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

Abstract

Between 2008 and 2014, nine sinkholes occurred in northeastern Elba Island (Tuscany, Italy), an area with mostly flat terrain (called “Il Piano”) separating the municipalities of Rio nell’Elba and Rio Marina. The last sinkhole damaged the only road (SP26) between the harbour of Rio Marina and the northwestern part of the island. A bypass was immediately built, but the SP26 remains closed. Considering that sinkholes could be densely clustered in sinkhole prone areas, their detection and forecasting are key aspects of local administrative policies. In this paper, we present the results of an integrated geophysical survey aimed at (i) characterizing the geology of the area surrounding the SP26, and (ii) assessing the subsoil void hazard around the road system to support the decision to replace or restore the SP26. Therefore, for the purposes of this research, 120 singlestation seismic noise measurements were taken following the horizontal‐to‐vertical spectral ratio (H/V) or Nakamura technique, while eight 2D electrical resistivity tomography (ERT) and 17 3D‐ERT/induced polarisation measurements were also carried out in the study area. The H/V method allowed the estimation of the mean thickness of the alluvium, whereas the 2D/3D‐ERTs and IPTs permitted the characterisation of the electrical behaviours of the materials and the localisation of the lenticular sand and gravel bodies within a sandy silt layer. The large amount of collected data made the zonation of the subsoil void hazards possible.

HVSR Analysis of Rockslide Seismic Signals to Assess the Subsoil Conditions and the Site Seismic Response

“…Nowadays, the HVSR is widely used both for environmental [49,50] and for structural [51][52][53] problems. For a more detailed discussion about the seismic noise method please refer to the wide literature [27,43,[54][55][56]. The main application of HVSR technique on landslide concerns the possibility to reconstruct Figure 2: (a) Regional Topographic Map and (b) satellite view of the "traditional" monitoring network and the passive seismic array installed to monitor the Torgiovannetto quarry.…”

A Review of the Advantages and Limitations of Geophysical Investigations in Landslide Studies

“…In general, 4D ERT has been more frequently employed thanks to the development of ER multichannel measuring systems that significantly reduced the acquisition time [20,140]. These systems [such as those employed in [141,142]], in fact, (i) are able to simultaneously acquire a number of potential measurements for a single pair of current electrodes and (ii) can be set up to provide ERT at specific times during the day. Nevertheless, even though tl-ERTs could be helpfully employed in landslide monitoring, since they could provide information about the water content changes (i.e., the data could be related to pore water pressure variations and, therefore, to landslide triggering mechanisms), there are still few examples of 4D ERTs in landslide areas [60,65,92].…”

Investigating the applicability of induced polarization method in ore modelling and drilling optimization: a case study from Abassabad, Iran

“…IP and ER methods are among the most applicable geophysical methods used in subsurface studies notably for selection of the best drilling points for exploration purposes (Bishop and Emerson 1999;Wynn and Grosz 2000;Ferdows and Ramazi 2015b;Hope and Andersson 2016). Some examples of their increased usage include copper exploration using 3D IP modelling in NSW, Australia (Whaite et al 2001), using combination of ER and IP in polymetal deposit in China (Yang, Liu and Wang 2008), gold exploration at the eastern desert of Egypt by IP measurement (Taha et al 2018), combination of ER, IP and microgravity to detect buried caves in Spain (Martínez-Moreno et al 2013), copper exploration using IP and ER in Iran (Ramazi and Jalali 2014), gold-silver deposit exploration by IP method in Russia (Gurin et al 2015), detection of the uranium mineralization zone in India (Biswas and Sharma 2016), integration of geophysical methods including IP and ER methods for massive sulphide exploration in Sweden (Tavakoli et al 2016), bitumen mineralization exploration in the west of Iran (Mashhadi, Mostafaei and Ramazi 2017), gold deposit exploration by 3D-induced polarization modelling in Indonesia (Halim et al 2017), 3D tomography of induced polarization and its application in polymetallic mine (Jun-Lu et al 2017), copper mineral exploration using 3D model of IP and resistivity in Brazil (Morriera et al 2018), investigation of a rock glacier by 3D tomography of IP and ER in France (Duvillard et al 2018) and urban area investigation by 3D IP and ER in Stockholm (Pazzi et al 2018;Rossi et al 2017Rossi et al , 2018.…”