habitat rupestre.pdf - Società Friulana di Archeologia

THE INFLUENCE OF GEOLOGICAL AND GEOMORPHOLOGIC FACTORS IN THE REALIZATIONOF ARTIFICIAL CAVESS. Del Prete 1 , M. Parise 21. Federazione Speleologica Campana, Gruppo Speleologico Natura Esplora, Italia2. Istituto di Ricerca per la Protezione Idrogeologica, CNR Bari, ItaliaThe habit of man to excavate artificial cavities began a verylong time ago. Man’s efforts were initially moved by the needto have a safe place to live, to control the surrounding territory,to collect and transport water, to exploit the natural resources.For all these purposes, he had to face a number ofgeological and morphological constraints that, depending onsite characteristics, guided, favoured or complicated the excavation.Therefore, all the phases in the “life” of an artificialcavity, from the original idea, to the planning and realization,up to its later evolution and possible conservation, depend insome ways on geology and morphology.Lithology of hosting rock is the first aspect to consider: therock mass must allow hand excavation but, at the same time,it should present physical-mechanical characteristics such tosupport the newly-formed cavity. The geological and structuralsetting, including the main fault lines and the discontinuitysystems in the rock mass, have to be particularly taken into account.Choice of the site where to locate an artificial cavity isalso dictated by morphology, the morphological factors being,in turn, strictly related to territory management and control.When safety reasons were considered to be the main priority,for instance, those sites that apparently were extremely difficultto excavate and to settle in were chosen. Morphologyis also strictly related to slope instability. Several rock settlementssituated at the borders of deep valleys and ravines aredirectly involved in mass movements, due to natural evolutionof the slopes and to open cracks produced by the tensionalrelease in the unsupported rock mass. Inside the artificial cavities,in turn, problems of instability may be observed. Locally,these may become so significant to compromise the overallstability of the structure. Slope instability processes deserve agreater attention from cavers and scientists, since their effectsmight be extremely dangerous for people visiting and workingin artificial cavities, and for the cultural heritage thereincontained as well.Availability of water resources is a further factor that controlledduring historical times the choice of sites for settlementsand towns. As a consequence, the hydrogeology playsa crucial role for artificial cavities, and particularly for thoseworks intended to collect and transport water to settlers andinhabitants. Aqueducts, tunnels, fountains are, for the reasonsabove, very important to study in the context of the geologicaland hydrogeological setting, considering at the same time thesocial and historical aspects of the community that designedand realized them.The present contribution is a first attempt in categorizing theaforementioned factors that play a role in the realization of artificialcavities. The topic is very wide, covering several interrelateddisciplines and field of research, and should deserve tobe treated with much greater detail and thoroughness. Nevertheless,our hope is to stimulate with this article the caversand the interested scientists in carrying out studies about thecrucial role that geology and morphology have in the developmentof artificial cavities.Fig. 1 Panoramic picture of the arched structure across Ponti della Valle valley; the broken line marks the hypogean track of the Caroline aqueduct along thefl ank of Longano hill, Caserta, Italy (photo: S. Del Prete).19volumeRicerca_OK_2012-11-15.indd 19 16/11/2012 15:00:44