Seismic Monitoring of a Rockslide: The Torgiovannetto Quarry (Central Apennines, Italy)

Near Surface Geophysics

Ceccatelli

Gracchi

et al. 2018

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.

Section: Discussionmentioning

confidence: 99%

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

Near Surface Geophysics

Ceccatelli

Gracchi

et al. 2018

“…In order to provide information on the nature, extent, and activation frequency of ancient landslides, standard detection, and mapping procedures need a combination of field-based studies and advanced techniques, such as remote sensing data analysis and geophysi- cal investigations (Ciampalini et al, 2015;Lotti et al, 2015;Del Soldato et al, 2016;Morelli et al, 2017;Pazzi et al, 2017a, b). In this context GB-InSAR represents a versatile and flexible technology, allowing for rapid changes in the type of data acquisition (geometry and temporal sampling) based on the characteristics of the monitored slope failure, which is capable of assessing the extent and the magnitude of the landslide residual hazard (Di Traglia et al, 2014a, b, 2015Carlà et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

GB-InSAR monitoring of slope deformations in a mountainous area affected by debris flow events

Frodella

Salvatici

Nat. Hazards Earth Syst. Sci.

et al. 2017

Abstract. Diffuse and severe slope instabilities affected the whole Veneto region (north-eastern Italy) between 31 October and 2 November 2010, following a period of heavy and persistent rainfall. In this context, on 4 November 2010 a large detrital mass detached from the cover of the Mt. Rotolon deep-seated gravitational slope deformation (DSGSD), located in the upper Agno River valley, channelizing within the Rotolon Creek riverbed and evolving into a highly mobile debris flow. The latter phenomena damaged many hydraulic works, also threatening bridges, local roads, and the residents of the Maltaure, Turcati, and Parlati villages located along the creek banks and the town of Recoaro Terme. From the beginning of the emergency phase, the civil protection system was activated, involving the National Civil Protection Department, Veneto Region, and local administrations' personnel and technicians, as well as scientific institutions. On 8 December 2010 a local-scale monitoring system, based on a ground-based interferometric synthetic aperture radar (GBInSAR), was implemented in order to evaluate the slope deformation pattern evolution in correspondence of the debris flow detachment sector, with the final aim of assessing the landslide residual risk and managing the emergency phase. This paper describes the results of a 2-year GB-InSAR monitoring campaign (December 2010-December 2012) and its application for monitoring, mapping, and emergency management activities in order to provide a rapid and easy communication of the results to the involved technicians and civil protection personnel, for a better understanding of the landslide phenomena and the decision-making process in a critical landslide scenario.

“…Earthquakes, landslides, floods, and volcanic eruptions are the most relevant processes that potentially can damage or increase the risk of human beings, properties or environment itself (Alcantara-Ayala 2002; Binda et al 2011;Lotti et al 2015;Morelli et al 2014, andDel Soldato et al 2016). They are usually classified as geohazards (Doornkamp 1989), and also could involve the interaction of human activities (McCall 1992;Lekkas 2000, andMorelli et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Monitoring of the vibration induced on the Arno masonry embankment wall by the conservation works after the May 25, 2016 riverbank landslide

Lotti

Chiara

et al. 2017

Geoenviron Disasters

Background: The concepts of disaster risk reduction and disaster risk management involve the development, improvement, and application of policies, strategies, and practices to minimize disaster risks throughout society. Nowadays, preserving architectural heritage and ancient monuments from disasters is an important issue in the cultural life of modern societies. The "health" of a building/structure may be evaluate by its deterioration or damage level: monitor the aging and promptly detect relevant damages, play a central role, and structure dynamic characterization and microtremor analysis are considered powerful techniques in this field. A wide bibliography about structures/ buildings seismic dynamic characterization is counterpoised to a missing one about their seismic response during conservation/safety works. This paper focus on the seismic response and monitoring of a historical masonry embankment wall during the conservation works carried out after a riverbank landslide that seriously damaged it. Results: The H/V results of the acquired traces show that main resonance frequency of the masonry embankment wall is between 4 Hz and 15 Hz, in agreement with the frequency range of roughly 10-meters-high, squat and monolithic structure. The whole monitoring period can be divided into three intervals corresponding to three different kind of workings: i) piling work; ii) parapet breakdown, excavation, embankment arrangement and foot wall consolidation; iii) backfill and restoring of the original condition, ordinary construction activities. The maximum peak component particle velocity substantial increase during the second period. All the stations have a higher energy content in the 10-20 Hz frequency range, but the spectra analysis clearly shows that the NS component, perpendicular to the wall, is the most stressed one. Moreover, despite the considerable distance from the August 24 Central Italy earthquake epicentre, the earthquake waveform is clearly recognizable at each station. In fact, the energy is focused around 2 Hz and the signals show directivity neither for the spectrum nor for the H/V. Conclusion: This work may contribute to characterize the vibrations induced by piling work at close range, and help to define the maximum acceptable vibration pattern for such structures, since literature is missing of such case studies. The maximum peak component particle velocity values clearly showed the work advancement. This paper also shows how the H/V technique is a valuable method to estimate the resonant frequency not only of buildings, but also of a squat and monolithic structure like the Lungarno Torrigiani masonry embankment wall.