Morphometry of the Campi Flegrei caldera (Southern Italy)

A high-resolution Digital Terrain Model (DTM) of Campi Flegrei caldera, obtained from an airborne LiDAR mission, has been analyzed in order to produce a 1:20,000-scale morphometric map of this volcanic area. The map consists of different thematic layers, which include: profile curvature, terrain ruggedness index, elevation range, as well as an up-to-date structural map and building distribution in the densely populated area. Results evidence that most of the relief is related to the occurrence of tuff-cones, tuff-ring, and the outer flanks of the caldera. Higher values of elevation characterize the upper portions of cones, while higher terrain ruggedness index values concentrate on the inner flanks of cones and in areas affected by gravity and erosional processes. The map also evidences the topographic expression of crater rims and of the major morphological scarps, which reflect ancient and uplifted shorelines and present-day cliffs

Corrigendum: Interpretation of spatiotemporal gravity changes accompanying the earthquake of 21 August 2017 on Ischia (Italy)

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Interpretation of spatiotemporal gravity changes accompanying the earthquake of 21 August 2017 on Ischia (Italy)

We analyse spatiotemporal gravity changes observed on the Ischia island (Italy) accompanying the destructive earthquake of 21 August 2017. The 29 May 2016 to 22 September 2017 time-lapse gravity changes observed at 18 benchmarks of the Ischia gravimetric network are first corrected for the gravitational effect of the surface deformation using the deformation-induced topographic effect (DITE) correction. The co-seismic DITE is computed by Newtonian volumetric integration using the Toposk software, a high-resolution LiDAR DEM and the co-seismic vertical displacement field derived from Sentinel-1 InSAR data. We compare numerically the DITE field with its commonly used Bouguer approximation over the island of Ischia with the outcome that the Bouguer approximation of DITE is adequate and accurate in this case. The residual gravity changes are then computed at gravity benchmarks by correcting the observed gravity changes for the planar Bouguer effect of the elevation changes at benchmarks over the same period. The residual gravity changes are then inverted using an inversion approach based on model exploration and growing source bodies, making use of the Growth-dg inversion tool. The found inversion model, given as subsurface time-lapse density changes, is then interpreted as mainly due to a co-seismic or post-seismic disturbance of the hydrothermal system of the island. Pros and weak points of such interpretation are discussed

The real-time multiparametric network of Campi Flegrei and Vesuvius

Volcanic processes operate over a wide range of time scale that requires different instruments and techniques to be monitored. The best approach to survey a volcanic unrest is to jointly monitor all the geophysical quantities that could vary before an eruption. The monitoring techniques are sometimes peculiar for each volcano, which has its own behavior. The simultaneous investigation of all the geophysical and geochemical parameters improves the sensibility and the understanding of any variation in the volcanic system. The Osservatorio Vesuviano is the INGV division charged of the Campi Flegrei and Vesuvius monitoring, two of the highest risk volcanic complexes in the world due to the large number of people living on or close to them. Each of them have peculiarities that increase the monitoring challenge: Campi Flegrei has high anthropic noise due to people living within its numerous craters; Vesuvius has a sharp topography that complicates the data transmission and analysis. The real time monitoring of the two areas involves several geophysical fields and the data are transmitted by a wide data-communication wired or radio infrastructure to the Monitoring Centre of Osservatorio Vesuviano: - The seismic network counts of 20 station sites in Campi Flegrei and 23 in Vesuvius equipped with velocimetric, accelerometric and infrasonic sensors. Some of them are borehole stations. - The GPS network counts of 25 stations operating at Campi Flegrei caldera and 9 stations at Vesuvius volcano. All the procedures for remote stations managing (raw data downloading, data quality control and data processing) take place automatically and the computed data are shown in the Monitoring Centre. - The mareographic network counts of 4 stations in the Campi Flegrei caldera coast and 3 close to the Vesuvius that transmit to the Monitoring Centre where the data are elaborated. - The tiltmetric network consist of 10 stations distributed around Pozzuoli harbor, the area of maximum ground uplift of Campi Flegrei, evidenced since 2005, and 7 stations distributed around the Vesuvius crater. Each tiltmetric station is also equipped with a temperature and magnetic sensor. The signals recorded are sent to the Monitoring Centre. - The 4 marine multiparametric stations installed in the Pozzuoli gulf send accelerometric, broad band, hydrophonic and GPS data to the Monitoring Centre. - The geochemical network counts of 4 multiparametric stations in the fumarolic areas of Campi Flegrei and 2 stations in the Vesuvius crater (rim and bottom) with data transmission to the Monitoring Centre. They collect soil CO2 flux, temperature gradient and environmental and meteorological parameters and transmit them directly to the Monitoring Centre. - The permanent thermal infrared surveillance network (TIRNet) is composed of 6 stations distributed among Campi Flegrei and Vesuvius. The stations acquire IR scenes at night-time of highly diffuse degassing areas. IR data are processed by an automated system of IR analysis and the temperatures values are sent to the Monitoring CentrePublishedVienna, Austria1IT. Reti di monitoraggio e sorveglianz

Morphometry of the Campi Flegrei caldera (Southern Italy)

A high-resolution Digital Terrain Model (DTM) of Campi Flegrei caldera, obtained from an airborne LiDAR mission, has been analyzed in order to produce a 1:20,000-scale morphometric map of this volcanic area. The map consists of different thematic layers, which include: profile curvature, terrain ruggedness index, elevation range, as well as an up-to-date structural map and building distribution in the densely populated area. Results evidence that most of the relief is related to the occurrence of tuff-cones, tuff-ring, and the outer flanks of the caldera. Higher values of elevation characterize the upper portions of cones, while higher terrain ruggedness index values concentrate on the inner flanks of cones and in areas affected by gravity and erosional processes. The map also evidences the topographic expression of crater rims and of the major morphological scarps, which reflect ancient and uplifted shorelines and present-day cliffs

Multidisciplinary approach for fault detection: Integration of PS-InSAR, geomorphological, stratigraphic and structural data in the Venafro intermontane basin (Central-Southern Apennines, Italy)

A multidisciplinary methodology, integrating stratigraphic, geomorphological and structural data, combined with GIS-aided analysis and PS-InSAR interferometric data, was applied to characterize the relationships between ground deformations and the stratigraphic and the morphostructural setting of the Venafro intermontane basin. This basin is a morphostructural depression related to NW-SE and NE-SW oriented high angle normal faults bordering and crossing it. In particular, a well-known active fault crossing the plain is the Aquae Juliae Fault, whose recent activity is evidenced by archeoseismological data. The approach applied here reveals new evidence of possible faulting, acting during the Lower to Upper Pleistocene, which has driven the morphotectonic and the environmental evolution of the basin. In particular, the tectonic setting emerging from this study highlights the influence of the NW-SE oriented extensional phase during the late Lower Pleistocene – early Middle Pleistocene, in the generation of NE-SW trending, SE dipping, high-angle faults and NW-SE trending, high-angle transtensive faults. This phase has been followed by a NE-SW extensional one, responsible for the formation of NW-SE trending, both NW and SE dipping, high-angle normal faults, and the reactivation of the oldest NE-SW oriented structures. These NW-SE trending normal faults include the Aquae Juliae Fault and a new one, unknown until now, crossing the plain between the Venafro village and the Colle Cupone Mt. (hereinafter named the Venafro-Colle Cupone Fault, VCCF). This fault has controlled deposition of the youngest sedimentary units (late Middle Pleistocene to late Upper Pleistocene) suggesting its recent activity and it is well constrained by PS-InSAR data, as testified by the increase of the subsidence rate in the hanging wall block

Surface temperature multiscale monitoring by thermal infrared satellite and ground images at Campi Flegrei volcanic area (Italy)

The Campi Flegrei volcanic area (Italy) is part of the Neapolitan volcanic district, a high volcanic risk area where population and human activities are exposed. It is monitored by INGV multi-platform surveillance networks systems. In this work we performed a comparison of the surface temperature in volcanic areas between satellite imagery in the Thermal Infrared (TIR) bandwidth and infrared thermal scenes acquired by ground cameras network (TIRNet). TIRS on LANDSAT and ASTER on NASA-TERRA provide thermal IR channels to monitor the evolution of the surface temperatures on Campi Flegrei area. The spatial resolution of the TIR LANDSAT8 data is 100 m and ASTER resolution is 90 m. Temporal resolution is 16 days for both satellites. TIRNet network has been developed by INGV-Osservatorio Vesuviano for long-term volcanic surveillance of Campi Flegrei caldera through the acquisition of thermal infrared images. The system is currently composed of 5 permanent stations equipped with FLIR A645SC cameras using a 640x480 resolution IR sensor. Acquisitions and data transmission are managed remotely through technology specially developed at INGV laboratories in Naples. To improve the systematic use of satellite data in the monitoring procedures of Volcanic Observatories, a suitable integration and validation strategy is needed, also considering that current satellite missions do not provide TIR data with optimal characteristics to observe small thermal anomalies that may indicate changes in the volcanic activity. The presented procedure has been applied to the analysis of Solfatara Crater and is based on 2 different steps: 1) two parallel processing chains to produce ground temperature data both from satellite and ground cameras; 2) data integration and comparison. The ground cameras images generally acquire scenes of portion of the crater slopes characterized by significant thermal anomalies due to fumarole fields. In order to compare the satellite and ground cameras scenes, it has been necessary to take into account the observation geometries. All thermal images of the TIRNet have been georeferenced to the UTM WGS84 system, a regular grid of 30x30 meters has been created to select polygonal areas corresponding only to the cells containing the georeferenced TIR images acquired by different TIRnet stations. The surface temperature images retrieved by ASTER and LANDSAT data, have been georeferenced and resampled in cells of 30x30 with a careful control in maintaining the original cell values. The results show a good correspondence between trends of surface ground temperatures and satellite temperatures. This allow to calibrate the surface temperatures of the satellite imagery and to extend the area of analysis of thermal anomalies in the Campi Flegrei caldera. The effectiveness of this methodology allow to integrate the temperature data acquired by TIRNet with the satellite temperature data acquiredbefore the installation of TIRNet ground network.PublishedVienna5V. Processi eruttivi e post-eruttivi6SR VULCANI – Servizi e ricerca per la società5IT. Osservazioni satellitar

Surface Temperature Multiscale Monitoring by Thermal Infrared Satellite and Ground Images at Campi Flegrei Volcanic Area (Italy)

Land Surface Temperature (LST) from satellite data is a key component in many aspects of environmental research. In volcanic areas, LST is used to detect ground thermal anomalies providing a supplementary tool to monitor the activity status of a particular volcano. In this work, we describe a procedure aimed at identifying spatial thermal anomalies in thermal infrared (TIR) satellite frames which are corrected for the seasonal influence by using TIR images from ground stations. The procedure was applied to the volcanic area of Campi Flegrei (Italy) using TIR ASTER and Landsat 8 satellite imagery and TIR ground images acquired from the Thermal Infrared volcanic surveillance Network (TIRNet) (INGV, Osservatorio Vesuviano). The continuous TIRNet time-series images were processed to evaluate the seasonal component which was used to correct the surface temperatures estimated by the satellite’s discrete data. The results showed a good correspondence between de-seasoned time series of surface ground temperatures and satellite temperatures. The seasonal correction of satellite surface temperatures allows monitoring of the surface thermal field to be extended to all the satellite frames, covering a wide portion of Campi Flegrei volcanic area

Perception of risk for natural hazards in Campania Region (Southern Italy)

As far as the European continent, Region Campania in Southern Italy presents an almost unique combination - in terms of both variety and intensity-of potential risks for the residents: this densely populated area is actually most notably exposed to hydrogeological (flood and landslides), seismic, volcanic hazards In such a setting, alongside with an up-to-date scientific approach to risks analysis and the constant update of emergency plans, it is of paramount importance that a “risk awareness culture” should be developed by the residents. In order to maximize the effectiveness of the communication campaigns to support and improve such a culture, a study of risk perception has been carried out in 12 municipalities and 2 territorial unions of Campania Region. Different areas have been examined, the overall exposure of each almost always being characterised by a prevalent specific risk: seismic, volcanic, hydrogeological. The results of this surveys show that the historical memory has a crucial role on the hazards perception. It's also worth of noting that few communities consider that they have been sufficiently well-informed by civil protection agencies and/or authorities about the natural hazards specific to their area and the practical procedures for evacuation. To overcome these deficiencies emergency plans should be designed, developed and practised through the collaboration of all key stakeholders, from civil protection authorities to the residents communities.Publishedid 1011646SR VULCANI – Servizi e ricerca per la societàJCR Journa

La valutazione delle deformazioni del suolo nella piana di Venafro mediante l’elaborazione di dati PSInSar, morfo-strutturali e stratigrafici

I bacini intramontani dell’Appennino centro-meridionale sono soggetti, sin dalla loro genesi (Pleistocene inferiore), a deformazioni del suolo, la cui non uniforme distribuzione e la cui diversa entità sono una risposta all’attività di faglie, intersecanti e bordanti le pianure, e al costipamento differenziale dei depositi costituenti le successioni sedimentarie di riempimento. Al fine di valutare la distribuzione spaziale dei movimenti verticali e le relative velocità, e di interpretarne correttamente le cause, è stato affrontato uno studio multidisciplinare che ha previsto l’elaborazione di dati radar con tecnica PSInSAR, lo studio geomorfologico e strutturale e l’analisi stratigrafica di dati di sottosuolo della piana di Venafro, ampia depressione tettonica interposta tra i M. delle Mainarde-M. di Venafro ed i M. del Matese e drenata dal F. Volturno. L’interpolazione dei dati PS, effettuata in ambiente GIS, riferita a due intervalli di tempo, 1995–2000 (ERS) e 2003–2008 (ENVISAT) ha permesso di valutare i ‘cumulative vertical displacements’ (mm), i ‘displacement rates’ (mm/a) e il ‘gradient field’ dei ‘displacement rates’, consentendo di individuare alcuni settori del bacino che si distinguono per tassi di subsidenza superiori alla media e per comportamento deformativo costante nel tempo. Risulta evidente una correlazione tra la distribuzione spaziale del quadro deformativo di natura interferometrica, lo sviluppo geometrico delle faglie che interessano la piana e la natura litologica del riempimento sedimentario. I valori maggiori di subsidenza si registrano nel settore centrale della piana, probabilmente indotti da un maggiore spessore dei depositi di riempimento, nonché dalla presenza di depositi argillo-sabbiosi poco addensati e più suscettibili al costipamento, così come dalla presenza di alcuni lineamenti tettonici orientati NE-SW e NW-SE. In particolare, i valori maggiori si registrano a valle di una scarpata morfologica, orientata NW-SE, coincidente anche con un importante ‘knick point’ del F. Volturno, oltre che a valle di una faglia, orientata NW-SE (Faglia dell’’Aquae Juliae’), attiva in tempi storici per aver dislocato l’acquedotto romano.PublishedFirenze2T. Tettonica attiva5IT. Osservazioni satellitariope