Neotectonics, landslides and planning : the case of Maratea (PZ), Basilicata, southern Italy
The thesis examines the geology and geomorphology of the town of Maratea, southern Italy, and their efffect on the development of the town. Maratea is situated at the mouth of a fault-controlled valley surrounded by high limestone mountains of Jurassic and Triassic age. Recent ground movements are associated with a 2km long fault plane scarp which runs along the eastern flank of the valley and the limestone strata above the Town Centre are affected by an excellent example of a deep-seated slope deformation known as a sackung. Six limestone blocks are located in the valley floor below the fault plane scarp and in addition the area is affected by earthquakes associated with the evolution of the Apennine chain. The area has experienced two phases of neotectonic activity. Evidence from the literature places the first of these at somewhere between 2.0 MY BP and 0.7 MY BP. Subsequently the valley was deepened by a further phase of neotectonic activity, fixed by a U-series date obtained by the author, at 46.4 +/-3.5 x 103 yrs BP. Since then landslide movements have predominated. The fault plane scarp is being exhumed from beneath covering deposits and lichenometric dating, based on the species Aspicilia calcarea, shows that up to 15m of scarp face has been exposed in the last 300 - 600 years. The movements are periodically accelerated by earthquake shaking. The limestone blocks are found to be stable features, although a piece of one block, which has broken away from the main block has tilted at various times. The dates of tilting have been determined by sectioning stalactites growing on the block and dating their observed growth phases by a first-order 14C method. Tilting apparently occurred at 2400 +/-300 yrs BP and within the last 400 years. Finally a questionnaire survey covering all 1008 buildings in Maratea indicated that earthquake shaking, exacerbated by the highly variable sub-surface geology of the valley, is the primary cause of damage. These preliminary findings reinforce the case for detailed neotectonic research as a prelude to development in unstable tectonic environments.