421 results on '"Jaboyedoff, Michel"'
Search Results
402. Jakarta: Mumbai—Two Megacities Facing Floods Engaged in a Marginalization Process of Slum Areas
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Texier-Teixeira, Pauline, Edelblutte, Emilie, Sudmeier-Rieux, Karen, editor, Fernández, Manuela, editor, Penna, Ivanna M., editor, Jaboyedoff, Michel, editor, and Gaillard, J.C., editor
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- 2017
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403. Overcoming Land Tenure Barriers in Shelter and Other Reconstruction Activities in Post-disaster Settings
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Jahn, Ina Rehema, Guadagno, Lorenzo, Gandia, Ethel, Bonnefoy, Valentin, Sudmeier-Rieux, Karen, editor, Fernández, Manuela, editor, Penna, Ivanna M., editor, Jaboyedoff, Michel, editor, and Gaillard, J.C., editor
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- 2017
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404. The Necessity of Early Warning Articulated Systems (EWASs): Critical Issues Beyond Response
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Alcántara-Ayala, Irasema, Oliver-Smith, Anthony, Sudmeier-Rieux, Karen, editor, Fernández, Manuela, editor, Penna, Ivanna M., editor, Jaboyedoff, Michel, editor, and Gaillard, J.C., editor
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- 2017
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405. Human Mobility in a Socio-Environmental Context: Complex Effects on Environmental Risk
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Guadagno, Lorenzo, Sudmeier-Rieux, Karen, editor, Fernández, Manuela, editor, Penna, Ivanna M., editor, Jaboyedoff, Michel, editor, and Gaillard, J.C., editor
- Published
- 2017
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406. Dike Risk: Revealing the Academic Links Between Disaster Risk Reduction, Sustainable Development, Climate Change, and Migration
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Pigeon, Patrick, Sudmeier-Rieux, Karen, editor, Fernández, Manuela, editor, Penna, Ivanna M., editor, Jaboyedoff, Michel, editor, and Gaillard, J.C., editor
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- 2017
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407. Disaster Risk Reduction in the Era of 'Homeland Security': The Struggle for Precautionary, Preventive, and Non-violent Approaches
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Hewitt, Kenneth, Sudmeier-Rieux, Karen, editor, Fernández, Manuela, editor, Penna, Ivanna M., editor, Jaboyedoff, Michel, editor, and Gaillard, J.C., editor
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- 2017
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408. Passive radio-frequency identification ranging, a dense and weather-robust technique for landslide displacement monitoring.
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Le Breton, Mathieu, Baillet, Laurent, Larose, Eric, Rey, Etienne, Benech, Philippe, Jongmans, Denis, Guyoton, Fabrice, and Jaboyedoff, Michel
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RADIO frequency identification systems , *WIRELESS sensor networks , *SLOPE stability , *ARTIFICIAL satellite tracking , *GEODETIC observations - Abstract
Abstract Ground deformation monitoring at a local scale requires accuracy, along with dense spatio-temporal resolution. Radio-Frequency Identification (RFID) technology is proposed as an alternative to classical geodetic methods for monitoring displacements of a landslide. Passive RFID tags allow for a very dense resolution, both in time and space, at the scale of a 100-m-long surface. By deploying 19 passive RFID tags on a landslide for 5 months, this study validates the technique by comparison with laser total station and wire extensometer data. The accuracy of the RFID technique was 1 cm during normal weather and up to 8 cm during snow events. The results demonstrate that RFID tag tracking can monitor landslide displacements with multiple sensors at low cost, providing dense spatio-temporal data. This technique could potentially be used for other applications such as monitoring volcanic activity, buildings, unstable rocks or snow cover. Highlights • Passive RFID is a new method to monitor surface displacements on a landslide. • RFID works across vegetation, fog, rain and snowfall. • This first prototype allows for a wireless monitoring at a range of 60 m. • Displacement accuracy reaches 1 cm in general and 8 cm with a snow cover. • Low-cost RFID tag network provides data with high spatio-temporal resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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409. Influence of environmental parameters on the seismic velocity changes in a clayey mudflow (Pont-Bourquin Landslide, Switzerland).
- Author
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Bièvre, Grégory, Franz, Martin, Larose, Eric, Carrière, Simon, Jongmans, Denis, and Jaboyedoff, Michel
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MUDFLOWS , *SEISMIC wave velocity , *CLAY soils , *LANDSLIDES , *RAINFALL - Abstract
Abstract An earthflow/mudflow of a few thousand cubic metres occurred at the toe of the Pont-Bourquin Landslide (PBL, Swiss Alps) in late August 2010. This event was preceded by a drop of about 6% in surface wave velocity (dV/V) determined from ambient vibration records. A seismic monitoring system made of three pairs of sensors was re-installed across the transportation and accumulation zones of the landslide in October 2011, allowing daily relative changes in seismic velocity to be measured for a period of 4.5 years. No similar drop in dV/V was observed during this period, consistently with the lack of significant landslide acceleration or earthflow/mudflow events. However, the three dV/V time series showed periodic and reversible variations in a range − 2% to 2%, suggesting a probable influence of seasonal parameters. They were cross-correlated to daily environmental (temperature and rainfall) and surface displacement time series. In the long term (yearly scale), dV/V variations are mainly driven by the temperature with short delays (30 to 50 days) indicating that the shallow layer (first 2 m) controls the dV/V variations. In the short term, the landslide response to precipitations exhibits a small decrease in dV/V with a delay of 2 to 5 days, in contrast with the displacement rate that almost instantaneously responds to the rainfall. The continuous seismic monitoring of PBL using ambient vibrations has proved to be a robust method for getting information at depth, with no data gap even during winters. The seasonal reversible seismic velocity variations turned out to be in a range lower than the drop observed before the August 2010 earthflow/mudflow, highlighting the interest of incorporating the dV/V technique in monitoring systems. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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410. Land use changes, landslides and roads in the Phewa Watershed, Western Nepal from 1979 to 2016.
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Vuillez, Cindy, Tonini, Marj, Sudmeier-Rieux, Karen, Devkota, Sanjaya, Derron, Marc-Henri, and Jaboyedoff, Michel
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LAND cover , *LAND use , *LANDSLIDES , *WATERSHEDS , *RAINFALL , *HYDROLOGIC cycle - Abstract
This paper details an investigation of land use/land cover changes (LULCC) for the period 1979–2016 in the Phewa Lake area watershed in Western Nepal based on an analysis of aerial photos, satellite images and ground-based observations. The main objective is to document LULCC with regards to forest, agriculture, built-up areas and roads in order to understand how sources of erosion have evolved during the investigated period. Results demonstrate that LULCC have led to a shift of active erosion areas from grazing zones around streams and forests in the northern part of the watershed to a much greater number of small failures along unplanned earthen rural roads, which have hugely increased in the watershed. The extreme rainfall event that occurred in July 2015 trigged a large number of small and large landslides, as prior to this date only 14 landslides were observed in the watershed compared with 174 after the event. More than 40% of newly triggered landslides intersect a road and 84% of them are located within a distance of 40 meter from a road. Roads are thus influencing slope stability through slope cutting, concentrating surface water, thus changing hydrological patterns, which are destabilizing upper slopes. This study quantifies observable trends of erosion in Phewa watershed, which are important for more sustainable management of rural road construction. Greater enforcement of regulations on road construction and more sustainable land management practices are required to reduce further environmental and economic impacts in Phewa Lake watershed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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411. The role of tectonic deformation on rock avalanche occurrence in the Pampeanas Ranges, Argentina.
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Penna, Ivanna M., Abellán, Antonio, Humair, Florian, Jaboyedoff, Michel, Daicz, Sergio, and Fauqué, Luis
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PLATE tectonics , *ROCK deformation , *STRUCTURAL geology , *PHOTOGRAMMETRY - Abstract
Both tectonic and long-term gravitational slope deformation in several mountain settings have been shown to be key drivers of large-scale slope instability. The roles of both mechanisms are investigated in this study of the Potrero de Leyes rock avalanche, one of the largest and better preserved slope failures in the Pampeanas ranges in Argentina. This rock avalanche involved 0.25 km 3 of highly fractured granitic rocks cropping out on an uplifted planation surface. The rock avalanche left a lobate deposit up to ~ 4 km run out into the piedmont. A field survey, 3D terrestrial LIDAR, photogrammetry, and gigapixel panoramic photos allowed us to map the structures on the headscarp and on the planation surface. We observed a dense network of fractures with joints sets striking NNE-SSW, ENE-WSW, and NW-SE, respectively representing foliation, Riedel, and anti-Riedel structures that developed during the Paleozoic, as suggested by previous studies. The decrease of rock mass strength caused by tectonic fracturing, the exposure of those highly fractured rocks along a tectonically active mountain front, and potential deep-seated gravitational deformation occurring along NNE-SSW foliation planes along the mountain front suggest that tectonic and gravitational processes were key causal factors leading to the occurrence of the Potrero de Leyes rock avalanche. [ABSTRACT FROM AUTHOR]
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- 2017
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412. Evidence of rock slope breathing using ground-based InSAR.
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Rouyet, Line, Kristensen, Lene, Derron, Marc-Henri, Michoud, Clément, Blikra, Lars Harald, Jaboyedoff, Michel, and Lauknes, Tom Rune
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ROCK slopes , *ROCKSLIDES , *INTERFEROMETRY , *SYNTHETIC aperture radar , *GROUNDWATER - Abstract
Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) campaigns were performed in summer 2011 and 2012 in the Romsdalen valley (Møre & Romsdal county, western Norway) in order to assess displacements on Mannen/Børa rock slope. Located 1 km northwest, a second GB-InSAR system continuously monitors the large Mannen rockslide. The availability of two GB-InSAR positions creates a wide coverage of the rock slope, including a slight dataset overlap valuable for validation. A phenomenon of rock slope breathing is detected in a remote and hard-to-access area in mid-slope. Millimetric upward displacements are recorded in August 2011. Analysis of 2012 GB-InSAR campaign, combined with the large dataset from the continuous station, shows that the slope is affected by inflation/deflation phenomenon between 5 and 10 mm along the line-of-sight. The pattern is not homogenous in time and inversions of movement have a seasonal recurrence. These seasonal changes are confirmed by satellite InSAR observations and can possibly be caused by hydrogeological variations. In addition, combination of GB-InSAR results, in situ measurements and satellite InSAR analyses contributes to a better overview of movement distribution over the whole area. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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413. Estimating rockfall and block volume scenarios based on a straightforward rockfall frequency model.
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Moos, Christine, Bontognali, Zeno, Dorren, Luuk, Jaboyedoff, Michel, and Hantz, Didier
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ROCKFALL , *ECONOMIES of scale , *RISK assessment , *BLOCK codes - Abstract
Rockfall causes a large number of accidents and fatalities in steep environments. A realistic quantification of rockfall risk is thus crucial for an effective prevention of damages and loss of lives. The estimation of rockfall and block volumes for different return periods thereby remains a major challenge. In this paper, we present a straightforward rockfall frequency model (RFM: Rockfall Frequency Model) and its application at 8 different sites at 7 locations in the Swiss Alps. The RFM assumes that the magnitude-frequency relationships of rockfall events and blocks follow a power law. The parameters of this distribution are estimated based on a simple classification of rock structures and on field inventories. Beside the block volume frequency, which is very sensitive to the consideration of large rockfall events, the frequency of rockfalls with at least one block with a minimum volume, is determined. The block size distributions measured in this study were well captured by power laws. The rockfall and block volumes calculated with the RFM were generally slightly higher than the scenarios of the official hazard assessments. The uncertainty analysis, however, revealed a high variability of the release scenarios with respect to the parameters of the RFM, increasing with the return period. Both, the rockfall volumes and the block volumes, are particularly sensitive to the estimated exponent of the power law distribution of the rockfall events. Nevertheless, the proposed RFM provides an objective and transparent approach to derive magnitude-frequency relationships of rockfall events and individual blocks even if historical inventories are missing or insufficient and is thus a promising alternative to merely expert-based approaches. • A straightforward rockfall frequency model allows for an objective estimation of rockfall and block release frequencies. • Block size distributions measured in the field were well fitted by power laws. • The uncertainty in the calculated release scenarios increases with the return period. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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414. Correction of terrestrial LiDAR intensity channel using Oren–Nayar reflectance model: An application to lithological differentiation.
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Carrea, Dario, Abellan, Antonio, Humair, Florian, Matasci, Battista, Derron, Marc-Henri, and Jaboyedoff, Michel
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LIDAR , *REFLECTANCE , *PETROLOGY , *BACKSCATTERING , *SIGNAL processing - Abstract
Ground-based LiDAR has been traditionally used for surveying purposes via 3D point clouds. In addition to XYZ coordinates, an intensity value is also recorded by LiDAR devices. The intensity of the backscattered signal can be a significant source of information for various applications in geosciences. Previous attempts to account for the scattering of the laser signal are usually modelled using a perfect diffuse reflection. Nevertheless, experience on natural outcrops shows that rock surfaces do not behave as perfect diffuse reflectors. The geometry (or relief) of the scanned surfaces plays a major role in the recorded intensity values. Our study proposes a new terrestrial LiDAR intensity correction, which takes into consideration the range, the incidence angle and the geometry of the scanned surfaces. The proposed correction equation combines the classical radar equation for LiDAR with the bidirectional reflectance distribution function of the Oren–Nayar model. It is based on the idea that the surface geometry can be modelled by a relief of multiple micro-facets. This model is constrained by only one tuning parameter: the standard deviation of the slope angle distribution ( σ slope ) of micro-facets. Firstly, a series of tests have been carried out in laboratory conditions on a 2 m 2 board covered by black/white matte paper (perfect diffuse reflector) and scanned at different ranges and incidence angles. Secondly, other tests were carried out on rock blocks of different lithologies and surface conditions. Those tests demonstrated that the non-perfect diffuse reflectance of rock surfaces can be practically handled by the proposed correction method. Finally, the intensity correction method was applied to a real case study, with two scans of the carbonate rock outcrop of the Dents-du-Midi (Swiss Alps), to improve the lithological identification for geological mapping purposes. After correction, the intensity values are proportional to the intrinsic material reflectance and are independent from range, incidence angle and scanned surface geometry. The corrected intensity values significantly improve the material differentiation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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415. From the source area to the deposit: Collapse, fragmentation, and propagation of the Frank Slide.
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Charrière, Marie, Humair, Florian, Froese, Corey, Jaboyedoff, Michel, Pedrazzini, Andrea, and Longchamp, Céline
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GEOMORPHOLOGICAL research , *ROCK deformation , *STRUCTURAL geology , *ELASTIC wave propagation , *REMOTE sensing - Abstract
The combination of structural data from the source area and descriptive data from the deposit's carapace, as well as remote sensing and statistical analysis, allows a better understanding of the collapse, fragmentation, and propagation processes of the Frank Slide rock avalanche. The in situ observed conservation of the stratigraphic sequence of the Turtle Mountain anticline's normal limb in the deposit is interpreted as the consequence of the collapse mode, involving simple shearing of the mass accompanied by a rotational movement, i.e., a "simple shear" parallel to the topography, and a breakage of the hinge, followed by overthrusting of the normal limb on the inverse limb. Coherence between the block size distributions of the source area and the deposit carapace is interpreted as a demonstration of the primary control of preexisting fracturing on the fragmentation processes. Remote-sensing indexes allow us to uncover a priori hidden morphological features preserved on the surface of the deposit, i.e., longitudinal and compressional features, as well as lobes. Their location on the carapace provides evidence of lateral heterogeneity in the propagation, highlighted by three different types of propagation behaviors. This comprehensive study not only provides elements that contribute to an understanding of the Frank Slide rock avalanche, but it also provides insight into essential parameters to take into account in further modeling of these types of phenomena. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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416. Building Farm Resilience in a Changing Climate: Challenges, Potentials, and Ways Forward for Smallholder Cocoa Production in Bolivia
- Author
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Stephan Rist, Maria Isabel Pillco, Monika Schneider, Johanna Jacobi, Patrick Bottazzi, Sudmeier-Rieux, Karen, Fernández, Manuela, Penna, Ivanna M., Jaboyedoff, Michel, and Gaillard, J.G.
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Bolivia ,010504 meteorology & atmospheric sciences ,Disaster risk reduction ,Land use ,Agroforestry ,business.industry ,Cash crop ,Environmental aspects ,Context (language use) ,04 agricultural and veterinary sciences ,Organic certification ,01 natural sciences ,Geography ,Agriculture ,Soil retrogression and degradation ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Crop husbandry ,Resilience (network) ,business ,0105 earth and related environmental sciences - Abstract
Migration from the Bolivian Altiplano to the Amazonian lowlands poses a number of challenges related to climate change adaptation and disaster risk reduction. Alto Beni, located in the Bolivian Yungas at the interface between two altitudinal zones, is a critical area in this respect. Unsustainable land use practices are leading to soil erosion, shallow landslides, as well as forest and biodiversity loss. Settlers from the Altiplano see themselves confronted with an ecosystem that does not support the agricultural systems they were once used to. Soil degradation and government incentives have promoted migration further into the rainforest, creating pressure on local indigenous groups and biodiversity. The best-suited land use system for the fragile soils and ecosystems in Alto Beni is diversified agroforestry, which is often combined with a cash crop such as cocoa or coffee. Many farmers practising such a system have organic certification and achieve a premium price for their cash crops. However, cocoa farmers in Alto Beni face many challenges. Prolonged droughts, heavy rains, floods, increased heat, and plant diseases are mentioned most by cocoa farmers. In this study we compile results from a research project on the resilience of organic and nonorganic cocoa farms to external risk factors and discuss them in the context of climate change adaptation, disaster risk reduction, and migration. Cocoa farmers who belong to a cooperative and had organic certification achieved higher resilience indicators than others, because they tended to cultivate cocoa in diversified agroforestry systems. Cooperatives fostered agroforestry through capacity-building, knowledge exchange, extension services, and awareness-raising. They also provided social insurances and enhanced mutual support among their members. Challenges within established cooperatives such as lack of technical support to farmers and knowledge exchange within and between organizations can hamper resilience building. Finally, the inclusion of new farmers into cocoa cooperatives seems critical to reducing outmigration and the reproduction of non-sustainable practices in other fragile areas. Multiple challenges remain to be addressed, however, including the enhancement of solidarity economy networks and their extension sectors other than export crops.
- Published
- 2017
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417. Quantifying 40 years of rockfall activity in Yosemite Valley with historical Structure-from-Motion photogrammetry and terrestrial laser scanning.
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Guerin, Antoine, Stock, Greg M., Radue, Mariah J., Jaboyedoff, Michel, Collins, Brian D., Matasci, Battista, Avdievitch, Nikita, and Derron, Marc-Henri
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OPTICAL scanners , *DIGITAL photogrammetry , *PHOTOGRAMMETRY , *ROCKFALL , *ROCKSLIDES , *VALLEYS , *VOLUME measurements - Abstract
Rockfalls and rockslides are often dominant geomorphic processes in steep bedrock landscapes, but documenting their occurrence can be challenging, requiring frequent monitoring and well resolved spatial data. Repeat application of remote sensing methods such as Terrestrial Laser Scanning (TLS) and Structure-from-Motion (SfM) photogrammetry can detect even very small rockfalls, but typically these acquisitions span only years and may not record rockfall activity representative of longer-term rates of cliff erosion. Inventory databases can extend rockfall records, but are commonly incomplete and prone to observation bias. We employed TLS and SfM on two adjacent cliffs (El Capitan and Middle Brother) in Yosemite Valley, integrating semi-annual data collections from 2010 to 2017 with "historical" (archival) SfM models derived from oblique photographs taken in 1976. Comparing the 1976 SfM models against more recent data allows for more accurate and precise rockfall detection and volume measurement over a 40-year period. Change detection indicates that 235 rockfalls occurred from the two cliffs, more than twice as many events as are recorded in Yosemite's inventory database. Although individual rockfall volumes reported in the inventory database vary from those measured by SfM-TLS, reported cumulative volumes are similar to measured volumes, likely because the large-volume events that account for most of the cumulative volume tend to be widely observed and well-documented. Volume-frequency relationships indicate that the cliffs erode predominantly by less frequent, larger-volume rockfalls, at rates of 0.9 to 1.7 mm/yr. Our study demonstrates how integrated SfM and TLS measurements, especially utilizing SfM models derived from historical imagery, allow detection and quantification of rockfalls spanning several decades, complementing and improving inventory databases, informing rockfall hazard assessment, and providing longer-term rates of cliff erosion. • 1976's photographs yielded high-resolution models of two cliffs in Yosemite Valley. • "Historical" models were compared to terrestrial lidar data acquired in 2010/2016. • 235 rockfalls were detected from the two monitored cliffs over a 40-year period. • Both cliffs experienced twice as many rockfalls as are recorded in the database. • Rockfall volume-frequency relationships indicate erosion rates of 0.9 to 1.7 mm/yr. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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418. Rockfall susceptibility assessment of carbonatic coastal cliffs, Palinuro (Southern Italy)
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Michel Jaboyedoff, Antonio Pignalosa, Antonio Santo, Valerio Sorrentino, Antonio Abellán, Battista Matasci, Ermanno Marino, Santo, Antonio, Pignalosa, Antonio, Marino, Ermanno, Jaboyedoff, Michel, Abellan, Antonio, Matasci, Battista, and Sorrentino, Valerio
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geography ,Discontinuity (geotechnical engineering) ,Rockfall ,geography.geographical_feature_category ,Tourist attraction ,Point cloud ,Cliff ,Geology ,Arch ,Spatial distribution ,Geomorphology - Abstract
This short note presents an approach to assess rockfall susceptibility based on terrestrial laser scanner (TLS) point cloud data at the cliff scale. The test area is coastal cliff situated in the southern part of the Campania Region (Centola Municipality, SW Italy), in which a natural arch was formed. Since this coastal area constitutes an important tourist attraction, a large number of people rest on a daily basis beneath the cliffs, increasing considerably the risk associated to rockfalls. The Terrestrial Laser Scanner (TLS) survey of the cliff was realized in june 2015. A structural analysis of the cliff was performed on the point cloud using Coltop 3D software. The different characteristics defining the discontinuity sets were extracted, including orientation, spacing and persistence. The kinematically unstable areas were mapped using a script that computes an index of susceptibility to rockfalls based on the spatial distribution of failure mechanisms. Results show that the kinematically feasible failures are not equally distributed along the cliff. The most important discontinuity set in terms of potential planar failure is K10 (71/097), for the toppling is K1 (60/218). The combination of K10 and K1 has the highest value of susceptibility for wedge failure.
- Published
- 2016
419. Risk and Global Change: Developing scientific methods for advocacy and awareness raising
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Peduzzi, Pascal and Jaboyedoff, Michel
- Subjects
Déclin des écosystèmes ,Changement climatique ,Modèles ,Télédétection ,Aléas naturels ,Système d'information géographique ,Changement environnemental global ,Risque - Abstract
Le risque de catastrophes résulte de l'intersection entre aléas, exposition et vulnérabilité. Chacune de ses composantes pouvant changer, le risque est dynamique et doit être réévalué périodiquement par les gouvernements, les assurances ou les agences de développement. Les recherches présentées ici ont été mandatées par les Nations Unies et par des agences œuvrant dans le développement et l'environnement. Les méthodes sont basées sur les systèmes d'information géographique, la télédétection, les bases de données et l'analyse statistique. Un modèle de risque global a été élaboré pour révéler la distribution des aléas, de l'exposition et des aléas, ainsi que pour l'identification des facteurs de risque sous-jacent de plusieurs aléas. Au niveau local, la méthode a été testée pour mettre en évidence l'influence du changement climatique et du déclin des écosystèmes sur l'aléa.
- Published
- 2012
420. Structural control of multi-scale discontinuities on slope instabilities in crystalline rock
- Author
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Molina, Freddy X.Y., Loew, Simon, and Jaboyedoff, Michel
- Subjects
DIGITAL ELEVATION MODELS + DIGITAL TERRAIN MODELS (GEODÄSIE) ,GEOGRAPHICAL INFORMATION SYSTEM ,ROCK MECHANICS (CIVIL ENGINEERING) ,MATTERTAL (CANTON OF VALAIS) ,NATURAL HAZARDS + NATURAL CATASTROPHES ,GNEIS (PETROGRAPHIE) ,GNEISS (PETROGRAPHY) ,STRUKTUR + TEXTUR + GEFÜGE (PETROGRAPHIE) ,FOLIATION (GEOLOGY) ,NATURGEFAHREN + NATURKATASTROPHEN ,STRUCTURE + TEXTURE + FABRICS (PETROGRAPHY) ,Earth sciences ,STEINSCHLAG (GEOMORPHOLOGIE) ,FELSMECHANIK (BAUINGENIEURWESEN) ,SCHIEFERUNG (GEOLOGIE) ,MATTERTAL (KANTON WALLIS) ,GEOGRAFISCHE INFORMATIONSSYSTEME ,DIGITAL ELEVATION MODELS + DIGITAL TERRAIN MODELS (GEODESY) ,ROCK-FALL + ROCK-SLIDE (GEOMORPHOLOGY) ,ddc:550 - Published
- 2010
421. Remote thermal detection of exfoliation sheet deformation.
- Author
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Guerin A, Jaboyedoff M, Collins BD, Stock GM, Derron MH, Abellán A, and Matasci B
- Abstract
A growing body of research indicates that rock slope failures, particularly from exfoliating cliffs, are promoted by rock deformations induced by daily temperature cycles. Although previous research has described how these deformations occur, full three-dimensional monitoring of both the deformations and the associated temperature changes has not yet been performed. Here we use integrated terrestrial laser scanning (TLS) and infrared thermography (IRT) techniques to monitor daily deformations of two granitic exfoliating cliffs in Yosemite National Park (CA, USA). At one cliff, we employed TLS and IRT in conjunction with in situ instrumentation to confirm previously documented behavior of an exfoliated rock sheet, which experiences daily closing and opening of the exfoliation fracture during rock cooling and heating, respectively, with a few hours delay from the minimum and maximum temperatures. The most deformed portion of the sheet coincides with the area where both the fracture aperture and the temperature variations are greatest. With the general deformation and temperature relations established, we then employed IRT at a second cliff, where we remotely detected and identified 11 exfoliation sheets that displayed those general thermal relations. TLS measurements then subsequently confirmed the deformation patterns of these sheets showing that sheets with larger apertures are more likely to display larger thermal-related deformations. Our high-frequency monitoring shows how coupled TLS and IRT allows for remote detection of thermally induced deformations and, importantly, how IRT could potentially be used on its own to identify partially detached exfoliation sheets capable of large-scale deformation. These results offer a new and efficient approach for investigating potential rockfall sources on exfoliating cliffs., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)
- Published
- 2021
- Full Text
- View/download PDF
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