Giuseppe Delmonaco

An Inventory-Based Approach to Landslide Susceptibility Assessment and its Application to the Virginio River Basin, Italy

An inventory-based method for the assessment of landslide susceptibility is presented in this article. The method has been tested in the Virginio River Basin, a tributary of the Arno River whose confluence is located about 20 km downstream from Florence (Italy). The scope of this study includes setting up a procedure for landslide hazard zoning to be applied by those urban planners typically working on small areas at large scale. The proposed method deals with traditional and well-known landslide hazard analyses, based on geomorphological tools, and its most original contribution is represented by the attempt to carry out and apply a technique for landslide hazard assessment that takes into account two different scales of analysis. The basis of a detailed landslide inventory and the first phase of this research was an in-depth geomorphological investigation at basin scale (1:25,000–1:10,000). This was aimed at indicating the most important factors influencing the landslide processes within the area, which also turned out to be the most generally accepted factors: a) slope gradient in which the landslide originated, b) lithology, and c) land cover. Once those factors were defined as thematic vector data, they were expressed using GIS overlay mapping, allowing the identification, for the entire Virginio River basin, of first-order homogeneous domains (Unique Condition Units, UCUs) that contain, for each landslide type, unique combinations (domains) of the selected hillslope stability factors. The domains are the basic Terrain Units for the subsequent landslide susceptibility assessment and mapping, which was carried out at slope scale (1:10,000–1:2,000). Landslide factors not identified in the first phase of analysis, but considered to have played an important role in contributing to the activation of the mass movements, so-called second-order landslide preparatory factors, have been taken into account in the second phase of the analysis. Once mapped and spatially referenced, these factors were overlain by vector-based GIS techniques to define second-order UCUs which, in turn, constituted the basis of a landslide susceptibility function. Essentially, this is a logic function based on the presence/absence of preparatory factors and slope instability indicators within previously selected Unique Condition Terrain Units. The final mapping of the areas characterized by different landslide susceptibility levels was performed by vector- and raster-based GIS techniques on the basis of the number and rank of the preparatory factors. The final landslide susceptibility classes, defined by a logical and easily replicable procedure, are considered to be useful in the decision-making procedures associated with territorial planning.

Implementation of advanced monitoring System Network in the Siq of Petra (Jordan)

The paper summarizes field survey results and analysis in the framework of a UNESCO project (Siq Stability Project) for the implementation of remote and field integrated monitoring systems aimed at the detection and control of active deformation of the Siq slopes (Petra, Jordan). Petra is located on the eastern side of the Dead Sea-Wadi Araba tectonic depression, in SW Jordan. The Siq is a 1.2 km long natural deep gorge in the sandstone mountains that connects the urban area of Wadi Musa with the monumental area of Petra. Since Nabataean times, the Siq is the main narrow entrance for some thousands tourists that access the archaeological area every day. Discontinuities of various type (bedding, joints, faults), mainly related to stratigraphic setting, tectonic activity and geomorphological evolution of the slope can be recognized. Rock-fall potential activity can be catastrophic according to evolution of the movement (extremely rapid) and involved rock mass volumes. Slope instability, acceleration of crack deformation and consequent increasing of rock-fall hazard conditions could threaten the safety of people walking through the Siq.

Rock-Fall Hazard Assessment in the Siq of Petra, Jordan

Rapid onset natural phenomena, such as earthquakes, floods and landslides, pose a major threat to cultural heritage and visitors in Petra The paper reports first results of a feasibility project, in cooperation with UNESCO and PNT, aimed at envisaging the stability conditions of the slope-forming rocks of the Siq that is the spectacular entrance for tourists to the monumental area of Petra. A field analysis was conducted to reconstruct, although preliminarily, the characteristics and orientation of discontinuities, main failure modes of potential unstable blocks, magnitude of phenomena, geomechanical parameters of materials. A first rock-fall hazard assessment has been defined and some potential monitoring techniques have been analyzed. Results will be used for the implementation of a forthcoming project addressed to landslide risk analysis of the Siq, as fundamental management tool of a master plan for sustainable tourist exploitation of the site.

Monitoring, Geomorphological Evolution and Slope Stability of Inca Citadel of Machu Picchu: Results from Italian INTERFRASI project

The Geology of Machu Picchu area is characterised by granitoid bodies that had been emplaced in the axial zones of the main rift system. Deformation of the granite, caused by cooling and tectonic phases, originated 4 main joint sets, regularly spaced (few decimetres to metres). Several slope instability phenomena have been identified and classified according to mechanism, material involved and state of activity. They are mainly related to rock falls, debris flows, rock slides and debris slides. Origin of phenomena is kinematically controlled by the structural setting and relationship with slope face (rock falls, rock slide and debris slides); the accumulated materials is the source for debris flow. Geomorphological evidences of deeper deformations are currently under investigation.

Multi-Temporal and Quantitative Geomorphological Analysis on the Large Landslide of Craco Village (M118)

The village of Craco (Basilicata, Italy), is being affected by severe landslide phenomena mainly due to the geological and geomorphological setting of the area. The village has been interested by a progressive abandon of the population after the occurrence in the time of landslides and earthquakes that caused the disruption of large portions of the urban settlement. Several landslide typologies can be recognized in the area: rock-falls in the upper part of the hill, rotational and translational earth slides, earth-flows, rock lateral spreading. The main purpose of the paper is to reconstruct the evolution of the geological and morphological dynamics acting on the southern slope of Craco, where the largest landslides occurred in the past.

Rock Slope Potential Failures in the Siq of Petra (Jordan)

The Siq is a 1.2 km naturally formed gorge that represents the main entrance to Petra (Jordan). Discontinuities of various type (bedding, joints, faults), mainly related to stratigraphic setting, tectonic activity and geomorphological evolution of the slope can be recognized. Structural condition determines a rock-fall potential activity that may involve unstable volumes, from 0.1 m3 up to over some hundreds m3. The latter can be catastrophic according to evolution of the movement (extremely rapid) and involved rock mass volumes. Slope instability, acceleration of crack deformation and consequent increasing of rock-fall hazard conditions could threaten the safety of people walking through the Siq. UNESCO, ISPRA and Jordan local authorities have implemented a project focused on landslide hazard assessment and risk mitigation strategies as a first step for the long-term conservation of the Siq. The paper reports preliminary data on landslide inventory, geomechanical properties of materials and assessment of landslide kinematics that affect the Siq of Petra.

General Environmental Condition of the Bamiyan Valley

Afghanistan is a mountainous country in a dry part of the world, which experiences extremes of climate and weather. Winters are cold and snowy, and summers hot and dry. The wet season generally runs from winter through early spring, but the country on the whole is dry, falling within the Desert or Desert Steppe climate classification. Very little snow falls in the lowland deserts of the southwest, but the snow season averages roughly October to April in the mountains and varies considerably with elevation.

Slope-Structure Stability Modeling for the Rock Hewn Church of Bet Aba Libanos in Lalibela (Ethiopia): Preliminary Results

Lalibela is located in the northern-central part of Ethiopia, approx. 600 km north of Addis Ababa in Northern Wollo, one of the most structural food deficit areas of the Amhara Region. The town, which has about 12000 inhabitants, is situated at an altitude of 2500 m (Fig. 26.1). In its center, a unique complex of 11 rock-hewn Christian Orthodox churches is loacted. The churches were cut out of the living rock some 800 years ago during the kingdom of King Lalibela (1167–1207) of the Zagwe dynasty. One of these churches, Biet Aba Libanos, is a monolithic church anchored to the rock from which it was carved. Two major damaging phenomena affect the church: weathering of volcanic tuff in the lower part of the edifice and sliding of the facade and lateral walls, as consequence of a prone discontinuity. A first destruction of the facade was already occurred in the past, as consequence of an old planar sliding, still in coincidence of the same joint. Presently, the walls prone to slide are the structures constructed to replace the original rock that collapsed during the slide as well as some of the original rock hewn lateral walls. Kinematical analysis and numerical modeling implemented, clearly evidence the hazardous conditions of the rock hewn church of Biet Aba Libanos and the need of a prompt and proper intervention.

Laser Scanning Analysis and Landslide Risk Assessment on Transportation Network: The Lugnano in Teverina (Umbria Region, Italy), Landslide Case Study

The present paper reports a multi-disciplinary team work, involving professionals, research institutes and public administration, for defining and applying low-impact techniques for risk assessment and mitigation of landslide areas. A study area located at Lugnano in Teverina (Umbria Region, Italy) and interested by landslides triggered by heavy rainfall and affecting important railway and road networks, was considered. A geological field survey has been carried out (including in situ and laboratory tests) in order to define strength parameters to be used in the stability analysis, for the detection of the most active area (residual risk) and implementation of preliminary design. In order to identify landslide surface and estimate the involved volumes, 3D laser scanner acquisition has been performed at different times. The obtained results stress the importance of performing different analysis in the light of reducing the impact of landslides on critical infrastructures by promoting low-environmental and sustainable solutions.

Integration of Geophysical Investigation to Landslide Analysis in the Archaeological Site of Stabiae (Italy)

The complex of the Roman villas of the ancient Stabiae is located over a morphological terrace near the edge of a steep slope that separates the archaeological site from the urban area of Castellammare di Stabia (Gulf of Naples). The hill is being affected by debris and earth flows that have endangered some ancient structures of the complex. The present work has reconstructed the slope dynamics and causes by means of a geomorphological and geotechnical approach coupled with geophysical investigation. A slope stability modelling, calibrated with landslide historical information and direct survey, has provided main failure mode and magnitude of recent events. Geophysical investigation has permitted to analyse the state of superficial terrains under prominent archaeological structures, providing important information on potential failure surfaces that can be mobilised in the near future in the lack of urgent mitigation measures in the most hazardous sectors of the slope.