsourlos and Tsokas 2001;Dobecki and Upchurch 2006;Pueyo Anchuela et al 2013;Cardarelli et al 2014;Pazzi et al 2016c). These methods are known to detect variations of the ground's physical properties et al , Lotti et al 2017Pazzi et al 2017b), (ii) the interactions between soil and buildings (Herak 2008;Pazzi et al 2016a, b), and (iii) the presence of underground voids, both natural or anthropic (Castellaro and Mulargia 2009a).…”