Rock falls impacting railway tracks. Detection analysis through an artificial intelligence camera prototype

During the last few years, several approaches have been proposed to improve early warning systems for managing geological risk due to landslides, where important infrastructures (such as railways, highways, pipelines, and aqueducts) are exposed elements. In this regard, an Artificial intelligence Camera Prototype (AiCP) for real-time monitoring has been integrated in a multisensor monitoring system devoted to rock fall detection. An abandoned limestone quarry was chosen at Acuto (central Italy) as test-site for verifying the reliability of the integratedmonitoring system. A portion of jointed rockmass, with dimensions suitable for optical monitoring, was instrumented by extensometers. One meter of railway track was used as a target for fallen blocks and a weather station was installed nearby. Main goals of the test were (i) evaluating the reliability of the AiCP and (ii) detecting rock blocks that reach the railway track by the AiCP. At this aim, several experiments were carried out by throwing rock blocks over the railway track. During these experiments, the AiCP detected the blocks and automatically transmitted an alarm signal

Non-Newtonian Gravity, Fluctuative Hypothesis and the Sizes of Astrophysical Structures

We show that the characteristic sizes of astrophysical and cosmological structures, where gravity is the only overall relevant interaction assembling the system, have a phenomenological relation to the microscopic scales whose order of magnitude is essentially ruled by the Compton wavelength of the proton. This result agrees with the absence of screening mechanisms for the gravitational interaction and could be connected to the presence of Yukawa correcting terms in the Newtonian potential which introduce typical interaction lengths. Furthermore, we are able to justify, in a straightforward way, the Sanders--postulated mass of a vector boson considered in order to obtain the characteristic sizes of galaxies.Comment: 11 pages. to appear in Mod. Phys. Lett.

Rock mass characterization coupled with seismic noise measurements to analyze the unstable cliff slope of the Selmun Promontory (Malta)

In the Mediterranean area, cliff slopes represent widespread high-risk landforms as they are highly frequented touristic places often interested by landslide processes. Malta represents a significant case study as several cliffs located all around the island are involved in instability processes, as evidenced by wide block-size talus distributed all along the coast line. These diffused instabilities are related to the predisponding geological setting of Malta Island, i.e. the over-position of grained limestone on plastic clay deposits, that induces lateral spreading phenomena associated to falls and topples of different-size rock blocks and is responsible for a typical landscape with stable plateau of stiff rocks bordered by unstable cliff slopes. The ruins of Gƫajn ƪadid Tower, the first of the thirteen watchtowers built in 1658 by the Gran Master Martin de Redin, stand out in the Selmun area. Currently the safety of this important heritage site, already damaged by an earthquake on October 12th 1856, is threaten by a progressive moving of the landslide process towards the stable plateau area. During autumn 2015, a field campaign was realized to characterize the jointed rock mass. A detailed engineering-geological survey was carried out to reconstruct the geological setting and to define the mechanical properties of the rock mass. Based on the surveyed joint spatial distribution, 58 single-station noise measurements were deployed to cover both the unstable zone and the stable area. The obtained 1-hour records were analyzed in the frequency domain for associating vibrational evidences to different instability levels, i.e. deriving the presence of already isolated blocks by the local seismic response. The here presented results can be a useful contribute to begin to asses defense strategies for the Selmun Promontory, in the frame of managing the landslide risk in the study area and preserving the local historical heritage

Investigating rock mass failure precursors using a multi-sensor monitoring system. Preliminary results from a test-site (Acuto, Italy)

In the last few years, several approaches and methods have been proposed to improve early warning systems for managing risks due to rapid slope failures where important infrastructures are the main exposed elements. To this aim, a multi-sensor monitoring system has been installed in an abandoned quarry at Acuto (central Italy) to realise a natural-scale test site for detecting rock-falls from a cliff slope. The installed multi-sensor monitoring system consists of: i) two weather stations; ii) optical cam (Smart Camera) connected to an Artificial Intelligence (AI) system; iii) stress- strain geotechnical system; iv) seismic monitoring device and nano-seismic array for detecting microseismic events on the cliff slope. The main objective of the experiment at this test site is to investigate precursors of rock mass failures by coupling remote and local sensors. The integrated monitoring system is devoted to record strain rates of rock mass joints, capturing their variations as an effect of forcing actions, which are the temperature, the rainfalls and the wind velocity and direction. The preliminary tests demonstrate that the data analysis methods allowed the identification of external destabilizing actions responsible for strain effects on rock joints. More in particular, it was observed that the temperature variations play a significant role for detectable strains of rock mass joints. The preliminary results obtained so far encourage further experiments

Constraining f(R)f(R) gravity by the Large Scale Structure

Over the past decades, General Relativity and the concordance $\Lambda$CDM model have been successfully tested using several different astrophysical and cosmological probes based on large datasets ({\it precision cosmology}). Despite their successes, some shortcomings emerge due to the fact that General Relativity should be revised at infrared and ultraviolet limits and to the fact that the fundamental nature of Dark Matter and Dark Energy is still a puzzle to be solved. In this perspective, $f(R)$ gravity have been extensively investigated being the most straightforward way to modify General Relativity and to overcame some of the above shortcomings. In this paper, we review various aspects of $f(R)$ gravity at extragalactic and cosmological levels. In particular, we consider cluster of galaxies, cosmological perturbations, and N-Body simulations, focusing on those models that satisfy both cosmological and local gravity constraints. The perspective is that some classes of $f(R)$ models can be consistently constrained by Large Scale Structure.Comment: 37 pages, 3 Tables, 6 Figures. Invited Review belonging "Special Issue Modified Gravity Cosmology: From Inflation to Dark Energy". The manuscript matches the accepted version. References update

Detection of nanoseismic events related to slope instabilities in the quarry district of Coreno Ausonio (Italy)

Le cave per l’estrazione di materiale roccioso rappresentano contesti in cui possono aver luogo eventi di instabilità gravitativa causati dalle continue sollecitazioni cui sono soggette le pareti produttive, principalmente connesse alle vibrazioni dovute alle esplosioni necessarie alle operazioni di disgaggio. La necessità di gestione del rischio da frana per la salvaguardia del personale impegnato nell’attività estrattiva ha portato, nel tempo, alla richiesta di attivare sistemi di monitoraggio nelle aree di coltivazione mineraria e di cava. Nel presente lavoro il monitoraggio nanosismometrico, una tecnica di geofisica passiva recentemente sviluppata per le indagini di microsismicità, è stato impiegato nel distretto di cave a cielo aperto di Coreno Ausonio (in provincia di Frosinone). Il monitoraggio nanosismometrico consente l’individuazione e la localizzazione di deboli eventi sismici, fino a magnitudo locale (ML) nell’ordine di -3, attraverso l’impiego di quattro sensori sismometrici disposti secondo una specifica geometria di array detta SNS (Seismic Navigation System). Dopo aver individuato una cava in cui erano programmate esplosioni per la volata delle pareti in roccia, nel corso del 2013 sono state organizzate 3 campagne di acquisizione durante tre giornate, pianificate in modo da monitorare l’area in un periodo compreso da qualche ora prima dell’esplosione alle 24 ore successive. Su una parete della cava non più produttiva è stato effettuato un rilevamento geologico-tecnico che ha permesso di individuare 4 principali sistemi di discontinuità e caratterizzarli in termini di giacitura, resistenza, rugosità, apertura, spaziatura e condizioni idrauliche secondo gli standard ISRM (1978). L’analisi di stabilità della parete in esame, tenuto conto della sua orientazione, ha restituito una scarsa propensione ad eventi di instabilità. Analizzando mediante il software NanoseismicSuite i dati sismometrici acquisiti è stato possibile ottenere i “supersonogrammi”, ovvero particolari spettrogrammi auto-adattanti alle variazioni del rumore sismico di fondo, dai quali sono state definite alcune caratteristiche specifiche di forma d’onda per diverse tipologie di eventi. In base ai supersonogrammi, è stato possibile individuare e localizzare 15 esplosioni, di cui 3 provenienti dalla cava di riferimento e 12 da cave adiacenti del distretto, e 27 deboli eventi di instabilità gravitativa, distinti in 23 eventi di collasso e 4 rotture legate alle fratturazione dell’ammasso roccioso. Le 3 esplosioni avvenute nella cava di riferimento, e quindi aventi coordinate di origine nota, sono state utilizzate per calibrare il modello di sottosuolo, successivamente impiegato per localizzare gli altri eventi registrati. Le rotture sono risultate originate in diverse zone del distretto estrattivo, mentre gli eventi di collasso sono stati localizzati in una specifica area e risultano essere avvenuti prevalentemente in un limitato intervallo di tempo a seguito delle 9 esplosioni registrate nella campagna del 26-27 luglio 2013. Non è stato possibile, invece, individuare eventi riconducibili ad instabilità negli orari di attività di cava a causa dell’elevato livello di rumore apportato dagli strumenti per l’estrazione e la lavorazione del materiale roccioso. Si è escluso che gli eventi di collasso fossero riconducibili direttamente all’attività di estrazione sia perché registrati al di fuori dell’orario di lavorazione delle cave sia perché, analizzando l’intera registrazione per intervalli orari, le frequenze tipiche dei macchinari di lavorazione non sono risultate energizzante. La zona di origine è risultata essere un’area nella quale sono stati rinvenuti detrito sciolto costituito da blocchi eterometrici ed una parete non in coltivazione con medesime caratteristiche delle discontinuità rispetto alla parete sulla quale era stato effettuato il rilevamento geologico-tecnico, ma con diversa orientazione. In definitiva, la fase di sperimentazione ha restituito dei risultati di indubbio interesse consentendo di mettere in evidenza alcune limitazioni del monitoraggio nanosismometrico nel contesto preso in esame, in particolare legate all’eccessiva rumorosità registrata nelle ore di attività di cava. La tecnica appare, comunque, un utile strumento di monitoraggio per i fenomeni gravitativi di debole intensità, in grado di contribuire alla gestione del rischio da frana in aree ad elevata attività antropica ed in ambienti naturalmente predisposti ad instabilità gravitative che possono interessare pareti in roccia.Nanoseismic monitoring is a passive geophysical technique used to identify and locate weak seismic events (down to local magnitudes, ML, around -3). This technique was applied in the open-pit quarry district of Coreno Ausonio (central Italy) to detect possible gravity-induced slope instabilities resulting from quarry rock blasting. After identifying an active quarry, an engineering-geological survey was carried out to characterise the jointed rock mass on an abandoned wall in front of the quarry. Four main joint sets were surveyed and their geometric and mechanical properties were measured in order to carry out stability analyses that evidenced scarce proneness to failure of the investigated wall. The analysis of seismic records obtained during three monitoring surveys, performed through the NanoseismicSuite software, made it possible to detect and characterise 15 blasts, of which 3 from the reference quarry and 12 from nearby quarries within the district, as well as 27 weak slope instability events (23 collapses and 4 failures). While failures originated from different areas of the quarry district, collapses occurred in a site characterised by an abandoned quarry having a wall more prone to gravity-induced instabilities than the one previously characterised