Weathering processes in volcanic tuff rocks of the "Rupe di Coroglio" (Naples, southern Italy): erosion-rate estimation and weathering forms

Abstract

The present work shows the preliminary data on the erosion rate estimation and weathering forms on the outcrop of the Neapolitan Yellow Tuff along the Rupe di Coroglio (Naples, southern Italy). This pyroclastic complex shows abundant alveolar and tafoni forms mostly related to salty seawater and salt spray processes that affect the western portion of the Posillipo hill. In this coastal environment, weathering forms such as alveolar, honeycombs or tafoni are very common producing from small to large deep cavities, development of which produces landslide phenomena. This area has been protected by consolidation interventions such as barrings, retaining walls and anchored structures. After 30 years from first interventions of consolidation, has been observed that some cables of the anchored structures protrude from rock escarpment with values between 5 and 12 cm. Based on these values an average erosion rate of 1.6÷4 mm/year was estimated.