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Classification of Seismic Signals at Vulcano, Italy, using Unsupervised Learning Techniques
No full textWe analyze the seismic signals recorded on the island of Vulcano (Italy) during a volcano unrest that started in 2021. From mid-September 2021 onward, a high number of very long-period and long-period events occurred, accompanied by large emissions of CO2 and the increased temperature of fumaroles at various sites of the island. The complexity of the seismic signals recorded during the unrest made standard amplitude-based monitoring techniques, such as RSAM, questionable, as part of the signals are not volcanogenic, such as the frequent close-by passage of ships. We therefore study the inventory of the recorded signals by exploiting machine learning procedures, in particular unsupervised classification techniques. Our studies aim at identifying varying classes of seismic events possibly related to volcanic dynamic as well as irrelevant signals, such as man-made noise. Self-Organizing Maps and Cluster Analysis were applied. As a result, we are able to visualize the development of signal characteristics efficiently. This can provide a useful contribution to volcanic surveillance purposes, which aim to identify changes heralding a “Vulcanian” eruption, an eruptive style with strong explosive characteristics.PublishedLacco Ameno, Ischia Island (Italy)OST5 Verso un nuovo Monitoraggi
OEDataRep: the new version of the Osservatorio Etneo Open Data Repository
No full textThe use of a generalist, non field specific Open Data based Repository, started at the INGV
Osservatorio Etneo of Catania (INGV OE) following the introduction of a first prototype, called
DataRep in late 2021. During this experimental period, DataRep was used as the institutional
data repository of the INGV OE, testing its functionalities, usage procedures and the interaction
with the national INGV metadata catalog (“Data Registry”) through its associated Metadata Editor
software. Due to the heterogeneous nature of data types managed at INGV OE, mainly
structured as temporal data (also known as time series) or catalogs of events (e.g. earthquakes,
eruptions), there has been an increasing interest in making the data repository interact with
another key software developed and distributed by the INGV OE: the TSDSystem (TimeSeries
Database System) framework. Among other features, the TSDSystem facilitates the collection of
time series from several sources, supporting their standardization within a unique and coherent
database structure, and allowing the retrieval of data in a convenient way by easily providing joint
requests of multiple time series at once that may be displayed on the same time axis. From the
interoperability of the three software involved the Metadata Editor, the data repository and the
TSDSystem users may uniquely interact with the web graphical user interface of the Metadata
Editor in order to describe the metadata associated with a future publication and upload them
together with the related files to the data repository. The latter will then act as a client of the
services exposed by the TSDSystem. Following this workflow, datasets that include time series
data published to the repository, will also be put atomically into the TSDSystem database.
Likewise, the same time series data will be retrieved from the TSDSystem and displayed by the
repository web interface. The integration of the three software platforms is at the core of a new
version of the DataRep repository that is now being phased out in favor of a new implementation
called OEDataRep, the acronym of Osservatorio Etneo Open Data Repository. This new version
involved a complete overhaul of the data repository software that has considerably improved
both the underlying infrastructure and the graphical user experienceINGVPublished1-34OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciN/A or not JC
Remotely Sensed Data, Morpho-Metric Analysis, and Integrated Method Approach for Flood Risk Assessment: Case Study of Wadi Al-Arish Landscape, Sinai, Egypt
No full textEvaluating and predicting the occurrence and spatial remarks of climate and rainfall-related destructive hazards is a big challenge. Periodically, Sinai Peninsula is suffering from natural risks that enthuse researchers to provide the area more attention and scientific investigation. Extracted information from the morpho-metric indices aids in understanding the flood potentiality over various sizes of drainage catchments. In this work, the morpho-metric analysis has been used in order to model the relative signals of flood vulnerability of 16 catchments in northern Sinai. The geospatial technique has been applied to process the digital elevation models (DEMs) in order to produce different analysis maps. Basic geometries, in addition to several morpho-metric indices, were extracted and analyzed by investigating the digital elevation models. Three different effective methods were applied separately to build up three models of flood susceptibility behaviors. Finally, two flood susceptibility signals were defined: the integration method and accurate pixel level conditions models. The integrated method analysis indicates that the western half of the study landscape, including catchments (12, 13, and 14), presents high levels of flood susceptibility in addition to catchment 9 in the eastern half, whereas the other catchments were found to provide moderate levels. The integrated flood susceptibility final map overlaid one of the most effective topographic indices (topographic position index, TPI). The integrated results aided in understanding the link of the general catchments morphometry to the in situ topography for mapping the different flood susceptibility locations over the entire study landscape. Therefore, this can be used for investigating the surface-specific reduction strategy against the impacts of flood hazards in the proposed landscape.Published1797JCR Journa
Age of the Valle del Bove formation and chronology of the post-collapse flank eruptions, Etna volcano (Italy)
No full textThe Valle del Bove is a profound and wide scar on the east Etna flank witnessing the Holocene main volcanotectonic
event of the volcano, frequently invaded by lava flows during the last centuries. The Valle del Bove
slope failure produced the Milo debris avalanche deposit on the lower east flank that is partially covered by the
Mongibello lavas and a pyroclastic succession. In this paper, we constrain for the first time the age of the Milo
debris avalanche deposit and the overlying lava succession exposed at three quarries recently caved at the valley
mouth through a multidisciplinary approach integrating stratigraphic and petrographic analyses, 14C, and
paleomagnetic dating. In particular, 14C age determinations of the Milo debris avalanche deposit indicate that the
initial stage of the catastrophic flank collapse of the Valle del Bove occurred at 7478–7134 BCE during the
Mesolithic age. Conversely, the main portion of the lava succession filling the valley floor emplaced after the sub-
Plinian picritic eruption occurred at 2579–2278 BCE (FS tephra layer) consistently with the increasing occurrence
frequency of flank eruptions documented in the geological record of Etna during the past 4000 yrs.
Paleomagnetic dating highlighted that in the study area the sub-Plinian eruption was followed by two quasicontemporaneous
flank eruptions during the Late Copper age (2600–2400 BCE), whereas other two flank
eruptions occurred during Greek-Roman and Medieval ages. These results have relevant implications on the
stratigraphy and evolution of Etna, particularly on the Valle del Bove initial collapse and the relative
emplacement of the Chiancone detritic-alluvial sequence.Published1077521V. Storia eruttivaJCR Journa
Spectral analysis of lava flows: Temporal and physicochemical effects
No full textIn a volcanic context, the spectral response of lava flows depends on several endogenous and exogenous factors, like chemical composition, passing of years and weathering. A deeper knowledge about lava properties can be inferred by investigating their spectral response in satellite images. Here, we compare the spectral response of lava in time, physical, and chemical characteristics, inspecting visible to infrared high spatial resolution ESA Sentinel-2 satellite images of different volcanoes. Our results show increasing and decreasing patterns of the lava spectral response as a function of time and physicochemical composition.Published144OSV1: Verso la previsione dei fenomeni vulcanici pericolosiJCR Journa
Impact assessment caused by bradyseism phenomena in the Campi Flegrei area
No full textCampi Flegrei (Italy) is among the areas with the greatest volcanic explosive risk in the world due to the dangerousness of the expected hazards, the high exposed value (about 500,000 people will be evacuated during the “alarm phase”), and the vulnerability of the urban settlements under the effect of the volcanic phenomena. The last two dramatic bradyseism phases occurred in 1969–1972 and 1982–1984 when Pozzuoli town was affected by rapid ground inflation, which brought an overall higher level of about 3.5 m and caused numerous earthquakes (M ≤ 4.2), with severe damage to buildings. During 1984, the seismicity was intense, with 33 events with 0.5 < M ≤ 3 and six with 3 < M ≤ 3.8. Subsequently, the Campi Flegrei caldera was characterized by general subsidence for about 20 years until 2005, when a new inflation period started and is still ongoing (∼1 m). The areal distribution of the recent uplift is characterized by the maximum vertical displacement in the town of Pozzuoli, with a radial decrease from the caldera center outwards. The need to better understand Campi Flegrei volcanic activity is fundamental to protecting the population from hazards linked to explosive volcanic eruptions and understanding the role of seismicity as a possible precursor of a potential eruption. In this perspective, as part of the activities of the PLINIVS Study Centre (Centre of Competence of Italian Civil Protection Department for Volcanic Risk), the authors developed a procedure, implemented in a web application, that relates the monitoring of the ground deformation with the behavior of buildings to evaluate the level of progressive damage to the ordinary Phlegraean buildings due to bradyseism in near real time. This study describes the models adopted for the three impact/risk factors (hazard, exposure, and vulnerability) used to estimate building damage.Published1129175OSV4: Preparazione alle crisi vulcanicheJCR Journa
Paperelle di gomma, bottiglie dei naufraghi e marine litter: strani ma utili proxy per lo studio delle correnti marine
No full textIl documento descrive i risultati due progetti di ricerca libera INGV (ML-DAR e ML-CSA) che hanno come obiettivo lo sviluppo di rifiuti marini tracciati a basso costo e lo studio del percorso che questi fanno allo sbocco dei fiumi in mare (il primo) con il coinvolgimento di volontari e studenti (il secondo).Published1-287TM.Sviluppo e Trasferimento TecnologicoN/A or not JC
Earthquake perception data highlight natural frequency details of Italian buildings
No full textAs the distance from an earthquake increases, the percentage of people who do not
feel it also increases. The average transition distance between ‘‘felt’’ and ‘‘not felt’’
reports is mainly determined by the magnitude and depth of the earthquake, but it
also depends on the observation floor and building height. Buildings act as resonators
and can amplify the shaking at specific frequencies.We analyzed over 286,000 crowdsourced
reports to study the effect of floor and building height on earthquake perception.
We found that, compared to average values, there is an increase in the
percentage of ‘‘felt’’ reports on the highest floors and a decrease in the lowest floors
of buildings of all heights.We determined the range within which an observer is likely
to feel an earthquake (perception boundary) and examined how it varies with magnitude.
We found that as the building height increases, people on higher floors perceive
medium to high magnitude earthquakes progressively better than lower magnitude
ones. We compared the perception boundary with a model of seismic response
spectra to estimate the vibration frequency perceived by observers on each floor/
building height combination. Our results show that the value of the fundamental
period increases with building height for the top floor, and that higher vibration
modes become more evident for buildings with more than 6 stories. In addition, we
observed that the height of the building also affects the vibration of the basement,
with the frequency tending to decrease as the building height increases. Concerning
macroseismic intensity estimation, we show that in tall buildings, observations made
on both the upper and lower floors must be considered outside the normal range,
and that earthquake perception also changes as a function of magnitude and distance,
pointing out the importance of collecting an adequate number of observations to
sample different locations of observers.Published1240-1254OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoJCR Journa
On the Comparison of Records from Standard and Engineered Fiber Optic Cables at Etna Volcano (Italy)
No full textDistributed Dynamic Strain Sensing (DDSS), also known as Distributed Acoustic Sensing (DAS), is becoming a popular tool in array seismology. A new generation of engineered fibers is being developed to improve sensitivity and reduce the noise floor in comparison to standard fibers, which are conventionally used in telecommunication networks. Nevertheless, standard fibers already have extensive coverage around the Earth's surface, so it motivates the use of the existing infrastructure in DDSS surveys to avoid costs and logistics. In this study, we compare DDSS data from stack instances of standard multi-fiber cable with DDSS data from a co-located single-fiber engineered cable. Both cables were buried in an area located 2.5 km NE from the craters of Mt. Etna. We analyze how stacking can improve signal quality. Our findings indicate that the stack of DDSS records from five standard fiber instances, each 1.5 km long, can reduce optical noise of up to 20%. We also present an algorithm to correct artifacts in the time series that stem from dynamic range saturation. Although stacking is able to reduce optical noise, it is not sufficient for restoring the strain-rate amplitude from saturated signals in standard fiber DDSS. Nevertheless, the algorithm can restore the strain-rate amplitude from saturated DDSS signals of the engineered fiber, allowing us to exceed the dynamic range of the record. We present measurement strategies to increase the dynamic range and avoid saturation.Published37354V. Processi pre-eruttiviJCR Journa
Multi-source data analysis to assess the past and present kinematics of the Pisciotta Deep-Seated Gravitational Slope Deformation (southern Italy)
No full textAlthough Deep-Seated Gravitational Slope Deformations are well-known in the literature, their evolution and kinematics are still poorly understood. Their behavior is often complex and characterized by small movements associated with steady-state creep, alternating with periods of stasis, or accelerating downslope movements that, in some cases, could result in sudden and catastrophic failure events. Therefore, a multidisciplinary approach is often required. In this work, we shed light on the complex geometry and kinematics of the Pisciotta DSGSD, a deep-seated roto-translational sliding involving structurally complex turbiditic rock mass and interacting with man-made infrastructures. To reveal the geometrical features and the spatial and temporal behavior of the analyzed phenomenon, a multidisciplinary investigation was performed. Typical DSGSD landforms were mapped employing in-situ surveys, aided by stereoscopic analysis of historical aerial images and high-resolution drone-based mapping. Structural data and ancillary ground-based surveys revealed the presence of a highly weathered and folded turbiditic sequence, with competent sandstone and calcarenite units alternated by tectonically disrupted, weak argillite and mudrock layers. Remote sensing measurements from optical imagery and Synthetic Aperture Radar satellite data assessed the DSGSD's past and current kinematics, allowing to distinguish a pre-failure period with accelerating displacement rates, a failure period with maximum displacement rates, and a current post-failure period with decelerating displacement rates. Analytical modeling established the deep reach (up to 85 m) of the studied DSGSD as it allowed the estimation of its bottom surface and volume, as verified by available boreholes and inclinometric measurements. Furthermore, numerical modeling outcomes highlighted how the progressive weakening and alteration of the DSGSD material, in conjunction with changes in groundwater dynamics, serve as the primary mechanisms driving the observed kinematics. The models also revealed the intricate interaction between the DSGSD and the neighboring infrastructures.Published113751OST5 Verso un nuovo MonitoraggioJCR Journa