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This paper analyses data regarding the seismicity and ground deformations of the island of Ischia. The goal is to describe these phenomena as a space–time process, exploring the mechanism as a whole in order to answer questions concerning why and how historical earthquakes occurred and the geological constrains at the time of the earthquake of 21 August 2017. According to our analysis, the genesis of earthquakes in the island may be due either to regional tensile tectonics or to increased pressure in a shallow magma source. The eruptive rest following the 1302 Arso lava flow, the seismic silence from 1883 and the ground sinking recorded at least from the end of the nineteenth century suggest a decline of pressure in the shallow magma source and in the action of the stress field generated by the spreading of the Tyrrhenian Basin. The mechanism that can generate the observed ground deformation field and seismicity is the gravitational and thermal loading of the island, because the load of the massif of Mt. Epomeo onto its hot substratum may induce the gravitational spreading that would have produced its sliding southwards and its rotation northwards. The surface of detachment plunges towards the south and emerges at a high angle at the northern edge of Mt. Epomeo, where coseismic ground effects and the greatest damage have been observed. This mechanism that generated the 21 August 2017 earthquake could be extended to historical seismicity.

Studying seismicity in a volcanic environment provides important information on the state of activity of volcanoes. The seismicity of the Neapolitan volcanoes, Campi Flegrei, Vesuvius, and Ischia, shows distinctive characteristics for each volcano, covering a wide range of volcanic seismicity patterns and types. In this study we relocated some significant volcano-tectonic (VT) earthquake swarms that occurred in Campi Flegrei and Vesuvius. Moreover, we compared the earthquake occurrence evolution, the magnitude and the seismic energy release of the three volcanoes. Also, we considered the results of seismic analysis in the light of geochemical and ground deformation data that contribute to defining the state of activity of volcanoes. In Campi Flegrei, which is experiencing a long term unrest, we identified a seismogenic structure at shallow depth in Pisciarelli zone that has been activated repeatedly. The increasing seismicity accompanies an escalation of the hydrothermal activity and a ground uplift phase. Even at Vesuvius a very shallow seismicity is recorded, which in recent years has shown an increase in terms of the number of events per year. Earthquakes are usually located right beneath the crater axis. They are concentrated in a volume affected by the hydrothermal system of Vesuvius. Finally, Ischia generally shows a low level of seismicity, however, in Casamicciola area events with a moderate magnitude can occur which are potentially capable of causing severe damage to the town and population, due to their small hypocentral depth (typically

With the Industrial Revolution the laws of physics were introduced to explain natural phenomena. At that time the Vesuvian Observatory emerged as the first volcanological observatory in the world to monitor the activity of Vesuvius on a permanent basis. Naples became an attractor for scholars, who were to analyze volcanic phenomena by developing relationships between the science of laws and those of processes. After World War I interest in Naples-based volcanology further increases, as attested by the founding in the city of Immanuel Friedlaender's International Institute of Volcanology. Following the twenty-year Fascist period, Italy had two objectives: to reconstruct the network of science laboratories and rebuild the approach to studying Earth Sciences through comparison with more advanced countries. Significant and original contributions were made regarding the new theory of global tectonics and the mitigation of natural risks.

Mount Vesuvius last erupted in March 1944. The eruption began with a modest effusive activity (18–21 March, phase I) and then moved on to a lava-fountain phase (21–22 March, phase II) that quickly culminated in a 24-h paroxysmal phase (22–23 March, phase III), during which the eruptive column reached its maximum altitude and ash carried by the wind was deposited at distances of up to 500 km from the volcano. Subsequently (phase IV), the ash cloud reached altitudes not exceeding 2 km above the crater and the explosions became discontinuous, alternating with frequent tremors. From April 7th the vent remained permanently closed. Since then, the current period of quiescence may be said to have begun. In our study we present a detailed geochemical study of the volcanic products emitted throughout the stages of the eruption, including an extreme distal ash sample, collected at the time of the eruption in Albania (Devoli) by the geologist Antonio Lazzari. The results indicate that magmatic differentiation took place in two crystallization stages under different temperature and pressure. Moreover, through the use of a numerical model of volcanic ash dispersion in the atmosphere as well as the collection of new witness accounts, we inferred the maximum height reached by the eruptive column (>8–10 km above the crater) as well as its impact on the environment and people, suggesting that the damage in the area and even the number of the victims could be higher than accepted until now.

We investigated the interseismic GPS velocity field across the transition zone between Central and Southern Apennine comprising the Meta–Mainarde-Venafro and Alto Molise–Sannio-Matese mounts. The kinematic field obtained by combining GPS network solutions is based on data collected by the unpublished episodic campaigns carried out on Southern Apennine Geodetic network (SAGNet from 2000 to 2013), IGM95 network ( Giuliani et al., 2009 from 1994 to 2007) and continuous GPS stations. The data collected after the 29 December 2013 earthquake (Mw 5.0) until early 2014 allowed estimating displacements at 15 SAGNet stations. The extension rate computed across the Matese massif along an anti-Apennine profile is 2.0±0.2 mm/yr. The interseismic velocities projected along the profile show that the maximum extension does not follow the topographic high of the Apennines but is shifted toward the eastern outer belt. No significant GPS deformation corresponding to inner faults systems of the Matese massif is detected. Taking into account our results and other geophysical data, we propose a conceptual model, which identifies the 2013–2014 seismic sequence as not due to an extensional deformation style usual along the Apennine chain. In fact, we have measured too large “coseismic” displacements, that could be explained as the result of tectonic regional stress, CO2-rich fluid migration and elastic loading of water in the karst Matese massif. We recognized a tensile source as model of dislocation of 2013–2014 earthquakes. It represents a simplification of a main fault system and fracture zone affecting the Matese massif. The dislocation along NE-dipping North Matese Fault System (NMFS) could be the driving mechanism of the recent seismic sequences. Moreover, to the first time the SAGnet GPS data collected from 1994 to 2014, are share and available to the scientific community in the open access data archive.

This article presents the results of a detailed study of the effects of the 1883 earthquake, which occurred at the island of Ischia (Gulf of Naples) and produced the total destruction of buildings in the epicentral area (Casamicciola town). Despite the moderate magnitude, this event was characterised by very high intensities (I max = XI degree MCS) mainly due to the shallow depth of the source. The study of the earthquake shows that the intensities, which decreased rapidly with distance, were affected by source directivity, according to the causative fault geometry and tectonic structures, while local amplification of damage was observed where soft soils outcrop. The attenuation of seismic intensity with distance was evaluated using the well-known relation of intensity versus epicentral distance (Blake’s method). The diverse gradients of attenuation, observed in different directions, were ascribed to the various geological features of the shallow crust of the island. In order to evaluate the role of geology in the damage level, we computed different attenuation models for stiff and soft soils outcropping on the island. A systematic local amplification of about 1 MCS degree associated to the presence of reworked tuffs was obtained. This study also shows the influence of geological conditions on the evaluation of macroseismic data and supplies useful elements to derive a predictive map of potential site effects.

This paper deals with the problem of seismicity at Mt. Vesuvius with a view to providing an estimation of the maximum expected earthquake. Integrated analysis of both historical and current seismicity as well as the geological conditions of Vesuvius and the surrounding areas show that seismogenetic structures may fall within the crater axis and at the boundaries of the volcanic complex. While activation of the whole seismogenetic volume detected by seismicity in the past 30 years would indicate a total seismic moment of Mo = 7.1E+ 15 Nm for a magnitude M = 4.5, knowledge of the area's geological structure suggests faulting surfaces of about 32 km2 with an associated magnitude of M = 5.4. The areas of maximum expected damage differ according to the orientation of the hypothesized structure. Analysis of geological and geophysical data and the damage associated to the AD 62 earthquake shows that the prevailing directions in the faulting planes are NE–SW in the eastern sector of the volcanic complex, and roughly WNW–ESE in the southern part of the volcano along the coast. Comparison of instrumental seismicity and historical data reveals two significantly different energy levels: a lower earthquake level with Mmax = 4.5, corresponding to current seismicity and that which accompanied volcanic activity in the eruptive period from 1631–1944; an upper level with Mmax = 5.4, represented by the AD 62 earthquake. The two levels correspond to two stress states and different seismogenetic structures.

A model of caldera resurgence was applied to the Island of Ischia to explain uplift, volcanic activity and tectonics on Mount Epomeo, as well as historical seismicity and slow ground movements recorded for the past 2000 years. A two-dimensional mechanical model was utilized for the crust, which was considered to be an elastic plate overlying a laccolith. Geometric dimensions and mechanical parameters were constrained using geological, geophysical and geochemical data. We propose that a laccolith, with a diameter L of c. 10 km, and a depth of up to 1 km in the centre of the island, triggered the caldera resurgence after the Mount Epomeo Green Tuff eruption forming the caldera (55 000 a BP). A bending phase and a punched laccolith phase are thought to have caused the observed deformations in the caldera. These processes control the tectonics at the boundary of the Mount Epomeo resurgent structure, volcanic activity and dynamics of the island. process starting between 33 000 and 28 000 years ago, forming the Mount Epomeo block. Total uplift, deduced from the present height of marine deposits and eustatic variations, is 710 m on the southern flank and 920–970 m on the northern flank, with an average uplift rate of 2.3 and 3 cm a−1 respectively (Barra et al. 1992; Tibaldi & Vezzoli 2004). This resurgence of the central part of the island is thought to be associated with the input of new magma at shallow depths, which from 28 000 to 18 000 a BP produced volcanic deposits of significantly different composition from those of previous eruptions (Civetta et al. 1991; Petrini et al. 2001). The resurgent block of Mount Epomeo, dominating the central sector of the island, is roughly square, with sides about 4 km long. The edges of the block are marked by a system of faults with NW–SE, NE–SW and N–S strikes (Fig. 2). The faults on the northern side of Mount Epomeo have been active over the last 800 years as seismogenetic sources, as testified by historical data. Furthermore, the horseshoeshaped structure of Mount Epomeo, open towards the southeast, and the large hummocky deposits off the south coast of Ischia, recently recognized by marine surveys, are consistent with an avalanche involving the summit of the Mount Epomeo resurgent block and the southern onshore caldera flank (Luongo et al. 1995; Cubellis & Luongo 1998; Marsella et al. 2001; The island of Ischia is a 46 km2 volcanic field emerging at the western edge of the Bay of Naples (Fig. 1). This field represents the emergent part of a more extensive volcanic area developed mainly to the west of the island (Vezzoli 1988; Bruno et al. 2002). It consists of volcanic rocks deriving from a number of eruptive centres which have been largely destroyed or covered by subsequent activity and can now be identified only in part. The oldest outcrops date back to about 150 000 a BP, while the most recent eruption occurred in 1301–1302 AD in the eastern sector of the island (Vezzoli 1988; Civetta et al. 1991). During this period, five phases of activity have been distinguished and grouped in an older cycle and a younger cycle, whose transition is defined by the great alkali-trachytic ignimbrite eruption of the Mount Epomeo Green Tuff (MEGT) (55 000 a BP) which was accompanied by a caldera collapse (Table 1). Although the boundaries of the caldera are ill-defined, it has an approximately elliptical shape 10x7 km2 (Fig. 2), with the longer axis trending east–west (Tibaldi & Vezzoli 1998). The caldera depression was filled – at first in sub-aerial and subsequently in submarine conditions – by the MEGT, the tuffs of the Citara Formation (CF) (about 44 000–33 000 a BP) and subaqueous epiclastic and pyroclastic deposits, Colle Jetto Formation (CJF). These deposits were involved in an uplift 182 S. CARLINO ET AL. Fig. 1. Digital terrain model (DTM) image of the Bay of Naples. Ischia Island is located in the western sector. Table 1. Volcanic activity phases of Ischia Older cycle Phase 1>150 000 a BP Older major pyroclastic activity Pre-Mount Epomeo Green Tuff activity Phase 2 50 000–75 000 a BP Lava dome emplacement Phase 3 55 000–33 000 a BP Younger major pyroclastic activity Younger cycle Mount Epomeo Green Tuff Phase 4 29 000–18 000 a BP Explosive and effusive activity in the Citara Formation southwestern and southestern sector Phase 5 10 000 a BP to 1302 AD Prehistoric and historical activity Chiocci et al. 2002; Cubellis et al. 2004; De Alteriis et al. 2004; Tibaldi & Vezzoli 2004; Carlino & Cubellis 2005). In general, the models used to interpret resurgence processes for large calderas – the thrust of the magma in a shallow source due to an increase in pressure or due to vesiculation; regional detumescence; or heat transfer from the magmatic basin to the surface aquifer system (Smith & Bailey 1968; Marsh 1984; Luongo et al. 1991; De Natale et al. 2001) – appear inadequate to explain resurgence in calderas of modest size, as in the case of the island of Ischia. The complexity of the problem also emerges from analysis of the models proposed since the early twentieth century. Indeed, Rittmann (1930) proposed volcano-tectonic horst mechanism, i.e. uplift by the intrusion of a shallow laccolith, to explain the structure of Mount Epomeo. More recently, Fusi et al. (1990) and Tibaldi & Vezzoli (1998) proposed that the resurgent process of Ischia was produced by volumetric variations in the subsurface magma body. Orsi et al. (1991) suggest a simple-shear stress for the resurgence, in which the source mechanism is an increase in magmatic pressure in the upper part of a shallow magma chamber. Luongo et al. (1995) and Cubellis & Luongo (1998) used a punched laccolith mechanism to model the uplift of Mount Epomeo. Acocella et al. (1997, 1999) and Molin et al. (2003), according to similar experimental models, proposed that the resurgent doming of Mount Epomeo is due to a trapdoor uplift mechanism, with a hinge in the southeastern part of the island. To remove the arbitrariness of the above solutions for the resurgence of Ischia we impose 183 CALDERA RESURGENCE OF ISCHIA ISLAND geological boundary conditions within the solution to the problem of the ground deformation. General and specific boundary conditions are deduced by high-quality field-mapping data and geochemical and geophysical surveys of the island. The bending model for Mount Epomeo

Rank-ordering analysis is applied to the intertimes between seismic events recorded in the Apennine belt between 40-42� N and 14-16� E from the 15th century onwards. It shows a power law capable of governing the intertimes between 1529 and 368 months and another power law which approximates a random simulation, for the intertimes shorter than 368 months. Only the first power law allows the computation of the return period of major events. Earthquakes with the same energy that are aligned according to different power laws imply the presence of two different populations, indicating, in turn, that the physics of seismic phenomena in the region examined is not straightforward, that the stress is probably not unidirectional and that it acts on a non-isotropic medium. The most probable estimated intertime value for the next event is found to be equal to 60 ± 20 years.

This paper presents the results of the use of Geographic Information Systems (GIS) inmanaging information on the effects of earthquakes in historical times on the island ofIschia. The unpublished sources on the Casamicciola earthquake of 28 July 1883 andthe extensive bibliography documenting the island's seismicity from 1228 showed theneed to proceed towards a type of data storage that would also allow management ofthe same data. Application of GIS techniques allowed us to insert, extract, handle,manage and analyse the data for the zoning of seismic damage on the island of Ischia.The end-product consists of information layers, such as maps of isoseismals, the damage, and hazard involved, as well as numerical tables associated to maps.

A macroseismic study of the earthquake of 9 October 1999, which took place at Vesuvius’ crater, was carried out. The event was not only the most energetic since the last eruption in 1944 but also one of the most energetic of those occurring in the Vesuvian area as shown by an analysis of historical seismicity. This paper contains the results obtained from an analysis of questionnaires sent out to all the schools in the Vesuvian and Neapolitan areas and the surrounding towns in the provinces of Caserta and Salerno. Over 10 000 questionnaires were administered, covering 92 sites, 18 of which were within the city of Naples. The percentage of positive reports concerning single effects was taken into account (the percentage response to Question 1 was called felt index ). Thus maps of earthquake intensity and felt index were drawn up, whose isoseisms show maximum values near the volcano and radially decreasing values. The surveyed intensity plane is remarkably dense. As far as 30 km from the epicenter, the distance between two radially consecutive sites of the surveyed plane is, on average, lower than 500 m. The maximum degree turned out to be V for sites whose mean distance R V from the epicenter was 7.0±2.3 km, maximum intensity being found for the towns of Boscotrecase, Cercola and S. Sebastiano, characterized by some of the sixth degree characteristics. Typical parameters such as epicentral intensity ( I 0 ), attenuation coefficients ( s ), and absorption factor ( b ) were determined. Their values range between 6.0 and 6.4 ( I 0 ), 3.9 and 4.1 ( s , Blake’s formula) and 0.1 for b , while magnitude ( M ) values range between 3.6 and 4.1. Furthermore, Q quality factor was determined by assuming direct proportionality between energy and felt index ( A ), peak frequency f =2–3 Hz and a wave velocity β =3.3 km/s. The values obtained are Q =60–90 and, subtracting geometrical spreading, Qa =100–150. Marked attenuation areas were found in the epicentral zone E and NE of the volcano and in the Phlegraean Fields associated with the source mechanism, scattering and the high temperature of a magmatic body. Historical eruptions were taken into account, which enabled us to gain an insight into seismicity associated with them. Also, effects expected for seismic events in the Vesuvian area were estimated, their magnitude ranging from 3 to 4.5.

The up^down motion at Campi Flegrei may be due to the internal dynamics of the system and does not necessarily require a push, such as a new input of magma, from outside. The different eruptive phases which have occurred at Campi Flegrei might be related to deterministic chaotic magma flows, similar to those studied in simple experimental systems and theoretically well schematized by the so-called Lorenz equations. Here, different convective cells are hypothesized to operate at decreasing time and spatial scales; they are found to reasonably explain the volcanic history of Campi Flegrei starting from the Campanian Ignimbrite phase, through the Yellow Tuff, up to the Monte Nuovo event and the recent bradyseismic crises. 3 2002 Elsevier Science B.V. All rights reserved.

A model of the crustal structures in the Campi Flegrei caldera has been developed from gravimetric data collected along a profile crossing the central zone of the caldera. The model includes a low-density body (2300 kg/ m3 in its inner core and 2400 kg/m3 in the outer), intruded into thermally metamorphosed basement (with a density of 2600 kg/m3); the top of this low-density body is at a depth of about 3 km. Sediments ranging from 1800 to 2200 kg/m3, which characterize the caldera fill, lie on the metamorphosed basement; the contact between the two lies at a depth of about 2.5 km. The model fits the gravity minimum found in the caldera and is in good agreement both with the volcanic history of the area and recent dynamic processes.

The port constituted the fundamental marine transporation element connecting the island and the mainland, providing easier access to the island and promoting the progressive growth of the local economy. At the time, Ischia showed great diversity between one zone and another, and much of the island was almost inaccessible and sparsely inhabited. Noted for its active volcanism from the early fourteenth century and persistent seismicity until 1883, “before 1853 this island was almost impracticable, … to the detriment of many natural advantages that it has over others, it had a wild appearance, to say the least” (Annali Civili del Regno delle Due Sicilie—Annals of the Kingdom of the Two Sicilies 1855).

A model of caldera resurgence has been applied to the Campi Flegrei (southern Italy) to interpret: (a) the processes observed during the recent bradyseismic crises of 1970–1972 and 1982–1984; (b) ground movements recorded for the past 2000 years; and (c) the volcanic history of the area. The two-dimensional mechanical model involves an area larger than the caldera itself. The crust is considered as a viscous plate overlying a viscous half-space. Geometric dimensions and mechanical parameters are the assumed variables and have been assigned a range of values of 50–100 km for length, 5–15 km for thickness, and 10 21 to 10 22 Pa s for viscosity. The process controlling volcanic activity in the Neapolitan area is attributed to a tensile stress field causing the opening of the Tyrrhenian Basin and the rising of the mantle to depths of about 15–25 km beneath Campi Flegrei. While regional tumescence can be related to magmatic upwelling, detumescence can be linked to the major eruptions in the area (the Green Tuff of Epomeo, Ischia, 55,000 yr B.P.; the Campanian Ignimbrite, 30–35.000 yr B.P.: and the Neapolitan Yellow Tuff, 12,000 yr B.P.), together involving more than 100 km 3 (DRE). We propose that regional detumescence is likely to have triggered caldera resurgence. Indeed, the model suggests that detumescence may have generated an axial tectonic stress of about 1000 bar (100 MPa), a value which is of the correct order of magnitude for initiating caldera resurgence in the Campi Flegrei. Furthermore, we show that such a stress decreases the vertical pressure needed for uplift to occur.

Sono state analizzate le condizioni meteo responsabili della catastrofe idrogeologica del 1910 a Ischia

The structures of the Somma-Vesuvius volcanic complex are modelled on the basis of the interpretation of gravity anomalies obtained from data available in the literature and acquired along a new profile along the coastline from Naples to Castellammare di Stabia. In order to highlight the contribution of shallow crustal structures, the residual anomalies were considered. A marked gravity low was recognised in the eastern sector of Vesuvius. Furthermore data interpretation was carried out along two profiles centred on the low gravity region in question: a first profile crossing the Vesuvius crater in direction WNW-ESE, and a second one in NNE-SSW direction. The 2 ½ D model obtained reveals a crustal structure characterised by sediments of 2.3 Mg/m3 density, overlying bedrock with a density of 2.6 Mg/m3. Near the volcanic system the model becomes more complex due to the presence of light sediments with a density of 2.1 Mg/m3 overlying a body with a density of 2.4 Mg/m3 which extends into depth. The latter is thought to be closely related to the zone of magma ascent developed along the volcanic axis. Along the coast the volcanic component is reduced and the model shows that the layer with a density of 2.3 Mg/m3 ranges in thickness from 0 to about 3500 m. An additional body between 1500 and 3000 m with a density of 2.4 Mg/m3 was considered in order to account for the slight rise in the residual anomaly in the area in the vicinity of Mt. Vesuvius.

Fashion is an important tool of knowledge of the intangible values that define the cultural profile of the places and, therefore, it is a theme of search useful to delineate the creative and experimental identity of the ample "Baia di Naples", beginning from the analysis of the activity developed by its protagonists in the most prolific season of the “Made in Italy”. In the history of Italian fashion, Naples and its “mythical” area have played a leading role, thanks to the work of some outstanding protagonists. This has been possible, not so much through the creative activity of those who left their hometown and moved to the capital city seeking fame, but rather thanks to those (Clarette Gallotti, Livio De Simone, Mario Valentino, Fausto Sarli and many other tailors and creative engaged in resort fashion), who have invested all their resources in the territories that they come from, contributing greatly to the consolidation of the role of the whole city of Naples in the larger frame of Italian fashion. Their success begins from the early of the Fifties, when the fashion, together with the tourism, it becomes an important tool to reviving Italy from the difficulties left by the war.