ABSTRACT
The Plio-Pleistocene clay area in Basilicata is characterized by high relative relief - the product of relatively rapid uplift during the last 800,000 years, together with accompanying incision. This clay area is approximately 195,700 ha. Mass movements tend to be polarized between the relatively shallow and the more deep-seated. The latter are controlled by aspects of the structural geology. Many of the larger deep-seated slides are overlain by permeable sands and gravels, and may date back to pluvial periods in the Quaternary.
The behaviour of the clays is controlled by the climate, which is strongly desiccating, with an annual soil moisture deficit in excess of 600mm. Rainfall is highly variable, both in time and space, with annual values ranging from 350mm to more than 1000mm. Infrequent heavy rainfall combined with the generally desiccated nature of the clays cause badlands type erosion, with the appearance of geomorphological features termed calanchi and biancane. The landforms are all extremely steep relative to the geotechnical properties of the soils in which they are formed.
The paper gives an overview of the geographical extent and the geomorphological character of the area, and is illustrated with examples of geohazards ranging from shallow and deep-seated slides, clay swelling and ground heave, and rapid erosion.
