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A major mining slope failure occurred in July 2012 on the East wall of the LAB Chrysotile mine in Canada. The major consequence of this failure was the loss of the local highway (Road 112), the main economic link between the region and the Northeast USA. This paper is part of a proposed integrated remote sensing-numerical modelling methodology to analyze mining rock slope stability. This paper presents the Light Detection and Ranging (LiDAR) monitoring of this slope failure. The main focus is the investigation of that rock slide using both terrestrial (TLS) and airborne (ALS) LiDAR scanning. Since 2010, four ALS and 14 TLS were performed to characterize and monitor the slide. First, laser scanning was used to investigate the geometry of the slide. The failure zone was 1100 m by 250 m in size with a mobilized volume of 25 hm. Laser scanning was then used to investigate the rock slide's 3D displacement, thereby enabling a better understanding of the sliding kinematics. The results clearly demonstrate the ability of the proposed approach to monitor and quantify large-scale rock mass failure. The slope was monitored for a period of 5 years, and the total displacement was measured at every survey. The maximum cumulative total displacement reached was 145 m. This paper clearly shows the ability of LiDAR scanning to provide valuable quantitative information on large rock mass failures involving very large displacements. [ABSTRACT FROM AUTHOR]

A major mining slope failure occurred in July 2012 on the East wall of the LAB Chrysotile mine in Canada. The major consequence of this failure was the loss of the local highway (Road 112), the main commercial link between the region and the Northeast USA. LiDAR scanning and subsequent analyses were performed and enabled quantifying the geometry and kinematics of the failure area. Using this information, this paper presents the back analysis of the July 2012 failure. The analyses are performed using deterministic and probabilistic limit equilibrium analysis and finite-element shear strength reduction analysis modelling. The impact of pit water infilling on the slope stability is investigated. The impact of the mining activity in 2011 in the lower part of the slope is also investigated through a parametric analysis. [ABSTRACT FROM AUTHOR]

Disturbed lacustrine deposits of eastern Canada have been associated with past seismic events in the intraplate Western Québec Seismic Zone (WQZ) and the Charlevoix–Kamouraska Seismic Zone (CKSZ). With five major earthquakes that occurred during historical times and hundreds of minor earthquakes, the CKSZ is the most active seismic zone in eastern Canada. Here we present new high-resolution multibeam bathymetric, subbottom profiler and sediment core data collected in Lake Témiscouata, southeastern Québec, the largest lake located within the influence of the CKSZ. The occurrence of mass-movements in the highly cohesive glaciolacustrine deposits of the lake produced a peculiar lacustrine landscape consisting of steep slide scars and residual mounds and very narrow residual crests. Our data indicate that postglacial times were marked by recurrent seismically-induced mass-movement events that cannot be individually identified in the sedimentary record due to the highly disturbed stratigraphy of the lake and to the absence of significant postglacial background sediments between events. The most recent recorded mass-movement is a distinct debris flow sediment layer on the lake floor that was deposited at ~ 1300 cal BP, very shortly after a distinct large-scale mass-movement event observed across the entire lake basin. The presence of silt layers in gyttja overlying these disturbed units suggests that the region was affected by other seismic events following this event, although no MMDs could be directly related to these layers. [ABSTRACT FROM AUTHOR]

The Charlevoix region, in southeastern Québec, is characterized by a dramatic landscape formed by the junction of the Laurentian Highlands, the Charlevoix Astrobleme and the St Lawrence Estuary. At the Last Glacial Maximum (LGM), the region was completely covered by the Laurentide Ice Sheet (LIS). The complex topography of the region was the stage of many of the major deglacial events of southern Quebec (e.g. Goldthwait Sea Invasion, St Lawrence Ice-Stream, Saint-Narcisse Episode). We present a detailed reconstruction of the pattern of retreat of the LIS in the Charlevoix region based on the interpretation of ice-marginal features (e.g. moraines, fans) and glaciolacustrine landforms and deposits, two extensive field campaigns, and the interpretation of high-resolution 3D digital aerial photographs and LiDAR data. Our results indicate five moraine complexes in the region: the Rochette, the Br^ulée, the Sainte-Anne, the Saint-Narcisse and the Mars-Batiscan complexes. Deltas, fans, finegrained sediments, littoral deposits, drainage breaches and deposits were used to identify 91 palaeo-proglacial lakes. The identification of these lakes and their relation to moraine complexes enabled the reconstruction of six stages of lake development during the Charlevoix deglaciation. The development of proglacial lakes occurred in all types of terrain (highlands, lowlands, transitory levels above marine limit). We conclude that local topography had a decisive effect on promoting both moraine deposition and lake development. We suggest that similar topographical regions (hilly-mountainous) that were affected by major ice-margin stabilizations during glacial retreat should have experience small lakes dominating valleys and topographical lows. [ABSTRACT FROM AUTHOR]

Early warning systems (EWSs) rely on the capacity to forecast a dangerous event with a certain amount of advance by defining warning criteria on which the safety of the population will depend. Monitoring of landslides is facilitated by new technologies, decreasing prices and easier data processing. At the same time, predicting the onset of a rapid failure or the sudden transition from slow to rapid failure and subsequent collapse, and its consequences is challenging for scientists that must deal with uncertainties and have limited tools to do so. Furthermore, EWS and warning criteria are becoming more and more a subject of concern between technical experts, researchers, stakeholders and decision makers responsible for the activation, enforcement and approval of civil protection actions. EWSs imply also a sharing of responsibilities which is often averted by technical staff, managers of technical offices and governing institutions. We organized the First International Workshop on Warning Criteria for Active Slides (IWWCAS) to promote sharing and networking among members from specialized institutions and relevant experts of EWS. In this paper, we summarize the event to stimulate discussion and collaboration between organizations dealing with the complex task of managing hazard and risk related to active slides. [ABSTRACT FROM AUTHOR]

Abstract: High-resolution seismic profiles along with physical and sedimentological properties of sediment cores from the Saguenay (Eastern Canada) and Reloncavi (Chile) Fjords allowed the identification of several decimeter to meter-thick turbidites. In both fjords, the turbidites were associated with large magnitude historic and pre-historic earthquakes including the 1663AD (M>7) earthquake in the Saguenay Fjord, and the 1960 (M 9.5), 1837 (M~8) and 1575AD major Chilean subduction earthquakes in the Reloncavi Fjord. In addition, a sand layer with exoscopic characteristics typical of a tsunami deposit was observed immediately above the turbidite associated with the 1575AD earthquake in the Reloncavi Fjord and supports both the chronology and the large magnitude of that historic earthquake. In the Saguenay Fjord, the earthquake-triggered turbidites are sometimes underlying a hyperpycnite associated with the rapid breaching and draining of a natural dam formed by earthquake-triggered landslides. Similar hyperpycnal floods were also recorded in historical and continental geological archives for the 1960 and 1575AD Chilean subduction earthquakes, highlighting the risk of such flood events several weeks or months after main earthquake. In both fjords, as well as in other recently recognized earthquake-triggered turbidites, the decimeter-to meter-thick normally-graded turbidites are characterized by a homogeneous, but slightly fining upward tail. Finally, this paper also emphasizes the sensitivity of fjords to record historic and pre-historic seismicity. [Copyright &y& Elsevier]

Migrating sediment waves have been reported in a variety of marine settings, including submarine levee–fan systems, floors of fjords, and other basin or continental slope environments. Examination of such wave fields reveals nine diagnostic characteristics. When these characteristics are applied to several features previously attributed to submarine landslide deformation, they suggest that the features should most likely be reinterpreted as migrating sediment-wave fields. Sites that have been reinterpreted include the ‘Humboldt slide’ on the Eel River margin in northern California, the continental slope in the Gulf of Cadiz, the continental shelf off the Malaspina Glacier in the Gulf of Alaska, and the Adriatic shelf. A reassessment of all four features strongly suggests that numerous turbidity currents, separated by intervals of ambient hemipelagic sedimentation, deposited the wave fields over thousands of years. A numerical model of hyperpycnal discharge from the Eel River, for example, shows that under certain alongshore-current conditions, such events can produce turbidity currents that flow across the ‘Humboldt slide’, serving as the mechanism for the development of migrating sediment waves. Numerical experiments also demonstrate that where a series of turbidity currents flows across a rough seafloor (i.e. numerical steps), sediment waves can form and migrate upslope. Hemipelagic sedimentation between turbidity current events further facilitates the upslope migration of the sediment waves. Physical modelling of turbidity currents also confirms the formation and migration of seafloor bedforms. The morphologies of sediment waves generated both numerically and physically in the laboratory bear a strong resemblance to those observed in the field, including those that were previously described as submarine landslides. [Copyright &y& Elsevier]