Active alluvial fans in Calabria, Southern Italy
Focus
A new map shows the location, extent and activity of more than 1000 active alluvial fans in Calabria, Southern Italy
Internal contact person: Loredana Antronico
Email: loredana.antronico@cnr.it
Alluvial fans are known to be areas of high geomorphic activity, where debris flows and flash floods caused by intense and prolonged rainfall are a major hazard. In Calabria, southern Italy, alluvial fans are numerous. The exact age of the alluvial fans is seldom known, but most of the fans in Calabria are considered recent in age (Holocene).
Due to the significant increase in urbanization in the last two centuries, many alluvial fans are disturbed by human activities, including agriculture, infrastructures, and housing (Fig. 1).
Fig. 1: Village of Bagaladi (Province of Reggio Calabria) built on two inactive alluvial fans.
Like in other areas, alluvial fans in Calabria are characterized by intermittent activity, controlled by the intensity and the frequency of hydrological processes in their catchments (Fig. 2). The presence of hydraulic engineering works within the watercourse and on the alluvial fan (e.g., check-dams, levees, bank protections) testifies the intense activity of the fans in the recent past.
Fig. 2: Photo comparison (from October 2009 to October 2011) of the active Inerà alluvial fan, located near the village of San Lorenzo at the confluence of T. Inerà with the Fiumara di Mèlito (souther Calabria). It should be noted that, within one winter season, the fan displays a significant alternation in the progradation/retrogradation process.
Currently inactive fans, characterized by erosion, have been subject to various human activities (e.g., construction of bridges, buildings, defensive works). As a result, structures, infrastructures and the population on these alluvial fans are at risk, in case of a reactivation of the fan.
In 2009, 2010 and 2011, the densely populated alluvial fans present along the southern Tyrrhenian coast of Calabria were severely impacted by debris flows and flash floods triggered by particulary intense rainfall events (Fig. 3).
Fig. 3: Map of recent alluvial fans present along the southern Tyrrhenian coast of Calabria and indication of the locations where debris flow damage occurred during the 2009, 2010, and 2011 rainfall events (red). Google Earth® 2011 images.
Further details
Link to the website of the Calabria region »
Antronico L, Greco R, Sorriso-Valvo M. 2015. Map of recent alluvial fans in Calabria (southern Italy). Journal of Maps, 1-12. DOI: 10.1080/17445647.2015.1047905.
Antronico L, Greco R, Robustelli G, Sorriso-Valvo M. 2015. Short-term evolution of an active basin–fan system, Aspromonte, south Italy. Geomorphology 228, 536-551. DOI: 10.1016/j.geomorph.2014.10.013.