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Petrazzuoli, Stefano Maria
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Petrazzuoli, Stefano Maria
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- PublicationRestrictedShort-term ground deformations and seismicity in the resurgent Campi Flegrei caldera Italy/: an example of active block-resurgence in a densely populated area(1999)
; ; ; ; ; ; ; ; ; ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Civetta, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Del Gaudio, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;de Vita, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Di Vito, M. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Isaia, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Petrazzuoli, S. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Ricciardi, G. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Ricco, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; ; ; The Campi Flegrei caldera is a complex structure in which resurgence occurs through a simple shearing mechanism. The most uplifted block inside the caldera is the La Starza block. The caldera has shown signs of unrest since 1969 with two bradyseismic events which generated a net vertical ground displacement of 3.5 m around the town of Pozzuoli. The first event occurred between 1969 and 1972, when the ground was uplifted of 1.74 m, while the second took place between 1982 and 1984 and produced a vertical displacement of 1.79 m. These events have been followed by subsidence with small uplifts of few centimeters. Uplifting events, despite the amount of ground displacement, are always accompanied by seismicity which is absent during subsidence. We have performed an analysis of the ground deformation and seismic data collected since 1970. The results obtained on the two independent sets of data are very much concordant. The ground deformation is not quasi bell-shaped as previously suggested, instead its geometry is strongly constrained by structural discontinuities. Seismicity is confined in a rectangular area, NE–SW elongated and centered on the La Starza block. The margins of this area are marked by earthquakes whose hypocenters describe vertical planes which reach depths of about 5 km. The hypocenters of the earthquakes located in the La Starza block are shallower than 3 km. Focal mechanisms of the earthquakes whose hypocenters describe a NNW–SSE fault plane in the Pozzuoli bay show reverse fault solutions, while those of the earthquakes located on the opposite side of the La Starza block show normal fault solutions. All these data well constraints the hypothesis that resurgence occurs through a simple shearing mechanism Orsi et al., 1996.. We have also performed a finite elements modeling of the ground deformation data. This modeling shows that the detected deformation can be accounted for by an overpressure of 75 MPa in a source with a radius of 1 km, located at 5 km depth in a medium characterized by the detected structural discontinuities. q1999 Elsevier Science B.V. All rights reserved238 14 - PublicationOpen AccessSeismic damage and destructive potential of seismic events(1995-11)
; ; ;Abruzzese, D.; Dipartimento di Ingegneria Civile, Universitá di <<Tor Vergata>>, Roma, Italy ;Petrazzuoli, S. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; This paper has been written within a research framework investigating the destructive potential of seismic events. The elastic response spectra seem insufficient to explain the behaviour of structures subject to large earthquakes in which they experience extensive plastic deformations. Recent works emphasise that there were many difficulties in the definition of a single pararneter linked to the destl-uctive potential of an earthquake. In this work a study on the effect of frequency content on structural damage has been carried out. The behaviour of two different elastoplastic oscillators has been analysed, considering several artificial earthquakes. The results obtained suggest a method for evaluating the destructive seismic potential of an earthquake through the response spectra ad the frequency content of the signal. and through the mechai~ical characteristics of the structures within the analysed area.149 102 - PublicationRestrictedSeismic risk mitigation at Ischia island (Naples, Southern Italy): An innovative approach to mitigate catastrophic scenarios(2019)
; ; ; ; ; ; ; ; ; ; ;; ;; ;Ischia island, in the province of Naples, is a densely populated volcanic island, in which small to moderate magnitude earthquakes occur. Due to the very shallowdepth of such events (< 2 km), they can generate serious damage and casualties, up to the complete destruction of urban centers located within short epicentraldistance. Almost all of the earthquakes at Ischia island occur at shallow depth, beneath the Northern slopes of the Mt. Epomeo horst, which is located very close to thetown of Casamicciola. In fact, Casamicciola was completely destroyed by the 1883 earthquake (2313 victims) and experienced intensities up to XI degree on theMercalli scale. Historical records show that the background seismicity here is almost absent, but larger earthquakes tend to occur in clusters, lasting some decadesand with intervals between consecutive events on the order of years to decades. The clustering in time and the very shallow hypocentres, which cause, with respect totectonic earthquakes of similar magnitude, larger effects though limited to a relatively small area, make the seismicity in this island very peculiar. Despite suchdestructive record, till now official hazard maps strongly underestimated the seismic hazard in this area. On August 21st 2017, a very shallow earthquake with rathersmall magnitude struck the area of Casamicciola, killing two people, injuring many more and causing huge damage and partial to total collapse of edifices located justabove the earthquake fault.The maximum acceleration recorded for this earthquake exceeded by more than a factor of two the reference acceleration that should be sustained by edifices,according to official hazard maps. We propose here a complete procedure to assess and mitigate the risk, which can be rapid and economically affordable and, at thesame time, can avoid further grief due to possible occurrence of other destructive earthquakes within a short time interval. We describe the most likely buildingcollapse and casualty scenarios, in case that low-to-moderate magnitude earthquakes would occur before the edifices would be appropriately reinforced and secured.Our scenarios demonstrate the urgent need for securing operations. The proposed procedures for assessing seismic hazard and for securing urban areas provide anexample that is potentially applicable to the whole Italian peninsula. They may allow in fact the mitigation of the destructive impact of a large number of earth-quakes, which in Italy are often characterized by low or moderate magnitudes605 6 - PublicationRestrictedEffects of the hydrothermal circulation on the strain field of the Campanian Plain (southern Italy)(2004)
; ; ; ;Milano, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Petrazzuoli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; Focal mechanisms of earthquakes and fault-slip data have been collected to constrain the strain regime acting in the hydrothermal zone and surrounding areas of the Campanian Plain (southern Italy), a NW–SE elongated structural depression. The NW–SE striking faults bounding the depression move in response to a NE–SW striking regional extension. Within the depression, an extended hydrothermal circulation occurs related to the Vesuvius, Campi Flegrei and Ischia active volcanoes. In this zone, the strike of the extension is N–S. Results from a finite element model constrained by the collected data show that the presence of a lower rigidity zone due to the hydrothermal circulation may explain (a) the observed deflection of the direction of regional extension, and (b) why large magnitude earthquakes occur at the boundaries of the hydrothermal zone and not along the faults delimiting the structural depression.190 78 - PublicationOpen AccessThe mechanics of Campi Flegrei unrests as related to plastic behaviour of the caldera borders(1999-06)
; ; ; ; ;Petrazzuoli, S. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Troise, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Pingue, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;De Natale, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; We present here a model which explains the mechanism of generation of unrest episodes at Campi Flegrei caldera from a mechanical point of view. The mechanism involves the effects of plastic zones at the borders of the inner collapsed area on both static deformations and seismicity. The large amount of ground uplift observed necessarily calls for plastic effects. These effects are interpreted as concentrated at the caldera borders: the generation of such plastic zones is simulated in terms of the mechanisms leading to the caldera collapse. In order to simulate the influence of such plastic zones on both ground deformations and seismicity we model them as surfaces of discontinuities free from shear stress within an elastic homogeneous half-space. The presence of such discontinuities allows the inner caldera block to move differentially from the outer areas, by slip along the plastic bordering zones. Such a differential uplift of the central block causes the concentration of the ground deformation. Our model explains a lot of puzzling observations at Campi Flegrei in terms of the effects of the caldera structure. The model is applicable to other caldera areas, which show typical evidence for the effects of such discontinuity zones, during unrest episodes.174 361 - PublicationRestrictedMonitoring system of buildings with high vulnerability in presence of slow ground deformations (The Campi Flegrei, Italy, case)(2011)
; ; ; ; ; ; ;Pingue, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Petrazzuoli, S. M.; Study Centre PLINIVS, University of Naples ‘‘Federico II’’, Naples, Italy ;Obrizzo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Tammaro, U.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;De Martino, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Zuccaro, G.; Study Centre PLINIVS, University of Naples ‘‘Federico II’’, Naples, Italy; ; ; ; ; In this work we illustrate the results of some laboratory and full scale experiments which have the purposes of analysing the performance of different types of monitoring equipments in detection of damage level in masonry buildings. Such experiments involved monitoring, by means of optical fibre strain-metre and total laser station, of a selected building that, owing to its position in the active caldera of the Campi Flegrei (Southern Italy), could undergo remarkable ground shaking and large, although very slow, ground movements (bradyseismic crises) of volcanic origin. The field geodetic monitoring has been realised by an automatic system of topographical 3D survey, based on two automatic Total Station Leica TCA2003 and by increasing the number of benchmarks of the levelling network in the area near the building. The experiments have shown that structure deformations caused by elastic phase, when the building undergoes elastic deformation, is close or under the limit of detection through laser total station (about 1–2 mm), while, when the damage occurs, deformations increase up to values beyond 10–20 mm easily detectable by geodetic methods. The optical fibre monitoring provides good results in elastic phase, whereas as the damage level rises up the data become more and more difficult to understand. In conclusion the paper shows that the geodetic techniques are very useful in structural quasi real-time monitoring for analysing the behaviour of masonry buildings damaged by ground movements induced by landslide phenomena, bradyseism or intrinsic structural yielding.500 50 - PublicationOpen AccessRapporto sugli eventi sismici del Beneventano(1990-04)
; ; ; ; ; ; ; ; ;Alessio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Gorini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Vilardo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Pinto, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Capello, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Iadicicco, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Amedeo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Petrazzuoli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; ; Not Present175 180 - PublicationOpen AccessTerremoto del 29 dicembre 2013 nel Matese (MW = 5.0). Indagine speditiva degli effetti nell’area epicentrale e analisi preliminare della sequenza sismica.(2014-10)
; ; ; ; ; ;Convertito, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Cubellis, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Marturano, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Obrizzo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Petrazzuoli, S. M.; Esperto di ingegneria sismica; ; ; ; Il 29 dicembre 2013 un terremoto di magnitudo Mw=5.0 (profondità 10.5 km) è avvenuto nell'area dei Monti del Matese alle ore 18:08:43 ora locale.389 295