Landslide processes and Andosols: the case study of the Campania region, Italy

The aim of this study is to examine the relationships between Andosols and fast mudflow landslides. The results are important both locally and in other volcanic areas of the world where this type of landslides occurs. Mudflow is a very rapid to extremely rapid flow (i.e. velocity 0.05-5 m/s) of plastica materials having high water content (Cruden and Varnes 1996; Hungr et al. 2001). Fast mudflow landslides are grave dangers to people and infrastructures as they do not have clear warning signs, they have a devastating power and they can potentially activate large amounts of materials across extended distances in very short time periods. In the last 100 years there have been more than 1100 natural catastrophic landslide and flooding events in the Campania region in Italy. Landslides, including both debris and mudflows, have caused the greatest amounts of damage, resulting in more than 550 injured or deceased victims over the past 50 years.The study of these processes in the Campania region is of primary importance for classifying zones of different landslide hazard risk (landslide hazard assessment). Previous work (Terribile at al. 2000ab, Basile et al. 2003) has been conducted in locations struck by the large mudflows of Sarno and Quindici in 1998, that produced 181 victims, serious damage to infrastructure and major modifications of the slope morphology. The work demonstrates that the presence of a complex sequence of Andosols, with properties specific to Andosols (i.e. high water retention, tixotropy, etc.), make these fertile ecosystems very vulnerable to disturbance. Geomorphological, hydrogeological, land use and anthropic factors are also important. This paper extends the study conducted in Sarno and Quindici to major landslide events in the Campania region.