The GOGIRA System: An Innovative Method for Landslides Digital Mapping

Landslide mapping techniques have had many improvements in recent decades, the main field of development has been on traditional cartographic techniques and to a lesser extent on indirect numerical cartography. As for Direct Numerical Cartography (DNC), only a few improvements have been made due to the complexity and economic cost of the new technologies. To meet this lack in DNC techniques GOGIRA (Ground Operative-system for GIS Input Remote-data Acquisition), a new system following the GIS (Geographic Information System) scheme, was developed. It is a suite of hardware and software tools, algorithms, and procedures for easier and cheaper DNC. Initial tests conducted on the Quincinetto landslide system (north-western Italy) demonstrated good results in terms of morphometric coherence and precision. A geomorphological map made with GOGIRA was compared with a highly detailed geomorphological map developed with modern tested methods. In conclusion GOGIRA proved to be a valid system for geomorphological DNC when applied to a complex landslide system, considering the early stage of developing results for linear and point mapping was excellent, as for polygonal elements more studies must be conducted to improve accuracy and precision

Future global debris flow susceptibility considering climate change, wildfire probability, and glacier retreat

The present-day impact of climate changes on debris flow magnitude, frequency, and susceptibility has been demonstrated in North and South America, Europe, Asia, and New Zealand. Such impacts are expected to increase under future emission scenarios. Future global debris flow susceptibility models provide an international perspective on areas worthy of further, more detailed analyses with regard to geographic changes in global debris flow susceptibility. In this study, future global debris flow susceptibility models are developed under RCP 2.6 and 8.5 IPCC Climate Change Scenarios. These models were further augmented with wildfire probability, and areas of potential glacier retreat, both of which can act as amplifiers to debris flow susceptibility. The results are projected against future urban centers, for a spatial view on potential human vulnerability. Key findings are (1) wildfire acts as a significant amplifier in area and magnitude of debris flow susceptibility in all modeling scenarios, (2) greater than 50% of the studied glaciers reside within higher susceptibility zones when wildfire is not considered, and greater than 75% when wildfire probability is considered, (3) 76 of the studied glaciers are within 5 km of eleven urban centers, (4) 11% of these “urban” glaciers are in higher susceptibility zones when wildfire probability is not considered, and 51% are in higher susceptibility zones when wildfire is considered, (5) about 12% of future urban centers will reside within higher susceptibility zones under both future climate change scenarios. Consideration of these factors, together with traditional environmental factors and triggers, and findings by local and regional glacier-related debris flow researchers, suggests a new paradigm in modeling debris flow susceptibility, at any scale

Investigation and numerical simulation of debris flow events in Rochefort basin (Aosta Valley—NW Italian Alps) combining detailed geomorphological analyses and modern technologies

This paper presents a multidisciplinary approach using modern technologies for the analysis and modelling of the debris flow that occurred at Torrent Rochefort (Aosta Valley—Italy) September 2015. A detailed on-site geological and geomorphological study was performed to highlight the main characteristics of the basin, useful for validating and calibrating dynamic simulations. The total mobilized volume was estimated by comparing a pre-event DTM and a post-event DTM generated from an unmanned aerial vehicle. A digital terrain model comparative analysis provided a quantitative estimation of erodible depths in diferent sectors of the Rochefort basin. Numerical modelling of the event was performed using the continuum mechanics-based code RASH3D that enabled a simulation of the dynamic debris motion on complex topography. The results demonstrate the importance of a detailed geomorphological study for the validation and calibration of numerical results. Finally, some considerations were inferred about the magnitude of unstable debris and the possible consequences on local infrastructures