Paolo Tommasi - Academia.edu (original) (raw)

Papers by Paolo Tommasi

Abstract The WLF3 B5.Session Monitoring, prediction and warning of landslides, as a part of WLF3 ... more Abstract The WLF3 B5.Session Monitoring, prediction and warning of landslides, as a part of WLF3 session Group B Sessions for Methods of Landslide Studies, gathers the main elements in the landslides risk reduction and landslides sustainable disaster management: monitoring, prediction and warning of landslides. Sixteen contributions from eleven countries around the world have been submitted and, after a review process, accepted for publishing. The best practice techniques and experiences on monitoring, prediction and warning of landslides caused by different triggering factors are presented in this Session. In this introduction to the WLF3 B5 Session Monitoring, prediction and warning of landslides, a short summary of each of the accepted papers is presented, dividedin terms of their general topics. Keywords landslides, monitoring, equipment, measurement, prediction, early warning system Monitoring, prediction and warning of landslides The WLF3 B5 Session Monitoring, prediction and warning of landslides, as a part of Group B Sessions for Methods of Landslide Studies, gathers the main elements in the landslides risk reduction and landslides sustainable disaster management: monitoring, prediction and warning of landslides. In landslides risk reduction and sustainable disaster management, the main roles have three closely connected elements: monitoring, prediction and warning of landslides. The monitoring of existing landslides, as well as locations susceptible to possible landsliding, using different techniques to produce the basic data for landslide prediction. Predictions of landslide occurrences should be based on a deep understanding of all processes which lead to slope failures in soil and rock mass slopes and their relationships with available measured monitoring data. Early warning systems, based on landslide monitoring results and landslide prediction, are the most economical landslide risk reduction measure. In this Session, the states of the art, best practice techniques and overall experiences in monitoring, prediction and warning of landslides caused by different triggering factors in different parts of the world are presented. Sixteen contributions from eleven countries (Brazil, China, Croatia, Hong Kong, India, Indonesia, Italy, Korea, Malaysia, Slovenia and United Kingdom) have been submitted and, after review process, accepted for publishing in this session. These contributions can be divided in the following general topics: • Technological developments; • Monitoring of landslides; • Early warning systems based on measurements of landslide displacements and soil properties, • Early warning systems based on rainfall monitoring and hydrological models; • Warning and emergency management. In this introduction to the WLF3 B5 Session Monitoring, prediction and warning of landslides, a short summary of each of the accepted papers is presented within previously defined general topics.

Journal of Volcanology and Geothermal Research, May 1, 2009

Focusing on the Island of Stromboli, this research investigates whether airborne remote sensing s... more Focusing on the Island of Stromboli, this research investigates whether airborne remote sensing systems, such as those based on digital photogrammetry and laser scanner sensors, can be adopted to monitor slope deformation and lava emplacement processes in active volcanic areas. Thanks to the capability of extracting accurate topographic data and working on flexible time schedules, these methods can be used

The paper initially reviews major issues of slope instability at active volcanoes on the basis of... more The paper initially reviews major issues of slope instability at active volcanoes on the basis of geotechnical and engineering geology literature. A detailed discussion is then provided with reference to two case studies on Italian insular active volcanoes: Stromboli and La Fossa (Vulcano Island). At Stromboli, the role of magma intrusion in initiating the instability phenomena associated to major eruptions and the particular mechanical behaviour of the volcaniclastic deposits in controlling the 2002 submarine failure are investigated by means of numerical and conceptual models based on an extensive geotechnical characterization. At La Fossa, the influence of flank erosion, hydrothermal alteration, and anomalous pore pressures produced by hydrothermal activity on the evolution of the NE sector of the volcanic edifice are described with the aid of numerical analyses based on laboratory and in situ investigations

Journal of Geotechnical and Geoenvironmental Engineering, Feb 1, 2010

During the 2002 eruption, the NW flank of Stromboli volcano (Southern Italy) experienced large la... more During the 2002 eruption, the NW flank of Stromboli volcano (Southern Italy) experienced large landslides that produced tsunami waves with a maximum runup of 10 m in height. This paper focuses on the geomechanical behavior of the loose volcaniclastic layers, the weakest component of the deposit forming the volcano flank. Tests on the coarse-grained volcaniclastic soil and on the rock material forming the grains were conducted in dry conditions, a feature of the subaerial slope. The rock material, in spite of its high porosity, exhibits relatively high stiffness and strength due to the remarkable continuity of the solid skeleton. Accordingly, the volcaniclastic soil is characterized by high shear strength. During shear tests, however, significant grain crushing occurs, which partly explains the nonlinear shear strength envelope and the strain softening associated with contractive behavior. Grain crushing was also found to affect compressibility and its time dependency, investigated under oedometric conditions.

Landslides, May 26, 2009

The island of Stromboli (Southern Italy) is a 4,000 m high volcanic edifice about 900 m above sea... more The island of Stromboli (Southern Italy) is a 4,000 m high volcanic edifice about 900 m above sea level. Most of the NW flank is formed by a wide scar (Sciara del Fuoco) filled by irregular alternations of volcaniclastic layers and thin lava flows. Between 29 th and 30 th December 2002, the Sciara del Fuoco slope was involved in a submarine and a subaerial retrogressive landslides,causing two tsunami waves with a maximum run-up of 10 m. Mechanisms underlying the rapid submarine landslide and the preceding slower deformation of the subaerial and submarine slope were investigated through large-scale ring shear tests on the saturated and dry volcaniclastic material. The shear behaviour of the material under different drainage conditions was analyzed during tests conducted at DPRI (Kyoto University). Pore pressure generation, mobilized shear strength and grain crushing, within a range of displacements encompassing the different stages of evolution of the slope, were considered. Experimental results indicate that, even at higher displacements, shear strength of the dry material explains the virtual stability of the slope. Conversely, full or partial liquefaction can be invoked to explain the submarine failure and the subsequent long run-out (more than 1,000 m) of the failed materials.

Journal of Geophysical Research, Oct 4, 2008

Geophysical monograph, Mar 19, 2013

... According to the reconstructed sequence, 2 days after the beginning of the eruption, the uppe... more ... According to the reconstructed sequence, 2 days after the beginning of the eruption, the upper part of the NE sector of the SdF slope experienced major displacements (few tens of meters). ... Mots-clés anglais / English Keywords. Mediterranean Sea. ; West Mediterranean. ; ...

Canadian Geotechnical Journal, Nov 1, 2009

Canadian Geotechnical Journal, 2006

The medieval town of Orvieto is built on the top of a pyroclastic slab overlying a gentle slope o... more The medieval town of Orvieto is built on the top of a pyroclastic slab overlying a gentle slope of overconsolidated clays. The clayey slope has been constantly affected by landslide phenomena in the form of slow movements and failure events, which in turn have periodically caused instability of the marginal areas of the pyroclastic slab. Since 1982 a number of Casagrande-type piezometers and inclinometers were installed in the northern slope of the Orvieto hill within the area that was involved in the huge Porta Cassia landslide in 1900. In this paper, after a brief description of the geology and the geotechnical properties of the slope, data obtained through the monitoring system are illustrated. Piezometric data are utilized to develop a conceptual model of the hydraulic conditions in the clayey slope, and inclinometer measurements are interpreted and correlated with the geotechnical ground profile and slope morphology to understand the present complex evolution of the clayey slope. Finally, the strong correlation among the rainfall regime, the piezometric levels, and the rate of movements is discussed, and the recurrence periods of critical cumulative rainfall on displacement trends are estimated on the basis of statistical methods.Key words: overconsolidated clays, slope movements, piezometric levels, rainfall.

Cambridge University Press eBooks, Aug 23, 2012

Taylor & Francis eBooks, Jul 13, 2007

Volcanic activity in the island of Vulcano is concentrated in the area of La Fossa cone, whose NE... more Volcanic activity in the island of Vulcano is concentrated in the area of La Fossa cone, whose NE sector is affected by deep-seated deformations and shallow failures along bedding planes. Quantitative data from laboratory investigations, borehole core logging and in-situ surveys were used for the analysis of instability phenomena and to assess their relationship with volcanic activity. The influence of the marine erosion along the sides of the NE sector on the state of stress and deformation of the volcanic edifice was evaluated by means of 3D numerical analyses based on the geological and geomechanical investigations

Marine Georesources & Geotechnology, Jul 1, 1998

The geotechnical properties of the fine‐grained sediments of the Tiber River prodelta slope are d... more The geotechnical properties of the fine‐grained sediments of the Tiber River prodelta slope are described. Laboratory investigations depict the overall physical and mechanical behavior of the sediments and give information regarding their in‐situ conditions due to gravitational campaction. In spite of relative homogeneity in terms of the basic geotechnical properties, noticeable differences between materials sampled at different water depths and

Landslides, Feb 13, 2019

Several shallow landslides occurred at La Fossa cone (Vulcano Island, Aeolian Archipelago, Italy)... more Several shallow landslides occurred at La Fossa cone (Vulcano Island, Aeolian Archipelago, Italy) in the last 30 years, during both unrests and periods of quiet volcanic activity. The main event occurred in 1988, during a volcanic unrest, when a landslide collapsed into the sea from the NE flank of La Fossa cone, producing a small tsunami. Hydrothermal activity has been suggested as a potential trigger for landslide generation in this area. However, no specific investigations were carried out to test this hypothesis. With the aim of filling this gap, we studied the mineralogy and hydraulic conductivity of La Fossa cone deposits, the relationships between shallow hydrothermal circulation and rainfall dynamics and their role in triggering slope failures. We also measured rainfall rate, volumetric soil moisture content and soil suction at two automated stations installed in areas with and without active hydrothermal circulation. We found that hydrothermally altered low-conductivity materials show higher background water contents and lower soil suctions than pristine deposits, and their water content is modulated by impulsive increments following rainfalls. This behaviour is due to the combination of lower permeability and direct condensation of hydrothermal vapour. We conclude that shallow hydrothermal circulation produces conditions for slope failures following transients in soil moisture content caused by rainfall infiltration. These considerations allow to identify the areas immediately NW and SE of the 1988 landslide as the most prone to future mass movements.

Springer eBooks, Dec 26, 2005

ABSTRACT

ISRM International Symposium - EUROCK 2002, 2002

... Rome, ITALY, paolo.tommasi@uniromal.it RIBACCHI, RENATO DISC - University "La Sapienza&q... more ... Rome, ITALY, paolo.tommasi@uniromal.it RIBACCHI, RENATO DISC - University "La Sapienza", Rome, ITALY, renato.ribacchi@uniromal.it ABSTRACT ... 2). A detailed description of measurement and processing procedures is reported by Cardarelli et al. (2002). Vs. ...

International Journal of Earth Sciences, Mar 31, 2020

Small-scale landslides affecting insular and coastal volcanoes are a relevant geohazard for the s... more Small-scale landslides affecting insular and coastal volcanoes are a relevant geohazard for the surrounding infrastructures and communities, because they can directly impact them or generate local but devastating tsunamis, as demonstrated by several historical accounts. Here, a review of such landslides and associated predisposing/triggering mechanisms is presented, with particular reference to the submarine volcanic flanks. We take into account, as a case study, the instability phenomena occurring on the Sciara del Fuoco (SdF, hereafter), a 2-km wide subaerial-submarine collapse scar filled by volcaniclastic products, which form the NW flank of the Stromboli volcano. Because of its steepness (> 30°) and the high amount of loose volcanic material funneled from the summit crater towards the sea, the submarine part of the SdF is prone to instability phenomena recurring at different spatial and temporal scale. Particularly, landsides with a volume of some millions of cubic meters, as the 2002 tsunamigenic landslide, can repeatedly affect the submarine slope. Based on the integration of 11 years (2002-2013) of morpho-bathymetric monitoring of the SdF with geotechnical characterization of volcaniclastic and lava flow materials, stability analyses of the subaerial and submarine slope and previous literature studies, we analyze the role of different triggering mechanisms in controlling the occurrence and size of submarine slope failures at the SdF, such as dykes intrusion as occurred in 2002 or the emplacement of a large delta as occurred in 2007.

Natural Hazards and Earth System Sciences, Mar 22, 2023

Among the almost 1400 landslides triggered by the shocks of the 2016-2017 central Italy seismic s... more Among the almost 1400 landslides triggered by the shocks of the 2016-2017 central Italy seismic sequence, only a limited number, all classifiable as rockslides, involved volumes larger than 1000 m 3. Four of these failures, including the three largest among the documented landslides, were described in terms of structural and geomechanical investigations in a previous paper. In this study, the estimated acceleration time histories at the rockslide sites were evaluated through a 2D simplified numerical model accounting for the attenuation phenomena and for the topographic effect of the rock cliffs from which the slide detached. Instantaneous stability analyses were carried out to obtain insights into the variability of the instantaneous margin of safety along the motion, over the entire spectrum of mechanisms that could be activated. Finally, some general suggestions on the pseudostatic verification method for 3D cases are proposed, which represent useful indications to hazard evaluation at local and regional scales.

CRC Press eBooks, Sep 29, 2022

Encyclopedia of earth sciences, 2018