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The city of Napoli and its active volcanoes
Full text linkSomma-Vesuvius and Campi Flegrei are among the most famous active volcanoes in the world and are part of the Neapolitan landscape. The activity of the volcanoes punctuated the human history since Bronze Age, as testified by archaeological finds recognised in the plain and relieves surrounding the volcanic area. The world-famous eruption of AD 79 consigned the Somma-Vesuvius to the history, because of the burying of some important roman tows like Pompeii and Herculaneum. The field trip dedicated to Somma-Vesuvius illustrates the volcanology of main historical eruptions, with special emphasis to the activity of the last 4000 years. The visit to the summit cone provides a panoramic view of the inner caldera wall. Deposits of the Plinian and subplinian eruptions can be observed in old quarries around the volcano. The AD 79 deposits are exposed in both quarries and archaeological excavations such Herculaneum and Oplontis, in which the interaction of the pyroclastic deposits with an inhabited area will be the argument for discussion about the present day volcanic hazard and risk in the Neapolitan area. A visit to the hystorical site of the Osservatorio Vesuviano will be the occasion to illustrate the born and the history of volcanic surveillance. The itinerary in the Campi Flegrei caldera, provides asn overview of i) the deposits of the Campanian Ignimbrite and Neapolitan Yellow Tuff caldera forming eruptions, ii) the pyroclastic density currents and fallout deposits of the post caldera volcanism, iii) different preserved volcano edifices and volcano tectonic structures, along with fumarolic and hydrothermal active field are hosted. A visit to the remnants of the Serapeum Roman market and the Pozzuoli harbour, are the best examples to discuss of caldera unrest at Campi Flegrei. The several diverse monitoring stations site at Solfatara and a visit to the Monitoring Centre of the Osservatorio Vesuviano provide an opportunity to illustrate the surveillance network of the INGV-OV for the Neapolitan volcanoes and discuss on the future eruption scenario and the related risk
Structural analysis of fractures, faults and dykes in the Somma-Vesuvio volcano
No full textA geological and structural survey on the Somma-Vesuvio volcanic edifice has been carried out with the main aims
to define the contribution of local versus regional stress field in the evolution of the volcano and the relationships
between caldera evolution, fractures and faults. Measurements of fractures, faults and dykes were collected, mainly
inside the caldera sector, and analyzed to characterize the fracture network affecting volcanic rocks. Structures were
recorded both in lavas and pyroclastic rocks. Most of fractures in lavas are cooling joints. Several cooling joint are
reactivated as normal faults, following the caldera collapse. Generally fractures both parallel and orthogonal to caldera
rim occur. Finally recent fractures are associated to gravity instability of volcano edifice are well evident in the eastern
sector of the Mt. Somma. Other normal faults characterized by low angle dips occur along the cliff of Mt. Somma.
Dykes appear as planar at places forming an en-echelon pattern or with a ramp-flat geometry. Fractures, dykes and fault
show some preferred orientations. A field stress map was carried out from inversion of meso-scale faults and fractures
Caldera evolution in Campi Flegrei: the role of fractures and faults
No full textFractures and faults hosted in volcanic rocks in Campi Flegrei were analyzed. The fracture pattern suggests a prevalence of NE-SW and NW-SE directions and secondarily N-S and E-W trends occur. Faults often appear as conjugate structures showing normal kinematics, at places associated with ductile deformation suggesting a syn-eruption deformation. However the most of faults, mainly hosted along the caldera/crater rims, are very steep with dominant normal and secondary reverse movements. Fractures and faults found in rocks older than 15 ka (Neapolitan Yellow Tuff included), measured in western and eastern sectors of the study area, indicate a rotation of ca. 30° of the main directions among these two sectors, whereas the younger rocks are widespread characterized by a slight prevalence of the “regional” NW-SE (Apennine) and NE-SW (anti-Apennine) directions. Faults occurring along the caldera/crater rims suggest a kinematic evolution characterized by the reactivation of tensile fractures previously formed in response to both regional extension and locale resurgent dom
Caldera unrest prior to intense volcanism in Campi Flegrei (Italy) at 4.0 ka B.P.: Implications for caldera dynamics and future eruptive scenarios
No full textThe Campi Flegrei caldera is one of the highest risk
volcanic areas on the Earth. Our research documents a
150 year-long period of intense volcanism following less
than 200 years of repose after the Agnano-Monte Spina
Plinian eruption (4.1 ka). The new data show that the
renewal of volcanism was preceded by an uplift of a few
tens of meters, triggered by mafic refilling of reservoirs at
depths of 3 km or less. Our studies also indicate for the first
time the occurrence of contemporaneous eruptions from
at locations in different sectors of the caldera. These results
suggest that a future eruptive crisis will likely be preceded
by several meters of caldera-wide uplift in response to
magma movements at depth. The trend of uplift of the
caldera since 1969 may thus represent the unrest expected
before a renewal of volcanism within an interval of decades
to centuries. Citation: Isaia, R., P. Marianelli, and A. Sbrana
(2009), Caldera unrest prior to intense volcanism in Campi
Flegrei (Italy) at 4.0 ka B.P.: Implications for caldera dynamics
and future eruptive scenarios, Geophys. Res. Lett., 36, L21303
Note Illustrative della Carta Geologica d’Italia alla scala 1:50.000, Foglio 446-447 Napoli (aree emerse)
No full textNote Illustrative della Carta Geologica d’Italia alla scala 1:50.000, Foglio 446-447 Napoli (aree emerse
Geomorphic analysis of digital elevation model generated from vintage aerial photographs: A glance at the pre-urbanization morphology of the active Campi Flegrei caldera
No full textAccurate digital elevation models represent the basic tool for a large spectrum of applications, including geological, architectonic, archaeological, and urbanistic studies. However, aggressive urbanization may significantly alter the morphology of areas of interest. Such is the case of the active Campi Flegrei caldera in southern Italy, where all the buildings, facilities, infrastructures, quarries, and landfills altered the original volcanic morphology. To avoid these limitations, we analyzed a set of vintage aerial photographs acquired in 1943 by Italy's Military Geographic Institute (IGM). We reconstructed the study area's topography before the deep anthropic modification from the 1960s onwards by applying Structure-from-Motion photogrammetric processing. On the reconstructed orthomosaic and a historical-Digital Surface Model (hDMS), we conducted geomorphic analyses along 18 longitudinal stream profiles outside, across the border, and inside the caldera, underlining that the rectilinear sections with preferred orientations and increased incision values suggest a strong structural underpinning on valley incision and stream paths. The analysis of the spatial distribution of sinuosity, SL index, Chi (χ) value and knickpoint maps suggests the presence of tectonic lineaments that influence the stream network from the pre-caldera (>40 ka) to recent times, producing articulated caldera and craters geometry as well as affecting the localization of volcanic vents. The comparison between the 1943 hDSM and 2013 LiDAR (Light Detection and Ranging) DSM allowed us to spotlight the areas that show the most significant differences due to anthropic intervention that obliterated critical features, thus supporting our motivation to use this base. Overall, the results indicate that long-lived volcano-tectonic and tectonic structures control the orientation of drainage patterns and their re-arrangements during volcano-tectonic deformation phases. Finally, a comprehensive structural map, based on the merged 1943 hDSM and the bathymetric DEM, is presented together with a conceptual evolutionary model of the stream network across the caldera border. Under the proper acquisition conditions, vintage aerial photographs can provide a useful tool for morphological analysis and can be applied to several topics in the geosciences
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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