Volcaniclastic debris flows in the Clanio Valley (Campania, Italy): insights for the assessment of hazard potential

The rugged and steep slopes of the Clanio Valley (Campania, Southern Italy), mantled by volcaniclastic deposits from explosive eruptions of Somma-Vesuvius and Phlegraean Fields volcanoes, have a great potential for generating volcaniclastic debris flows. During the well-known meteorological event of May 5–6, 1998, which triggered tens of debris flows causing enormous damage and casualties in the area of Sarno–Quindici–Siano–Bracigliano (SQSB), the Clanio Valley was also affected by these hazardous phenomena. Debris flows were triggered by the failure of the volcaniclastic cover of the carbonate relief in the form of soil slips, mainly on the sides of steep valleys (slope between 26° and 45°). of the hazard potential was created on the basis of both field and computer-assisted morphometric data. Three classes, characterised by a high, medium and low hazard potential, were distinguished. Within the higher class, a better and more detailed zonation was obtained by studying the shape of the disrupted and undisrupted basins during the May 5–6, 1998 event in the nearby Sarno–Quindici–Siano–Bracigliano area. This type of morphometric analysis can be applied rapidly by using a digital elevation model (DEM), which allows a rapid investigation of large-scale areas. Such an approach can be useful in areas characterised by similar geological and geomorphological settings.