Esposito, E.

Vengono presentati i risultati preliminari della campagna oceanografica CAFE_07 - Leg 3, svoltasi nei Golfi di Napoli e Pozzuoli, nel Gennaio 2008, a bordo della Nave Oceanografica (N/O) URANIA del CNR. Lo scopo della campagna è stato l’acquisizione di profili sismici multicanale di elevata risoluzione dedicati allo studio stratigrafico-strutturale degli apparati vulcanici affioranti e sepolti nell’offshore Napoletano, ed il rilievo batimetrico di dettaglio dell’area sommersa. I dati raccolti sono consistiti in circa 800 km di profili sismici a riflessione multicanale di alta risoluzione, con acquisizione sismica simultanea da due sorgenti GI-gun operanti con potenza e frequenze differenti,mediante due cavi idrofonici. Durante la navigazione sono stati anche acquisiti profili sismici a riflessione monocanale di altissima risoluzione (sub-bottom CHIRP) e dati batimetrici mediante ecoscandaglio multifascio (multibeam). Il grid di acquisizione sismica multicanale è consistito in alcuni profili lunghi attraverso il Golfo di Napoli e da una fitta griglia di profili più corti, con interasse di circa 150 m, allo scopo di ottenere una copertura sismica quasi 3-D del Golfo di Pozzuoli. Questo set di dati costituisce una parte delle indagini di dettaglio richieste per la stesura di una proposta di perforazione del settore sommerso dei Campi Flegrei da sottomettere all’Integrated Ocean Drilling Program (IODP) ed è di supporto alla realizzazione di un progetto di perforazione profonda dei Campi Flegrei presentato all’International Continental Drilling Program (ICDP). We present the preliminary results of the oceanographic cruise CAFE_07 – Leg 3, conducted in the Napoli and Pozzuoli Bays in January 2008, on board of the Research Vessel (R/V) URANIA of the CNR. The aim of the cruise was the acquisition of high resolution multi-channel seismic profiles to understand the stratigraphic-structural setting of the Pozzuoli Bay area, with specific reference to the major offshore volcanic features, as well as the acquisition of bathymetric data on the seafloor morphology of the Bay. About 800 km of seismic profiles were acquired simultaneously by two acquisition systems, each characterized by different seismic source and streamer configuration, operating at different frequency ranges. Moreover shallow high resolution seismic reflection profiles (sub-bottom CHIRP) and multibeam echo-sounder bathymetry data have been recorded. The seismic grid consisted in a number of assistant profiles acquired over the Bay of Naples, along with a dense network of profiles with average distance of about 150 m between navigation routes, in order to obtain a quasi 3-D seismic coverage of the Pozzuoli Bay. This data set represents a part of the requirements for on-site detailed investigations (“site survey”) that are necessary for the development of an Integrated Ocean Drilling Program (IODP) proposal dedicated to the offshore drilling of the Campi Flegrei and is a relevant complement in the site survey of an ongoing project that has been submitted to the International Continental Drilling Program (ICDP).

Seismically induced environmental effects (in particular, surfacefaults, ground cracks, slope failures, liquefaction, soil compaction, hydrological changes, tsunamis) are assumed to provide fundamentalinformation on the earthquake size and its intensity field, crucial for a more efficient seismic hazard assessment. Accordingly, this study is aimed at substantiating this assumption by showing that the knowledge about ground effects acquired in recent earthquakes, when combined with that illustrated in historical documents, allows to buildan improved picture of historic seismic events, with respect to that usually provided by the solely damage-based macroseismic scales. In this perspective, the environmental effects are analysed and cataloguedof three of the most ruinous earthquakes in Southern Italy of the last two centuries: the July 26,1805, Molise event (XI MCS, M 6.8), the July 23, 1930, Irpinia event (X MCS, M 6.7), and the November 23, 1980 Campania-Basilicata event (X MSK, Ms 6.9). The distribution of the earthquake environmental effects, in particular their distance from the known or supposed causative fault, has been investigated to obtain a more detailed and comprehensive picture of the macroseismic field, a key parameter in seismic hazard assessment and seismic zonation. KEY WORDS: historical seismicity, intensity, ground effects, earthquake

As regards the July 26, 1805 earthquake, a detailed study on the damage suffered by the town of Isernia has been carried out. As a first step in our research, we analyzed a manuscript of the time, in which describes damage to public buildings, churches and some notable houses caused by the earthquake. In order to identify such damaged sites, several archival sources and documents from 1816 to 1955 have been examined, on account of the remarkable changes in toponymy which occurred after 1861 and caused by the 1943 bombing. Moreover, due to the lack of cartography of the time, a 1875 map or the town has been used and compared with the land registry maps of a later period. The analysis of the 1805 damage pattern shows that the historical centre of the Isernia town is divided into three areas whose damage level is fairly differem: such areas are respectively located in the southern, central and northern part of the town with an increase in damage from South to North.