Non-Invasive Methodological Approach to Detect and Characterize High-Risk Sinkholes in Urban Cover Evaporite Karst: Integrated Reflection Seismics, PS-InSAR, Leveling, 3D-GPR and Ancillary Data. A NE Italian Case Study

Abstract

Sinkholes linked to cover evaporite karst in urban environments still represent a challenge in terms of their clear identification and mapping considering the rehash and man-made structures. In the present research, we have proposed and tested a methodology to identify the subsiding features through an integrated and non-invasive multi-scale approach combining seismic reflection, PS-InSAR (PSI), leveling and full 3D Ground Penetrating Radar (GPR), and thus overpassing the limits of each method. The analysis was conducted in a small village in the Alta Val Tagliamento Valley (Friuli Venezia Giulia region, NE Italy). Here, sinkholes have been reported for a long time as well as the hazards linked to their presence. Within past years, several houses have been demolished and at present many of them are damaged. The PSI investigation allowed the identification of an area with higher vertical velocities; seismic reflection imagined the covered karst bedrock, identifying three depocenters; leveling data presented a downward displacement comparable with PSI results; 3D GPR, applied here for the first time in the study and characterization of sinkholes, defined shallow sinking features. Combining all the obtained results with accurate field observations, we identified and mapped the highest vulnerable zone.

Sinkhole subsidence monitoring combining terrestrial laser scanner and high‐precision levelling

“…This is a non-invasive near-surface geophysical method, commonly applied in sinkhole investigations (e.g. Busetti et al, 2020;Ronen et al, 2019;Zarroca et al, 2017), which allows imagining the subsurface materials with short acquisition and processing times. It consists of a control unit and two antennas: one transmits electromagnetic waves to the ground and the other records the time delay and intensity of the reflected waves.…”

Surface deformation analysis in Northeast Italy by using PS-InSAR and GNSS data 

“…That approach has been successfully employed in several studies in the Himalaya-Tibet region (Grandin et al, 2012;Pezzo et al, 2012;Karimzadeh et al, 2013;Liu et al, 2018), California (Fialko, 2006;Tong et al, 2013;Chaussard et al, 2016), Anatolia (Wright et al, 2001;Walters et al, 2011;Hussain et al, 2016;Weiss et al, 2020), and in Italy (Cheloni et al, 2014;Pezzo et al, 2015Pezzo et al, , 2020bSerpelloni et al, 2016;Anderlini et al, 2020). Other studies can also be mentioned related to the other natural and anthropogenic phenomena, such as subsidence (Teatini et al, 2005;Tosi et al, 2010Tosi et al, , 2013Osmanoǧlu et al, 2011;Da Lio and Tosi, 2018;Del Soldato et al, 2018;Polcari et al, 2018;Farolfi et al, 2019aFarolfi et al, , 2019bFloris et al, 2019), landslides and slope instabilities (Žibret et al, 2012;Komac et al, 2015;Notti et al, 2015;Aslan et al, 2020), sinkholes (Busetti et al, 2020), volcanic processes Pezzo et al, 2020a;Beccaro et al, 2021), monitoring of infrastructures, reservoirs and mining activities (Perski et al 2009;Klemm et al, 2010;Ab Latip et al, 2015;Gama et al, 2020).…”

A joint geophysical approach to tune an integrated sinkhole monitoring method in evaporitic environments

“…Different surface and subsurface investigation methods to identify and characterize sinkholes have been applied throughout the world. Among the others, we can report aerial and satellite image analysis (Dou et al., 2015; Festa et al., 2012; Gutiérrez et al., 2011; Panno & Luman, 2013), topographic map analysis (Basso et al., 2013; Brinkmann et al., 2008; Gutiérrez et al., 2011), field surveys (Bruno et al., 2008; Gutiérrez et al., 2007), LiDAR (Kim et al., 2019; Zhu et al., 2014, 2020), InSAR (Baer et al., 2018; Busetti et al., 2020; Galve et al., 2015; Guerrero et al., 2021; Intrieri et al., 2015; Jones & Blom, 2014; Malinowska et al., 2019; Oliver‐Cabrera et al., 2020; Orhan et al., 2021; Shi et al., 2019; Solari et al., 2020; Theron et al., 2017), ground‐based monitoring (Desir et al., 2018; Kersten et al., 2017; Kobe et al., 2019; Sevil et al., 2017; Zhende et al., 2013), geophysical surveys (De Ritis et al., 2020; García‐Moreno & Mateos, 2011; Krawczyk et al., 2012; Kühn et al., 2011; Margiotta et al., 2012; Malehmir et al., 2016; Pazzi et al., 2018; Ronen et al., 2019; Samyn et al., 2014; Stierman, 2004; Waltham et al., 2005; Wust‐Bloch & Joswig, 2006), hydrogeochemical studies (Delkhahi et al., 2020; Taheri et al., 2021) and trenching (Carbonel et al., 2015; Gutiérrez et al., 2018; Sevil et al., 2017) have been used in a series of multidisciplinary and multi‐technique investigations.…”

“…Sinkholes, that are natural sub-circular depressions of various dimensions and depths, are caused by the dissolution of soluble rocks or deposits in addition to internal erosion and/or gravitational processes (Gutiérrez, 2016;Parise, 2015;Waltham et al, 2005). These phenomena are globally widespread, for example in France (Thierry et al, 2009), Germany (Dahm et al, 2010;Krawczyk et al, 2012) Lithuania (Paukstys et al, 1999), Russia (Koutepov et al, 2008), Spain (Gutiérrez et al, 2008;Sevil et al, 2020), the United Kingdom (Cooper, 1998;Cooper et al, 2011), Albania (Parise et al, 2004), USA (Kuniansky et al, 2016), South Africa (Buttrick & van Schalkwyk, 1998), Iran (Karimi & Taheri, 2010;Taheri et al, 2015Taheri et al, , 2019 and Italy (Busetti et al, 2020;Calligaris et al, 2017aCalligaris et al, , 2020De Waele et al, 2017;Nisio, 2008 and all the references therein). They often have serious consequences in urban areas, causing physical and socio-economic damage to existing man-made structures and have a high risk factor due to their rapid occurrence and evolution (Intrieri et al, 2015;Martinotti et al, 2017;Zini et al, 2015 and all the references therein).…”