Volcanic risk and evolution of the territorial system in Campania volcanic areas

165

VOLCANIC RISK AND EVOLUTION OF THE TERRITORIAL SYSTEM IN THE VOLCANIC AREAS OF CAMPANIA

Paola Petrosino *, 1 · Ines Alberico 2 · Stefania Caiazzo 2 · Alessandro Dal Piaz 2,3

Lucio Lirer 1 · Roberto Scandone 4

1. Dipartimento di Scienze della Terra, University of Napoli « Federico II », Largo S. Marcellino 10, i 80138 Napoli, Italy2. Centro Interdipartimentale di Ricerca Ambiente (c.i.r.am.), University of Napoli « Federico II »,

Via Mezzocannone 16, i 80134 Napoli, Italy3. Dipartimento di Urbanistica University of Napoli, « Federico II » Via Forno Vecchio 36, i 80138 Napoli, Italy

4. Dipartimento di Fisica « E. Amaldi », University Roma 3, Via della Vasca Navale 84, i 00164 Roma, Italy

AbstractThe present research deals with the assessment of volcanic risk in the Campanian area exposed to Campi Flegrei and Somma-Vesuvio ac-tivity. The project involved volcanologists and territory planners, which together investigated the relationship between the volcanic hazard and the evolution of territorial system in the last century in Campania. Thanks to this co-operation, new hazard and risk maps, together with a detailed analysis of the urban settlement, were produced. They made it possible to deduce that, although most part of the Campania region in the past has been, and most probably will be in the next future, threatened by products coming from both the volcanic sources, the territorial system evolution was quite insensitive to these hazardous phenomena. The main result of the study was to point out the seriousness of the present conditions of the areas exposed to volcanic risk, and the urgency of a territorial planning aimed at the cohabita-tion with the volcanic sources and at the achievement of acceptable levels of security. In this regard, the maps, diff erent in scale, and the socio-economical investigations here performed can off er a valid support for Local Authorities and for the territorial Agencies operating in the area (Autorità di Bacino, arpa, Civil Defence, etc.), since they might represent a very useful basis for territorial planning and for decision making in a hazardous territory like the area exposed to volcanic risk in Campania.

Keywords : Somma-Vesuvio, Campi Flegrei, Volcanic hazard, Territorial system, Spatial analysis

* Address for correspondence : P. Petrosino : petrosin@unina.it

1. Introduction

Somma-Vesuvio and Campi Flegrei Volcanoes shaped the landscape of the campanian area and, with their ac-tivity, have threatened the life and properties of people living in the area long time ago. Bronze age settlements yield the evidence of the destruction caused by eruptions occurred either at Campi Flegrei or Vesuvio (Giacomelli and Scandone 2001). Major explosive eruptions occurring in 79 ad, 472 ad and in 1631, caused extensive losses of life and properties. Thus, the assessment of the volcanic risk in the Campanian area caused by both Campi Flegrei and Somma-Vesuvio activity is a need we aim to fulfi l in the present paper. We also analyze the relationship between the volcanic hazard and the evolution of the territorial system during the last century.

In summary, the present research was focused on the following main topics :

- Refi ning of the volcanic hazard maps for the Campania region exposed to the Campi Flegrei and Somma-Vesuvio volcanic activity.

- Performing a new kind of hazard thematic maps through the use of GIS software, by superimposing vol-canic hazard areas contours to the recent ortho-photo representation of Campania region.

- Investigating primary hazard (the hazard directly re-lated to the eruption products) and secondary hazard (the hazard due to remobilization of pyroclastic material dur-ing the intereruptive periods, connected to the very fre-quent heavy rain episodes).

- Reconstructing the historical evolution of the Campa-nian territorial system zones exposed to the volcanic risk, from the end of the 19th century to the present.

- Estimating if and how much in the last century the

territorial transformation has been conditioned by the risk and recognizing the characters of the territorial system where the relationship between volcanic risk, territory and behaviour of the local communities is clear.

- Evaluating possible risk mitigation measures and pro-posing new settlement rules.

The correct territorial management in active volcanic areas requires the evaluation of the Risk, as defi ned by the unesco risk formula (Fournier d’Albe 1979) :

R = H × E × V

where H is the hazard, E the exposed value, V the vulner-ability index.

The fi rst attempts to map volcanic hazard were per-formed by Barberi et alii (1977, 1983), Scandone (1977) and Carta et alii (1981), and were followed more recently by many scientifi c papers aimed at the assessment of this parameter, prompted mostly by the publication of the Plan of Civil Defence for Somma-Vesuvio in 1995 (Dipartimen-to Protezione Civile 1995).

In regard to Somma Vesuvio, Scandone (1977), Scan-done and Cortini (1982), Scandone et alii (1993), and Lirer and Vitelli (1998) mapped the area exposed to possible lava fl ow hazard. Lirer et alii (2001a) and Cioni et alii (2003) presented hazard maps for pyroclastic fall activity. Finally, Lirer et alii (2001a), Todesco et alii (2002), Esposti Ongaro et alii (2002) and Nunziante et alii (2003), although through diff erent scientifi c approaches, assessed pyroclastic density current (pdc) hazard and evaluated their dynamic over-pressure.

Lirer et alii (2001b) investigated the role played by topographic obstacles in controlling the distribution of the eruption products of Campi Flegrei in the last 10 ky. Hazard and risk maps obtained by simulation of the ef-

Miscellanea « Acta Vulcanologica » · Vol. 16 (1-2), 2004 : 163-178

P. Petrosino et alii

166

fects of eruptions with diff erent vei and vents located in diff erent points of the Campi Flegrei caldera have been also published (Alberico et alii 2002). Recently, Rossano et alii (2004) performed pyroclastic current simulations and published the possible distribution of their products in case of a future event. Orsi et alii (2004) published a map of the areas probably aff ected by pyroclastic fl ows and falls coming from Campi Flegrei.

The quoted literature highlights the utmost attention of the scientifi c world to volcanic hazard assessment. This parameter is well known to depend only on the volcano behaviour and can be estimated by investigating its previ-ous activity. Therefore, when aiming at the reduction of volcanic risk (R) as a basis for the decision making in active volcanic areas, the hazard (H), if it is correctly evaluated, cannot be changed by the action of man. The exposed value (E) is the only parameter of the risk formula that can be controlled. Through the interaction between volcanol-ogists and territorial planners we attempted to identify the main problem in dealing with the reduction of Volcanic Risk in an area with a high density of population.

A fi rst qualitative analysis suggests that the territorial system evolution was, on the whole, not sensitive to the presence of the two active volcanic areas. Both volcanoes, however, may exhibit explosive activity in the future with short premonition times for the evacuation of the popu-lation in the endangered areas. A single volcanic hazard map both for Campi Flegrei and Somma-Vesuvio has been produced in this paper with an unique methodological ap-proach, where the areas possibly exposed to the activity of both volcanoes are encompassed. At the same time the evolution of the whole Campanian territorial system in the last century has been analyzed, some case studies have been investigated and fi nally, we tried to deduce if a relationship between volcanic hazard and territorial evolu-tion exists.

2. Hazard and Risk Maps

The analysis of the eruptive history of Somma-Vesuvio in the past 10 ky reveals the recurrence of highly explo-sive events followed by repose periods, during which low vei strombolian and/or vulcanian events took place. The whole set of eruptive mechanisms and of related deposits has to be taken into account for the evaluation of volcanic hazard.

A hazard map for the area was made by Lirer et alii (2001a) using the plinian and sub-plinian activity of the last 10 ky bp ; in this period fi ve plinian or sub-plinian eruptions (Ottaviano, 7900 yr. bp ; Avellino, 3700 yr. bp ; the 79 ad ; the 472 AD ; the 1631) and approximately 10 violent Strombo-lian eruptions (protohistorical activity, medieval activity, eruption of 1906, eruption of 1944) occurred.

The mapping of the eruption products, as deduced from the literature and fi eld data at disposal of the research group, was the fi rst step aiming at drawing the isopach maps for the single eruptive events. Then the loads of dif-ferent thickness of pyroclastic fall deposits have been taken into account to defi ne, for each eruption, the area encom-passed by the maximum sustainable load, as stated by the Civil Defence Department at 300 kg/m2 (Dipartimento di Protezione Civile 1995). The intersection of these areas gives a ‘frequency map’, where single points record how

many times the maximum sustainable load was exceeded in the past 10 ky bp. According to this methodological ap-proach, high frequency means high probability for that point to be hurt in case of a future event, i.e. high hazard. Suitably reclassifying the frequency classes, the volcanic hazard map for pyroclastic fall in the vesuvian area was fi nally constructed.

A similar methodology was used to generate the pdc hazard map. The invaded areas of the three main eruptions (Avellino, 79 AD, 472 AD) were intersected. The boundary of the area is the 50 cm thickness contour of the respective deposits mapped in the fi eld. This value has been chosen as a threshold, since for the about 50 cm thick pyroclastic fl ow deposits of 79 AD eruption, outcropping at present in the Terzigno area, a dynamic overpressure of 1-2 kPa was calculated (Fraldi et alii 2002). These values signify a high destructive power on both ancient roman buildings and on present building typologies of the vesuvian area, in case of a future event (Nunziante et alii 2003).

Four diff erent hazard areas were identifi ed (Plate 1) :1. a perivolcanic high hazard area where both roof col-

lapse and pdc damage are expected ; 2. an external area, towards the ne, of intermediate haz-ard where roof collapses are prevalent over pdc damages ; 3. a more distal low hazard area, where only rare roof collapse can occur ; 4. an area, located se from the volcano, of very low hazard for plinian fall deposits, due to the low frequency of plinian episodes with wind in that direction.In the Campi Flegrei volcanic fi eld, the absence of a central vent implies the need to evaluate ‘where’ the next erup-tion could occur. A methodology similar to Somma-Vesu-vio was applied for pyroclastic fall deposits, taking into ac-count the distribution of the two main plinian-subplinian eruptions of the last 10 ky : the Pomici Principali (10 ky bp) and the Monte Spina (4.0 ky bp) eruptions. Besides, many PDC simulations have been made in the Campi Flegrei area (Alberico et alii 2002), attributing a vent opening probabil-ity value, deduced by geological, structural, geophysical and geochemical data analysis to the simulations’ starting points.

A hazard map summing up the results of the simula-tions for VEI 3 and VEI 4 eruptions was obtained by using the trademark GIS software ArcView 3.2. High hazard areas are the Agnano Plain and the coastal area of the Pozzuoli municipality. The important role of topographic barriers on controlling the emplacement of PDC deposits clearly emerges from both VEI maps : Camaldoli and Posillipo Hills are possible obstacles for the emplacement of PDC of intermediate VEI toward Napoli. Higher VEI eruptions, on the contrary, would spread their products over the whole city area.

The hazard map here presented (Plate 1) encompasses VEI = 4 events ; fi ve areas of decreasing hazard are deduced :

1. the coastal area of Pozzuoli municipality and the Ag-nano Plain area, where both the invasion and vent opening probability are very high ;

2. an external area of intermediate hazard ; 3. a more external low hazard area, where the vent open-

ing probability is low and that could be reached only by very diluted tails of PDC coming from inside the caldera ;

4. a very low hazard area, located North of Napoli, reached by the PDC in a very restricted number of simulations.

Volcanic risk and evolution of the territorial system in Campania volcanic areas

167

5. an Easterly area, of low hazard for plinian fall deposits, whose eff ects add up to the ones coming from Somma-Vesuvio.

The contours of diff erent hazard areas have been report-ed on the orthophoto maps, courtesy to ciram of Assessora-to alla Ricerca Scientifi ca of Regione Campania and the obtained map make it possibile to easily point out the high exposed value of the two areas. Highly urbanized areas are located inside the Campi Flegrei caldera (Pozzuoli, Bacoli, Monte di Procida municipalities and part of Napoli), along the vesuvian coastline (Ercolano, Torre del Greco, Torre Annunziata municipalities). In particular, Napoli lies bet-ween the two volcanic areas and is exposed to phlaegrean fall products and, in the eastern part, to PDC coming from Somma-Vesuvio (Alberico et alii 2005). Nearby the urban-ized area, a part of territory where, although in the 1 :75,000 representation the urbanization seems continuous, wide zones devoted to agriculture and to greenhouses still exist (e.g., Agro Nocerino Sarnese and Castellammare di Stabia neighbourhood). The single hazard class extensions have been calculated ; both for Campi Flegrei and Somma-Vesu-vio, low hazard areas cover the largest extensions.

Risk maps (Plate 2) have been evaluated taking into account the urbanized areas as of 1998, deduced from the thematic maps 1 :10,000 of Provincia di Napoli. For the are-as falling in the other Campanian provinces, the urbanized areas were digitalized directly on the orthophoto. Then the extension of the areas falling in a single risk class was calculated. Note that hazard classes 3 and 4 were joined in one risk class. Single class urbanized area/total urbanized area plots, reported in Plate 2, make it possible to observe that urbanized area in the low risk class for Somma-Vesu-vio is very wide, due to the presence of many municipali-ties in the low and very low hazard class (Plate 1). As far as Campi Flegrei is concerned, the highest hazard class is also the most populated, since municipalities located along the coastline have an extremely high rate of population.

3. The Evolution of the Territorial Systemin the Volcanic Risk Areas of Campania

The part of the research strictly concerned with the prob-lems of the urban settlements is particularly focused on the reconstruction of the historical evolution of the territorial system from the end of the 19th century until today, in the areas of Campania exposed to the volcanic risk, includ-ing the Campi Flegrei zone, the urban area of Napoli and its close neighbourhood, the whole area of Vesuvio (both coastal and interior towns of Agro Sarnese-Nocerino), the towns in the northeast of the Vesuvian area, Casalnuovo, Acerra, Pomigliano, Marigliano and Nola.

The research aims mainly at investigating the pecu-liar features of the urbanization processes in a territory strongly characterized by the volcanic risk and at estimat-ing if and how much, in the last century, the territorial transformation has been infl uenced by the risk. Finally, it aims at recognizing the features of the territorial system where the relationship among volcanic risk, territory and behaviour of the local communities is clear.

The research is based on a complex concept of territory, which considers physical places, their transformations in time and the use of space by the communities closely con-nected and documents the last phases of territorial settling in the areas of Campania exposed to the volcanic risk (Dal

Piaz 1985, 1994). It recognizes the confi gurations main-tained through time, and that still represent elements of reference and territorial stability (the historical infrastruc-tures, the net of the centres, the organization of agricul-tural territories) and the diff erent use of resources in time (the agricultural areas, the rural villages and farms ; the areas of naturalistic and cultural excellence). The study highlights the present functional structure and the modi-fi cation of the role of the city centres with respect to spe-cifi c elements (location of equipments and services at the territorial level ; industrial production and services). The quantitative eff ect of the modifi cations (the demographic and building increase, new infrastructures, territorial con-sumption) and the diff erent morphologic features of the settlements (features of inhabited landscape, recent urban typologies, recent expansions of settlements in the agri-cultural areas) were investigated.

Today the areas of Campania exposed to volcanic risk, which make up the most part of Napoli Province, are strongly characterized by a huge extension of the urban-ized zones, a high number of inhabitants, territorial struc-tures often dense and congested (Caiazzo and Dal Piaz 1995).

The main inhabited zones that can be recognized are1 :- the area of Napoli with dense and close urbanized

zones that extends toward the northern towns of Casoria, Arzano, Casavatore and Afragola ;

- the territorial system located south of the Vesuvio (Er-colano-S. Vito quarter) and the coastal system (Ercolano, Torre del Greco), whose recent modifi cations made them areas of environmental crisis (anthropic pressure ; dense settling expansions toward agricultural areas ; illegal ex-pansions ; clear processes of degradation, abandonment, congestion) ;

- the territorial system located east of Monte Somma, to-ward the Agro Sarnese plain (Ottaviano, Terzigno), show-ing intense urban expansions, mainly in the agricultural areas, and inadequate building typologies, unaff ected by the values and the qualities of the places ;

- the territorial system located north of Monte Somma (Somma Vesuviana-Marigliano), where the urban centres developed along the slopes of the volcano, until few dec-ades ago still characterized by agricultural activity and by total stability conditions, but recently characterized by the expansion of centres that joined along the main roads, so that the inhabited zones increased ;

- the territorial system of Campi Flegrei, interested in the most recent years by intense urban expansion (spread of buildings in agricultural areas) and by the recent build-ing of numerous infrastructures completely careless of the environmental values of the area.

From the early 1900 to 2001 in the investigated areas the population increased 200% (Plate 3). From 1901 to 1931 the population constantly grew in the whole terri-tory, increasing up to 40% in the coastal area of Vesuvio. In this area the towns of Portici and S. Giorgio a Cre-mano showed the highest increase, with a value of 100% in S. Giorgio a Cremano and of 70% in Portici (Fig. 1). In this time span, in fact, the coastal area of Vesuvio became attractive to settlers due to the closeness of the city of Napoli, the historical road that goes without interruption

1 For single municipalities location see Plate 1.

P. Petrosino et alii

168

from Via Marina to the ‘Miglio d’Oro’, the fi xed charac-ter of the historical urbanization (the country houses of Pazzigno, S. Giovanni, Barra ; the numerous villas of the nobles with wide green areas ; the archaeological areas). In addition, the access to the area was facilitated by the public infrastructures, namely the railway Naples-Portici, opened in 1839, the Circumvesuviana railway and the highway A3 Napoli-Salerno.

The wide industrial area located east of the city of Napo-li, planned with the Legg e Speciale per il risorgimento economico della città di Napoli in 1904 and progressively carried into eff ect in the twenties and thirties, together with the older industrial sites of Torre Annunziata and Castellammare di Stabia, in the fi rst decades of the 20th century, gave to the coastal area of Vesuvio a character of economic and territo-rial liveliness that caused a strong increase of population.

Until the thirties the new residential settlements were prevalently located along the main roads between the towns, close to the existing historical centres ; in the fol-lowing years, on the contrary, the constructions spread along the new roads connecting the inhabited centres to the highway.

In these years the developed areas began to expand, but the relationship between the natural system and the ter-ritorial system was still stable and the landscape around Vesuvio was still strongly recognizable either in the coastal areas, with the organization of sea-coast settlements, or in the agricultural areas with the presence of country houses and farms, together with wide cultivated areas.

In the same years the interior area of Vesuvio displayed a homogeneous landscape, strongly characterized as agri-cultural, with a system of medium and small centres, con-nected by only one road oriented east-west (State road 268) and by a secondary cross road connecting to the Via Appia (State road 7bis). This area is recognizable and clearly dif-ferent from the costal area of Vesuvio, also because it is less related to the urban area of Napoli and more related to the towns of the Pomigliano d’Arco and Nola area.

In the three decades from 1901 to 1931 the centres whose population signifi cantly increased are to the east, Boscorea-le, Boscotrecase and Terzigno, and to the west, Cercola, S. Sebastiano and Pollena. From a demographic point of view, therefore, the population increased on the east side, in the bigger towns and in the towns near the coastal area

Fig. 1. a) Table of resident population for single municipalities of the coastal area of Vesuvio in the 1901-2001 time span ; b) Plot of resident population for single municipalities of the coastal area of Vesuvio in the 1901-2001 time span ; c) Plot of resident population for the whole coastal area of Vesuvio in the 1901-2001 time span.

Volcanic risk and evolution of the territorial system in Campania volcanic areas

169

of Vesuvio and of the Nocerino-Sarnese plain, on the west side the towns closer to the area of Napoli (Fig. 2).

In the fi rst decades of the 20th century towns similar to those of the interior area of Vesuvio are recognizable in the northern wide agricultural plain, crossed by the canal of Regi Lagni. In the cartography of 1936 (Plate 3) the centres of Acerra, Pomigliano d’Arco and Nola are dense and separated : the inhabited areas mainly border the his-torical cores, the extensions are not signifi cant either along the State road 7bis, or along the road connecting the towns

(Acerra-Pomigliano d’Arco, Pomigliano d’Arco-S. Anasta-sia, Marigliano-Somma Vesuviana). Many cou n try houses and farms are located in the agricultural territories, which are extremely variegated, because of the dense network of canals, the numerous paths between farms, the shape of fi elds and the uncountable manufactures spread on the territory.

Diff erently from the area of Vesuvio, morphologically more homogeneous, where the cores of the territorial sys-tems are spread radial around the Vesuvio, keeping in time

Fig. 2. a) Table of resident population for single municipalities of the northern Somma-Vesuvio area in the 1901-2001 time span ; b) Plot of resident population for single municipalities of the northern Somma-Vesuvio area in the 1901-2001 time span ; c) Plot of resident population for the whole northern Somma-Vesuvio area in the 1901-2001 time span.

P. Petrosino et alii

170

their close relationship and using the slopes for agriculture, in the area of Campi Flegrei the elements of territorial systems have been shaping themselves as autonomous parts clearly recognizable in their borders. In this area, until the fi rst decades of last century, the urban areas are close to each other and spread along the coast or along the main local and territorial connecting roads. The territory is characterized mainly by agriculture with terrace cultiva-tion and a dense net of paths between farms. The resident population small up to the fi fties, substantially and quickly increased in the sixties and seventies : both the population and the number of buildings doubled in Pozzuoli and Ba-coli, while in Soccavo the population increased 300% and the rooms 400% (Fig. 3).

In the two decades from 1931 to 1951 the towns of the costal area of Vesuvio continued to grow : the population of all the centres increased by 40-50%. From 1951 to 1971 the costal area experienced an increase of 54%. The towns of S. Giorgio a Cremano (increase of 154%), Portici (in-crease of 115%), Pompei and Torre del Greco (increase of about 40%) grew more than the others.

In those years the building expansion became mas-sive, building construction along the existing roads began to fi ll the gaps and from the sixties the linear fusion of Torre del Greco and Torre Annunziata was completed. The new building construction pushed from the coast up-wards along the River Sarno toward the Agro Nocerino and reached Pompei and Scafati. In S. Giorgio a Cremano, Portici and Ercolano the urbanized zone covered the main part of the area between the state road and the Napoli-Salerno highway, with extended residential quarters and

high buildings. The residential expansion widens out also on the other side of the highway, on the foot slopes of the volcano : at S. Giorgio a Cremano the up-hill built areas reach the expanding areas of S. Sebastiano, at Ercolano sparse constructions were more frequent and some exist-ing cores (S. Vito at Ercolano) began to expand (Fig. 4).

Along the coastal area of Vesuvio the fusion of the ur-ban areas began since the early sixties, forming the ‘ur-ban area of Vesuvio’, where all recognizable features were progressively lost : the new buildings, mainly intensive and residential, were built overshadowing the historical build-ings with absolute disregard to the values and quality of the places.

Since the sixties, in the down slope area of Vesuvio, the population and the buildings increased, especially in some centres near the urban area of Napoli, such as S. Sebastiano, Cercola, Massa di Somma, and in some towns in the East-ern area of Vesuvio, closely connected to the territory of Agro Sarnese-Nocerino, such as Ottaviano and S. Giuseppe Vesuviano. The most signifi cant transformations of the set-tlement took place in the years from 1971 to 2001.

In the seventies and eighties the chief city of Napoli and many centres of the Vesuvio coastal zone, already congested by traffi c and degradation, became saturated. On the other hand, the location of some big factories in Pomigliano (Alfa Sud, Alfa Romeo, Aeritalia), of some industrial agglomerations of asi (Industrial Development Area), and of large service establishments (cis, Whole-sale centre of Campania development), together with the substantial increase and enforcement of the net of roads, quickened the process of urbanization of the areas along

Fig. 3. a) Table of resident population for single municipalities of the Campi Flegrei area in the 1901-2001 time span ; b) Plot of resident popula-tion for single municipalities of the Campi Flegrei area in the 1901-2001 time span ; c) Plot of resident population for the whole Campi Flegrei area in the 1901-2001 time span.

Volcanic risk and evolution of the territorial system in Campania volcanic areas

171

Fig. 4. Territorial system evolution in the last century in the S. Vito (Ercolano) area.

P. Petrosino et alii

172

the road from Pomigliano to Baiano and of the interior areas near Vesuvio.

In the last twenty years the territorial system of S. Ana-stasia, Somma Vesuviana, Ottaviano records substantial increases in population and in the expansion of buildings construction either along the main roads, or in the agri-cultural areas, intruding even into the slopes of Vesuvio, were some little factories and some building typologies were located, absolutely incoherently with the features of the environmental context.

The territorial system of Campi Flegrei reports a sub-stantial population increase as well. In the last twenty years the previous expansion, characterized mainly by the fu-sion of centres along the main roads and at the margin of the urban consolidated areas and by the completion of the great residential quarters (Toiano and Monteruscello), continued with an expansion of various forms and intensi-ties on the whole phlegrean territory.

New small centres and single buildings occupy at ran-dom environmental valuable territories and high-risk areas ; the new areas (residences, hotels and restaurants) are dispersed along the slopes of craters and in the ag-ricultural areas connected through a thick and irregular road network bringing about a state of degradation and congestion.

4. Case Studies

4. 1. Hazard Maps

In order to analyze the evolution of the territorial system and to defi ne if it was somewhat sensitive to the hazard due both to explosive eruptions and to the remobilization of loose pyroclastic materials, blanketing the volcano slopes and the limestone relief of the perivolcanic area (Lirer et alii 2001c), we studied in detail two cases : the subsets of Napoli municipality of Bagnoli, Fuorigrotta and Soccavo located inside the Campi Flegrei caldera and the S. Ana-stasia and Somma Vesuviana municipalities in the Somma-Vesuvio perivolcanic area.

For both study areas volcanic hazard maps for pyroclas-tic fall and PDC deposits were drawn. The used methodol-ogy is based upon two criteria : the maximum load that the buildings of the area can suff er due to the piling up of fall deposits and the frequency, i.e., the number of times that a destructive event occurred in the area in the last 10 ky bp.

For Campi Flegrei test area, the pyroclastic fall activity of the Pomici Principali (10.0-8.0 ky bp) and Monte Spina (4.0 ky bp) eruptions have been taken into account. By selecting the isopachs of products exceeding or equal to the maximun sustainable load we deduce that for both eruptions in the whole Soccavo subset and in most part of Bagnoli and Fuorigrotta this value was exceeded (Fig. 5).

As far as PDC values are concerned (Fig. 6) the Bagnoli subset falls in the intermediate-high hazard area, Fuori-

Fig. 5. Frequency map of the pyroclastic fall deposits occurred in the Campi Flegrei area in the last 10 ky bp. Dashed area : emplacement area of both Pomici Principali and Monte Spina eruption pyroclastic fall products (frequency 2). White area : emplacement area either of Pomici Principali or Monte Spina eruption pyroclastic fall products (frequency 1).

Fig. 6. Pyroclastic Density Currents hazard map of Campi Flegrei area obtained by performing simulations based on the energy cone method (Alberico et alii 2002).

Volcanic risk and evolution of the territorial system in Campania volcanic areas

173

grotta in the intermediate-low hazard area and Soccavo in the low hazard area.

Fall products of the Pomici Principali and Monte Spina eruptions, in the Campi Flegrei test area, vary, in thickness, from 75 to 180 cm. On the slopes bordering the Piana di Agnano and on the Camaldoli Hill (relief of Pianura and Soccavo) they reach the maximum thickness, whereas on the Posillipo Hill their thickness decreases gradually from north to south (Fig. 7).

Landslides and hyperconcentrated fl ood fl ows of these fi ne grained loose deposits are triggered when favourable conditions occur (Calcaterra et alii 2003). The distribution of these phenomena, as the database of Uffi cio Difesa Suo-lo of Napoli municipality records, is concentrated on the Camaldoli Hill and Piana di Agnano Eastern slopes (Fig. 8), where the Campi Flegrei fall deposits of the last 10 ky display the maximum thickness.

As far as the Somma-Vesuvio area is concerned, pyro-clastic fall deposits exceeding the maximum sustainable load, both of vesuvian and phlegraean origin, blanket the whole territory of Somma Vesuviana and S. Anastasia. The area was divided in three frequency classes and the urban centres fall in the intermediate frequency class (Fig. 9).

The thickness of the pyroclastic fall deposits of the last 10 ky varies between 1,675 cm on the highest part of the Somma relief and 119 cm on the lowest part. Similarly to the Campi Flegrei area, however, these thicknesses are deduced by the isopach maps and do not take into ac-count the remobilization phenomena occurred after the emplacement (Fig. 10), so they may diff er in some sites from the ones presented here. The huge thickness of the loose pyroclastic materials together with the potential en-ergy due to the relief slope made, in the past, lahar events very frequent along the Somma northern slope (Rolandi et alii 2004). Some of the biggest events happened dur-ing an eruption or immediately after, triggered by both the climatic eff ect of explosive activity producing heavy rainfalls, and the easy erosion of the pyroclastic material that blanketed the strato-volcano and the adjacent hills-lopes. Loose volcanic deposits in the head waters of rivers were eroded producing fl ooding and extremely high rates of sedimentation far downstream from Somma-Vesuvio (Rolandi et alii 1998, 2004), in the Somma Vesuviana and S. Anastasia plain.

In the inter-eruptive phases, like the present, lahar events remarkable in magnitude can sometimes occur, as testifi ed by the deposits emplaced in the 79-472 AD time span along the Torre Annunziata-Torre del Greco coast line (Lirer et alii 2001c) and by the landslides occurred in May 1998 in the Siano-Sarno area (Pareschi et alii 2002, Rolandi et alii 2002).

Figure 11 reports the frequency of PDC, in the inset of the Somma and S. Anastasia area from the hazard map. A frequency 2 is recorded in the highest part of the Somma slope for both municipalities, the town centre of S. Ana-stasia is completely exposed to PDC hazard (frequency 3) whereas the town centre of Somma Vesuviana only partly falls in the frequency 3 hazard area.

4. 2. Territorial System

Both the sample areas, Bagnoli-Fuorigrotta-Soccavo and S. Anastasia-Somma Vesuviana, even if diff erent as to their urban history, roles, shapes and way of growth, are similar as to some peculiar features.

The areas can be considered as representative segments of complex territorial systems from the naturalistic, mor-phological and landscape point of view, characterized and structured by strong features, directly perceptible on a vast scale : for the phlaegrean area, the lines of the crater bowls, the sides of the hills of Posillipo and Vomero, the plain of Fuorigrotta-Bagnoli and Soccavo-Pianura, the indented coast ; for the Vesuvio area, the cone of the volcano, the hydrographic cuts, the down slope area.

In both areas a strong naturalistic structure sets against an urbanized territory, with strong internal variegation, result of an intense and confused process of urbanization, absolutely unmindful, especially in the latest years, of the volcanic risk.

The territory between Fuorigrotta and Bagnoli is a plain descending lightly to the west, delimited by some morpho-logical structures : towards the sea the plain is closed by the slopes of Monte S. Angelo and Monte Spina, to the south east by the hill of Posillipo, to the north by an area that joins the hill of Posillipo and the plain of Soccavo.

The simple morphological structure of the plain of Fuo-rigrotta-Bagnoli is set against a territory, in which the in-tense urbanization, started at the end of the 19th century producing distinct urban areas according to the times in which they were organized and consolidated, to the ways they were realized, to the roles they played in the urban structure.

This urbanization hardly followed a urban plan and so the western area grew without rules, with an agglomera-

Fig. 7. Total thickness map of the pyroclastic fall deposits occurred in the Campi Flegrei area in the last 10 ky bp.

P. Petrosino et alii

174

Fig. 8. Landslide distribution occurred between 1986 and 1997 in Bagnoli, Fuorigrotta e Soccavo areas whit slope map, landslide distribution , type and number of landslides.

Fig. 9. Frequency map of the pyroclastic fall deposits occurred in the Somma-Vesuvio area in the last 10 ky bp. The frequency range of the legend (e.g. 1-3) means how many times the single points of the area were blanketed by pyroclastic fall deposits in the past 10 ky bp.

Fig. 10. Total thickness map of pyroclastic fall deposits occurred in the Somma-Vesuvio area in the last 10 ky bp.

Volcanic risk and evolution of the territorial system in Campania volcanic areas

175

tion of quarters and infrastructures of little integrated functions and morphological contradictions.

The old views of the 17th century and the maps of the 18th century represent the territory of Fuorigrotta-Bagnoli as a wide agricultural area with homogeneous features, mainly characterized by arboretum in the high part and by gardens near the beach, with a few settlements and country houses, because of the extent of the swampy area that made it unhealthy, and with a single road connecting Piedigrotta, Fuorigrotta, Bagnoli and Pozzuoli.

At the beginning of the 19th century, the drainage and control of waters brought with it land reclamation, and after 1830 new interest in the coastal areas of Bagnoli, through the opening of new resorts and a global renewal of the tourist activities (De Lucia and Janniello 1976).

The infrastructural works began in 1875 and, together with building construction and settlement of industries in the following decades, caused substantial changes in the territorial system. The new tram line, the Cumana rail-way between Montesanto and Torregaveta, the tunnel of Piedigrotta, the project of the Direct Road from Napoli to Rome began to divide and diff erentiate the territory and the quarters of Fuorigrotta, Cavalleggeri di Aosta and Bagnoli progressively acquired diff erent qualities and ur-ban roles.

The project of the residential quarter Giusso dates back to 1888, but it was realized in the twenties ; the quarter, with a chess-board shape with low houses used as sum-mer residences outside the urban area, is the fi rst step of an intense urbanization in which the area of Bagnoli-Fuo-rigrotta will be involved.

After the Law of Francesco Saverio Nitti for the Risorgi-mento economico della città di Napoli passed in 1904, in the area of Coroglio, was chosen the site for the Ironworks of ilva, which began to work in 1909. This location will forever compromise the environmental and landscape fea-tures of the area of Coroglio and its touristic vocation. It will condition the following development of the quarters of Bagnoli and Fuorigrotta.

Fig. 11. Frequency map of pyroclastic density currents occurred in the Somma-Vesuvio area in the last 10 yr bp. The frequency in the legend (e.g. 1) means how many times the single points of the area were invaded by pyroclastic fl ows in the past 10 ky bp.

The lack of planning and co-ordination in the urban plan-ning choices for the western area of Napoli became evident and serious in the following years with the fi nancing of the Istituto Autonomo Case Popolari. In 1913 the construction of the Rione Duca d’Aosta, along via Leopa r di began. Bet-ween via Nuova Bagnoli and the ilva establishment, iacp realized the Rione Bagnoli from 1927 to 1932 and from 1928 to 1930, in an area north of the railway station of Campi Flegrei, the Rione Miraglia was realized (Fig. 12).

In 1937 began the building of the Mostra d’Oltremare with the demolition of the existing buildings and, one year later, the project for the reclamation of Fuorigrotta, on an area of about 450,000 m2 to be used for about 20.000 inhabitants was passed. In 1939 the college of Gil, made up of 21 buildings, today site of the nato, was built.

After the Second World War the quarters of Fuorigrotta were mainly concerned in the public fi nancing : wide areas were urbanized, with the building of working class neigh-bourhoods, casually set in the urban structure, laid upon one another without any organization and morphological and functional coherence, like an unimportant appendix of the city (Rione Domiziana, Quartiere via Consalvo, Rione viale Augusto, Quartiere Cavalleggeri d’Aosta, Quartieri ina via Campegna, Rione ina casa at Bagnoli).

In the early sixties the enlargement of the ilva, which became the italsider was decided. Next to it were locat-ed the Cementir, the Eternit and the Montecatini. They nearly entirely occupied the area till the quarter of Caval-leggeri d’Aosta.

In the sixties the western area began to strengthen its character of peripheral area : the number of existing fl ats doubled in Bagnoli and triplicated in Fuorigrotta ; at Soc-cavo was realized the Rione Traiano, through a public fi nancing that would support residential building also in the following years, extended and confused in the areas around.

The area of Agnano became a recreational area, with the race course, football and bow shot playground. The area of Pisciarelli was destined to the industrial activities, small industrial and trading, reason why it has been congested and confused in the most recent years.

The confused growth of Fuorigrotta had its climax in the seventies with the building of Rione S. Paolo, just next to the football stadium and next to the cross roads to the Ring of Napoli.

Fuorigrotta and Bagnoli recorded a substantial increase of population in the decade from 1951 to 1961. At Fuo-rigrotta the growth was constant, even if less strong un-til 1971, it stopped in the following decades, recording a decrease of 3% in the decade from 1971 to 1981 and a stronger decrease of 19% in the decade from 1981 to 1991. For Bagnoli the demographic path is quite constant from 1961 to 1991, in the decade from 1981 to 1991, on the contrary, it registered an important decrease of more than 5,000 inhabitants. The evolution of construction for Fuorigrotta and Bagnoli has been similar to the evolution of the residential population in the last decades : a strong increase of fl at (46%) and room (56%) construction in the decade from 1961 to 1971 was followed by a huge decrease in the construction in the next decades, with no fl at and no signifi cant rooms increase.

The territory of Somma Vesuviana is 30.74 km2 and it is morphologically quite variegated : it includes, to the

P. Petrosino et alii

176

Fig. 12. Territorial system evolution in the last century in the Fuorigrotta and Bagnoli area.

1 - QUARTIERE GIUSSOA BAGNOLISMALL HOUSES TWO THREE STOREYS BUILDINGS

2 - RIONE COCCHIAA BAGNOLIFOUR STOREYS BUILDINGS AND THREESTOREYS VILLAS

3 - RIONE DUCA D’AOSTAA FUORIGROTTAFOUR STOREYS BUILDINGS

4 - RIONE MIRAGLIAA FUORIGROTTAFOUR STOREYS BUILDINGS

5 - RIONE IN VIA CONSALVOFUORIGROTTAFIVE STOREYS LINEAR BUILDINGS

6 - RIONI IN VIALE AUGUSTOAND RIONE GIULIO CESAREFIVE STOREYS BUILDINGS (LINEAR AND WITHEXTERNAL ACCESWAY BUILDINGS

7 - RIONE DOMITIANABAGNOLITWO-THREE STOREYS BUILDINGS

8 - RIONE VIA LEOPARDIAND RIONE IN VIA LEPANTOFUORIGROTTA

9 - QUARTIERE INA CASAA BAGNOLIONE-TWO STOREYS VILLASFOUR-FIVE STOREYS BUILDINGS

10 - QUARTIERE LAUROFUORIGROTTA

11 - CASE INA-INAILFUORIGROTTATHREE STOREYS LINEAR BUILDINGSSEVEN STOREYS TOWER-BUILDINGS

12 - RIONE LA LOGGETTATHREE-FOUR STOREYS BUILDINGS

13 - RIONE INA-CASAAGNANOBUILDINGS WITH DIFFERENT TYPOLOGY ANDHEIGHT (UP TO SEVEN STOREYS BUILDINGS)

14 - RIONE INA-CASASOCCAVO-CANZANELLABUILDINGS WITH DIFFERENT TYPOLOGY ANDHEIGHT

15 - RIONE TRAIANOLINEAR BUILDINGS AND TOWER-BUILDINGS(UP TO EIGHT STOREYS BUILDINGS)

16 - RIONE CAVALLEGGERID’AOSTALINEAR BUILDINGS AND TOWER-BUILDINGS(UP TO EIGHT STOREYS BUILDINGS)

recent area greatycharacterized bydisorder anddeterioration;presence of differentactivites mainly ofindustrial and trademind

disused industrial area(Italsider-Bagnoli)

tangenziale

State road

railway line

underground line

urbanization in 1936 urbanization in 1960 urbanization in 2000

Volcanic risk and evolution of the territorial system in Campania volcanic areas

177

south, a wide area of the cone of the volcano stretching north along the slopes of Vesuvio and widening out in the plain of Somma.

Somma Vesuviana is part of the northern territorial system, it is characterized by small and medium centres, set radially around the Volcano, and due to its location, history and settlement features, plays a role of reference and of relation among the interior towns of the area of Vesuvio and the urban area of Napoli.

The settle area lies at the foot of the volcano and it includes some more recent parts, along the main infra-structures, connecting the towns (connection West-East of Napoli-Ottaviano ; connection South-North toward the highway and the area of Pomigliano and Nola). The urban organization is typical of a rapidly settled area and it has been substantially modifi ed in its ‘central’ part during the last four decades existing poor conditions of life, in the urban zones, because of a congested traffi c level, degrada-tion and abandonment of the historical textures, contra-dicting morphologies. It was modifi ed also in the recently expanded areas, especially in agricultural areas along the cross roads, because of the absolutely casual union of func-tions and of the little signifi cance and coherence in the buildings (Plate 3).

Investigating the processes of expansion of the built areas from the end of the 19th century until today, we no-ticed that until the mid fi fties the inhabited structure was substantially the same, excepting some little extension on the borders of the historical areas and at the ends of some urban roads.

In the eighties the urban development consistently in-volved the centre of Somma : on the historical cores, until the fi fties close and recognizable, strongly connected to the environmental context, new wide areas were covered with structures, many unfi nished little related to the existing areas and to the context, either from a morphological or functional point of view.

In the eighties the expansion of the central areas grew along the main territorial and local roads and it became common to build in the agricultural areas, which in some parts were dense either for the widening of some agglom-erations, or for the new buildings along the roads.

In the last twenty years, from 1980 to 2000, the build-ings where mainly characterized as intensifi cation of the territorial system, either residential, or productive along the connecting roads : nowadays the built areas extend from the centre toward the near towns of S. Anastasia, Ot -taviano, Marigliano and they all nearly join. In these more recent expansions trading functions among towns, produc-tive activities and tourist structures prevail. The agricultur-al areas, especially those near the settlements, are casually mixed with the built areas and they are residual.

In the last years even the slopes of Vesuvio, especially the areas along the road to the church of Madonna al Ca-stello, are aff ected by an increase in buildings, that, even if less dense than the areas considered before, are anyway signifi cant with regard to the environmental and landscape context and have features not coherent with the places, either for the residential building or for the many receptive and recreational activities.

The comparison of the data about the residential popu-lation at the end of the 19th century and today highlights the constant growth of Somma Vesuviana and especially

highlights the population increase of the last forty years, with a variation in ten years nearly constant of 12-15% and a maximum in the decade from 1981 to 1991 of 24%.

4. 3. Comparison between Volcanic Hazardand Territorial Evolution

Comparing the hazard maps and the results of the territo-rial analysis in the Campi Flegrei test area (Fig. 13a, b) we can highlight that the urbanization in the high hazard zone increased after the second world war, when the popular and the residential districts (quartiere Giusso), located far from each other, were connected by new popular build-ings. This huge urbanization followed no rule, so the popu-lation in the quarters of Fuorigrotta, Bagnoli and Soccavo greatly increased until the 1980. Even though the number of people that live in the test area, as in the whole Napoli city, is at present slightly decreasing, the exposed value (E) it is still too high for an active volcanic area.

More in detail, the most recenly urbanized areas cor-respond to the highest PDC volcanic hazard area, e.g., the Parco S. Paolo, located on the backside of the soccer sta-dium, was built after 1970.

Notwithstanding the correct territorial policy that led to the decision to dismiss the factories in the Coroglio intermediate PDC hazard area (ex ilva at Bagnoli) and to place a natural reserve instead, in the high hazard area of the Agnano plain a very recent urbanization, dedicated to commercial and handicraft activities, together with private residential edifi ces, is growing. These buildings greatly en-hance the exposed value in the area.

The non reinforced concrete plan fl oors of the edifi ces built before 1950 (Rione Miraglia, Rione Duca d’Aosta), could collapse in case of an explosive eruption emplac-ing fall products, if the load of the deposits exceeds the threshold value.

The urban development in the Campi Flegrei test area appears, at least, not sensitive to the landslide hazard. We can notice, in fact, that the urban settlement beneath Mon-te Spina and Monte S. Angelo slopes and directly below the Camaldoli Hill, where many landslide occurred in the 1986-1997 time span, have all been built after the sixties, some very recently.

The Somma-Vesuviana and S. Anastasia municipalities, representing the Somma-Vesuvio test area, in spite of the very high volcanic hazard, showed in the last century a relevant population increase which continues still now. Since 1950, the urbanized areas of both municipalities have strongly increased along the main road connecting the towns located beneath the Somma slope (Fig. 14a, b). In particular, S. Anastasia grew in the area were the hazard from PDC is higher. The new settled area of Somma Vesuvia-na lies where, besides the high PDC hazard, the pyroclastic fall hazard increases. Somma Vesuviana, diff erently from S. Anastasia, expands also toward the Somma slope, along the road connecting downtown area to Madonna di Ca-stello, an area where both the hazard for primary products and for the remobilization of loose pyroclastic material is very high.

Similarly to the Campi Flegrei test area, Somma Vesuvia-na and S. Anastasia show, both in the urban centres and in the rural zone, non reinforced concrete plan fl oors that might collapse in case of the emplacement of fall products that exceed the threshold value.

P. Petrosino et alii

178

5. Conclusive Remarks

The investigation of the case studies reported in the previ-ous section shows the validity of the integrated volcano-logical and territorial approach to volcanic risk assessment. This kind of analysis might represent, in our opinion, a tool for local Administrators planning the future evolution of the perivolcanic towns. The true key point of the presented investigation, in fact, is the diff erent relationship between territory and volcanic risk even for towns located very near each other (e.g. Somma Vesuviana-S. Anastasia).

Through the descriptions and the considerations devel-oped till now it is evident that the conditions of the areas of Campania exposed to the volcanic risk are serious.

The seriousness of this condition is determined by the wickerwork of some factors present since 1960 and that are recognized in the greater part of the analyzed areas. These factors are :

- the massive growth of the urbanization and the locali-zation of some urban settlements in high-risk areas ;

- the absence in the urban planning of dimensional and organizational criteria taking into account the possible oc-currence of a future volcanic event ;

- the absence of suitable normative prescriptions stat-ing the building typologies and the distances of the single buildings from each other ;

- the lacking organization (dimensional and functional) in the infrastructural net.

This condition imposes the urgency of a territorial plan-ning, at local and regional scale, oriented to mitigate the eff ects of the incorrect actions made in these areas, and it appears necessary to reduce the urban settling weights and to begin a requalifi cation that regards the topics of the cohabitation with the volcanic risk and that is oriented to guarantee acceptable levels of security.

Fig. 13. a, b) Relationship between volcanic hazard and territorial system evolution for pyroclastic fall deposits (a) and PDC (b) for the Campi Flegrei area.

Fig. 14. a, b) Relationship between volcanic hazard and territorial system evolution for pyroclastic fall deposits (a) and PDC (b) for the Somma-Vesuvio area.

Volcanic risk and evolution of the territorial system in Campania volcanic areas

179

Acknowledgement

The authors wish to thank J. M. Espindola and an anon-ymous reviewer, whose suggestions greatly improved the manuscript. This work is part of the project of the Regional Center of Competence « Analysis and Moni-toring of the Environmental Risk » supported by TheEuropean Community on Provision 3.16.

ReferencesAlberico I., Petrosino P., Zeni G., D’Andrea F. and Lirer L. (2005). geocity :

a drill-hole database as a tool to assess geological hazard in Napoli urban area. « Environmental Geology », 47, 751-762.

Alberico I., Lirer L., Petrosino P. and Scandone R. (2002). A methodology for the evaluation of volcanic risk in Campi Flegrei. « J. Volcanol. Geo-therm. Res. », 116, 63-78.

Barberi F., Marinelli G., Rosi M. and Santacroce R. (1977). Il rischio da lahar nel Somma-Vesuvio. Atti del Convegno « I vulcani attivi dell’area napoletana », Napoli, 93-95.

Barberi F., Rosi M., Santacroce R. and Sheridan M. F. (1983). Volcanic Hazard Zonation : Mt. Vesuvio. In : H. Tazieff , J. C. Sabroux (eds.), Forecasting Volcanic Hazard, Elsevier.

Caiazzo S. and Dal Piaz A. (1995). Napoli organizzazione territoriale, po-litiche, interventi degli anni ’80. In : Aree metropolitane in Italia, Milano, Franco Angeli.

Calcaterra D., De Riso R. and Santo A. (2003). Landslide hazard risk map-ping : exsperiences from Campania (Italy) In : Atti International Confer-ence « Fast Slope movements 2003 », Napoli 1, Pàtron.

Carta S., Figari R., Sartoris G., Sassi E. and Scandone R. (1981). A statistical model for Vesuvio and its volcanological implications. « Bull. Volcanol. », 44, 2, 129-151.

Cioni R., Longo A., Macedonio G., Santacroce R., Sbrana A., Sulpizio R. and Andronico A. (2003). Assessing pyroclastic fall hazard assessment through fi eld data and numerical simulation : Example from Vesuvio. « J. Geophys. Res. », 103 (B2), 10.1029/2001JB000642.

Dal Piaz A. (1985). Quarant’anni di urbanistica, Milano, Franco Angeli.Dal Piaz A. (1994). Criteri di pianifi cazione territoriale in un’area a rischio

multiplo : il caso dell’area napoletana. In : Rischi naturali ed impatto an-tropico nell’area metropolitana napoletana, Napoli, Guida (« Acta na-politana »).

De Lucia V. and Jannnello A. (1976). L’urbanistica a Napoli dal dopoguerra ad oggi. « Urbanistica », 65.

Dipartimento della Protezione Civile (1995). Pianifi cazione Nazionale di E - me rgenza dell’area vesuviana, Roma, Presidenza del Consiglio dei Mi-nistri 1995.

Esposti Ongaro T., Neri A., Todesco M. and Macedonio G. (2002). Pyroclas-tic fl ow hazard assessment at Vesuvio (Italy) by using numerical mod-eling. ii. Analysis of fl ow variables. « Bull. Volcanol. », 64, 178-191.

Fournier D’Albe E. M. (1979). Objective of volcanic monitoring and predic-tion. « J. Geol. Soc. London », 136, 321-326.

Fraldi M., Lirer L., Nunziante L., Petrosino P., Scotellaro S. and Cicirelli C. (2002). Analysis of ad 79 eruption pyroclastic currents impact and present risk assessment for buildings at Vesuvio. agu Chapman Confer-ence on Volcanism and the Earth’s atmosphere, Santorini, Greece, 17-21 June 2002, Abstract.

Giacomelli L. and Scandone R. (2001). Vesuvio, Pompei, Ercolano. Eruzioni ed escursioni, Milano, BeMa, 1-128.

Lirer L. and Vitelli L. (1998). Volcanic risk assessment and mapping in the vesuvian area using GIS. « Natural Hazards », 17, 1-15.

Lirer L., Petrosino P., Alberico I. and Postiglione I. (2001a). Long term vol-canic hazard forecast based on Somma-Vesuvio past eruptive activity. « Bull. Volcanol. », 63, 45-60.

Lirer L., Petrosino P. and Alberico I. (2001b). Volcanic hazard assessment at volcanic fi elds : the Campi Flegrei case history. « J. Volcanol. Geotherm. Res. », 101, 1-4, 55-75.

Lirer L., Vinci A., Alberico I., Gifuni T., Bellucci F., Petrosino P. and Tinterri R. (2001c). Occurrence of inter-eruption debris fl ow and hyperconcen-trated fl ood-fl ow deposits on Vesuvio volcano, Italy. « Sedimentary Geol-ogy », 139, 151-167.

Nunziante L., Fraldi M., Lirer L., Petrosino P., Scotellaro S. and Cicirelli C. (2003). Analysis of AD 79 eruption pyroclastic currents impact and present risk assessment for buildings at Vesuvio. « Bull. Volcanol. », 65, 154-176.

Orsi G., Di Vito M. A. and Isaia R. (2004). Volcanic hazard assessment at the restless Campi Flegrei caldera. « Bull. Volcanol. », 66, 514-530.

Pareschi M. T., Santacroce R., Sulpizio R. and Zanchetta G. (2002). Volcani-clastic debris fl ows in the Clanio Valley (Campania, Italy) : insights for the assessment of hazard potential. « Geomorphology », 43, 3-4, 219-231.

Rolandi G., Petrosino P. and Mc Geehin J. (1998). The interplinian activ-ity at Somma-Vesuvius in the last 3500 years. « J. Volcanol. Geotherm. Res. », 82, 19-52.

Rolandi G., Bertolini F., Cozzolino G., Esposito N. and Sannino D. (2002). Sull’origine delle coltri piroclastiche presenti sul versante occidentale del Pizzo d’Alvano (Sarno-Campania) (« Quaderni di Geologia Applicata », 7, 1), 37-47.

Rolandi G., Munno R and Postiglione I. (2004). The ad 472 eruption of Somma volcano. « J. Volcanol. Geotherm. Res. », 104, 67-92.

Rossano S., Mastrolorenzo G. and De Natale G. (2004). Numerical simulation of pyroclastic density currents on Campi Flegrei topography : a tool for statistical hazard estimation. « J. Volcanol. Geotherm. Res. », 132, 1, 1-14.

Scandone R. (1977). Il rischio da colate di lava e implicazioni socio-eco-nomiche, Atti del Convegno « I Vulcani Attivi dell’Area Napoletana », Napoli, 103-106.

Scandone R., Arganese G. and Galdi F. (1993). The evaluation of Volcanic Risk in the Vesuvian area. « J. Volcanol. Geotherm. Res. », 58, 263-271.

Scandone R. and Cortini M. (1982). Il Vesuvio : un vulcano ad alto rischio. « Le Scienze », 93, 70-80.

Todesco M., Neri A., Esposti Ongaro T., Papale P., Macedonio G., San-tacroce R. and Longo A. (2002). Pyroclastic fl ow hazard assessment at Vesuvio (Italy) by using numerical modeling. i. Large-scale dynamics. « Bull. Volcanol. », 64, 155-177.