The spatio-temporal dynamics of the Ciprnik complex landslide, Tamar Valley, Julian Alps, Slovenia

Abstract

Mass movements represent important processes that shape relief in Alpine areas. In this article, we present the spatio-temporal dynamics of the Ciprnik landslide (Julian Alps, NW Slovenia) and interpret its triggering and evolution. In the study area, mass movement activity is characterised by two phases: normal deposition on the fluvial fans that dominated up to 2000, and a more active phase related to the triggering of the Ciprnik complex landslide and formation of an additional de-bris-flow fan. The Ciprnik landslide started as a translational movement over the discontinuity plane that was mobilised into a debris-flow. The triggering and slope failure resulted from a combination of tectonics (i.e. dip-slope position of the strata, and strong fracturing), lithology (alternation of thin beds of carbonates and fine-grained clastics), and accumulation of precipitation. The debris-flow fan remains active and interfingers with adjacent active fluvial fans.