Geomorphological investigations on landslide dams

Abstract

Background: The study of past landslide dams and their consequences has gained a considerable significance for forecasting induced hydraulic risk on people and property. Landslide dams are rather frequent in Italy, where a broad climatic, geological and morphological variability characterize different part of the peninsula, and have already been studied in literature, focusing different geographical regions with different levels of detail. In order to develop specific tools to assess the landslide dam formation and stability, the first step is to realize a large data archive including a big number of data, collected with a consistent methodology to standardize the quality. Description: For this reason, this paper reports the results of an extensive bibliographic work and geomorphologic investigation on landslide dams that lead to the development of the wider systematic inventory in Italy. Through the revision and the update of scientific works and historical reports, three hundreds of landslide dams from the Alps to the Southern Apennine and Sicily were identified. During investigations and through cartographic and aerial photos interpretation, several geomorphic parameters of the landslide, the dam body, the valley and the lake, if any, have been determined, or estimated using historical and bibliographical documents analysis. Conclusions: The collected data were resumed in a database, formed by 57 information fields easy to collect and measure to privilege intuitive usability and future implementation. In order to describe the characteristics of landslide dams in Italy some specific analysis on the different types of landslide movements and their volume, the dam longevity, the main triggers and their geographical distribution were carried out.

Landslide damming hazard susceptibility maps: a new GIS-based procedure for risk management

“…Step I: preliminary operations To reduce the processing time and improve the visualization effect, it is recommended to remove a series of unnecessary data. The river blockage takes place almost exclusively in hilly or mountainous areas and preferentially along steep slopes (Costa and Schuster 1988;Fan et al 2014;Tacconi Stefanelli et al 2015. For this reason, sections that run in flat areas (with less than 5°slopes and below 150 m a.s.l.)…”

“…Population can suffer casualties and restoration costs are often substantial and of two categories: direct (e.g., safety measures and infrastructure rebuilding) and indirect, more difficult to estimate (e.g., damage caused to industrial and agricultural productivity or loss in real estate value delayed in time). It is widely recognized (Costa and Schuster 1988;Ermini and Casagli 2003;Tacconi Stefanelli et al 2015) that most of landslide dams last a short period of time.…”

Controls on the formation of potential landslide dams and dammed lakes in the Austrian Alps

“…6). Korup (2004) and Tacconi Stefanelli et al (2015) determined index thresholds, which separate their landslide dams into different obstruction and stability classes:…”

“…Many landslide dams tend to fail shortly after formation (Tacconi Stefanelli et al, 2015), while resistant dams get filled by sediments, complicating their documentation and the assessment of their impoundment potential. Thus, most landslide dam and lake inventories only contain relatively large dams.…”

Collapsed material movement of deep-seated landslides caused by Typhoon Talas 2011 on the Kii Peninsula, Japan

“…The likelihood that collapsed material from a landslide will form a dam depends on the topographic factors involved in the interaction between river and slope dynamics [Dal Sasso et al ., 2014;Stefanelli et al ., 2015]. Collapsed material due to slope failures in Miyagi Prefecture caused by the 2008 Iwate-Miyagi earthquake easily formed landslide dams in areas where the streambank slope had large relative height and the streambed had a relatively gentle inclination (third-to fifth-order streams) [Ishikawa and Ishikawa, 2012].…”