Geological, geomechanical and geostatistical assessment of rockfall hazard in San Quirico Village (Abruzzo, Italy)

NASA Astrophysics Data System (ADS)

Chiessi, Vittorio; D'Orefice, Maurizio; Scarascia Mugnozza, Gabriele; Vitale, Valerio; Cannese, Christian

2010-07-01

This paper describes the results of a rockfall hazard assessment for the village of San Quirico (Abruzzo region, Italy) based on an engineering-geological model. After the collection of geological, geomechanical, and geomorphological data, the rockfall hazard assessment was performed based on two separate approaches: i) simulation of detachment of rock blocks and their downhill movement using a GIS; and ii) application of geostatistical techniques to the analysis of georeferenced observations of previously fallen blocks, in order to assess the probability of arrival of blocks due to potential future collapses. The results show that the trajectographic analysis is significantly influenced by the input parameters, with particular reference to the coefficients of restitution values. In order to solve this problem, the model was calibrated based on repeated field observations. The geostatistical approach is useful because it gives the best estimation of point-source phenomena such as rockfalls; however, the sensitivity of results to basic assumptions, e.g. assessment of variograms and choice of a threshold value, may be problematic. Consequently, interpolations derived from different variograms have been used and compared among them; hence, those showing the lowest errors were adopted. The data sets which were statistically analysed are relevant to both kinetic energy and surveyed rock blocks in the accumulation area. The obtained maps highlight areas susceptible to rock block arrivals, and show that the area accommodating the new settlement of S. Quirico Village has the highest level of hazard according to both probabilistic and deterministic methods.

Quantitative rock-fall hazard and risk assessment for Yosemite Valley, Yosemite National Park, California

USGS Publications Warehouse

Stock, Greg M.; Luco, Nicolas; Collins, Brian D.; Harp, Edwin L.; Reichenbach, Paola; Frankel, Kurt L.

2014-01-01

Rock falls are common in Yosemite Valley, California, posing substantial hazard and risk to the approximately four million annual visitors to Yosemite National Park. Rock falls in Yosemite Valley over the past few decades have damaged structures and caused injuries within developed regions located on or adjacent to talus slopes highlighting the need for additional investigations into rock-fall hazard and risk. This assessment builds upon previous investigations of rock-fall hazard and risk in Yosemite Valley and focuses on hazard and risk to structures posed by relatively frequent fragmental-type rock falls as large as approximately 100,000 (cubic meters) in volume.

Anthropocene rockfalls travel farther than prehistoric predecessors

PubMed Central

Borella, Josh Walter; Quigley, Mark; Vick, Louise

2016-01-01

Human modification of natural landscapes has influenced surface processes in many settings on Earth. Quantitative data comparing the distribution and behavior of geologic phenomena before and after human arrival are sparse but urgently required to evaluate possible anthropogenic influences on geologic hazards. We conduct field and imagery-based mapping, statistical analysis, and numerical modeling of rockfall boulders triggered by the fatal 2011 Christchurch earthquakes (n = 285) and newly identified prehistoric (Holocene and Pleistocene) boulders (n = 1049). Prehistoric and modern boulders are lithologically equivalent, derived from the same source cliff, and yield consistent power-law frequency-volume distributions. However, a significant population of modern boulders (n = 26) traveled farther downslope (>150 m) than their most-traveled prehistoric counterparts, causing extensive damage to residential dwellings at the foot of the hillslope. Replication of prehistoric boulder distributions using three-dimensional rigid-body numerical models that incorporate lidar-derived digital topography and realistic boulder trajectories and volumes requires the application of a drag coefficient, attributed to moderate to dense slope vegetation, to account for their spatial distribution. Incorporating a spatially variable native forest into the models successfully predicts prehistoric rockfall distributions. Radiocarbon dating provides evidence for 17th to early 20th century deforestation at the study site during Polynesian and European colonization and after emplacement of prehistoric rockfall. Anthropocene deforestation enabled modern rockfalls to exceed the limits of their prehistoric predecessors, highlighting a shift in the geologic expression of rockfalls due to anthropogenic activity. Reforestation of hillslopes by mature native vegetation could help reduce future rockfall hazard. PMID:27652344

Rockfall Hazard Process Assessment : Implementation Report

DOT National Transportation Integrated Search

2017-10-01

The Montana Department of Transportation (MDT) commissioned a new research program to improve assessment and management of its rock slope assets. The Department implemented a Rockfall Hazard Rating System (RHRS) program in 2005 and wished to add valu...

A Novel DEM Approach to Simulate Block Propagation on Forested Slopes

NASA Astrophysics Data System (ADS)

Toe, David; Bourrier, Franck; Dorren, Luuk; Berger, Frédéric

2018-03-01

In order to model rockfall on forested slopes, we developed a trajectory rockfall model based on the discrete element method (DEM). This model is able to take the complex mechanical processes at work during an impact into account (large deformations, complex contact conditions) and can explicitly simulate block/soil, block/tree contacts as well as contacts between neighbouring trees. In this paper, we describe the DEM model developed and we use it to assess the protective effect of different types of forest. In addition, we compared it with a more classical rockfall simulation model. The results highlight that forests can significantly reduce rockfall hazard and that the spatial structure of coppice forests has to be taken into account in rockfall simulations in order to avoid overestimating the protective role of these forest structures against rockfall hazard. In addition, the protective role of the forests is mainly influenced by the basal area. Finally, the advantages and limitations of the DEM model were compared with classical rockfall modelling approaches.

Rockfall triggering by cyclic thermal stressing of exfoliation fractures

USGS Publications Warehouse

Collins, Brian D.; Stock, Greg M.

2016-01-01

Exfoliation of rock deteriorates cliffs through the formation and subsequent opening of fractures, which in turn can lead to potentially hazardous rockfalls. Although a number of mechanisms are known to trigger rockfalls, many rockfalls occur during periods when likely triggers such as precipitation, seismic activity and freezing conditions are absent. It has been suggested that these enigmatic rockfalls may occur due to solar heating of rock surfaces, which can cause outward expansion. Here we use data from 3.5 years of field monitoring of an exfoliating granite cliff in Yosemite National Park in California, USA, to assess the magnitude and temporal pattern of thermally induced rock deformation. From a thermodynamic analysis, we find that daily, seasonal and annual temperature variations are sufficient to drive cyclic and cumulative opening of fractures. Application of fracture theory suggests that these changes can lead to further fracture propagation and the consequent detachment of rock. Our data indicate that the warmest times of the day and year are particularly conducive to triggering rockfalls, and that cyclic thermal forcing may enhance the efficacy of other, more typical rockfall triggers.

Report on the "Shakedown" test of Oregon's rockfall hazard rating system.

DOT National Transportation Integrated Search

1989-04-01

Oregon Rockfall Hazard Rating System (RHRS) was field tested at over 50 locations statewide to determine where clarification and improvements to the system were needed. Field use of the system demonstrated many areas where refinements were valuable. ...

The importance of source area mapping for rockfall hazard analysis

NASA Astrophysics Data System (ADS)

Valagussa, Andrea; Frattini, Paolo; Crosta, Giovanni B.

2013-04-01

A problem in the characterization of the area affected by rockfall is the correct source areas definition. Different positions or different size of the source areas along a cliff result in different possibilities of propagation and diverse interaction with passive countermeasures present in the area. Through the use of Hy-Stone (Crosta et al., 2004), a code able to perform 3D numerical modeling of rockfall processes, different types of source areas were tested on a case study slope along the western flank of the Mt. de La Saxe (Courmayeur, AO), developing between 1200 and 2055 m s.l.m. The first set of source areas consists of unstable rock masses identified on the basis of field survey and Terrestrial Laser Scanning (IMAGEO, 2011). A second set of source areas has been identified by using different thresholds of slope gradient. We tested slope thresholds between 50° and 75° at 5° intervals. The third source area dataset has been generating by performing a kinematic stability analysis. For this analysis, we mapped the join sets along the rocky cliff by means of the software COLTOP 3D (Jaboyedoff, 2004), and then we identified the portions of rocky cliff where planar/wedge and toppling failures are possible assuming an average friction angle of 35°. Through the outputs of the Hy-Stone models we extracted and analyzed the kinetic energy, height of fly and velocity of the blocks falling along the rocky cliff in order to compare the controls of different source areas. We observed strong variations of kinetic energy and fly height among the different models, especially when using unstable masses identified through Terrestrial Laser Scanning. This is mainly related to the size of the blocks identified as susceptible to failure. On the contrary, the slope gradient thresholds does not have a strong impact on rockfall propagation. This contribution highlights the importance of a careful and appropriate mapping of rockfall source area for rockfall hazard analysis and the design of passive countermeasures.

Development of a rockfall hazard rating matrix for the State of Ohio.

DOT National Transportation Integrated Search

2005-03-01

Although Ohio is not considered a "mountainous state", it is well documented that rockfalls are prevalent. Rockfalls pose a : considerable risk to traffic safety, create maintenance problems, and exert a strain on limited maintenance funds available ...

Development of a Rockfall Hazard Rating Matrix for the State of Ohio

DOT National Transportation Integrated Search

2005-03-01

Although Ohio is not considered a "mountainous state", it is well documented that rockfalls are prevalent. Rockfalls pose a : considerable risk to traffic safety, create maintenance problems, and exert a strain on limited maintenance funds available ...

Rock face stability analysis and potential rockfall source detection in Yosemite Valley

NASA Astrophysics Data System (ADS)

Matasci, B.; Stock, G. M.; Jaboyedoff, M.; Oppikofer, T.; Pedrazzini, A.; Carrea, D.

2012-04-01

Rockfall hazard in Yosemite Valley is especially high owing to the great cliff heights (~1 km), the fracturing of the steep granitic cliffs, and the widespread occurrence of surface parallel sheeting or exfoliation joints. Between 1857 and 2011, 890 documented rockfalls and other slope movements caused 15 fatalities and at least 82 injuries. The first part of this study focused on realizing a structural study for Yosemite Valley at both regional (valley-wide) and local (rockfall source area) scales. The dominant joint sets were completely characterized by their orientation, persistence, spacing, roughness and opening. Spacing and trace length for each joint set were accurately measured on terrestrial laser scanning (TLS) point clouds with the software PolyWorks (InnovMetric). Based on this fundamental information the second part of the study aimed to detect the most important failure mechanisms leading to rockfalls. With the software Matterocking and the 1m cell size DEM, we calculated the number of possible failure mechanisms (wedge sliding, planar sliding, toppling) per cell, for several cliffs of the valley. Orientation, spacing and persistence measurements directly issued from field and TLS data were inserted in the Matterocking calculations. TLS point clouds are much more accurate than the 1m DEM and show the overhangs of the cliffs. Accordingly, with the software Coltop 3D we developed a methodology similar to the one used with Matterocking to identify on the TLS point clouds the areas of a cliff with the highest number of failure mechanisms. Exfoliation joints are included in this stability analysis in the same way as the other joint sets, with the only difference that their orientation is parallel to the local cliff orientation and thus variable. This means that, in two separate areas of a cliff, the exfoliation joint set is taken into account with different dip direction and dip, but its effect on the stability assessment is the same. Areas with a high density of possible failure mechanisms are shown to be more susceptible to rockfalls, demonstrating a link between high fracture density and rockfall susceptibility. This approach enables locating the most probable future rockfall sources and provides key elements needed to evaluate the potential volume and run-out distance of rockfall blocks. This information is used to improve rockfall hazard assessment in Yosemite Valley and elsewhere.

Application of the Unity Rockfall Model to Variable Surface Material Conditions

NASA Astrophysics Data System (ADS)

Sala, Zac; Hutchinson, D. Jean; Ondercin, Matthew

2017-04-01

Rockfall is a geological process that poses risks to the safe operation of transportation infrastructure in mountainous environments world wide. The Unity rockfall model was created as a tool for 3D rockfall simulation as part of the Railway Ground Hazards Research Program, studying the impact of geotechnical hazards affecting Canadian railways [1]. The Unity rockfall model demonstrates the applicability of 3D video game engines for the development of realistic simulations, leveraging high-resolution site data collected using remote sensing techniques. Currently work is being done to further calibrate the model as an engineering tool for decision support. Calibration datasets include high-resolution terrestrial LiDAR and helicopter photogrammetry data collected as part of an ongoing rockfall monitoring program along the Thompson River Valley in south-central British Columbia, Canada. Change detection techniques developed as part of the program have been used to construct a database of rockfall event history and to develop magnitude-frequency relationships for rockfalls in the area [2][3]. Data collected as part of a controlled rock-rolling field program in Christchurch, New Zealand [4] is also being utilized for model calibration. Data on block dynamics for the artificially triggered rockfalls were collected through the use of embedded motion sensors and a sixteen camera setup. These experiments provide detailed information on block kinematics, and capture each impact point of the rockfall with the slope, thus offering a valuable dataset for comparison with modelling results. The research reported here explores the ability of the game engine based modelling technique to simulate rockfall under the variable slope conditions present at each of the sites where calibration data was collected. This includes steep natural rock slopes, with debris-talus cover, as well as shallower slopes with soil cover and vegetation. The varying slope conditions in each environment affect the dominant processes controlling rockfall movement downslope. In comparison to rock on rock collisions, impacts with soil and talus exhibit lower restitution values, with more energy loss occurring, but less overall fragmentation expected. The current modelling efforts present example workflows for each case, showing the steps taken to run realistic simulations using the Unity rockfall model. A comparison of the setup, model inputs and methods implemented in the model for each case study demonstrates the adaptability of the tool to different rockfall environments. References: [1] Ondercin, M.: An Exploration of Rockfall Modelling Through Game Engines, M.A.Sc Thesis, Queen's University, Kingston, 2016 [2] Kromer, R., Hutchinson, D.J., Lato, M., Gauthier, D., and Edwards, T. 2015. Identifying rock slope failure precursors using LiDAR for transportation corridor hazard management. Engineering Geology, 195, 93-103. doi:10.1016/j.enggeo.2015.05.012 [3] van Veen, M., Hutchinson, D.J., Kromer, R., Lato, M., and Edwards, T. (Submitted September 2016) Effects of Sampling Interval on the Frequency-Magnitude Relationship of Rockfalls Detected from Terrestrial Laser Scanning using Semi-Automated Methods. Landslides, MS number: LASL-D-16-00258. [4] Vick, L.M.: Evaluation of Field Data and 3D Modelling for Rockfall Hazard Assessment, Ph.D Thesis, University of Canterbury, Christchurch, 2015

Rockfall travel distances theoretical distributions

NASA Astrophysics Data System (ADS)

Jaboyedoff, Michel; Derron, Marc-Henri; Pedrazzini, Andrea

2017-04-01

The probability of propagation of rockfalls is a key part of hazard assessment, because it permits to extrapolate the probability of propagation of rockfall either based on partial data or simply theoretically. The propagation can be assumed frictional which permits to describe on average the propagation by a line of kinetic energy which corresponds to the loss of energy along the path. But loss of energy can also be assumed as a multiplicative process or a purely random process. The distributions of the rockfall block stop points can be deduced from such simple models, they lead to Gaussian, Inverse-Gaussian, Log-normal or exponential negative distributions. The theoretical background is presented, and the comparisons of some of these models with existing data indicate that these assumptions are relevant. The results are either based on theoretical considerations or by fitting results. They are potentially very useful for rockfall hazard zoning and risk assessment. This approach will need further investigations.

The modified "Rockfall Hazard Rating System": a new tool for roads risk assessment

NASA Astrophysics Data System (ADS)

Budetta, P.

2003-04-01

This paper contains a modified method for the analysis of rockfall hazard along roads and motorways. The method is derived from that one developed by Pierson et alii at the Oregon State Highway Division. The Rockfall Hazard Rating System (RHRS) provides a rational way to make informed decisions on where and how to spend construction funds. An exponential scoring graph is used to represent the increase in hazard that is reflected in the nine categories forming the classification (slope height, ditch effectiveness, average vehicle risk, percent of decision site distance, roadway width, geological character, quantity of rockfall/event, climate and rock fall history). The resulting total score contains the essential elements regarding the evaluation of the consequences ("cost of failure"). In the modified method, the rating for the categories "ditch effectiveness", "decision sight distance", "rodway width", "geologic characteristic" and "climate and water circulation" have been rendered more easy and objective. The main modifications regard the introduction of the Romana's Slope Mass Rating improving the estimate of the geologic characteristics, of the volume of the potentially unstable blocks and underground water circulation. Other modifications regard the scoring determination for the categories "decision sight distance" and "road geometry". For these categories, the Italian National Council's standards (CNR) have been used. The method must be applied in both the traffic directions because the percentage of reduction in the "decision sight distance" greatly affects the results. An application of the method to a 2-km-long section of the Sorrentine road (n° 145) in Southern Italy was pointed out. A high traffic intensity affects the entire section of the road and rockfalls periodically cause casualties, as well as a large amount of damage and traffic interruptions. The method was applied on seven cross section traces of slopes adjacent to the Sorrentine road and the total final scores range between 275 and 450. For these slopes, the analysis shows that the risk is unacceptable and it must reduced using urgent remedial works. Further applications in other geological environments are welcomed.

Introducing Meta-models for a More Efficient Hazard Mitigation Strategy with Rockfall Protection Barriers

NASA Astrophysics Data System (ADS)

Toe, David; Mentani, Alessio; Govoni, Laura; Bourrier, Franck; Gottardi, Guido; Lambert, Stéphane

2018-04-01

The paper presents a new approach to assess the effecctiveness of rockfall protection barriers, accounting for the wide variety of impact conditions observed on natural sites. This approach makes use of meta-models, considering a widely used rockfall barrier type and was developed from on FE simulation results. Six input parameters relevant to the block impact conditions have been considered. Two meta-models were developed concerning the barrier capability either of stopping the block or in reducing its kinetic energy. The outcome of the parameters range on the meta-model accuracy has been also investigated. The results of the study reveal that the meta-models are effective in reproducing with accuracy the response of the barrier to any impact conditions, providing a formidable tool to support the design of these structures. Furthermore, allowing to accommodate the effects of the impact conditions on the prediction of the block-barrier interaction, the approach can be successfully used in combination with rockfall trajectory simulation tools to improve rockfall quantitative hazard assessment and optimise rockfall mitigation strategies.

Quantitative rock-fall hazard and risk assessment for Yosemite Valley, Yosemite National Park, California

USGS Publications Warehouse

Stock, Greg M.; Luco, Nicolas; Collins, Brian D.; Harp, Edwin L.; Reichenbach, Paola; Frankel, Kurt L.

2012-01-01

caused injuries within developed regions located on or adjacent to talus slopes, highlighting the need for additional investigations into rock-fall hazard and risk. This assessment builds upon previous investigations of rock fall hazard and risk in Yosemite Valley (Wieczorek et al., 1998, 1999; Guzzetti et al., 2003; Wieczorek et al., 2008), and focuses on hazard and risk to structures posed by relatively frequent fragmental-type rock falls (Evans and Hungr, 1999), up to approximately 100,000 m3 in volume.

Dynamic rockfall risk assessment along the SS113 coastal road (Northern Sicily)

NASA Astrophysics Data System (ADS)

Mastrolembo, V. Brunella; Penna, Ivanna; Voumard, Jérémie; Jaboyedoff, Michel

2016-04-01

Rockfalls are natural hazards that usually affect only small areas. However, due to the big amount of material that can be moved and the associated kinetic energy they can cost serious damages to infrastructures and people. Even fairly small rockfall fragments are a significant hazard if deposited on a highway or along a rail-road track since they are not easily detected and can cause accidents or derailments. Rockfalls can also cause the closure of streets resulting in long term indirect economic losses due to transportation delays as well as to the impact on the commercial and tourist activities. In letterature there are numerous examples of rockfall risk assessments along transportation corridors, most of them are based on the use of standard risk estimation methods. The latters are static approaches founded on a macroscopic view of road traffic, assumed as uniform in space and time, thus characterized by average values of parameters. Lately, a new dynamic approach has been developed within the 'risk analysis group' at the University of Lausanne (Voumard, 2013). It consists of a kinematic interpretation of road traffic where vehicles are parametrized as single entities with different characteristics, speed, dimensions and behaviour. We apply this new approach to estimate the dynamic risk due to rockfall occurrence on the SS113 national road running along the northern coast of Sicily. In this work we focus our attention on a ≈10 km section along which the SS113 road and a railway connect all the costal villages going through very steep cliffs and very close to the sea with evident problems of erosion and maintenance. The area is a tourist destination and many hotels and facilities are found along the road. Moreover the area was already hit in the past by numerous rockfalls resulting in the closure of the road for periods running from a few days up to a few years with big direct and indirect damages to the local socio-economic activities. In order to achieve a rockfall risk assessment we apply a two steps approach. First, we realize an hazard estimation along the SS113 road applying a classical approach to evaluate the propagation area, so the probability of impact and storage of boulders on the road lanes. Then, we use this result as input to realize a dynamic estimation of risk for vehicles traveling on the road. Using the TSiNaHa numerical simulator we estimate the risk relative to different combinations of rockfall scenarios and traffic variables. The aim of the work is to get informations that could be used by local politicians and decision makers to take decisions both, about permanent mitigation measures and emergency actions to be taken during the alert phase or after the occurrence of a rockfall.

Assessment of rockfall risk along roads

NASA Astrophysics Data System (ADS)

Budetta, P.

2004-03-01

This paper contains a method for the analysis of rockfall risk along roads and motorways. The method is derived from the Rockfall Hazard Rating System (RHRS) developed by Pierson et al. (1990) at the Oregon State Highway Division. The RHRS provides a rational way to make informed decisions on where and how to spend construction funds. Exponential scoring functions are used to represent the increases, respectively, in hazard and in vulnerability that are reflected in the nine categories forming the classification. The resulting total score contains the essential elements regarding the evaluation of the degree of the exposition to the risk along roads. In the modified method, the ratings for the categories "ditch effectiveness", "geologic characteristic", "volume of rockfall/block size", "climate and water circulation" and "rockfall history" have been rendered more easy and objective. The main modifications regard the introduction of Slope Mass Rating by Romana (1985, 1988, 1991) improving the estimate of the geologic characteristics, of the volume of the potentially unstable blocks and the underground water circulation. Other modifications regard the scoring for the categories "decision sight distance" and "road geometry". For these categories, the Italian National Council's standards (Consiglio Nazionale delle Ricerche - CNR) have been used (CNR, 1980). The method must be applied in both the traffic directions because the percentage of reduction in the decision sight distance greatly affects the results. An application of the modified method to a 2km long section of the Sorrentine road (no 145) in Southern Italy was developed. A high traffic intensity affects the entire section of the road and rockfalls periodically cause casualties, as well as a large amount of damage and traffic interruptions. The method was applied to seven cross sections of slopes adjacent to the Sorrentine road. For these slopes, the analysis shows that the risk is unacceptable and it should be reduced using urgent remedial works.

A new rapid method for rockfall energies and distances estimation

NASA Astrophysics Data System (ADS)

Giacomini, Anna; Ferrari, Federica; Thoeni, Klaus; Lambert, Cedric

2016-04-01

Rockfalls are characterized by long travel distances and significant energies. Over the last decades, three main methods have been proposed in the literature to assess the rockfall runout: empirical, process-based and GIS-based methods (Dorren, 2003). Process-based methods take into account the physics of rockfall by simulating the motion of a falling rock along a slope and they are generally based on a probabilistic rockfall modelling approach that allows for taking into account the uncertainties associated with the rockfall phenomenon. Their application has the advantage of evaluating the energies, bounce heights and distances along the path of a falling block, hence providing valuable information for the design of mitigation measures (Agliardi et al., 2009), however, the implementation of rockfall simulations can be time-consuming and data-demanding. This work focuses on the development of a new methodology for estimating the expected kinetic energies and distances of the first impact at the base of a rock cliff, subject to the conditions that the geometry of the cliff and the properties of the representative block are known. The method is based on an extensive two-dimensional sensitivity analysis, conducted by means of kinematic simulations based on probabilistic modelling of two-dimensional rockfall trajectories (Ferrari et al., 2016). To take into account for the uncertainty associated with the estimation of the input parameters, the study was based on 78400 rockfall scenarios performed by systematically varying the input parameters that are likely to affect the block trajectory, its energy and distance at the base of the rock wall. The variation of the geometry of the rock cliff (in terms of height and slope angle), the roughness of the rock surface and the properties of the outcropping material were considered. A simplified and idealized rock wall geometry was adopted. The analysis of the results allowed finding empirical laws that relate impact energies and distances at the base to block and slope features. The validation of the proposed approach was conducted by comparing predictions to experimental data collected in the field and gathered from the scientific literature. The method can be used for both natural and constructed slopes and easily extended to more complicated and articulated slope geometries. The study shows its great potential for a quick qualitative hazard assessment providing indication about impact energy and horizontal distance of the first impact at the base of a rock cliff. Nevertheless, its application cannot substitute a more detailed quantitative analysis required for site-specific design of mitigation measures. Acknowledgements The authors gratefully acknowledge the financial support of the Australian Coal Association Research Program (ACARP). References Dorren, L.K.A. (2003) A review of rockfall mechanics and modelling approaches, Progress in Physical Geography 27(1), 69-87. Agliardi, F., Crosta, G.B., Frattini, P. (2009) Integrating rockfall risk assessment and countermeasure design by 3D modelling techniques. Natural Hazards and Earth System Sciences 9(4), 1059-1073. Ferrari, F., Thoeni, K., Giacomini, A., Lambert, C. (2016) A rapid approach to estimate the rockfall energies and distances at the base of rock cliffs. Georisk, DOI: 10.1080/17499518.2016.1139729.

Seasonal rockfall risk assessment along transportation network: a sample from Mallorca (Spain)

NASA Astrophysics Data System (ADS)

Mateos, Rosa Maria; Garcia, Inmaculada; Reichenbach, Paola; Herrera, Gerardo; Rius, Joan; Aguilo, Raul; Roldan, Francisco J.

2014-05-01

In the literature there are numerous works focusing on rockfall risk assessment along transportation corridors which take into account several factors, including the annual average traffic volume. Few papers examine in detail examples with a strong seasonal distribution of people travelling along roads, in particular in regions with a great importance for tourism. In these areas, potential blockages along the road network can cause significant economic losses, considering not only direct costs, but also indirect ones related to a reduction in tourism arrivals, with the consequent loss of jobs and profits. In this work we present a methodology for rockfall risk assessment focusing on the reliability and applicability of the evaluation in a test site located in the island of Mallorca, a region which welcomes over 11.3 million visitors per year and where tourism represents the main source of income (83% of its GDP). The Ma-10 road (111 km), located in the north-western sector of the island along the coastal face of the Tramuntana range, has been affected by 85 rockfall events during the past 18 years, which caused repairing costs valued at approximately 2M Euro (Mateos et al., 2013). Rockfalls are triggered by heavy rainfall and freeze-thaw cycles and, for these reasons, autumn and winter can be considered as the most hazardous seasons (Mateos et al., 2012). The road has heavy traffic estimated at 7.200 vehicles per day on average, with a seasonal variation of people travelling in vehicles, the summer being most prominent- up to 6 times the average- due to the pattern of tourism arrivals. To analyse the seasonal rockfall hazard and risk along the Ma-10 road, we obtained the extent of the areas potentially subject to rockfall hazards using STONE, a physically-based rockfall simulation computer program (Guzzetti et al, 2002). The availability of historical rockfalls mapped in detail allowed checking the STONE results, and identifying a hazardous area on the southern section of the road. For the risk analysis, four scenarios depending on the seasonal people exposition have been taken into account, considering the autumn as the season with the highest risk. This methodology can be applied to highly touristy areas such Mallorca, where the safety of the population and its visitors must be the priority of all concerned. References : Guzzetti, F., Crosta G., Detti, R. Agliardi, F., 2002: STONE: A computer program for the three-dimensional simulation of rock-falls. Computers Geosciences 28 (2002) 1079-1093. Mateos, R.M., García-Moreno, I., Azañón, J.M., 2012. Freeze-thaw cycles and rainfall as triggering factors of mass movements in a warm Mediterranean region: the case of the Tramuntana Range (Majorca, Spain). Landslides (2012), 9: 417-432. Mateos, R.M., García- Moreno, I., Herrera, G., Mulas, J., 2013b. Damage caused by recent mass-movements in Majorca (Spain), a region with a high risk due to tourism. Landslide Science and Practice. Claudio Margottini, Paolo Canuti and Kyoji Sassa (Editors). Volume 7: Social and Economic Impact and Policies. 105-113.

Rockfall hazard mapping along a mountainous road in Switzerland using a GIS-based parameter rating approach

NASA Astrophysics Data System (ADS)

Baillifard, F.; Jaboyedoff, M.; Sartori, M.

A posteriori studies of rock slope instabilities generally show that rockfalls do not occur at random locations: the failure zone can be classified as sensitive from geomorphological evidence. Zones susceptible to failure can there-fore be detected. Effects resulting from degrading and triggering factors, such as groundwater circulation and freeze and thaw cycles, must then be assessed in order to evaluate the probability of failure. A simple method to detect rock slope instabilities was tested in a study involving a 2000 m3 rockfall that obstructed a mountainous road near Sion (Switzerland) on 9 January 2001. In order to locate areas from which a rock-fall might originate, areas were assessed with respect to the presence or absence of five criteria: (1) a fault, (2) a scree slope within a short distance, (3) a rocky cliff, (4) a steep slope, and (5) a road. These criteria were integrated into a Geographic Information System (GIS) using existing topo-graphic, geomorphological, and geological vector and raster digital data. The proposed model yields a rating from 0 to 5, and gives a relative hazard map. Areas yielding a high relative hazard have to meet two additional criteria if they are to be considered as locations from which a rockfall might originate: (1) the local structural pattern has to be unfavourable, and (2) the morphology has to be susceptible to the effects of degrading and triggering factors. The rockfall of 9 January 2001, has a score of 5. Applied to the entire length of the road (4 km), the present method reveals two additional areas with a high relative hazard, and allows the detection of the main instabilities of the site.

Quantifying rockfall risk on roads in the Port Hills, Christchurch, New Zealand

NASA Astrophysics Data System (ADS)

Unterrader, Stefan; Fuchs, Sven

2016-04-01

The Canterbury earthquake sequence starting on 22 September 2010 triggered widespread mass movements in the Port Hills area of Christchurch, the largest agglomeration of New Zealand's South Island. The MW 6.2 Christchurch earthquake of 22 February 2011 in particular generated the largest ground motions ever recorded in New Zealand and as a result initiated several thousands of rockfalls. Over 6,000 boulders were released and mapped shortly after the event. The risk from rockfall to residents in the Port Hills was quantitatively assessed by the regulatory authorities in order to develop an adjusted land zoning policy. Apart from damaging residential buildings many of these boulders also hit several road sections across the Port Hills. Due to the inherent differences between identifying hazard and risk to people in static structures and in moving objects, a recently carried out risk assessment of rockfall was limited to exposed properties. However, given the importance of local road infrastructure for commuter traffic, local risk management strategies would clearly benefit from quantifying the threat of boulders endangering traffic lines. For this study, existing datasets describing the hazard including recently estimated frequency-magnitude bands for earthquakes and non-seismic triggering events, boulder production rates, boulder size distribution and associated run-out distances, were used. These data were provided by the Christchurch City Council's (CCC) GIS web service. A digital layer of the local road network as well as a detailed dataset of traffic counts was used for GIS analysis, and the probability of individuals being hit by boulders was calculated for each road segment that intersects one or more rockfall hazard zones. Finally, risk was computed. The method applied follows a state-of-the-art approach in risk assessment which is generally based on the risk equation defining risk as the probability of occurrence of an event times the expected loss. More specifically, both the annual collective risk and individual risk of being hit by rockfalls on the Port Hills traffic lines were calculated. Both risk terms were assessed by drawing on a well-established method originally developed for evaluating snow avalanche risk on high-alpine pass roads. In order to reflect the discontinuous distribution of rockfall across the hazard zone (i.e. boulders will only hit certain points or follow one specific run-out path compared to the typical snow avalanche run-out behaviour) the original risk equation was adjusted. Hence, (1) the annual collective risk as well as the individual risk of being hit by rockfalls when travelling on the local road network was quantified, (2) the temporal dynamics of most susceptible elements at risk (i.e. commuter traffic) were identified and related dynamics in risk were assessed, and (3) the specific case of waiting traffic and the associated increase in fatality risk compared to moving traffic was computed. The results of this study provide first insights in both the collective and individual rockfall fatality risk on important traffic lines across the Port Hills. Road sections that are most prone to rockfall hazard were clearly identified in high spatial resolution. Sensitivity analysis of main parameters showed that the decrease in seismic hazard expected over the next decades resulted in decreasing rockfall hazard and therefore decreasing fatality risk even if currently increasing traffic volumes will further rise. Furthermore, a closer look on the individual risk of commuters was addressing some of the challenges within the inherent static approach of the risk concept, namely the temporal dynamics in traffic flow. It was further shown that the main traffic line, Tunnel Road, is characterized by a strongly diurnal variability including two traffic peaks between 7 and 9 a.m. and around 5 to 6 p.m. Additionally, the influence of road blockage by boulders falling onto endangered road sections was also responsible for an increasing annual fatality risk of road users on most of the studied road sections. Several conceptual shortcomings in previous studies were addressing this issue, particularly with respect to simplifying assumptions repeatedly made during the risk computation. The results of this study highlight some of the most important aspects in this regard. Finally, the risk of being hit by rockfalls while travelling on the roads of the study area were compared to other risks faced (and tolerated) by the New Zealand citizens. The spatio-temporal dynamics in rockfall risk across the Port Hills road network clearly had shown the inherent limitations of any static risk assessment. Fatality numbers in the Port Hills were low during the 22 February 2011 event because the earthquake hit around noon and it is shown that similar ground shaking intensities occurring during rush hour are likely to cause several fatalities on the main transportation lines. These risks are further increased as traffic jams are very likely to form after extensive road blockage. In addition, rockfall hitting critical infrastructure not only pose fatality risk to people travelling along these lines but also affect the ability of emergency response teams to safely assess parts of the area which otherwise would be cut off. This temporal aspect has yet to be incorporated into local risk management strategies. The clear identification of the road segments most prone to boulder hits can serve the authorities as decision support for any future mitigation works.

Implementation of numerical simulations for rockfall hazard mapping in the Norddal municipality, Norway.

NASA Astrophysics Data System (ADS)

Yugsi Molina, Freddy Xavier; Oppikofer, Thierry; Otterå, Solveig; Hermanns, Reginald; Taurisano, Andrea; Wasrud, Jaran; Are Jensen, Odd; Rødseth Kvakland, Marte

2013-04-01

The Norwegian Water Resources and Energy Directorate (NVE) in cooperation with the Geological Survey of Norway (NGU) are implementing a nationwide program to systematically produce hazard maps for rockfalls, debris flows and snow avalanches in steep terrains. Activities during this program mapping are being carried out by both institutions, and for some areas, outsourced to the private sector. The results presented in this contribution focus on the rockfall component only, and are part of the hazard mapping activities carried out by NGU. Results from all parties involved will further lead in future, in combination with the components on debris flows and snow avalanches, to the preparation of guidelines for landslide hazard mapping. Those will be presented and recommended for the use of private consultants that work on municipality level. The first goal of the project is the preparation of hazard maps for critical areas where a large number of people are exposed to the threat of such type of mass movements. Results from a pilot area in Sylte (Norddal municipality) were presented in the EGU general assembly in 2012. The main objective of this contribution is to present the first finished rockfall hazard maps generated by NGU during the execution of the program. The results presented in this contribution were obtained for the Norddal municipality (Møre og Romsdal county). The area was selected based on the hazard mapping plan of Norway published in 2011, where Norddal is considered a priority area. The area is located in a valley over-steepened by glacial erosion that is characterized by high cliffs of medium to coarse-grained quartz-dioritic to granitic gneisses of Proterozoic age. Multiple scree deposits product of older and recent rockfall activity can be seen along the bottom at both valley flanks. Sylte, the main locality in the Norddal municipality, is located at the valley outlet to the fjord. Several other smaller localities are found along the valley. A spatial geodatabase containing information regarding block sources, block shape and size, rock type, geometry and material properties along the potential rockfall tracks, and presence of natural energy attenuators (i.e. forest) was generated with data obtained during field work. Remote sensing imagery (high resolution aerial photographs), and a high resolution airborne LiDAR-based terrain model (1 m of spatial resolution) were used to extrapolate the information collected during field work to the full extent of the study area. Based on statistical analysis of the observed rock blocks a probability density function of the block size was obtained. This information was used to define the frequency of rockfall events of different sizes. Three scenarios were generated that follow the Norwegian regulations for construction (the Norwegian Building Act) for three different return periods: 100, 1000, and 5000 years. Numerical simulations using Rockyfor3D v. 5.0 (www.ecorisq.org) were performed for the three selected scenarios. Curves representing the maximum reach of blocks for every defined scenario with the sufficient energy to cause enough damage on buildings and houses that could threat the life of their inhabitants were used to define the hazard maps. Results show a good fit with the location of scree deposits found during field recognition. According to the results for events corresponding to the 100 year return period, populated areas are out of the hazardous zones except for the area of Sylte due to the proximity of the village to a large rock cliff. 1000 and 5000 year scenarios show some other localities along the valley prone to be affected by rockfalls. Maps will be communicated to local authorities to help defining short and long term policies regarding land use.

Research notes.

DOT National Transportation Integrated Search

1995-04-01

As many of you already know, our new Rockfall Hazard Rating System (RHRS) has gained wide national acceptance and international interest. Our most recent effort, a study of rockfall over 1/4H:1V presplit slopes, represents the first installment in th...

Numerical Simulation of Pipeline Deformation Caused by Rockfall Impact

PubMed Central

Liang, Zheng; Han, Chuanjun

2014-01-01

Rockfall impact is one of the fatal hazards in pipeline transportation of oil and gas. The deformation of oil and gas pipeline caused by rockfall impact was investigated using the finite element method in this paper. Pipeline deformations under radial impact, longitudinal inclined impact, transverse inclined impact, and lateral eccentric impact of spherical and cube rockfalls were discussed, respectively. The effects of impact angle and eccentricity on the plastic strain of pipeline were analyzed. The results show that the crater depth on pipeline caused by spherical rockfall impact is deeper than by cube rockfall impact with the same volume. In the inclined impact condition, the maximum plastic strain of crater caused by spherical rockfall impact appears when incidence angle α is 45°. The pipeline is prone to rupture under the cube rockfall impact when α is small. The plastic strain distribution of impact crater is more uneven with the increasing of impact angle. In the eccentric impact condition, plastic strain zone of pipeline decreases with the increasing of eccentricity k. PMID:24959599

Lidar-Based Rock-Fall Hazard Characterization of Cliffs

USGS Publications Warehouse

Collins, Brian D.; Greg M.Stock,

2017-01-01

Rock falls from cliffs and other steep slopes present numerous challenges for detailed geological characterization. In steep terrain, rock-fall source areas are both dangerous and difficult to access, severely limiting the ability to make detailed structural and volumetric measurements necessary for hazard assessment. Airborne and terrestrial lidar survey methods can provide high-resolution data needed for volumetric, structural, and deformation analyses of rock falls, potentially making these analyses straightforward and routine. However, specific methods to collect, process, and analyze lidar data of steep cliffs are needed to maximize analytical accuracy and efficiency. This paper presents observations showing how lidar data sets should be collected, filtered, registered, and georeferenced to tailor their use in rock fall characterization. Additional observations concerning surface model construction, volumetric calculations, and deformation analysis are also provided.

A 3D Analysis of Rock Block Deformation and Failure Mechanics Using Terrestrial Laser Scanning

NASA Astrophysics Data System (ADS)

Rowe, Emily; Hutchinson, D. Jean; Kromer, Ryan A.; Edwards, Tom

2017-04-01

Many natural geological hazards are present along the Thompson River corridor in British Columbia, Canada, including one particularly hazardous rocky slope known as the White Canyon. Railway tracks used by Canadian National (CN) and Canadian Pacific (CP) Railway companies pass through this area at the base of the Canyon slope. The geologically complex and weathered rock face exposed at White Canyon is prone to rockfalls. With a limited ditch capacity, these falling rocks have the potential to land on the tracks and therefore increase the risk of train derailment. Since 2012, terrestrial laser scanning (TLS) data has been collected at this site on a regular basis to enable researchers at Queen's University to study these rockfalls in greater detail. In this paper, the authors present a summary of an analysis of these TLS datasets including an examination of the pre-failure deformation patterns exhibited by failed rock blocks as well as an investigation into the influence of structural constraints on the pre-failure behavior of these blocks. Aligning rockfall source zones in an early point cloud dataset to a later dataset generates a transformation matrix describing the movement of the block from one scan to the next. This process was repeated such that the motion of the block over the entire TLS data coverage period was measured. A 3D roto-translation algorithm was then used to resolve the motion into translation and rotation components (Oppikofer et al. 2009; Kromer et al. 2015). Structural information was plotted on a stereonet for further analysis. A total of 111 rockfall events exceeding a volume of 1 m3 were analyzed using this approach. The study reveals that although some rockfall source blocks blocks do not exhibit detectable levels of deformation prior to failure, others do experience cm-level translation and rotation on the order of 1 to 6 degrees before detaching from the slope. Moreover, these movements may, in some cases, be related to the discontinuity planes on the slope that were confining the block. It is concluded that rock blocks in White Canyon may be classified as one of five main failure mechanisms based on their pre-failure deformation and structure: planar slide, topple, rotation, wedge, and overhang, with overhang failures representing a large portion of rockfalls in this area. Overhang rockfalls in the White Canyon are characterized by blocks that (a) are not supported by an underlying discontinuity plane, and (b) generally do not exhibit pre-failure deformation. Though overhanging rock blocks are a structural subset of toppling failure, their behavior suggests a different mechanism of detachment. Future work will further populate the present database of rockfalls in White Canyon and will expand the study to include other sites along this corridor. The ultimate goal of this research is to establish warning thresholds based on deformation magnitudes for rockfalls in White Canyon to assist Canadian railways in better understanding and managing these slopes.

Forensic analysis of rockfall scars

NASA Astrophysics Data System (ADS)

de Vilder, Saskia J.; Rosser, Nick J.; Brain, Matthew J.

2017-10-01

We characterise and analyse the detachment (scar) surfaces of rockfalls to understand the mechanisms that underpin their failure. Rockfall scars are variously weathered and comprised of both discontinuity release surfaces and surfaces indicative of fracturing through zones of previously intact rock, known as rock bridges. The presence of rock bridges and pre-existing discontinuities is challenging to quantify due to the difficulty in determining discontinuity persistence below the surface of a rock slope. Rock bridges form an important control in holding blocks onto rockslopes, with their frequency, extent and location commonly modelled from the surface exposure of daylighting discontinuities. We explore an alternative approach to assessing their role, by characterising failure scars. We analyse a database of multiple rockfall scar surfaces detailing the areal extent, shape, and location of broken rock bridges and weathered surfaces. Terrestrial laser scanning and gigapixel imagery were combined to record the detailed texture and surface morphology. From this, scar surfaces were mapped via automated classification based on RGB pixel values. Our analysis of the resulting data from scars on the North Yorkshire coast (UK) indicates a wide variation in both weathering and rock bridge properties, controlled by lithology and associated rock mass structure. Importantly, the proportion of rock bridges in a rockfall failure surface does not increase with failure size. Rather larger failures display fracturing through multiple rock bridges, and in contrast smaller failures fracture occurs only through a single critical rock bridge. This holds implications for how failure mechanisms change with rockfall size and shape. Additionally, the location of rock bridges with respect to the geometry of an incipient rockfall is shown to determine failure mode. Weathering can occur both along discontinuity surfaces and previously broken rock bridges, indicating the sequential stages of progressively detaching rockfall. Our findings have wider implications for hazard assessment where rock slope stability is dependent on the nature of rock bridges, how this is accounted for in slope stability modelling, and the implications of rock bridges on long-term rock slope evolution.

Effects of protection forests on rockfall risks: implementation in the Swiss risk concept

NASA Astrophysics Data System (ADS)

Trappmann, Daniel; Moos, Christine; Fehlmann, Michael; Ernst, Jacqueline; Sandri, Arthur; Dorren, Luuk; Stoffel, Markus

2016-04-01

Forests growing on slopes below active rockfall cliffs can provide effective protection for human lives and infrastructures. The risk-based approach for natural hazards in Switzerland shall take such biological measures just like existing technical protective measures into account, provided that certain criteria regarding condition, maintenance and durability are met. This contribution describes a project in which we are investigating how the effects of protection forests can be considered in rockfall risk analyses in an appropriate way. In principle, protection forests reduce rockfall risks in three different ways: (i) reduction of the event magnitude (energy) due to collisions with tree stems; (ii) reduction of frequency of occurrence of a given scenario (block volume arriving at the damage potential); (iii) reduction of spatial probability of occurrence (spread and runout) of a given scenario in case of multiple fragments during one event. The aim of this work is to develop methods for adequately implementing these three effects of rockfall protection forests in risk calculations. To achieve this, we use rockfall simulations taking collisions with trees into account and detailed field validation. On five test sites, detailed knowledge on past rockfall activity is gathered by combining investigations of impacted trees, analysis of documented historical events, and deposits in the field. Based on this empirical data on past rockfalls, a methodology is developed that allows transferring real past rockfall activity to simulation results obtained with the three-dimensional, process-based model Rockyfor3D. Different ways of quantifying the protective role of forests will be considered by comparing simulation results with and without forest cover. Combining these different research approaches, systematic considerations shall lead to the development of methods for adequate inclusion of the protective effects of forests in risk calculations. The applicability of the developed methods will be tested on the case study slopes in order to ensure practical applicability to a broad range of rockfall situations on forested slopes.

A re-analysis of 533 rockfalls occurred since 2003 in the Mont Blanc massif for the study of their relationship with permafrost

NASA Astrophysics Data System (ADS)

Ravanel, Ludovic; Magnin, Florence; Deline, Philip

2015-04-01

Rockfall is one of the main natural hazards in high mountain regions and its frequency is growing, especially since two decades. Collapses at high elevation are with an increasing certainty assumed to be a consequence of the climate change through the warming permafrost. In the Mont Blanc massif, data on present rockfalls (occurrence time when possible, accurate location, topographical and geological settings, volume, weather and snow conditions) were acquired for 2003 and for the period 2007-2014 thanks to a satellite image of the massif and a network of observers in the central part of the massif, respectively. The study of the 533 so-documented rockfalls shows a strong correlation at the year scale between air temperature and rockfall. Along with this data acquisition, a statistical model of the Mean Annual Rock Surface Temperature (MARST) for the 1961-1990 period has been implemented on a 4-m-resolution DEM of the Mont Blanc massif. The model runs with Potential Incoming Solar radiation (PISR) calculated with GIS tools and air temperature parameters computed from Chamonix Météo France records. We cross here the data on rockfalls with the permafrost distribution model to show that: (i) rockfall occurs mainly over modeled negative MARST (context of permafrost); (ii) simulated warm permafrost areas (> -2°C) are the most affected by instabilities; (iii) as the 1961-1990 period is supposed to be representative of the conditions at depth that are not affected by the climate warming during the two last decades, the latest results are mainly valuable for rockfalls related to pluri-decadal signal; and (iv) the higher (close to 0°C) the MARST, the deeper the detachment (possibly related to the deepening of the permafrost active layer). These results and field observations confirm that warming permafrost corresponds to the main required configuration for rockfall triggering at high elevation. In addition, we show that rockfalls for which ice observed in their scar indicates the presence of permafrost can be used to validate the permafrost distribution model.

Improved characterization, monitoring and instability assessment of high rock faces by integrating TLS and GB-InSAR

NASA Astrophysics Data System (ADS)

Bianchetti, Matteo; Agliardi, Federico; Villa, Alberto; Battista Crosta, Giovanni; Rivolta, Carlo

2015-04-01

Rockfall risk analysis require quantifying rockfall onset susceptibility and magnitude scenarios at source areas, and the expected rockfall trajectories and related dynamic quantities. Analysis efforts usually focus on the rockfall runout component, whereas rock mass characterization and block size distribution quantification, monitoring and analysis of unstable rock volumes are usually performed using simplified approaches, due to technological and site-specific issues. Nevertheless, proper quantification of rock slope stability and rockfall magnitude scenarios is key when dealing with high rock walls, where widespread rockfall sources and high variability of release mechanisms and block volumes can result in excessive modelling uncertainties and poorly constrained mitigation measures. We explored the potential of integrating field, remote sensing, structural analysis and stability modelling techniques to improve hazard assessment at the Gallivaggio sanctuary site, a XVI century heritage located along the State Road 36 in the Spluga Valley (Italian Central Alps). The site is impended by a subvertical cliff up to 600 m high, made of granitic orthogneiss of the Truzzo granitic complex (Tambo Nappe, upper Pennidic domain). The rock mass is cut by NNW and NW-trending slope-scale structural lineaments and by 5-6 fracture sets with variable spatial distribution, spacing and persistence, which bound blocks up to tens of cubic meters and control the 3D slope morphology. The area is characterised by widespread rock slope instability from rockfalls to massive failures. Although a 180 m long embankment was built to protect the site from rockfalls, concerns remain about potential large unstable rock volumes or flyrocks projected by the widely observed impact fragmentation of stiff rock blocks. Thus, the authority in charge started a series of periodical GB-InSAR monitoring surveys using LiSALabTM technology (12 surveys in 2011-2014), which outlined the occurrence of unstable spots spread over the cliff, with cm-scale cumulative displacements in the observation period. To support the interpretation and analysis of these data, we carried out multitemporal TLS surveys (5 sessions between September 2012 and October 2014) using a Riegl VZ-1000 long-range laser scanner. We performed rock mass structural analyses on dense TLS point clouds using two different approaches: 1) manual discontinuity orientation and intensity measurement from digital outcrops; 2) automatic feature extraction and intensity evaluation through the development of an original Matlab tool, suited for multi-scale applications and optimized for parallel computing. Results were validated using field discontinuity measurements and compared to evaluate advantages and limitations of different approaches, and allowed: 1) outlining the precise location, geometry and kinematics of unstable blocks and block clusters corresponding to radar moving spots; 2) performing stability analyses; 3) quantifying rockwall changes over the observation period. Our analysis provided a robust spatial characterization of rockfall sources, block size distribution and onset susceptibility as input for 3D runout modelling and quantitative risk analysis.

Rockfall hazard assessment, risk quantification, and mitigation options for reef cove resort development, False Cape, Queensland, Australia

NASA Astrophysics Data System (ADS)

Schlotfeldt, P.

2009-04-01

GIS and 2-D rock fall simulations were used as the primary tools during a rock fall hazard assessment and analyses for a major resort and township development near Cairns, Queensland in Australia. The methods used included 1) the development of a digital elevation model (DEM); undertaking rock fall trajectory analyses to determine the end points of rockfalls, the distribution of kinetic energy for identified rock fall runout Zones, and 3) undertaking event tree analyses based on a synthesis of all data in order to establish Zones with the highest risk of fatalities. This paper describes the methodology used and the results of this work. Recommendations to mitigate the hazard included having exclusions zones with no construction, scaling (including trim blasting), construction of berms and rockfall catch fences. Keywords: GIS, rockfall simulation, rockfall runout Zones, mitigation options INTRODUCTION False Cape is located on the east side of the Trinity inlet near Cairns (Figure 1). Construction is underway for a multi-million dollar development close the beach front. The development will ultimately cover about 1.5 km of prime coast line. The granite slopes above the development are steep and are covered with a number of large, potentially unstable boulders. Sheet jointing is present in the in-situ bedrock and these combined with other tectonic joint sets have provided a key mechanism for large side down slope on exposed bedrock. With each rock fall (evidence by boulders strew in gullies, over the lower parts of the slope, and on the beach) the failure mechanism migrates upslope. In order for the Developer to proceed with construction he needs to mitigate the identified rock fall hazard. The method used to study the hazard and key finding are presented in this paper. Discussion is provided in the conclusion on mitigation options. KEY METHODS USED TO STUDY THE HAZARD In summary the methods used to study the hazard for the False Cape project include; 1. The development of a digital elevation model (DEM) used to delineate rock fall runout Zones [1] that included the spatial location of boulder fields mapped within Zones(Figure 2). A Zone is defined as an area above the development on steep sided slopes where falling rocks are channeled into gullies / and or are contained between topographic features such as ridges and spurs that extend down the mountainside. These natural barriers generally ensure that falling rocks do not fall or roll into adjacent Zones; 2. The use of ‘Flow Path Tracing Tool' in Arc GIS spatial analyst to confirm typical descents of boulders in Zones. These were shown to correlated strongly with the endpoints of boulders observed within the development and major clusters of boulders on the beach front; 3. The use of 2-D rockfall trajectory analyses [2] using sections cut along typical 3-D trajectory paths mapped out in ARC GIS per Zone. Sections along typical paths in Zones simulated, to some degree, the 3-D affect or path of rocks as they bounce roll down slope (Figure 3); 4. The calibration of rockfall input parameters (coefficients of normal and tangential restitution, slope roughness, friction angle, etc.) using field identified endpoints and size of fallen rock and boulder; and 5. Undertaking risk evolutions in order to quantify the potential risk for each independent rockfall Zone. KEY FINDINGS FROM THE STUDIES The key findings from the study include; 1. Multiple potentially unstable in-situ boulders (some in excess of several thousand tonnes) are present above the development. 2. Similar geological structures (dykes, jointing, etc.) are present in the boulders on the beach front and within the development exposed in-situ bedrock located above the development. Measurement and comparison of the orientation of these geological structures present in boulders with that observed in the in-situ bedrock provided strong evidence that that the boulders have mitigated down slope. 3. Eight discrete Rockfall Runout Zones were identified using the digital elevation model set up in ARC GIS (Figure 4). The boundaries were field verified as far as possible. The identified Zones formed the basis of all subsequent work. 4. Once calibrated the rockfall trajectory modeling showed that only between 1% and in the worst case 28% of falling rocks (percentage of 1000 seeding events) per Zones would actually reach the development. While this indicated a reduced likelihood of an incident and hence the risk, the kinetic energy in the case of an impact in most Zones was so high (for the given design block size) that the consequence would be untenable without some form of mitigation. 5. An event tree analysis showed that five out of the eight Zones identified had risk profiles that fell above or very close to what was considered to be an acceptable annual probability of occurrence of a fatality or fatalities. CONCLUSIONS Each Zone has unique characteristics that influence the risk profile associated with the rock fall hazard to the development. Mitigation options and recommendations needed to be adjusted accordingly to fit the physical characteristics and assessed risk profile of each Zone. These included: 1. The possible implantation of exclusion zones (no build areas); 2. Scaling (including controlled blasting) to reduce the potential kinetic energy associated with identified potentially unstable boulders; and 3. The design and construction of Berms and rockfall catch fences.

Quantification of controls on regional rockfall activity and talus deposition, Kananaskis, Canadian Rockies

NASA Astrophysics Data System (ADS)

Thapa, Prasamsa; Martin, Yvonne E.; Johnson, E. A.

2017-12-01

Rockfall is a significant geomorphic process in many mountainous regions that also poses a notable natural hazard risk. Most previous studies of rockfall erosion have investigated the mechanics and rates of local rockwall retreat and talus deposition, with only a few investigations of rockfall and/or associated talus considering larger spatial scales (i.e., drainage basin, mountain range). The purpose of the current research is to investigate the areal extent of rockfall-talus and controlling factors of its distribution over regional spatial scales (of order 102 km2) in Kananaskis, Canadian Rockies to inform our understanding of its significance in mountain development. To achieve this goal, a large talus inventory is collected and analyzed for 11 steep tributaries of the Kananaskis River, Canadian Rockies. Talus accumulations associated with rockfall provide evidence about the nature and rates of rockfall activity that supplies sediment to these deposits and are the focus of the present study. To quantify the controls of rockfall-talus activity in this region, we analyze the association of talus deposits with structural geology, glacial topography, and temperature-related weathering (i.e., frost cracking). A total of 324 talus polygons covering a surface area of 28.51 km2 are delineated within the 11 study basins, with the number of talus polygons in each study basin ranging from 1 to 73. Analysis of the talus inventory shows that cirques and glacially sculpted valleys are locations of notable talus accumulation in Kananaskis, with other locations of significant talus deposition being associated with thrust faults. We also found that the upper elevations at which talus deposits are typically found are the general range of elevations experiencing a notable number of days in the frost cracking window when this window is defined as - 3 to - 15 °C; no such association is found for the frost cracking window of - 3 to - 8 °C. Estimates of average erosion rates for all study basins combined are between 0.15 mm y- 1 (lower estimate) to 3.1 mm y- 1 (upper estimate). Rockfall activity is expected to have been most active for the several millennia following deglaciation (during the paraglacial period) when hillslopes were oversteepened.

The impact of overlapping processes on rockfall hazard analysis - the Bolonia Bay study (southern Spain)

NASA Astrophysics Data System (ADS)

Fernandez-Steeger, T.; Grützner, C.; Reicherter, K.; Braun, A.; Höbig, N.

2009-04-01

For rockfall simulations, competitive case studies and data sets are important to develop and evaluate the models or software. Especially for empirical or data driven stochastic modelling the quality of the reference data sets has a major impact on model skills and knowledge discovery. Therefore, rockfalls in the Bolonia Bay close to Tarifa (Spain) were mapped. Here, the siliciclastic Miocene rocks (megaturbidites) are intensively joined and disaggregated by a perpendicular joint system. Although bedding supports stability as the dip is not directed towards the rock face, the deposits indicate a continuous process of material loss from the 80 m high cliff of the San Bartolome mountain front by single large rock falls. For more than 300 blocks data on size, shape, type of rock, and location were collected. The work concentrated on rockfall blocks with a volume of more than 2 m³ and up to 350 m³. Occasionally very long "runout" distances of up to 2 km have been observed. For all major source areas and deposits, runout analysis using empirical models and a numerical trajectorian model has been performed. The most empirical models are principally based on the relation between fall height and travel distance. Beside the "Fahrböschung" from Heim (1932) the "shadow angle" introduced by Evans and Hungr (1993) is most common today. However, studies from different sites show a wide variance of the angle relations (Dorren 2003, Corominas 1996). The reasons for that might be different environments and trigger mechanisms, or varying secondary effects such as post-depositional movement. Today, "semi" numerical approaches based on trajectorian models are quite common to evaluate the rockfall energy and the runout distance for protection measures and risk evaluations. The results of the models highly depend on the quality of the input parameters. One problem here might be that some of the parameters, especially the dynamic ones, are not easy to determine and the quality of the digital elevation model has an large impact on energy estimations and travel paths. In the course of this study the model of "shadow angel", "Fahrböschung" and a numerical simulation using "Rockfall 6.2" (Spang & Sonser 1995) have been applied to the mapped rockfall deposits. The results revealed a good coherence of all three modeling attempts in some cases. Especially for deposition areas where many single rockfall events could be identified as young all models performed well and showed nearly identical results. In other areas with large deposits and long travel distances, the model predictions vary strongly and the shadow angles do not fit the usual ranges at all. Here, post-depositional transport by surface-near landslides in a piggy-back style is postulated. Medium- and large-scaled landslides and creep in soils are proven in the whole bay. Landslide bodies can be observed in the deposition areas and were proved with GPR. Additionally, the weathered marls and clays of the Flysch deposits below the rock face are highly active and likely to be subject to sliding after heavy rainfalls. Another reason for the extraordinary long runout distances might be seismic triggering. Paleoseismological and archeoseismological investigations already showed that the study area suffered destructive earthquakes even in historical times (Silva et al 2009). This trigger mechanism was simulated for various blocks, but did not lead to the expected results in all cases. Strong winds have also to be considered as an additionally trigger mechanism for rockfalls by leverage as wind forces > 5 Bft are present in the forested study area more than 300 days per year. The results show that simple stochastic analysis using large data sets without taking triggering mechanism and geological environment in consideration may lead to mere general models. More data sets and comparative studies are necessary to evaluate the threshold values for the empirical models like the shadow angle. Anyhow the results from the described investigation show that on a screening and planning level the results of the empirical methods are quite good. Especially for numerical simulation, where back analysis is common to parameterize the models, the identification of "ideal" rockfalls is essential for a good simulation performance and subsequently for an appropriate planning of protection measures. References Corominas, J. 1996. The angle of reach as a mobility index for small and large landslides. Canadian Geotechnical Journal, 33, 260 - 271. Dorren, L.K. 2003. A review of rockfall mechanics and modeling approaches. Progress in Physical Geography, 27 (1), 69 - 87. Evans, S. & Hungr, O. 1993. The assessment of rockfall hazard at the base of talus slopes. Canadian Geotechnical Journal, 30, 620 - 636. Heim, A. 1932. Bergsturz und Menschenleben. Vjschr. d. Naturforsch Ges. Zürich, 216 pp. Silva P.G., Reicherter K., Grützner C., Bardají T., Lario J., Goy J.L., Zazo C., & Becker-Heidmann P. 2009. Surface and subsurface paleoseismic records at the ancient Roman city of Baelo Claudia and the Bolonia Bay area, Cádiz (South Spain). Geol Soc of London Spec. Vol.: Paleoseismology: Historical and prehistorical records of earthquake ground effects for seismic hazard assessment. In press. Spang, R. M. & Sonser, Th. 1995. Optimized rockfall protection by "ROCKFALL". Proc 8th Int Congress Rock Mechanics, 3, 1233-1242.

Risk Management for Wilderness Programs.

ERIC Educational Resources Information Center

Schimelpfenig, Tod

This paper discusses subjective hazards in wilderness activities and suggests means of assessing and managing related risks. Wilderness educators conveniently group hazards into objective and subjective ones. Objective hazards such as rockfall, moving water, and weather, while not necessarily predictable, are visible and understandable. Subjective…

Laser Scanning Systems and Techniques in Rockfall Source Identification and Risk Assessment: A Critical Review

NASA Astrophysics Data System (ADS)

Fanos, Ali Mutar; Pradhan, Biswajeet

2018-04-01

Rockfall poses risk to people, their properties and to transportation ways in mountainous and hilly regions. This catastrophe shows various characteristics such as vast distribution, sudden occurrence, variable magnitude, strong fatalness and randomicity. Therefore, prediction of rockfall phenomenon both spatially and temporally is a challenging task. Digital Terrain model (DTM) is one of the most significant elements in rockfall source identification and risk assessment. Light detection and ranging (LiDAR) is the most advanced effective technique to derive high-resolution and accurate DTM. This paper presents a critical overview of rockfall phenomenon (definition, triggering factors, motion modes and modeling) and LiDAR technique in terms of data pre-processing, DTM generation and the factors that can be obtained from this technique for rockfall source identification and risk assessment. It also reviews the existing methods that are utilized for the evaluation of the rockfall trajectories and their characteristics (frequency, velocity, bouncing height and kinetic energy), probability, susceptibility, hazard and risk. Detail consideration is given on quantitative methodologies in addition to the qualitative ones. Various methods are demonstrated with respect to their application scales (local and regional). Additionally, attention is given to the latest improvement, particularly including the consideration of the intensity of the phenomena and the magnitude of the events at chosen sites.

Rock shape, restitution coefficients and rockfall trajectory modelling

NASA Astrophysics Data System (ADS)

Glover, James; Christen, Marc; Bühler, Yves; Bartelt, Perry

2014-05-01

Restitution coefficients are used in rockfall trajectory modelling to describe the ratio between incident and rebound velocities during ground impact. They are central to the problem of rockfall hazard analysis as they link rock mass characteristics to terrain properties. Using laboratory experiments as a guide, we first show that restitution coefficients exhibit a wide range of scatter, although the material properties of the rock and ground are constant. This leads us to the conclusion that restitution coefficients are poor descriptors of rock-ground interaction. The primary problem is that "apparent" restitution coefficients are applied at the rock's centre-of-mass and do not account for rock shape. An accurate description of the rock-ground interaction requires the contact forces to be applied at the rock surface with consideration of the momentary rock position and spin. This leads to a variety of rock motions including bouncing, sliding, skipping and rolling. Depending on the impact configuration a wide range of motions is possible. This explains the large scatter of apparent restitution coefficients. We present a rockfall model based on newly developed hard-contact algorithms which includes the effects of rock shape and therefore is able to reproduce the results of different impact configurations. We simulate the laboratory experiments to show that it is possible to reproduce run-out and dispersion of different rock shapes using parameters obtained from independent tests. Although this is a step forward in rockfall trajectory modelling, the problem of parametersing real terrain remains.

Rock-fall potential in the Yosemite Valley, California

USGS Publications Warehouse

Wieczorek, G.F.; Morrissey, M.M.; Iovine, Giulio; Godt, Jonathan

1999-01-01

We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.

Quantifying, Analysing and Modeling Rockfall Activity in two Different Alpine Catchments using Terrestrial Laserscanning

NASA Astrophysics Data System (ADS)

Haas, F.; Heckmann, T.; Wichmann, V.; Becht, M.

2011-12-01

Rockfall processes play a major role as a natural hazard, especially if the rock faces are located close to infrastructure. However these processes cause also the retreat of the steep rock faces by weathering and the growth of the corresponding talus cones by routing debris down the talus cones. That's why this process plays also an important role for the geomorphic system and the sediment budget of high mountain catchments. The presented investigation deals with the use of TLS for quantification and for analysis of rockfall activity in two study areas located in the Alps. The rockfaces of both catchments and the corresponding talus cones were scanned twice a year from different distances. Figure 1 shows an example for the spatial distribution of surface changes at a rockface in the Northern Dolomites between 2008 and 2010. The measured surface changes at this location yields to a mean rockwall retreat of 0.04 cm/a. But high resolution TLS data are not only applicable to quantify rockfall activity they can also be used to characterize the surface properties of the corresponding talus cones and the runout distances of bigger boulders and this can lead to a better process understanding. Therefore the surface roughness of talus cones in both catchments was characterized from the TLS point clouds by a GIS approach. The resulting detailed maps of the surface conditions on the talus cones were used to improve an existing process model which is able to model runout distances on the talus cones using distributed friction parameters. Beside this the investigations showed, that also the shape of the boulders has an influence on the runout distance. That's why the interrelationships between rock fragment morphology and runout distance of over 600 single boulders were analysed at the site of a large rockfall event. The submitted poster will show the results of the quantification of the rockfall activity and additionally it will show the results of the analyses of the talus cones and of the large rockfall event and applying these results to an existing rockfall model.

Rockfall hazard and risk assessment: an example from a high promontory at the historical site of Monemvasia, Greece

NASA Astrophysics Data System (ADS)

Saroglou, H.; Marinos, V.; Marinos, P.; Tsiambaos, G.

2012-06-01

The paper presents the kinematics of rock instability of a high limestone promontory, where the Monemvasia historical site is situated, in Peloponnese in Southern Greece. The instability phenomena poses a significant threat to the town located at the base of the slope. Rockfall episodes occurred in the past due to the relaxation of the high cliff, whereas significant undermining of the castle frontiers has been observed at the slope crest. The predominant types of instability are of planar, wedge and toppling failure of medium to large blocks. In order to investigate the existing stability conditions and decide upon the protection measures, stability and rockfall analyses were carried out for numerous slope sections under different loading conditions and protection measures were suggested. A rock-fall risk rating system is proposed, which is based on morphological and structural criteria of the rock mass and on vulnerability and consequences. The rating system is applied for individual sections along the slope and a risk map was produced, which depicted areas having different degree of risk against rockfall occurrences.

High-resolution three-dimensional imaging and analysis of rock falls in Yosemite valley, California

USGS Publications Warehouse

Stock, Gregory M.; Bawden, G.W.; Green, J.K.; Hanson, E.; Downing, G.; Collins, B.D.; Bond, S.; Leslar, M.

2011-01-01

We present quantitative analyses of recent large rock falls in Yosemite Valley, California, using integrated high-resolution imaging techniques. Rock falls commonly occur from the glacially sculpted granitic walls of Yosemite Valley, modifying this iconic landscape but also posing signifi cant potential hazards and risks. Two large rock falls occurred from the cliff beneath Glacier Point in eastern Yosemite Valley on 7 and 8 October 2008, causing minor injuries and damaging structures in a developed area. We used a combination of gigapixel photography, airborne laser scanning (ALS) data, and ground-based terrestrial laser scanning (TLS) data to characterize the rock-fall detachment surface and adjacent cliff area, quantify the rock-fall volume, evaluate the geologic structure that contributed to failure, and assess the likely failure mode. We merged the ALS and TLS data to resolve the complex, vertical to overhanging topography of the Glacier Point area in three dimensions, and integrated these data with gigapixel photographs to fully image the cliff face in high resolution. Three-dimensional analysis of repeat TLS data reveals that the cumulative failure consisted of a near-planar rock slab with a maximum length of 69.0 m, a mean thickness of 2.1 m, a detachment surface area of 2750 m2, and a volume of 5663 ?? 36 m3. Failure occurred along a surfaceparallel, vertically oriented sheeting joint in a clear example of granitic exfoliation. Stress concentration at crack tips likely propagated fractures through the partially attached slab, leading to failure. Our results demonstrate the utility of high-resolution imaging techniques for quantifying far-range (>1 km) rock falls occurring from the largely inaccessible, vertical rock faces of Yosemite Valley, and for providing highly accurate and precise data needed for rock-fall hazard assessment. ?? 2011 Geological Society of America.

Investigation and hazard assessment of the 2003 and 2007 Staircase Falls rock falls, Yosemite National Park, California, USA

USGS Publications Warehouse

Wieczorek, G.F.; Stock, Gregory M.; Reichenbach, P.; Snyder, J.B.; Borchers, J.W.; Godt, J.W.

2008-01-01

Since 1857 more than 600 rock falls, rock slides, debris slides, and debris flows have been documented in Yosemite National Park, with rock falls in Yosemite Valley representing the majority of the events. On 26 December 2003, a rock fall originating from west of Glacier Point sent approximately 200 m 3 of rock debris down a series of joint-controlled ledges to the floor of Yosemite Valley. The debris impacted talus near the base of Staircase Falls, producing fragments of flying rock that struck occupied cabins in Curry Village. Several years later on 9 June 2007, and again on 26 July 2007, smaller rock falls originated from the same source area. The 26 December 2003 event coincided with a severe winter storm and was likely triggered by precipitation and/or frost wedging, but the 9 June and 26 July 2007 events lack recognizable triggering mechanisms. We investigated the geologic and hydrologic factors contributing to the Staircase Falls rock falls, including bedrock lithology, weathering, joint spacing and orientations, and hydrologic processes affecting slope stability. We improved upon previous geomorphic assessment of rock-fall hazards, based on a shadow angle approach, by using STONE, a three-dimensional rock-fall simulation computer program. STONE produced simulated rock-fall runout patterns similar to the mapped extent of the 2003 and 2007 events, allowing us to simulate potential future rock falls from the Staircase Falls detachment area. Observations of recent rock falls, mapping of rock debris, and simulations of rock fall runouts beneath the Staircase Falls detachment area suggest that rock-fall hazard zones extend farther downslope than the extent previously defined by mapped surface talus deposits.

Characterization of Joint Sets Through UAV Photogrammetry on Sedimentary Rock Sea Cliffs and Abrasion Platforms in Northern Taiwan

NASA Astrophysics Data System (ADS)

Hsieh, P. C.; LU, A.; Yeh, C. H.; Huang, W. K.; Lin, H. H.; Lin, M. L.

2017-12-01

Rockfall hazards are very common in obsequent slope and oblique slope. In the coastal area of northern Taiwan, many sea cliffs are formed by obsequent slope and oblique slope. A famous case of rockfall failure happened on Aug. 31, 2013, a 150-ton rock block fell on the highway in Badouzi, Keelung, during a high intensity rainfall event which was caused by Typhoon No.15 (Kong-rey). To reduce this kind of rockfall hazard, it is important to characterize discontinuous planes in the bedrock because rock blocks are mainly divided from bedrock by two or more sets of discontinuous planes including joint planes and the bedding plane. For doing characterization of those fracture patterns of joint sets, it is necessary to do detailed field investigations. However, the survey of discontinuous planes, especially joint sets, are usually difficult and cannot get enough characterization data about joint sets. The first reason is that doing field investigations on the surface of sea cliffs is very dangerous and difficult for engineers or geologists to approach the upper part of outcrop. The second reason is the complexity of joint sets. In Badouzi area, each cliff is constituted by many different layers such as sandstone, shale, or alternations of sandstone and shale, and each layer has different fracture pattern of joint sets. In this study, we use UAV photogrammetry as a solution of these difficulties. UAV photogrammetry can produce a high-resolution digital surface model (DSM), orthophoto, and anaglyph of sea cliffs and abrasion platforms. Than we use self-developed geoprocessing toolsets to auto-trace joint planes with DSM data and produce fracture pattern of joint sets semi-automatically and systematically. Our method can provide basic information for rock mass rating on rock slope stability and rockfall hazards evaluation.

Rockfall activity of cliff inferred from deposit and cone method

NASA Astrophysics Data System (ADS)

Jaboyedoff, M.; Baillifard, F.; Rouiller, J.-D.

2003-04-01

Assuming that fresh scree slopes are significant indicators of recent rockfall activity, they can be used as activity indicators for a given rockfall source area. Using simple geometric rules and a DTM (digital elevation model), the propagation zone can be estimated by considering that each potential rockfall source cell (corresponding to the entire cliff) can generate a scree slope within a cone with a slope ranging from 27° to 37°. Thus, the count of pixels representing rockfall deposits that are contained in this cone represents a relative scale of recent rockfall activity. According to Evans and Hungr (1993), the source cell can be chosen at the bottom of the cliff, with lower angles. Choosing the entire cliff or the bottom of the cliff as source area depends on the morphology of the slope situated below the cliff. The cone can also be laterally limited in order to avoid the counting of illogical rock slope trajectories (+-20°). In Switzerland, the vectorized 1:25,000 topographic map (vector25) can provide scree slope and cliff area data sets. Results obtained using this method show good agreement with field observations, although it is evident that the highest topographic reliefs are favored by this method, as verified in the Alps. Compared to the method of Menendéz Duarte and Marquínez (2002), which uses GIS-calculated watersheds as propagation areas, the present method does not take small changes of topography into account. References Evans, S.G. and Hungr, O. The assessment of rockfall hazard at the base of talus slopes. Canadian Geotechnical Journal, 30/4, 620-636, 1993. Menendéz Duarte, R. and Marquínez, J. The influence of environmental and lithologic factors on rockfall at a regional scale: an evaluation using GIS. Geomorphology, 43, 117-136, 2002.

Rockfall risk assessment for a road along the coastal rocky slope of Maratea (Basilicata Region, Italy)

NASA Astrophysics Data System (ADS)

Pellicani, R.; Spilotro, G.; Colangelo, G.; Petraglia, A.; Pizzo, V.

2012-04-01

The rockfall risk has been evaluated for the Tirrena Inferiore State Road SS18 between 220+600 and 243+670 Kilometers in the coastal area of Maratea (Basilicata, Italy) through a specific multilayer technique. These results are particularly significant as validated in field through the occurrence of rockfall events after the study. The study part of "Tirrena Inferiore" SS18 road is often affected by rockfalls, which periodically (coinciding with abundant rainfalls, earthquakes and temperature lowering) cause large amount of damage and traffic interruptions. In order to assess the rockfall risk and define the countermeasure needed to mitigate the risk, an integrated index-based and physically-based approach was implemented. The roadway is subject to slopes with steep rocky vertical or sub-vertical faces affected by different systems of discontinuities, that show a widespread fracturing. The superficial parts of slopes are characterized by gaping fracturing, often karstified. Several historical rockfall events were recognized in the area and numerous geomechanical analyses, finalized to the stability analysis of rock walls, were carried out. The localization of the potentially unstable areas and the quantification of relative rockfall risk were evaluated through three successive phases of analysis. First, a map based on SMR (Slope Mass Rating) Index of Romana (1985) was produced, through a spatial analysis of both geomechanical parameters, such as the RMR Index of Bieniawski, and the distribution of the discontinuities. This approach therefore allowed the estimation of the potentially unstable zones and their classification on the basis of the resulting stability degree. Subsequently, an analysis of the rockfall trajectories in correspondence to the most unstable zones of slope was carried out by using ROTOMAP, a 3-dimensional rock-fall simulation software. The input data for computing the rockfall trajectories are the following: (1) digital terrain model (DTM), (2) location of rock-fall release points (source areas), (3) geometrical parameters of block rolling, such as limit angle of flight, impact and rebound, and (4) geomechanical parameters of block rolling, such as the coefficients of normal and tangential energy restitution. For each DTM cell the software calculates the number of blocks passing through, the maximum rock-fall velocity and the maximum flying height. These information were used in order to verify the efficiency of the existing rockfall protection systems. Finally, the rockfall risk map was realized through the evaluation of the spatial distribution of the following three parameters: (i) lithology, (ii) kinematic compatibility, and (iii) historical rockfall events. After quantifying the risk, the most suitable typologies of rockfall protection systems were identified for the most unstable sections of slopes. The importance and usefulness of this study derives from the validation of the obtained results, in terms of risk, through the occurrence of new rockfall events in those areas for which the highest level of rockfall risk was defined in previous study.

Fast rockfall hazard assessment along a road section using the new LYNX Mobile Mapper Lidar

NASA Astrophysics Data System (ADS)

Dario, Carrea; Celine, Longchamp; Michel, Jaboyedoff; Marc, Choffet; Marc-Henri, Derron; Clement, Michoud; Andrea, Pedrazzini; Dario, Conforti; Michael, Leslar; William, Tompkinson

2010-05-01

The terrestrial laser scanning (TLS) is an active remote sensing technique providing high resolution point clouds of the topography. The high resolution digital elevations models (HRDEM) derived of these point clouds are an important tool for the stability analysis of slopes. The LYNX Mobile Mapper is a new TLS generation developed by Optech. Its particularity is to be mounted on a vehicle and providing a 360° high density point cloud at 200-khz measurement rate in a very short acquisition time. It is composed of two sensors improving the resolution and reducing the laser shadowing. The spatial resolution is better than 10 cm at 10 m range and at a velocity of 50 km/h and the reflectivity of the signal is around 20% at a distance of 200 m. The Lidar is also equipped with a DGPS and an inertial measurement unit (IMU) which gives real time position and georeferences directly the point cloud. Thanks to its ability to provide a continuous data set from an extended area along a road, this TLS system is useful for rockfall hazard assessment. In addition, this new scanner decrease considerably the time spent in the field and the postprocessing is reduced thanks to resultant georeferenced data. Nevertheless, its application is limited to an area close to the road. The LYNX has been tested near Pontarlier (France) along roads sections affected by rockfall. Regarding to the tectonic context, the studied area is located in the Folded Jura mainly composed of limestone. The result is a very detailed point cloud with a point spacing of 4 cm. The LYNX presents detailed topography on which a structural analysis has been carried out using COLTOP-3D. It allows obtaining a full structural description along the road. In addition, kinematic tests coupled with probabilistic analysis give a susceptibility map of the road cut or natural cliffs above the road. Comparisons with field survey confirm the Lidar approach.

Seismic monitoring of small alpine rockfalls - validity, precision and limitations

NASA Astrophysics Data System (ADS)

Dietze, Michael; Mohadjer, Solmaz; Turowski, Jens M.; Ehlers, Todd A.; Hovius, Niels

2017-10-01

Rockfall in deglaciated mountain valleys is perhaps the most important post-glacial geomorphic process for determining the rates and patterns of valley wall erosion. Furthermore, rockfall poses a significant hazard to inhabitants and motivates monitoring efforts in populated areas. Traditional rockfall detection methods, such as aerial photography and terrestrial laser scanning (TLS) data evaluation, provide constraints on the location and released volume of rock but have limitations due to significant time lags or integration times between surveys, and deliver limited information on rockfall triggering mechanisms and the dynamics of individual events. Environmental seismology, the study of seismic signals emitted by processes at the Earth's surface, provides a complementary solution to these shortcomings. However, this approach is predominantly limited by the strength of the signals emitted by a source and their transformation and attenuation towards receivers. To test the ability of seismic methods to identify and locate small rockfalls, and to characterise their dynamics, we surveyed a 2.16 km2 large, near-vertical cliff section of the Lauterbrunnen Valley in the Swiss Alps with a TLS device and six broadband seismometers. During 37 days in autumn 2014, 10 TLS-detected rockfalls with volumes ranging from 0.053 ± 0.004 to 2.338 ± 0.085 m3 were independently detected and located by the seismic approach, with a deviation of 81-29+59 m (about 7 % of the average inter-station distance of the seismometer network). Further potential rockfalls were detected outside the TLS-surveyed cliff area. The onset of individual events can be determined within a few milliseconds, and their dynamics can be resolved into distinct phases, such as detachment, free fall, intermittent impact, fragmentation, arrival at the talus slope and subsequent slope activity. The small rockfall volumes in this area require significant supervision during data processing: 2175 initially picked potential events reduced to 511 potential events after applying automatic rejection criteria. The 511 events needed to be inspected manually to reveal 19 short earthquakes and 37 potential rockfalls, including the 10 TLS-detected events. Rockfall volume does not show a relationship with released seismic energy or peak amplitude at this spatial scale due to the dominance of other, process-inherent factors, such as fall height, degree of fragmentation, and subsequent talus slope activity. The combination of TLS and environmental seismology provides, despite the significant amount of manual data processing, a detailed validation of seismic detection of small volume rockfalls, and revealed unprecedented temporal, spatial and geometric details about rockfalls in steep mountainous terrain.

Slope-scale dynamic states of rockfalls

NASA Astrophysics Data System (ADS)

Agliardi, F.; Crosta, G. B.

2009-04-01

Rockfalls are common earth surface phenomena characterised by complex dynamics at the slope scale, depending on local block kinematics and slope geometry. We investigated the nature of this slope-scale dynamics by parametric 3D numerical modelling of rockfalls over synthetic slopes with different inclination, roughness and spatial resolution. Simulations were performed through an original code specifically designed for rockfall modeling, incorporating kinematic and hybrid algorithms with different damping functions available to model local energy loss by impact and pure rolling. Modelling results in terms of average velocity profiles suggest that three dynamic regimes (i.e. decelerating, steady-state and accelerating), previously recognized in the literature through laboratory experiments on granular flows, can set up at the slope scale depending on slope average inclination and roughness. Sharp changes in rock fall kinematics, including motion type and lateral dispersion of trajectories, are associated to the transition among different regimes. Associated threshold conditions, portrayed in "phase diagrams" as slope-roughness critical lines, were analysed depending on block size, impact/rebound angles, velocity and energy, and model spatial resolution. Motion in regime B (i.e. steady state) is governed by a slope-scale "viscous friction" with average velocity linearly related to the sine of slope inclination. This suggest an analogy between rockfall motion in regime B and newtonian flow, whereas in regime C (i.e. accelerating) an analogy with a dilatant flow was observed. Thus, although local behavior of single falling blocks is well described by rigid body dynamics, the slope scale dynamics of rockfalls seem to statistically approach that of granular media. Possible outcomes of these findings include a discussion of the transition from rockfall to granular flow, the evaluation of the reliability of predictive models, and the implementation of criteria for a preliminary evaluation of hazard assessment and countermeasure planning.

The role of forests in reducing hydrogeomorphic hazards.

Treesearch

Matt E. Sakals; John L. Innes; David J. Wilford; Roy C. Sidle; Gordon E. Grant

2006-01-01

Increasingly, forests are being valued for goods and services beyond wood fibre; one of these is protection forests. Functions provided by natural and managed forests have been associated with reduced hazards from floods, debris floods, debris flows, snow avalanches and rockfalls. Maintaining a high level of protection may require active management, as forests are...

Comparing Newmark

NASA Astrophysics Data System (ADS)

Rodríguez-Peces, M. J.; García-Mayordomo, J.; Azañón-Hernández, J. M.; Jabaloy-Sánchez, A.

2009-04-01

The Lorca Basin (Eastern Betic Cordillera, SE Spain) is one of the most seismically active regions of Spain. In this area there are well known cases of earthquake-induced slope instabilities associated to specific earthquakes (e.g., Bullas 2002, La Paca 2005). Furthermore, this area is characterized by moderate magnitude seismicity which mainly produces rock-falls and avalanches. In this work we present the results of our research at regional and site scales. For the regional scale, we have used a geographic information system (GIS) to develop an implementation of the Newmark's sliding rigid block method. We have particularly proposed a new variation of Newmark's method to consider soil and topographic amplification effects. Subsequently, we produced "Newmark displacement" maps for both probabilistic and deterministic seismic scenarios in the Lorca Basin. Probabilistic seismic scenarios consider three hazard maps in terms of peak ground acceleration (PGA) on rock corresponding to the 475-, 975- and 2475-year return periods (exceedance probability of 10, 5 and 2% in 50 years, respectively) in the Murcia Region. Deterministic seismic scenarios consider the occurrence of the most probable earthquake for a 475-year return period (Mw=5.0) at every location, or either a complete rupture of Lorca-Totana (Mw=6.7) or Puerto Lumbreras-Lorca (Mw=6.8) segments of Alhama de Murcia Fault. The Newmark displacement maps allowed us to identify areas with the highest potential seismic hazard, and also locate areas for future particular studies. We have found that rock-falls produced during the last earthquakes in Lorca Basin (e.g., Bullas 2002, La Paca 2005) match very well with areas with values of Newmark displacement lower than 2 cm in all the seismic scenarios considered. Therefore, it seems that low values of Newmark displacements are very likely associated with rock-falls. To support this hypothesis we have applied the Newmark method at a site scale. To do this, we have selected La Paca rock-fall which was generated during La Paca 2005 earthquake (mbLg=4.7, IEMS=VI-VII). We have used a terrestrial laser scanner in order to obtain a high resolution digital elevation model of La Paca rock-fall area. Moreover, we have performed a back-analysis based on field data to estimate the static safety factor previous to the earthquake and the critical acceleration. Furthermore, we have selected a representative strong ground motion record for La Paca earthquake from international databases. The critical acceleration and the peak ground acceleration values obtained from the strong ground motion record allowed us to estimate the actual soil and topographic amplification effects. Finally, we have calculated analytically the real Newmark displacement at La Paca rock-fall and we have compared this displacement with our GIS estimation in order to improve the calibration of Newmark's method at the regional scale.

Analysis of the Spatio-Temporal Evolution of the Rockfalls in the Crater of Piton de la Fournaise Volcano, La Réunion, and their Link with the Eruptive Activity

NASA Astrophysics Data System (ADS)

Durand, V.; Mangeney, A.; Hibert, C.; Haas, F.; Peltier, A.; Kowalski, P.; Lauret, F.; Brunet, C.; Delorme, A.; Wegner, K.; Satriano, C.; Bonilla, L. F.; Aissaoui, E. M.; Protin, A.

2017-12-01

The seismic and photogrammetric networks of the Piton de la Fournaise volcano (La Réunion Island) are very well appropriate to study seismic signals generated by rockfalls in the Dolomieu crater. In particular, seismic data make it possible to precisely locate the rockfalls and recover the volume of each rockfall. Rockfall locations and volumes are validated comparing them to the ones obtained using photogrammetric data. We thus obtain an accurate catalog of 5802 rockfalls over the 2014-2016 period. This period is especially active, with 7 eruptions, after a break of 4 years. The analysis of the catalog reveals that the recovery of the eruptive activity unsettles the crater edges, increasing the average volume of the rockfalls. It also highlights that rain and seismicity could increase the volume of individual rockfalls. However, it seems that the pre-eruptive seismicity is the main triggering factor for larger volumes, with a delay of several days. We infer that the repetitive vibrations due to the high number of seismic events induce a cyclic fatigue of the material, leading to the collapse of large volumes. To better understand and discriminate the influence of seismicity and rainfall on the rockfall volumes, we investigate in the same way the transition period, from 2010 to 2014, during which there is no eruption. Finally, we show that before an eruption, the largest rockfalls tend to migrate towards the location of the eruption.

Rockfall risk evaluation using geotechnical survey, remote sensing data, and GIS: a case study from western Greece

NASA Astrophysics Data System (ADS)

Nikolakopoulos, Konstantinos; Depountis, Nikolaos; Vagenas, Nikolaos; Kavoura, Katerina; Vlaxaki, Eleni; Kelasidis, George; Sabatakakis, Nikolaos

2015-06-01

In this paper a specific example of the synergistic use of geotechnical survey, remote sensing data and GIS for rockfall risk evaluation is presented. The study area is located in Western Greece. Extensive rockfalls have been recorded along Patras - Ioannina highway just after the cable-stayed bridge of Rio-Antirrio, at Klokova site. The rockfalls include medium- sized limestone boulders with volume up to 1.5m3. A detailed engineering geological survey was conducted including rockmass characterization, laboratory testing and geological - geotechnical mapping. Many Rockfall trajectory simulations were done. Rockfall risk along the road was estimated using spatial analysis in a GIS environment.

Rockfalls in the Duratón canyon, central Spain: Inventory and statistical analysis

NASA Astrophysics Data System (ADS)

Tanarro, Luis M.; Muñoz, Julio

2012-10-01

This paper presents an initial analysis of the rockfall processes affecting the walls of the canyon of the River Duratón. This 34 km long meandering canyon in the basin of the River Duero in central Spain (41°18' N, 3°45' W) has evolved in a large-scale outcrop of Late Cretaceous calcareous rocks (dolomite and limestone) deformed into a series of asymmetrical folds. Its vertical scarps range from 80 to 100 m; its width varies from 150 to 300 m; and its floor is between 30 and 50 m wide. The research consisted of drawing up an inventory of rockfalls from a field survey and mapping the fallen blocks deposited on the basal talus or on the canyon floor, which in turn allowed the original location of each block on the scarps to be identified and located on the orthophotos available. A Digital Elevation Model (DEM) was produced using a Geographic Information System (GIS) and maps made of the aspects and slopes. The aspect of each rockfall data point was determined, and this initial database was completed with other significant parameters (location on the valley side, relationship with the tectonic structure and relative age). An approximate delimitation was also produced of the potential rockfall source area, by reclassifying the slopes according to morphometric criteria. The result is a geomorphic rockfall inventory map, showing the distribution of the rockfalls and a basic statistical analysis to allow a preliminary evaluation of the rockfall characteristics in relation to both their topoclimatic location (aspect) and their structural location (with or counter to the dip of the strata) and to the current geomorphic dynamic through a study of recent scars on the scarps. Recent rockfalls have also been related to the meteorological conditions in which they occurred.

Semi-Automatic Determination of Rockfall Trajectories

PubMed Central

Volkwein, Axel; Klette, Johannes

2014-01-01

In determining rockfall trajectories in the field, it is essential to calibrate and validate rockfall simulation software. This contribution presents an in situ device and a complementary Local Positioning System (LPS) that allow the determination of parts of the trajectory. An assembly of sensors (herein called rockfall sensor) is installed in the falling block recording the 3D accelerations and rotational velocities. The LPS automatically calculates the position of the block along the slope over time based on Wi-Fi signals emitted from the rockfall sensor. The velocity of the block over time is determined through post-processing. The setup of the rockfall sensor is presented followed by proposed calibration and validation procedures. The performance of the LPS is evaluated by means of different experiments. The results allow for a quality analysis of both the obtained field data and the usability of the rockfall sensor for future/further applications in the field. PMID:25268916

Analysis of seismic signals related to rockfalls in the Dolomieu crater, Piton de la Fournaise, La Réunion

NASA Astrophysics Data System (ADS)

Durand, Virginie; Mangeney, Anne; Lebouteiller, Pauline; Hibert, Clément; Ovpf Team

2015-04-01

The seismic and photogrammetric networks of the volcano of the Piton de la Fournaise (La Réunion Island), maintained by the OVPF, are well appropriate for the study of seismic signals generated by rockfalls. In this work, we focus on the signals generated by rockfalls occurring in the Dolomieu crater. The aim of this study is to understand the link between rockfall and volcanic activity. One key question is as to whether the number and characteristics of rockfalls can provide a precursor to the occurrence of an eruption. Another scope of this work is to determine if there is a link between the rockfall activity and the precipitations, changes of temperature and seismic activity. For this, we analyze the rockfall activity preceding the June 2014 eruption. To detect the events, we use a method based on the Kurtosis function that picks the beginning of the signals. Then we localize the events using the arrival time of the waves and a propagation model computed with the Fast Marching Method. Finally, we calculate the seismic energy generated by these rockfalls. Thus, we obtain a catalog of events that we can exploit to determine the characteristics and the temporal evolution of the rockfall activity in the Dolomieu crater. A power law is observed between the seismic energy and the duration of rockfalls, making possible to calculate the rockfall volume from the ratio between seismic and potential energy. From previous studies on the Piton de la Fournaise volcano, we can infer that rockfall activity in the crater is correlated with eruptions: the rockfall activity seems to begin before the eruption time. We compare the spatio-temporal changes of the rockfall characteristics to the volcanic, seismic, and rain activity. We show in particular that the rockfall size seems to be different if the intrusion of magma reaches the surface or not, providing potential precursors to the occurrence of an eruption.

Risk analysis for roadways subjected to multiple landslide-related hazards

NASA Astrophysics Data System (ADS)

Corominas, Jordi; Mavrouli, Olga

2014-05-01

Roadways through mountainous terrain often involve cuts and landslide areas whose stability is precarious and require protection and stabilization works. To optimize the allocation of resources, government and technical offices are increasingly interested in both the risk analysis and assessment. Risk analysis has to consider the hazard occurrence and the consequences. The consequences can be both direct and indirect. The former include the costs regarding the repair of the roadway, the damage of vehicles and the potential fatalities, while the latter refer to the costs related to the diversion of vehicles, the excess of distance travelled, the time differences, and tolls. The type of slope instabilities that may affect a roadway may vary and its effects as well. Most current approaches either consider a single hazardous phenomenon each time, or if applied at small (for example national) scale, they do not take into account local conditions at each section of the roadway. The objective of this work is the development of a simple and comprehensive methodology for the assessment of the risk due to multiple hazards along roadways, integrating different landslide types that include rockfalls, debris flows and considering as well the potential failure of retaining walls. To quantify risk, all hazards are expressed with a common term: their probability of occurrence. The methodology takes into consideration the specific local conditions along the roadway. For rockfalls and debris flow a variety of methods for assessing the probability of occurrence exists. To assess the annual probability of failure of retaining walls we use an indicator-based model that provides a hazard index. The model parameters consist in the design safety factor, and further anchorage design and construction parameters. The probability of failure is evaluated in function of the hazard index and next corrected (in terms of order of magnitude) according to in situ observations for increase of two dynamic factors: the service load and the wall deformation. The consequences are then calculated for each hazard type according to its characteristics (mechanism, magnitude, frequency). The difference of this method in comparison with other methodologies for landslide-related hazards lies in the hazard scenarios and consequence profiles that are investigated. The depth of analysis permits to account for local conditions either concerning the hazard or the consequences (the latter with respect to the very particular characteristics of the roadway such as traffic, number of lanes, velocity…). Furthermore it provides an extensive list of quantitative risk descriptors, including both individual and collective ones. The methodology was made automatic using the data sheets by Microsoft Excel. The results can be used to support decision-taking for the planning of protection measures. Gaps in knowledge and restrictions are discussed as well.

Visualizing and modelling complex rockfall slopes using game-engine hosted models

NASA Astrophysics Data System (ADS)

Ondercin, Matthew; Hutchinson, D. Jean; Harrap, Rob

2015-04-01

Innovations in computing in the past few decades have resulted in entirely new ways to collect 3d geological data and visualize it. For example, new tools and techniques relying on high performance computing capabilities have become widely available, allowing us to model rockfalls with more attention to complexity of the rock slope geometry and rockfall path, with significantly higher quality base data, and with more analytical options. Model results are used to design mitigation solutions, considering the potential paths of the rockfall events and the energy they impart on impacted structures. Such models are currently implemented as general-purpose GIS tools and in specialized programs. These tools are used to inspect geometrical and geomechanical data, model rockfalls, and communicate results to researchers and the larger community. The research reported here explores the notion that 3D game engines provide a high speed, widely accessible platform on which to build rockfall modelling workflows and to provide a new and accessible outreach method. Taking advantage of the in-built physics capability of the 3D game codes, and ability to handle large terrains, these models are rapidly deployed and generate realistic visualizations of rockfall trajectories. Their utility in this area is as yet unproven, but preliminary research shows that they are capable of producing results that are comparable to existing approaches. Furthermore, modelling of case histories shows that the output matches the behaviour that is observed in the field. The key advantage of game-engine hosted models is their accessibility to the general public and to people with little to no knowledge of rockfall hazards. With much of the younger generation being very familiar with 3D environments such as Minecraft, the idea of a game-like simulation is intuitive and thus offers new ways to communicate to the general public. We present results from using the Unity game engine to develop 3D voxel worlds and terrain models from detailed LiDAR and photogrammetric data obtained at a complex slope above a railway corridor in British Columbia, Canada. The data was collected with sufficient frequency that single event rockfall paths were detectable, permitting the impact points and the final resting spots to be determined using LiDAR change detection methods. These specific case histories, including the high resolution, detailed slope geometry from the LiDAR data sets were modelled using game engines, as well as the conventional GIS based and specific rockfall modelling packages. The game engine results compare favourably and in some case outperform conventional tools in terms of rockfall trajectory and slope accuracy, physical realism, data handling capacity, and performance.

A rockfall hazard assessment for a residential area by using 2D and 3D simulation models: A case study from North Turkey

NASA Astrophysics Data System (ADS)

Akgün, Aykut; Yakut, Mehmet

2017-04-01

Rockfalls are one of the most common and important mass movement type encountered throughout both the World and Turkey. In Turkey, especially in Black Sea Region, rock fall cases frequently occur due to the steep topography, lithological characteristics, improper land use and structural elements such as discontinuity density. As a consequence of rock fall cases, serious injury and loss of lives can be observed in the area. In this study, a residential area located in Trabzon city (Northeast part of Black Sea Region, Turkey) was handled in point of rock fall hazard assessment. In the area, several rock fall cases occurred, and one of them occurred in year of 2009, resulted two people died. The last one also occurred in year of 2016, and the source of both cases are the same location. In the area, several houses and working places are available, and up to now any effective protection measurements have been installed. The area is also located near a highway connecting Trabzon city to the southeast region of Turkey, and daily vehicle number is highly considerable. Due to all these sensitive issues, the area was selected to be study location. In order to make a rock fall hazard assessment in the area to determine and propose an effective mitigation system, a 2D and 3D simulation models were applied. Initially a digital elevation model (DEM) of the area was obtained by a 1:1000 scale digital topographical sheets. By using the obtained digital terrain data, detailed cross sections of the slope profiles were created. Then, a detailed field and photo survey was carried out to detect the dangerous and hanging rock blocks that may be source for a possible rock fall cases. The physico-mechanical properties of the intact rock material were determined so that they can be used to be input parameters for the rock fall simulation models. To create simulation models, Rocfall 6.0®, Rockfall Analyst for ArcGIS and CONEFALL softwares were used. Using the Rockfall Analyst extension for ArcGIS and CONEFALL software, propagation and runout distances of possible rock fall cases were evaluated. By Rocfall 6.0® software, possible rock fall paths and proper mitigation measurements such as protection barriers or ditches were also assessed. At the end of the assessment processes, a detailed rock fall hazard map was produced for the area. With the help of this map, an important extent of area was determined to be under rock fall threat. This obtained map is also expected to be considered by the local governmental authorities to make persistent hazard mitigation measurements in the area. Keywords: Rock fall, simulation, hazard, Turkey

Development of a rockfall hazard rating matrix for the State of Ohio : executive summary report.

DOT National Transportation Integrated Search

2005-06-30

The geology in Ohio is characterized by the : presence of gently dipping, harder, more competent : strata (siltstones, sandstones, limestones) alternating : with softer, less competent strata (claystones, : mudstones, sha les). This type of stratigra...

Development of a Rockfall Hazard Rating Matrix for the State of Ohio : Executive Summary Report

DOT National Transportation Integrated Search

2005-06-01

The geology in Ohio is characterized by the : presence of gently dipping, harder, more competent : strata (siltstones, sandstones, limestones) alternating : with softer, less competent strata (claystones, : mudstones, sha les). This type of stratigra...

Rapid 3-D analysis of rockfalls

USGS Publications Warehouse

Stock, Greg M.; Guerin, A.; Avdievitch, Nikita N.; Collins, Brian D.; Jaboyedoff, Michel

2018-01-01

Recent fatal and damaging rockfalls in Yosemite National Park indicate the need for rapid response data collection methods to inform public safety and assist with management response. Here we show the use of multiple-platform remote sensing methods to rapidly capture pertinent data needed to inform management and the public following a several large rockfalls from El Capitan cliff in Yosemite Valley, California.

Multi-temporal change image inference towards false alarms reduction for an operational photogrammetric rockfall detection system

NASA Astrophysics Data System (ADS)

Partsinevelos, Panagiotis; Kallimani, Christina; Tripolitsiotis, Achilleas

2015-06-01

Rockfall incidents affect civil security and hamper the sustainable growth of hard to access mountainous areas due to casualties, injuries and infrastructure loss. Rockfall occurrences cannot be easily prevented, whereas previous studies for rockfall multiple sensor early detection systems have focused on large scale incidents. However, even a single rock may cause the loss of a human life along transportation routes thus, it is highly important to establish methods for the early detection of small-scale rockfall incidents. Terrestrial photogrammetric techniques are prone to a series of errors leading to false alarm incidents, including vegetation, wind, and non relevant change in the scene under consideration. In this study, photogrammetric monitoring of rockfall prone slopes is established and the resulting multi-temporal change imagery is processed in order to minimize false alarm incidents. Integration of remote sensing imagery analysis techniques is hereby applied to enhance early detection of a rockfall. Experimental data demonstrated that an operational system able to identify a 10-cm rock movement within a 10% false alarm rate is technically feasible.

Natural hazard risk assessment and management in the Matter valley, Swiss Alps

NASA Astrophysics Data System (ADS)

Herz, T.; King, L.; Philippi, S.

2003-04-01

The Matter valley has a length of about 40 km and is surrounded by some of the highest peaks of the Alps resulting in extreme altitudinal differences and a continental character of the climate. These climatic conditions cause a high glacier equilibrium line and therefore a periglacial belt of a large vertical extend. Due to the high relief energy, all kinds of natural hazards typical for high mountain environments occur. The steep western slopes are dominated by rockfalls, slope instabilities in bedrock and avalanches. A widespread cover of unconsolidated sediments on the eastern slopes induces landslides and debris flows, which often reach down to the valley bottom where they can dam up the river. Increasing population and modern land use forms required a more and more sensitive attitude towards natural hazard potentials in this endangered area. Assessment and management of natural hazard risks have been much improved during the last fifteen years and increasing amounts of money are spent each year in order to safeguard settlements, traffic lines, and other objects of the technical infrastructure. Numerous investigations concerning natural hazard risks have been made and the results are considered in the actual land use planning of the Canton. The planning law of the Canton Valais defines risk zones as areas, which are endangered by natural hazards like avalanches, rockfalls, landslides and floodings. Risk assessment is done by overview maps (scale 1:25,000) which are specified by detailed risk analyses consisting of registers and detailed maps (scale 1:2,000 to 1:10,000). These analyses are integrated in the land zoning by defining zones of high, medium and low danger, associated with corresponding prohibitions, restrictions and conditions for utilisation. At present, the incorporation of the avalanche and rockfall register in local zoning plans is completed in most communities of the Canton Valais. An additional inventory of 200 slope instabilities was elaborated and must be considered in present and future local zonation updates. However, zones threatened by floods are only indicated on maps of overview and no planning standards for the management of debris flow hazards exist so far. The Canton is currently carrying out numerous projects of active disaster prevention comprising measurements and constructional precautions against avalanches and slope instabilities as well as monitoring systems and early warning stations.

Some Open Issues on Rockfall Hazard Analysis in Fractured Rock Mass: Problems and Prospects

NASA Astrophysics Data System (ADS)

Ferrero, Anna Maria; Migliazza, Maria Rita; Pirulli, Marina; Umili, Gessica

2016-09-01

Risk is part of every sector of engineering design. It is a consequence of the uncertainties connected with the cognitive boundaries and with the natural variability of the relevant variables. In soil and rock engineering, in particular, uncertainties are linked to geometrical and mechanical aspects and the model used for the problem schematization. While the uncertainties due to the cognitive gaps could be filled by improving the quality of numerical codes and measuring instruments, nothing can be done to remove the randomness of natural variables, except defining their variability with stochastic approaches. Probabilistic analyses represent a useful tool to run parametric analyses and to identify the more significant aspects of a given phenomenon: They can be used for a rational quantification and mitigation of risk. The connection between the cognitive level and the probability of failure is at the base of the determination of hazard, which is often quantified through the assignment of safety factors. But these factors suffer from conceptual limits, which can be only overcome by adopting mathematical techniques with sound bases, not so used up to now (Einstein et al. in rock mechanics in civil and environmental engineering, CRC Press, London, 3-13, 2010; Brown in J Rock Mech Geotech Eng 4(3):193-204, 2012). The present paper describes the problems and the more reliable techniques used to quantify the uncertainties that characterize the large number of parameters that are involved in rock slope hazard assessment through a real case specifically related to rockfall. Limits of the existing approaches and future developments of the research are also provided.

Rock falls from Glacier Point above Camp Curry, Yosemite National Park, California

USGS Publications Warehouse

Wieczorek, Gerald F.; Snyder, James B.

1999-01-01

A series of rock falls from the north face of Glacier Point above Camp Curry, Yosemite National Park, California, have caused reexamination of the rock-fall hazard because beginning in June, 1999 a system of cracks propagated through a nearby rock mass outlining a future potential rock fall. If the estimated volume of the potential rock fall fails as a single piece, there could be a risk from rock-fall impact and airborne rock debris to cabins in Camp Curry. The role of joint plane orientation and groundwater pressure in the fractured rock mass are discussed in light of the pattern of developing cracks and potential modes of failure.

Rockfall induced seismic signals: case study in Montserrat, Catalonia

NASA Astrophysics Data System (ADS)

Vilajosana, I.; Suriñach, E.; Abellán, A.; Khazaradze, G.; Garcia, D.; Llosa, J.

2008-08-01

After a rockfall event, a usual post event survey includes qualitative volume estimation, trajectory mapping and determination of departing zones. However, quantitative measurements are not usually made. Additional relevant quantitative information could be useful in determining the spatial occurrence of rockfall events and help us in quantifying their size. Seismic measurements could be suitable for detection purposes since they are non invasive methods and are relatively inexpensive. Moreover, seismic techniques could provide important information on rockfall size and location of impacts. On 14 February 2007 the Avalanche Group of the University of Barcelona obtained the seismic data generated by an artificially triggered rockfall event at the Montserrat massif (near Barcelona, Spain) carried out in order to purge a slope. Two 3 component seismic stations were deployed in the area about 200 m from the explosion point that triggered the rockfall. Seismic signals and video images were simultaneously obtained. The initial volume of the rockfall was estimated to be 75 m3 by laser scanner data analysis. After the explosion, dozens of boulders ranging from 10-4 to 5 m3 in volume impacted on the ground at different locations. The blocks fell down onto a terrace, 120 m below the release zone. The impact generated a small continuous mass movement composed of a mixture of rocks, sand and dust that ran down the slope and impacted on the road 60 m below. Time, time-frequency evolution and particle motion analysis of the seismic records and seismic energy estimation were performed. The results are as follows: 1 A rockfall event generates seismic signals with specific characteristics in the time domain; 2 the seismic signals generated by the mass movement show a time-frequency evolution different from that of other seismogenic sources (e.g. earthquakes, explosions or a single rock impact). This feature could be used for detection purposes; 3 particle motion plot analysis shows that the procedure to locate the rock impact using two stations is feasible; 4 The feasibility and validity of seismic methods for the detection of rockfall events, their localization and size determination are comfirmed.

Analysis of geohazards events along Swiss roads from autumn 2011 to present

NASA Astrophysics Data System (ADS)

Voumard, Jérémie; Jaboyedoff, Michel; Derron, Marc-Henri

2014-05-01

In Switzerland, roads and railways are threatened throughout the year by several natural hazards. Some of these events reach transport infrastructure many time per year leading to the closing of transportation corridors, loss of access, deviation travels and sometimes infrastructures damages and loss of human lives (3 fatalities during the period considered). The aim of this inventory of events is to investigate the number of natural events affecting roads and railways in Switzerland since autumn 2011 until now. Natural hazards affecting roads and railway can be classified in five categories: rockfalls, landslides, debris flows, snow avalanches and floods. They potentially cause several important direct damages on transportation infrastructure (roads, railway), vehicles (slightly or very damaged) or human life (slightly or seriously injured person, death). These direct damages can be easily evaluated from press articles or from Swiss police press releases. Indirect damages such as deviation cost are not taken into account in this work. During the two a half last years, about 50 events affecting the Swiss roads and Swiss railways infrastructures were inventoried. The proportion of events due to rockfalls is 45%, to landslides 25%, to debris flows 15%, to snow avalanches 10% and to floods 5%. During this period, three fatalities and two persons were injured while 23 vehicles (car, trains and coach) and 24 roads and railways were damaged. We can see that floods occur mainly on the Swiss Plateau whereas rockfalls, debris flow, snow avalanches and landslides are mostly located in the Alpine area. Most of events occur on secondary mountain roads and railways. The events are well distributed on the whole Alpine area except for the Gotthard hotspot, where an important European North-South motorway (hit in 2003 with two fatalities) and railway (hit three times in 2012 with one fatalities) are more frequently affected. According to the observed events in border regions of Switzerland, the trend in the Alps is similar.

Instability of a highly vulnerable high alpine rock ridge: the lower Arête des Cosmiques (Mont Blanc massif, France)

NASA Astrophysics Data System (ADS)

Ravanel, L.; Deline, P.; Lambiel, C.; Vincent, C.

2012-04-01

Glacier retreat and permafrost degradation are actually more and more thought to explain the increasing instability of rock slopes and rock ridges in high mountain environments. Hot summers with numerous rockfalls we experienced over the last two decades in the Alps have indeed contributed to test/strengthen the hypothesis of a strong correlation between rockfalls and global warming through these two cryospheric factors. Rockfalls from recently deglaciated and/or thawing areas may have very important economic and social implications for high mountain infrastructures and be a fatal hazard for mountaineers. At high mountain sites characterized by infrastructures that can be affected by rockfalls, the monitoring of rock slopes, permafrost and glaciers is thus an essential element for the sustainability of the infrastructure and for the knowledge/management of risks. Our study focuses on a particularly active area of the Mont Blanc massif (France), the lower Arête des Cosmiques, on which is located the very popular Refuge des Cosmiques (3613 m a.s.l.). Since 1998, when a rockfall threatened a part of the refuge and forced to major stabilizing works, observations allowed to identify 10 detachments (20 m3 to > 1000 m3), especially on the SE face of the ridge. Since 2009, this face is yearly surveyed by terrestrial laser scanning to obtain high-resolution 3D models. Their diachronic comparison gives precise measurements of the evolution of the rock slope. Eight rock detachments have thus been documented (0.7 m3 to 256.2 m3). Rock temperature measurements at the ridge and the close Aiguille du Midi (3842 m a.s.l.), and observations of the evolution of the underlying Glacier du Géant have enable to better understand the origin of the strong dynamics of this highly vulnerable area: (i) rock temperature data suggest the presence of warm permafrost (i.e. close to 0°C) from the first meters to depth in the SE face, and cold permafrost in the NW face; (ii) as suggested by the occurrence of rockfalls mainly during or at the end of hot periods in summer, degradation of the cleft ice - observed in several rockfall scars - has likely participated in the triggering of several if not all of these rockfalls; (iii) alternation of the ice content increase during segregation phases and its decrease during the summer periods has probably modified the geotechnical properties of the rock mass, especially since rockfalls have mostly been triggered in the active layer; (iv) evolution of the glacier have also directly interfered with the stability of the SE face of the ridge: rockfalls at the foot of the rockslopes were only possible because of the lowering of the glacier in the recent years. Rockfalls that occurred at the lower Arête des Cosmiques thus probably result from the combination between permafrost activity/degradation and glacier shrinkage.

The influence of environmental and lithologic factors on rockfall at a regional scale: an evaluation using GIS

NASA Astrophysics Data System (ADS)

Menéndez Duarte, Rosana; Marquínez, Jorge

2002-02-01

Analysis of the spatial distribution of rockfall deposits at a regional scale (over an area of 250 km 2 of northern Spain) using a cartographic database supported by a Geographic Information System (GIS) reveals several relationships between rockfall activity and environmental variables. Recent rockfall activity is inferred when recent scree is preserved at the bottom of the rock slopes. In order to identify the slope source areas of the scree we have mapped the deposit's drainage basin, applying topographic criteria, and we have combined these basins with the rock slopes map. A method for setting the basin boundaries automatically will replace manual cartography. This method is based on algorithms available within many commercial software programs and originally planned to analyse the behaviour of fluids over a topographic surface. The results obtained by combining the rockfall area source map with the geology and DTM show the relationships between the distribution of rockfall deposits and lithology, elevation and slope of the rockwall and a strong control of the joint type and density. Elevation influence on rockfall has been associated with climatic variations with elevation. Other variables, such as orientation, show complex influences that are difficult to interpret.

Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

NASA Astrophysics Data System (ADS)

Török, Ákos; Barsi, Árpád; Bögöly, Gyula; Lovas, Tamás; Somogyi, Árpád; Görög, Péter

2018-02-01

Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System) was used to collect images which were processed by Pix4D mapper (structure from motion technology) to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS) with the use of seven ground control points. The obtained digital surface model (DSM) was processed (vegetation removal) and the derived digital terrain model (DTM) allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method). Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE-WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS).

Spatially distributed rockfall activity inferred from talus deposits and corresponding rockwall areas in the Gradenbach catchment (Schober Mountains, Austria)

NASA Astrophysics Data System (ADS)

Götz, Joachim; Buckel, Johannes; Heckmann, Tobias

2013-04-01

The analysis of alpine sediment cascades requires the identification, differentiation and quantification of sediment sources, storages, and transport processes. This study deals with the origin of alpine sediment transfer and relates primary talus deposits to corresponding rockwall source areas within the Gradenbach catchment (Schober Mountains, Austrian Alps). Sediment storage landforms are based on a detailed geomorphological map of the catchment which was generated to analyse the sediment transfer system. Mapping was mainly performed in the field and supplemented by post-mapping analysis using LIDAR data and digital orthophotos. A fundamental part of the mapping procedure was to capture additional landform-based information with respect to morphometry, activity and connectivity. The applied procedure provides a detailed inventory of sediment storage landforms including additional information on surface characteristics, dominant and secondary erosion and deposition processes, process activity and sediment storage coupling. We develop the working hypothesis that the present-day surface area ratio between rockfall talus (area as a proxy for volume, backed by geophysical analysis of selected talus cones) and corresponding rockwall source area is a measure of rockfall activity since deglaciation; large talus cones derived from small rockwall catchments indicate high activity, while low activity can be inferred where rockfall from large rock faces has created only small deposits. The surface area ratio of talus and corresponding rockwalls is analysed using a landform-based and a process-based approach. For the landform-based approach, we designed a GIS procedure which derives the (hydrological) catchment area of the contact lines of talus and rockwall landforms in the geomorphological map. The process-based approach simulates rockfall trajectories from steep (>45°) portions of a DEM generated by a random-walk rockfall model. By back-tracing those trajectories that end on a selected talus landform, the 'rockfall contributing area' is delineated; this approach takes account of the stochastic nature of rockfall trajectories and is able to identify, for example, rockfall delivery from one rockwall segment to multiple talus landforms (or from multiple rockfall segments to the same deposit, respectively). Using both approaches, a total of 290 rockwall-talus-subsystems are statistically analysed indicating a constant relationship between rockfall source areas and corresponding areas of talus deposits of almost 1:1. However, certain rockwall-talus-subsystems deviate from this correlation since sediment storage landforms of similar size originate from varying rockwall source areas and vice versa. This varying relationship is assumed to be strongly controlled by morphometric parameters, such as rockwall slope, altitudinal interval, and aspect. The impact of these parameters on the surface area ratio will be finally discussed.

Natural hazard fatalities in Switzerland from 1946 to 2015

NASA Astrophysics Data System (ADS)

Andres, Norina; Badoux, Alexandre; Techel, Frank

2017-04-01

Switzerland, located in the middle of the Alps, is prone to several different natural hazards which regularly cause fatalities. To explore temporal trends as well as demographic and spatial patterns in the number of natural hazard fatalities, a database comprising all natural hazard events causing fatalities was compiled for the years 1946 until 2015. The new database includes avalanche, flood, lightning, windstorm, landslide, debris flow, rockfall, earthquake and ice avalanche processes. Two existing databases were incorporated and the resulting dataset extended by a comprehensive newspaper search. In total the database contains 635 natural hazard events causing 1023 fatalities. The database does not include victims which exposed themselves to an important danger on purpose (e.g. high risk sports). The most common causes of death were snow avalanches (37 %), followed by lightning (16 %), floods (12 %), windstorms (10 %), rockfall (8 %), landslides (7 %) and other processes (9 %). Around 14.6 fatalities occurred on average each year. A distinct decrease of natural hazard fatalities could be shown over the last 70 years, which was mostly due to the decline in the number of avalanche and lightning fatalities. Thus, nearly three times as many people were killed by natural hazard processes from 1946 to 1980 than from 1981 to 2015. Normalisation of fatality data by population resulted in a clearly declining annual crude mortality rate: 3.9 deaths per million persons for the first 35 years and 1.1 deaths per million persons for the second 35 years of the study period. The average age of the victims was approximately 36 years and about 75% were males. Most people were killed in summer (JJA, 42%) and winter (DJF, 32 %). Furthermore, almost two-thirds of the fatalities took place in the afternoon and evening. The spatial distribution of the natural hazard fatalities over Switzerland was quite homogeneous. However, mountainous parts of the country (Prealps, Alps) were somewhat more prone to fatal events compared to the Swiss Plateau and the Jura. It appears that the overall natural hazard mortality rate in Switzerland over the past 70 years has been relatively low in comparison to rates in other countries or rates of other types of fatal accidents in Switzerland. Nevertheless, the collected data provides a valuable base for analysis and helps authorities to better identify higher risk demographic groups and regions, and accordingly target these to reduce the number of victims.

Rockfall exposures in Montserrat mountain

NASA Astrophysics Data System (ADS)

Fontquerni Gorchs, Sara; Vilaplana Fernández, Joan Manuel; Guinau Sellés, Marta; Jesús Royán Cordero, Manuel

2015-04-01

This study shows the developed methodology to analyze the exposure level on a 1:25000 scale, and the results obtained by applying it to an important part of the Monataña de Montserrat Natural Park for vehicles with and without considering their occupants. The development of this proposal is part of an ongoing study which focuses more in-depth in the analysis of the rockfall risk exposure in different scales and in different natural and social contexts. This research project applies a methodology to evaluate the rockfall exposure level based on the product of the frequency of occurrence of the event by an exposure function of the vulnerable level on a 1:25,000 scale although the scale used for the study was 1:10,000. The proposed methodology to calculate the exposure level is based on six phases: 1- Identification, classification and inventory of every element potentially under risk. 2- Zoning of the frequency of occurrence of the event in the studied area. 3- Design of the exposure function for each studied element. 4- Obtaining the Exposure index, it can be defined as the product of the frequency of occurrence by the exposure function of the vulnerable element through SIG analysis obtained with ArcGis software (ESRI) 5- Obtaining exposure level by grouping into categories the numerical values of the exposure index. 6- Production of the exposition zoning map. The different types of vulnerable elements considered in the totality of the study are: Vehicles in motion, people in vehicles in motion, people on paths, permanent elements and people in buildings. Each defined typology contains all elements with same characteristics and an exposure function has been designed for each of them. For the exposure calculation, two groups of elements have been considered; firstly the group of elements with no people involved and afterwards same group of elements but with people involved. This is a first comprehensive and synthetic work about rockfall exposure on the Montserrat Mountain. It is important to mention that the exposure level calculation has been obtained from natural hazard data do not protected by defense works. Results of this work enable us to consider best strategies to reduce rockfalls risk in the PNMM. It is clear that, apart from the required structural defense works, some of them already made, implementation of strategies not involving structural defense is, in the medium and long term, the best policy to mitigate the risk. In the PNMM case, rethinking of mobility and traffic management on the mountain access would be definitely helpful to achieve a minimized geological risk.

Discrete modelling of drapery systems

NASA Astrophysics Data System (ADS)

Thoeni, Klaus; Giacomini, Anna

2016-04-01

Drapery systems are an efficient and cost-effective measure in preventing and controlling rockfall hazards on rock slopes. The simplest form consists of a row of ground anchors along the top of the slope connected to a horizontal support cable from which a wire mesh is suspended down the face of the slope. Such systems are generally referred to as simple or unsecured draperies (Badger and Duffy 2012). Variations such as secured draperies, where a pattern of ground anchors is incorporated within the field of the mesh, and hybrid systems, where the upper part of an unsecured drapery is elevated to intercept rockfalls originating upslope of the installation, are becoming more and more popular. This work presents a discrete element framework for simulation of unsecured drapery systems and its variations. The numerical model is based on the classical discrete element method (DEM) and implemented into the open-source framework YADE (Šmilauer et al., 2010). The model takes all relevant interactions between block, drapery and slope into account (Thoeni et al., 2014) and was calibrated and validated based on full-scale experiments (Giacomini et al., 2012).The block is modelled as a rigid clump made of spherical particles which allows any shape to be approximated. The drapery is represented by a set of spherical particle with remote interactions. The behaviour of the remote interactions is governed by the constitutive behaviour of the wire and generally corresponds to a piecewise linear stress-strain relation (Thoeni et al., 2013). The same concept is used to model wire ropes. The rock slope is represented by rigid triangular elements where material properties (e.g., normal coefficient of restitution, friction angle) are assigned to each triangle. The capabilities of the developed model to simulate drapery systems and estimate the residual hazard involved with such systems is shown. References Badger, T.C., Duffy, J.D. (2012) Drapery systems. In: Turner, A.K., Schuster R.L., editors. Rockfall: Characterization and Control. Washington, DC: Transportation Research Board, 554-576. Giacomini, A., Thoeni, K., Lambert, C., Booth, S., Sloan, S.W. (2012) Experimental study on rockfall drapery systems for open pit highwalls. International Journal of Rock Mechanics and Mining Sciences 56, 171-181. Šmilauer, V., Catalano, E., Chareyre, B., Dorofenko, S., Duriez, J., Gladky, A., Kozicki, J., Modenese, C., Scholtès, L., Sibille, L., Stránskỳ, J., Thoeni, K. (2010) Yade Documentation. The Yade Project, 1st ed., http://yade-dem.org/doc/. Thoeni, K., Giacomini, A., Lambert, C., Sloan, S.W., Carter, J.P. (2014) A 3D discrete element modelling approach for rockfall analysis with drapery systems. International Journal of Rock Mechanics and Mining Sciences 68, 107-119. Thoeni, K., Lambert, C., Giacomini, A., Sloan, S.W. (2013) Discrete modelling of hexagonal wire meshes with a stochastically distorted contact model. Computers and Geotechnics, 49, 158-69.

Rockfall hazard assessment by means of the magnitude-frequency curves in the Montserrat Massif (central Catalonia, Spain): first insights

NASA Astrophysics Data System (ADS)

Janeras, Marc; Domènech, Guillem; Pons, Judit; Prat, Elisabet; Buxó, Pere

2016-04-01

Montserrat Massif is located about 50 km North-West of Barcelona (Catalonia, North-Eastern Spain). The rock massif is constituted by an intercalation of conglomerate and fine layers of siltstones due to the Montserrat fan-delta sedimentation within the Eocene age. The current relief is consequence of the several depositional episodes and the later tectonic uplift, leading to stepped slopes up to 250 m high, and a total height difference close to 1000 m. Montserrat Mountain has been a pilgrimage place since the settlement of the monastery, around the year 1025, and a spot of touristic interest, mostly within the last 150 years, when the first rack railway was inaugurated to reach the sanctuary. The amount of 2.4 M visitors in 2014 reveals the potential risk derived from rockfalls. To assess and mitigate this risk, a plan funded by the Catalan government is currently under development. Three rockfall mechanisms and magnitude ranges have been identified (Janeras et al. 2011): 1) physicochemical weathering causing the detachment of pebbles and aggregates (0.0001 - 0.1 m3); 2) thermic-induced tensions responsible for the generation of slabs and plates (0.1 - 10 m3); and 3) intersection of structural joints within the rock mass resulting in blocks of 10 - 10,000 m3. In order to quantify the rockfall hazard, a magnitude-frequency analysis has been performed starting from an event-based inventory gathered from field surveillance and historical research. A methodology has been applied to take the maximum profit of only 30 registers with information on volume and date. The massif has been split into several domains with sampling homogeneity. For each one, there have been defined several periods of time during which, all the rockfall events of a given volume have been recorded. Thus, the magnitude-frequency relationship, for each domain, has been calculated. Results show that the curves are well fitted by a power law with exponents ranging from -0.59 to -0.68 for magnitudes between 1 and 1000 m3. For the Monastery area, one event of a volume equal or higher than 1 m3 is expected within 6 years; for the parking area, a similar return period corresponds to a volume of 10 m3. These spatial differences detected between areas of the Montserrat massif (up to one order of magnitude) must be further explored. Extrapolation of these results to the whole massif leads to 9 events per year equal or larger than 10 m3. Finally, results have been compared with those obtained by TLS campaigns, in two pilot zones, capable of detecting small-sized rockfalls activity (Janeras et al. 2015), as well as by photointerpretation of noticeable events (Royán & Vilaplana, 2012) obtaining a satisfactory agreement. References: Janeras, Jara, López, Marturià, Royán, Vilaplana, Aguasca, Fàbregas, Cabranes, Gili; 2015. Using several monitoring techniques to measure the rock mass deformation in the Montserrat Massif. ISGG2015: Earth and Environmental Science 26 (2015) 012030. Royán & Vilaplana; 2012. Distribución espacio-temporal de los desprendimientos de rocas en la montaña de Montserrat. Cuaternario y Geomorfología (2012), 26 (1-2), 151-170.

GlacierRocks - Glacier-Headwall Interaction and its Influence on Rockfall Activity

NASA Astrophysics Data System (ADS)

Hartmeyer, Ingo; Keuschnig, Markus; Krautblatter, Michael; Helfricht, Kay; Leith, Kerry; Otto, Jan-Christoph

2017-04-01

Climate models predict continued climate warming and a decrease of Austrian glaciers to less than 20% of their present area by the end of this century. Rockfall from freshly exposed headwalls has been documented as an increasing risk factor with considerable significance for man and high-alpine infrastructure. Recent findings of a five-year terrestrial laserscanning campaign (2011-2016) monitoring glacial headwalls at the Kitzsteinhorn (3.203 m a.s.l.), Hohe Tauern Range, Austria, show the dramatic impact of glacier thinning on adjacent headwalls: 80 % of the detected rockfall volumes were triggered from areas located less than 20 m above the current glacier surface. Despite these implications, little is known about the thermal, mechanical and hydrological processes that operate at the glacier-headwall interface (randkluft). Systemic in-situ monitoring of stability-relevant parameters are lacking, leaving fundamental gaps in the understanding of rockfall preconditioning in glacial headwalls and the geomorphological evolution of glaciated catchments. In this contribution we introduce the recently approved research project 'GlacierRocks', which starts in 2017 and will run for at least three years. 'GlacierRocks' will establish the worldwide first research site for long-term monitoring of stability-relevant processes inside a randkluft system. Based on the acquired monitoring data 'GlacierRocks' is pursuing three overall aims at (1) gaining a better understanding of rockfall preconditioning in randklufts and related geomorphological shaping of headwalls, (2) analyzing poorly understood glacial thinning dynamics near headwalls, and (3) estimating present and future rockfall hazard potential in headwalls on a regional scale. The three system components (headwall, glacier, randkluft) will be investigated by combining geomorphological, glaciological and meteorological methods. 'GlacierRocks' will continuously monitor rock temperature, rock moisture, frost cracking, glacier ice temperature, glacier ice motion, randkluft depth/width changes and a series of meteorological parameters. The study site of 'GlacierRocks' is located in the summit region of the Kitzsteinhorn (3.203 m a.s.l.), which is home to an interdisciplinary Open Air Lab (OPAL) focusing on permafrost and rockfall monitoring. Utilizing the existing infrastructure of the OPAL and collaborating with several Kitzsteinhorn-based partner projects, 'GlacierRocks' will make a concerted effort to shed light on poorly understood processes operating at the transition zone between subglacial and subaerial process domains.

Identification of potential rockfall source areas at a regional scale using a DEM-based geomorphometric analysis

NASA Astrophysics Data System (ADS)

Loye, A.; Jaboyedoff, M.; Pedrazzini, A.

2009-10-01

The availability of high resolution Digital Elevation Models (DEM) at a regional scale enables the analysis of topography with high levels of detail. Hence, a DEM-based geomorphometric approach becomes more accurate for detecting potential rockfall sources. Potential rockfall source areas are identified according to the slope angle distribution deduced from high resolution DEM crossed with other information extracted from geological and topographic maps in GIS format. The slope angle distribution can be decomposed in several Gaussian distributions that can be considered as characteristic of morphological units: rock cliffs, steep slopes, footslopes and plains. A terrain is considered as potential rockfall sources when their slope angles lie over an angle threshold, which is defined where the Gaussian distribution of the morphological unit "Rock cliffs" become dominant over the one of "Steep slopes". In addition to this analysis, the cliff outcrops indicated by the topographic maps were added. They contain however "flat areas", so that only the slope angles values above the mode of the Gaussian distribution of the morphological unit "Steep slopes" were considered. An application of this method is presented over the entire Canton of Vaud (3200 km2), Switzerland. The results were compared with rockfall sources observed on the field and orthophotos analysis in order to validate the method. Finally, the influence of the cell size of the DEM is inspected by applying the methodology over six different DEM resolutions.

UAV-based mapping, back analysis and trajectory modeling of a coseismic rockfall in Lefkada island, Greece

NASA Astrophysics Data System (ADS)

Saroglou, Charalampos; Asteriou, Pavlos; Zekkos, Dimitrios; Tsiambaos, George; Clark, Marin; Manousakis, John

2018-01-01

We present field evidence and a kinematic study of a rock block mobilized in the Ponti area by a Mw = 6.5 earthquake near the island of Lefkada on 17 November 2015. A detailed survey was conducted using an unmanned aerial vehicle (UAV) with an ultrahigh definition (UHD) camera, which produced a high-resolution orthophoto and a digital terrain model (DTM). The sequence of impact marks from the rock trajectory on the ground surface was identified from the orthophoto and field verified. Earthquake characteristics were used to estimate the acceleration of the rock slope and the initial condition of the detached block. Using the impact points from the measured rockfall trajectory, an analytical reconstruction of the trajectory was undertaken, which led to insights on the coefficients of restitution (CORs). The measured trajectory was compared with modeled rockfall trajectories using recommended parameters. However, the actual trajectory could not be accurately predicted, revealing limitations of existing rockfall analysis software used in engineering practice.

An engineering rock classification to evaluate seismic rock-fall susceptibility and its application to the Wasatch Front

USGS Publications Warehouse

Harp, E.L.; Noble, M.A.

1993-01-01

Investigations of earthquakes world wide show that rock falls are the most abundant type of landslide that is triggered by earthquakes. An engineering classification originally used in tunnel design, known as the rock mass quality designation (Q), was modified for use in rating the susceptibility of rock slopes to seismically-induced failure. Analysis of rock-fall concentrations and Q-values for the 1980 earthquake sequence near Mammoth Lakes, California, defines a well-constrained upper bound that shows the number of rock falls per site decreases rapidly with increasing Q. Because of the similarities of lithology and slope between the Eastern Sierra Nevada Range near Mammoth Lakes and the Wasatch Front near Salt Lake City, Utah, the probabilities derived from analysis of the Mammoth Lakes region were used to predict rock-fall probabilities for rock slopes near Salt Lake City in response to a magnitude 6.0 earthquake. These predicted probabilities were then used to generalize zones of rock-fall susceptibility. -from Authors

Modelling mass movement susceptibility for Alpine infrastructure in the Karavank Mountains (Austria/Slovenia)

NASA Astrophysics Data System (ADS)

Bauer, C.; Kern, K.; Lieb, G. K.

2012-12-01

The aim of this study is the generation of indicative susceptibility maps on a regional scale that can be used as a decision support tool for land use management (i.e. risk potential on alpine infrastructure). The study in particular focuses on geomorphological processes (rockfall and debris flows in unconsolidated rock) that reshape the land surface by erosion, transport and deposition. When interacting with human activity (e.g. road, alpine trails) such naturally occurring processes can quickly become natural hazards. The study area is located in the Karavank Mountains, a border region between Austria and Slovenia, and covers approx. 200 sq km with maximum altitudes above 2.000 m a.s.l. (Hochstuhl: 2.237 m a.s.l.). The Karavanks form an east-west striking mountain chain (approx. 120 km total length) of the southeastern Alps that consists mainly of thick Triassic carbonate sequences and, with less extent, Paleozoic carbonate rocks crystalline rocks. The mountain chain is separated into the Northern Karavanks and the Southern Karavanks by a structural boundary (Periadriatic Line). In addition, the area is known for extreme weather events due to Adriatic cyclones with daily accumulated precipitation of more than 200 mm that regularly trigger hazardous and torrential processes like rockfall events and debris flows. To assess the triggering factors and trajectories, two different disposition and process models (one for rockfall and one for debris flow, respectively) were developed. The information about potential source areas was obtained by combining various types of information (e.g. DTM derivatives, geotechnical units, vegetation). Threshold slope values for potential rockfall source areas were attributed to different lithological units according to field observations. The defined threshold slope angles cover values from 42° in Triassic carbonates up to 46° in massive crystalline rocks. For debris flows areas with a slope inclination < 20° as well as areas with dense vegetation were excluded as potential source areas. In the next step, the rockfall runout zones were estimated empirically using the cone method. This model is based on the idea that an individual falling rock can reach any place in the area situated inside a cone of given aperture. In contrast, for modelling debris flows, a multiple flow directions method was used to calculate potential pathways and velocities. The method is implemented as a random walk in conjunction with a Monte Carlo approach (using 1000 iterations). Both models were calibrated with field observation data (e.g. GPS measurements) and in addition, model results were validated with high resolution aerial photographs. By overlaying the modelling results with road and trail network information, susceptibility maps were created. These maps clearly show that large parts of the existing Alpine infrastructure are potentially affected by the modelled processes. Therefore, the resulting susceptibility maps provide as a useful tool to indicate areas prone to rockfall and debris flow as well as for the maintenance of the road and trail networks.

Assessment of rockfall susceptibility by integrating statistical and physically-based approaches

NASA Astrophysics Data System (ADS)

Frattini, Paolo; Crosta, Giovanni; Carrara, Alberto; Agliardi, Federico

In Val di Fassa (Dolomites, Eastern Italian Alps) rockfalls constitute the most significant gravity-induced natural disaster that threatens both the inhabitants of the valley, who are few, and the thousands of tourists who populate the area in summer and winter. To assess rockfall susceptibility, we developed an integrated statistical and physically-based approach that aimed to predict both the susceptibility to onset and the probability that rockfalls will attain specific reaches. Through field checks and multi-temporal aerial photo-interpretation, we prepared a detailed inventory of both rockfall source areas and associated scree-slope deposits. Using an innovative technique based on GIS tools and a 3D rockfall simulation code, grid cells pertaining to the rockfall source-area polygons were classified as active or inactive, based on the state of activity of the associated scree-slope deposits. The simulation code allows one to link each source grid cell with scree deposit polygons by calculating the trajectory of each simulated launch of blocks. By means of discriminant analysis, we then identified the mix of environmental variables that best identifies grid cells with low or high susceptibility to rockfalls. Among these variables, structural setting, land use, and morphology were the most important factors that led to the initiation of rockfalls. We developed 3D simulation models of the runout distance, intensity and frequency of rockfalls, whose source grid cells corresponded either to the geomorphologically-defined source polygons ( geomorphological scenario) or to study area grid cells with slope angle greater than an empirically-defined value of 37° ( empirical scenario). For each scenario, we assigned to the source grid cells an either fixed or variable onset susceptibility; the latter was derived from the discriminant model group (active/inactive) membership probabilities. Comparison of these four models indicates that the geomorphological scenario with variable onset susceptibility appears to be the most realistic model. Nevertheless, political and legal issues seem to guide local administrators, who tend to select the more conservative empirically-based scenario as a land-planning tool.

Rockfall trajectory modelling by the integration of Digital Terrestrial Photogrammetry, Laser Scanning and GIS

NASA Astrophysics Data System (ADS)

Francioni, Mirko; Salvini, Riccardo; Riccucci, Silvia; Guastaldi, Enrico; Ortolano, Fabrizio; Bonciani, Filippo; Callegari, Ivan; Fantozzi, Pierlorenzo

2010-05-01

The present paper describes the runout analysis of rocky unstable blocks on the slope, 500 m wide and 600 m high, overhanging the railroad line Domodossola - Iselle, Italy. In addition to the traditional geological, geomorphological and engineering-geological surveys, DTP (Digital Terrestrial Photogrammetry) by means of an helicopter was used to perform a detailed analysis of rocky blocks sited in inaccessible areas. In order to accomplish the analysis, DTP was combined with LS (Laser Scanning) to build the DDSM (Digital Dense Surface Model) of the slope. Aim of the work is the assessment of the rockfalls potentially dangerous for the railroad line, the assessment of the efficiency of existing protection measures and the prompt of mitigation strategies and monitoring. In order to collect the exact position and size of blocks and wedges, a digital interpretation of stereopairs coming from DTP has been carried out. The photointerpretation has been used to realize the land cover map (ex. outcropping rock, soil covered by vegetation) and to recognize the mitigation and protection measures already installed. Starting from blocks position the DDSM has allowed to determine the probable trajectories of rockfall along the slope. These have been calculated by means of a GIS procedure by the use of the ArcHydro module of EsriTM ArcMap assuming a correspondence between probable trajectories and flowdirection. The morphologic profile of rock falling paths has been obtained by the interpolation of 3D points coming from a properly procedure developed inside EsriTM Arcinfo Workstation environment integrated with the Easy Profiler tool of EsriTM ArcMap. The physical-mechanical characteristics of blocks, the morphologic profile, the land cover and the location of the protection barriers (classified according to the height - from 2 to 4 m - and to the preservation status), have been used as input data in RocFall2D (RoscienceTM) software to calculate the runout analysis. Local slope land cover has been managed by a statistical approach utilizing the coefficient of normal and tangential restitution; in this way probabilistic results about rockfall end point and kinetic energy along the falling path and on the barriers have been obtained. Considering the railroad line proximity, the analysis has shown the high probability to reach the train track for some unstable block. Some other ends their fall mainly in correspondence of vegetated and less steep areas; the remaining blocks are stopped by the existing protection measures. Results from this work have allowed the hazard zoning in respect to the railway; moreover, comparing them with results coming from the rock slope stability analysis, it has been possible to suggest the proper protection methods in different areas.

Empirical Model for Predicting Rockfall Trajectory Direction

NASA Astrophysics Data System (ADS)

Asteriou, Pavlos; Tsiambaos, George

2016-03-01

A methodology for the experimental investigation of rockfall in three-dimensional space is presented in this paper, aiming to assist on-going research of the complexity of a block's response to impact during a rockfall. An extended laboratory investigation was conducted, consisting of 590 tests with cubical and spherical blocks made of an artificial material. The effects of shape, slope angle and the deviation of the post-impact trajectory are examined as a function of the pre-impact trajectory direction. Additionally, an empirical model is proposed that estimates the deviation of the post-impact trajectory as a function of the pre-impact trajectory with respect to the slope surface and the slope angle. This empirical model is validated by 192 small-scale field tests, which are also presented in this paper. Some important aspects of the three-dimensional nature of rockfall phenomena are highlighted that have been hitherto neglected. The 3D space data provided in this study are suitable for the calibration and verification of rockfall analysis software that has become increasingly popular in design practice.

ALP-RISK, a smartphone app for collecting data on geomorphic phenomena at high altitude in the Mont Blanc region

NASA Astrophysics Data System (ADS)

Ravanel, Ludovic; Deline, Philip

2014-05-01

A network of observers (mountain guides, hut keepers and mountaineers) has been created from 2005 for the Mont Blanc massif in order to acquire data on rockfall in permafrost-affected rock walls. This network, fully operational since 2007, is based on observation sheets or oral communications and has documented nearly 350 events with volume between 100 and 45,000 m3. Their analysis confirmed and helped to better understand the role of the permafrost degradation as main triggering factor. To i) reinforce this network, ii) facilitate its observation work and iii) develop it as well in space (the whole Mont Blanc region, or eventually the whole western Alps) as in a thematic point of view (all glacial and periglacial brutal phenomena), the Alp-Risk app has been created in the framework of the Alcotra PrévRisk Mont-Blanc project. The latter (2011-13) has been developed to improve the prevention of individual and collective natural hazards around the Mont Blanc massif. The app was created for I-Phones and Androids in three languages (French, English and Italian) and allows, as intuitively and quickly as possible, transmitting data on natural hazards in high mountain (snow and ice avalanche, landslides and rockfalls, landslides, moraine destabilization, water pocket outburst flood, torrential flood, and others) to both practitioners (observations available directly on the app via an interface web), scientists, and possibly local managers. Alp-Risk thus constitutes a new step for participatory science in the Mont Blanc region.

Analysis of the seismic signals generated by controlled single-block rockfalls on soft clay shales sediments: the Rioux Bourdoux slope experiment (French Alps).

NASA Astrophysics Data System (ADS)

Hibert, Clément; Provost, Floriane; Malet, Jean-Philippe; Bourrier, Franck; Berger, Frédéric; Bornemann, Pierrick; Borgniet, Laurent; Tardif, Pascal; Mermin, Eric

2016-04-01

Understanding the dynamics of rockfalls is critical to mitigate the associated hazards but is made very difficult by the nature of these natural disasters that makes them hard to observe directly. Recent advances in seismology allow to determine the dynamics of the largest landslides on Earth from the very low-frequency seismic waves they generate. However, the vast majority of rockfalls that occur worldwide are too small to generate such low-frequency seismic waves and thus these methods cannot be used to reconstruct their dynamics. However, if seismic sensors are close enough, these events will generate high-frequency seismic signals. Unfortunately we cannot yet use these high-frequency seismic records to infer parameters synthetizing the rockfall dynamics as the source of these waves is not well understood. One of the first steps towards understanding the physical processes involved in the generation of high-frequency seismic waves by rockfalls is to study the link between the dynamics of a single block propagating along a well-known path and the features of the seismic signal generated. We conducted controlled releases of single blocks of limestones in a gully of clay-shales (e.g. black marls) in the Rioux Bourdoux torrent (French Alps). 28 blocks, with masses ranging from 76 kg to 472 kg, were released. A monitoring network combining high-velocity cameras, a broadband seismometer and an array of 4 high-frequency seismometers was deployed near the release area and along the travel path. The high-velocity cameras allow to reconstruct the 3D trajectories of the blocks, to estimate their velocities and the position of the different impacts with the slope surface. These data are compared to the seismic signals recorded. As the distance between the block and the seismic sensors at the time of each impact is known, we can determine the associated seismic signal amplitude corrected from propagation and attenuation effects. We can further compare the velocity, the energy and the momentum of the block at each impact to the true amplitude and the energy of the corresponding part of the seismic signal. Finding potential correlations and scaling laws between the dynamics of the source and the high-frequency seismic signal features constitutes an important breakthrough to understand more complex slope movements that involve multiple blocks or granular flows. This approach may lead to future developments of methods able to determine the dynamics of a large variety of slope movements directly from the seismic signals they generate.

Rockfall magnitude-frequency estimation: how data acquistion strategies influence methodological results

NASA Astrophysics Data System (ADS)

Guerin, Antoine; Abellán, Antonio; Jesús Royán, Manuel; Carrea, Dario; Vilaplana, Joan Manuel; Jaboyedoff, Michel

2014-05-01

The modelling of rock cliff erosion rates through rockfall magnitude-frequency is a well-known technique extensively carried out before by many authors (e.g. Barlow et al., 2012; Guerin et al., 2014). These studies show how the relation between frequency (F) and magnitude (M) of rockfalls is well fitted by a negative power law [F = a*M ^ (-b)], the value of its parameters varying considerably according to differences in type of material, structural settings, climate, etc. Nevertheless, little insight is given into how methodological and instrumental issues influence power law, typically into how data acquisition accuracy, minimum level of detection and spatio-temporal resolution influence this relationship. Extensive Terrestrial Laser Scanner (TLS) campaigns were carried out during more than six years (from Nov.2007 to Dec.2013) in order to monitor a semi-circular rock wall of 150 m width and 25 m height, situated in Puigcercós (Pallars Jussà, Catalonia, Spain). The analysed cliff represents the main outcrop of a landslide that took place in 1881, the scarp being affected by a high number of rockfalls per year (Royan et al., 2013). The spatial-temporal rockfall frequency is determined by comparison of very dense point clouds (about 500 points/m2) acquired in 22 fieldwork campaigns at different dates. The TLS data processing (data filtering, alignment, georeferencing, meshing and comparison) was carried out with the ImInspect module of Polyworks software. The analysis of the magnitude-frequency parameters was carried out for each period of comparison using a script specifically developed in Matlab software. We used the image processing toolbox aiming to extract rockfall areas (number of pixels) and centroids for each event. We carried out an exploratory analysis in order to investigate how certain parameters linked to data acquisition -spatial and temporal resolution, level of detection, etc.- influence the complementary cumulative distributions of the rockfall frequency. Furthermore, for each observation period, we have examined if there exists a correlation between the rockfall characteristics (magnitude and frequencies) and the associated weather conditions (precipitations, temperature, wind). In this work we demonstrated how the acquisition strategies play a significant role on the exponent value of magnitude-frequency cumulative distributions. Moreover, the level of detection influenced the detected number of small rockfalls and therefore, the censoring effect linked to the presence of underrepresented volumes. Nevertheless, no clear correlation has been made regarding atmospheric conditions yet; a great quantity of parameters should be taken into account in order to clearly identify a trend.

Past landscape dynamics in mountain territories: historical trajectory of vulnerability in the Vars catchment (French Alps)

NASA Astrophysics Data System (ADS)

Puissant, Anne; Cioloboc, Florin; Schlosser, Arnaud; Gazo, Aurelien; Martin, Brice; Malet, Jean-Philippe

2016-04-01

Over the last decades and centuries, mountain landscapes have experiment natural and man-made landcover/use changes with mainly the development of tourism activities and the reduction of agro-pastoral activities. These transformations have directly influenced the spatial organization of mountain landscapes. To better anticipate the future exposure of the territory to natural hazards, decision-makers need retrospective analyses of the past changes. In the frame of the SAMCO project, whose objective is to propose mountain risk assessment methodologies in the context of global changes, this research presents a retrospective analysis of land cover/use changes (from 1948 to 2013) in the Vars catchment (French South Alps) submitted to several natural hazards (rockfall, landslide, and flood). Database of elements at risk has been built for five dates and evolution of vulnerability is performed through a versatile GIS-based analysis tool developed for the estimation of vulnerability indicators (physical, economical, social) at a fine scale (1:5000). Results allow identifying several areas with different trajectories of vulnerability which can be use as input data for risk analysis and define future trends.

Multi-hazard risk analysis for management strategies

NASA Astrophysics Data System (ADS)

Kappes, M.; Keiler, M.; Bell, R.; Glade, T.

2009-04-01

Risk management is very often operating in a reactive way, responding to an event, instead of proactive starting with risk analysis and building up the whole process of risk evaluation, prevention, event management and regeneration. Since damage and losses from natural hazards raise continuously more and more studies, concepts (e.g. Switzerland or South Tyrol-Bolozano) and software packages (e.g. ARMAGEDOM, HAZUS or RiskScape) are developed to guide, standardize and facilitate the risk analysis. But these approaches focus on different aspects and are mostly closely adapted to the situation (legislation, organization of the administration, specific processes etc.) of the specific country or region. We propose in this study the development of a flexible methodology for multi-hazard risk analysis, identifying the stakeholders and their needs, processes and their characteristics, modeling approaches as well as incoherencies occurring by combining all these different aspects. Based on this concept a flexible software package will be established consisting of ArcGIS as central base and being complemented by various modules for hazard modeling, vulnerability assessment and risk calculation. Not all modules will be developed newly but taken from the current state-of-the-art and connected or integrated into ArcGIS. For this purpose two study sites, Valtellina in Italy and Bacelonnette in France, were chosen and the hazards types debris flows, rockfalls, landslides, avalanches and floods are planned to be included in the tool for a regional multi-hazard risk analysis. Since the central idea of this tool is its flexibility this will only be a first step, in the future further processes and scales can be included and the instrument thus adapted to any study site.

Rockfall susceptibility mapping of Yosemite Valley (USA) using a high-resolution digital elevation model

NASA Astrophysics Data System (ADS)

Pannatier, A.; Oppikofer, T.; Jaboyedoff, M.; Stock, G. M.

2009-04-01

In Yosemite National Park (California, USA) rockfalls from the steep valley flanks are frequent (>600 documented events in 150 years) and threaten infrastructure in this popular tourist area. This study focuses on a methodology to map the susceptibility to rockfall initiation based on a high-resolution digital elevation model (HRDEM) obtained from aerial laser scanning (1 meter cell size). This methodology is based on geometric factors derived from the HRDEM, i.e., the steepness of the topography, the presence of joints or fractures enabling either a planar or a wedge failure mechanism, and a high denudation potential. The slope angle histogram computed using standard GIS routines was simulated using Gaussian distributions, which were attributed to different parts of the topography, i.e., the cliffs, the valley flanks and the valley floor. Slopes steeper than 36° are found to form cliffs and thus potentially lead to rockfalls. A morpho-structural analysis of the HRDEM was performed in Coltop3D software to determine the major discontinuity sets that shape the topography. Kinematic analyses were made for each of these 7 discontinuity sets in order to determine the HRDEM cells that fulfil the geometric criteria for a planar or wedge failure mechanism. Most of the cliffs in Yosemite Valley enable one or both of these failure mechanisms. The denudation potential was assessed using the sloping local base level (SLBL) concept. The SLBL defines a basal erosion surface and the above lying rock masses (up to 400 m in some of the vertical cliffs) are susceptible to erosion by mass wasting. A thickness of 20 m above the SLBL surface was chosen as lower limit for the denudation potential criterion. The HRDEM cells that satisfy 1, 2 or all 3 criteria are considered having low, moderate and high susceptibility to rockfall initiation. The areas with highest susceptibility (El Capitan, Glacier Point, Yosemite Falls and Half Dome) coincide well with post-glacial talus accumulations and historic rockfall sources. Compared to previous maps of potential rockfall sources that were mainly based on the slope angle criterion, this study provides a more refined analysis of potential rockfall sources and is useful for focussing detailed field investigations on those areas with high susceptibility.

Numerical modelling of new rockfall interception nets

NASA Astrophysics Data System (ADS)

von Boetticher, Albrecht; Volkwein, Axel; Wendeler, Corinna

2010-05-01

The design and certification of effective rockfall protection barriers is mainly achieved through 1:1 prototype testing. In order to reduce development costs of a prototype it is recommended that pre-studies using numerical simulations are performed. A large component to modelling rockfall protection systems is the numerical simulation of the nets. To date there exist several approaches to model the different mesh types such as ring nets or diagonal meshes (Nicot 1999, Cazzani et al. 2002, Volkwein 2004). However, the consideration of chain link meshes has not yet been realised. Chain link meshes are normally found as standard fence structures. However, they also exist in setups using high-strength steel and wire bundles. These variants show an enormous capacity to retain loads e.g. rockfalls, and at the same time are very efficient due to their low demand of steel material. The increasing application of chain link mesh in barrier systems requires an accurate model is available to complete prototype studies. A new approach now aims to perform a Finite Element simulation of such chain link meshes. The main challenge herein is to achieve the net deformation behaviour that is observed in field tests also in the simulation. A simulation using simple truss elements would not work since it neglects the out-of-plane-height of the mesh construction providing important reserves for local and global high deformations. Thus addressing this, a specially developed Discrete Element is able to reconstruct the mechanical behaviour of the single chain wire (bundles). As input parameters it utilises typical properties such as longitudinal and transversal mesh widths, and break loads resulting from in-plane-tension tests and steel strength. The single chain elements then can be combined to a complete mesh (e.g. 130 x 65 mm, 3 - 4 mm wire with a strength of 1770 N-mm2). Combining these elements with a supporting structure consisting of posts, ropes and energy absorbers, enables the simulation of protection barriers used for natural hazards such as rockfalls or even landslides. The contribution explains the mechanical behaviour of the chain mesh, the calibration procedures and their application in flexible rockfall protection systems. The investigated meshes are built using three or four millimeter wire with a minimum yield strength of 1770 N-mm2: The maximal load in longitudinal mesh direction ranges about 130 - 380 kN-m and transversal 50 - 170 kN-m. The mesh size varies from 83 × 143 mm to 292 × 500 mm. References Cazzani, A., Mongiovi, L. and Frenez, T. (2002) Dynamic Finite Element Analysis of Interceptive Devices for Falling Rocks, International Journal of Rock Mechanics & Mining Sciences. 39,303-321. Volkwein, A. (2004) Numerische Simulation von flexiblen Steinschlagschutzsystemen. Diss. ETH Nr. 15641. Nicot, F. (1999) Etude du comportement méchanique des ouvrages souples de protection contre les éboulements rocheux. Diss. Ecole Centrale de Lyon.

The Status and Prospect of Research into Protective Structures of Bridge Piers against Rockfall Impact

NASA Astrophysics Data System (ADS)

Gao, Liang; Zhang, Shan; Zhang, Junfa; Wu, Xiangnan

2017-06-01

Rockfall impact on bridge piers threats severely the mountain bridge structures of lifeline engineering. Intended for mountain bridge pier protection against rockfall impact, the paper conducted comprehensive reviews on the research status of impact effects, anti-collision structure, impact response to rockfall, and protective design at home and abroad, and proposed a new-type protective structure against rockfall impact. In addition, the paper carried out deep studies on such key scientific issues as impact effect calculation, protective materials against rockfall impact, damage mechanism of protective units, and parameter optimization on the system of protective structures against rockfall impact as well, aiming to strength disaster prevention of mountain bridge structures.

Three-dimensional Reconstruction of Block Shape Irregularity and its Effects on Block Impacts Using an Energy-Based Approach

NASA Astrophysics Data System (ADS)

Zhang, Yulong; Liu, Zaobao; Shi, Chong; Shao, Jianfu

2018-04-01

This study is devoted to three-dimensional modeling of small falling rocks in block impact analysis in energy view using the particle flow method. The restitution coefficient of rockfall collision is introduced from the energy consumption mechanism to describe rockfall-impacting properties. Three-dimensional reconstruction of falling block is conducted with the help of spherical harmonic functions that have satisfactory mathematical properties such as orthogonality and rotation invariance. Numerical modeling of the block impact to the bedrock is analyzed with both the sphere-simplified model and the 3D reconstructed model. Comparisons of the obtained results suggest that the 3D reconstructed model is advantageous in considering the combination effects of rockfall velocity and rotations during colliding process. Verification of the modeling is carried out with the results obtained from other experiments. In addition, the effects of rockfall morphology, surface characteristics, velocity, and volume, colliding damping and relative angle are investigated. A three-dimensional reconstruction modulus of falling blocks is to be developed and incorporated into the rockfall simulation tools in order to extend the modeling results at block scale to slope scale.

Thin-skinned Mass-wasting Responsible for Rapid, Edifice-wide Deformation at Arenal Volcano

NASA Astrophysics Data System (ADS)

Ebmeier, S. K.; Biggs, J.; Muller, C.; Avard, G.

2014-12-01

Volcanic edifices are built rapidly, at rates far exceeding those of erosion. The resulting mechanical failure of the edifices of both active and quiescent volcanoes can result in hazards on a range of scales, from rockfall to sector collapse. The stability of a volcanic edifice depends on the ratio of its exogenous growth to mass loss due to erosion, deformation and mass wasting. Geodetic measurements of edifice spreading have mostly been associated with local zones of extension at island volcanoes and relatively few observations have been made at continental stratovolcanoes. We present measurements of displacement and surface property changes at Arenal, Costa Rica, a continental stratovolcano that stopped erupting in 2010 after almost 42 years of activity. High resolution TerraSAR-X data (2011-2013) have increased the area covered geodetically by ~40%, allowing us to make measurements of displacements close to Arenal's summit for the first time. InSAR and intensity change observations provide evidence of frequent rockfalls and of shallow landslides (5-11 m thick, total volume = 1.9×107 m3 DRE). Rockfall and shallow translational landsliding have a stabilizing effect on Volcán Arenal's edifice that reduces the potential for external triggering of slope failure. We map 16 shallow landslides (5-11 m depth, 4% of post-1968 deposits) and expect failure planes to be associated with layers of blocky debris and lava crust. Unstable material on Arenal's upper slopes is removed steadily, potentially reducing sensitivity to external triggers: the 2012 Nicoya Earthquake (Mw 7.6) had no measurable impact on the velocities of sliding units, but did result in an elevated area of rockfall. This demonstrates the importance of mass wasting for the stability of young volcanic edifices.

Optimising 4-D surface change detection: an approach for capturing rockfall magnitude-frequency

NASA Astrophysics Data System (ADS)

Williams, Jack G.; Rosser, Nick J.; Hardy, Richard J.; Brain, Matthew J.; Afana, Ashraf A.

2018-02-01

We present a monitoring technique tailored to analysing change from near-continuously collected, high-resolution 3-D data. Our aim is to fully characterise geomorphological change typified by an event magnitude-frequency relationship that adheres to an inverse power law or similar. While recent advances in monitoring have enabled changes in volume across more than 7 orders of magnitude to be captured, event frequency is commonly assumed to be interchangeable with the time-averaged event numbers between successive surveys. Where events coincide, or coalesce, or where the mechanisms driving change are not spatially independent, apparent event frequency must be partially determined by survey interval.The data reported have been obtained from a permanently installed terrestrial laser scanner, which permits an increased frequency of surveys. Surveying from a single position raises challenges, given the single viewpoint onto a complex surface and the need for computational efficiency associated with handling a large time series of 3-D data. A workflow is presented that optimises the detection of change by filtering and aligning scans to improve repeatability. An adaptation of the M3C2 algorithm is used to detect 3-D change to overcome data inconsistencies between scans. Individual rockfall geometries are then extracted and the associated volumetric errors modelled. The utility of this approach is demonstrated using a dataset of ˜ 9 × 103 surveys acquired at ˜ 1 h intervals over 10 months. The magnitude-frequency distribution of rockfall volumes generated is shown to be sensitive to monitoring frequency. Using a 1 h interval between surveys, rather than 30 days, the volume contribution from small (< 0.1 m3) rockfalls increases from 67 to 98 % of the total, and the number of individual rockfalls observed increases by over 3 orders of magnitude. High-frequency monitoring therefore holds considerable implications for magnitude-frequency derivatives, such as hazard return intervals and erosion rates. As such, while high-frequency monitoring has potential to describe short-term controls on geomorphological change and more realistic magnitude-frequency relationships, the assessment of longer-term erosion rates may be more suited to less-frequent data collection with lower accumulative errors.

Analysis of Low-Light and Night-Time Stereo-Pair Images for Photogrammetric Reconstruction

NASA Astrophysics Data System (ADS)

Santise, M.; Thoeni, K.; Roncella, R.; Diotri, F.; Giacomini, A.

2018-05-01

Rockfalls and rockslides represent a significant risk to human lives and infrastructures because of the high levels of energy involved in the phenomena. Generally, these events occur in accordance to specific environmental conditions, such as temperature variations between day and night, that can contribute to the triggering of structural instabilities in the rock-wall and the detachment of blocks and debris. The monitoring and the geostructural characterization of the wall are required for reducing the potential hazard and to improve the management of the risk at the bottom of the slopes affected by such phenomena. In this context, close range photogrammetry is largely used for the monitoring of high-mountain terrains and rock walls in mine sites allowing for periodic survey of rockfalls and wall movements. This work focuses on the analysis of low-light and night-time images of a fixed-base stereo pair photogrammetry system. The aim is to study the reliability of the images acquired over the night to produce digital surface models (DSMs) for change detection. The images are captured by a high-sensitivity DLSR camera using various settings accounting for different values of ISO, aperture and time of exposure. For each acquisition, the DSM is compared to a photogrammetric reference model produced by images captured in optimal illumination conditions. Results show that, with high level of ISO and maintaining the same grade of aperture, extending the exposure time improves the quality of the point clouds in terms of completeness and accuracy of the photogrammetric models.

Quantifying the effect of forests on frequency and intensity of rockfalls

NASA Astrophysics Data System (ADS)

Moos, Christine; Dorren, Luuk; Stoffel, Markus

2017-02-01

Forests serve as a natural means of protection against small rockfalls. Due to their barrier effect, they reduce the intensity and the propagation probability of falling rocks and thus reduce the occurrence frequency of a rockfall event for a given element at risk. However, despite established knowledge on the protective effect of forests, they are generally neglected in quantitative rockfall risk analyses. Their inclusion in quantitative rockfall risk assessment would, however, be necessary to express their efficiency in monetary terms and to allow comparison of forests with other protective measures, such as nets and dams. The goal of this study is to quantify the effect of forests on the occurrence frequency and intensity of rockfalls. We therefore defined an onset frequency of blocks based on a power-law magnitude-frequency distribution and determined their propagation probabilities on a virtual slope based on rockfall simulations. Simulations were run for different forest and non-forest scenarios under varying forest stand and terrain conditions. We analysed rockfall frequencies and intensities at five different distances from the release area. Based on two multivariate statistical prediction models, we investigated which of the terrain and forest characteristics predominantly drive the role of forest in reducing rockfall occurrence frequency and intensity and whether they are able to predict the effect of forest on rockfall risk. The rockfall occurrence frequency below forested slopes is reduced between approximately 10 and 90 % compared to non-forested slope conditions; whereas rockfall intensity is reduced by 10 to 70 %. This reduction increases with increasing slope length and decreases with decreasing tree density, tree diameter and increasing rock volume, as well as in cases of clustered or gappy forest structures. The statistical prediction models reveal that the cumulative basal area of trees, block volume and horizontal forest structure represent key variables for the prediction of the protective effect of forests. In order to validate these results, models have to be tested on real slopes with a wide variation of terrain and forest conditions.

Regional-scale controls on the spatial activity of rockfalls (Turtmann Valley, Swiss Alps) - A multivariate modeling approach

NASA Astrophysics Data System (ADS)

Messenzehl, Karoline; Meyer, Hanna; Otto, Jan-Christoph; Hoffmann, Thomas; Dikau, Richard

2017-06-01

In mountain geosystems, rockfalls are among the most effective sediment transfer processes, reflected in the regional-scale distribution of talus slopes. However, the understanding of the key controlling factors seems to decrease with increasing spatial scale, due to emergent and complex system behavior and not least to recent methodological shortcomings in rockfall modeling research. In this study, we aim (i) to develop a new approach to identify major regional-scale rockfall controls and (ii) to quantify the relative importance of these controls. Using a talus slope inventory in the Turtmann Valley (Swiss Alps), we applied for the first time the decision-tree based random forest algorithm (RF) in combination with a principal component logistic regression (PCLR) to evaluate the spatial distribution of rockfall activity. This study presents new insights into the discussion on whether periglacial rockfall events are controlled more by topo-climatic, cryospheric, paraglacial or/and rock mechanical properties. Both models explain the spatial rockfall pattern very well, given the high areas under the Receiver Operating Characteristic (ROC) curves of > 0.83. Highest accuracy was obtained by the RF, correctly predicting 88% of the rockfall source areas. The RF appears to have a great potential in geomorphic research involving multicollinear data. The regional permafrost distribution, coupled to the bedrock curvature and valley topography, was detected to be the primary rockfall control. Rockfall source areas cluster within a low-radiation elevation belt (2900-3300 m a.s.l,) consistent with a permafrost probability of > 90%. The second most important factor is the time since deglaciation, reflected by the high abundance of rockfalls along recently deglaciated (< 100 years), north-facing slopes. However, our findings also indicate a strong rock mechanical control on the paraglacial rockfall activity, declining either exponentially or linearly since deglaciation. The study demonstrates the benefit of combined statistical approaches for predicting rockfall activity in deglaciated, permafrost-affected mountain valleys and highlights the complex interplay between rock mechanical, paraglacial and topo-climatic controls at the regional scale.

An open source GIS-based tool to integrate the fragmentation mechanism in rockfall propagation

NASA Astrophysics Data System (ADS)

Matas, Gerard; Lantada, Nieves; Gili, Josep A.; Corominas, Jordi

2015-04-01

Rockfalls are frequent instability processes in road cuts, open pit mines and quarries, steep slopes and cliffs. Even though the stability of rock slopes can be determined using analytical approaches, the assessment of large rock cliffs require simplifying assumptions due to the difficulty of working with a large amount of joints, the scattering of both the orientations and strength parameters. The attitude and persistency of joints within the rock mass define the size of kinematically unstable rock volumes. Furthermore the rock block will eventually split in several fragments during its propagation downhill due its impact with the ground surface. Knowledge of the size, energy, trajectory… of each block resulting from fragmentation is critical in determining the vulnerability of buildings and protection structures. The objective of this contribution is to present a simple and open source tool to simulate the fragmentation mechanism in rockfall propagation models and in the calculation of impact energies. This tool includes common modes of motion for falling boulders based on the previous literature. The final tool is being implemented in a GIS (Geographic Information Systems) using open source Python programming. The tool under development will be simple, modular, compatible with any GIS environment, open source, able to model rockfalls phenomena correctly. It could be used in any area susceptible to rockfalls with a previous adjustment of the parameters. After the adjustment of the model parameters to a given area, a simulation could be performed to obtain maps of kinetic energy, frequency, stopping density and passing heights. This GIS-based tool and the analysis of the fragmentation laws using data collected from recent rockfall have being developed within the RockRisk Project (2014-2016). This project is funded by the Spanish Ministerio de Economía y Competitividad and entitled "Rockfalls in cliffs: risk quantification and its prevention"(BIA2013-42582-P).

Comparison of three GIS-based models for predicting rockfall runout zones at a regional scale

NASA Astrophysics Data System (ADS)

Dorren, Luuk K. A.; Seijmonsbergen, Arie C.

2003-11-01

Site-specific information about the level of protection that mountain forests provide is often not available for large regions. Information regarding rockfalls is especially scarce. The most efficient way to obtain information about rockfall activity and the efficacy of protection forests at a regional scale is to use a simulation model. At present, it is still unknown which forest parameters could be incorporated best in such models. Therefore, the purpose of this study was to test and evaluate a model for rockfall assessment at a regional scale in which simple forest stand parameters, such as the number of trees per hectare and the diameter at breast height, are incorporated. Therefore, a newly developed Geographical Information System (GIS)-based distributed model is compared with two existing rockfall models. The developed model is the only model that calculates the rockfall velocity on the basis of energy loss due to collisions with trees and on the soil surface. The two existing models calculate energy loss over the distance between two cell centres, while the newly developed model is able to calculate multiple bounces within a pixel. The patterns of rockfall runout zones produced by the three models are compared with patterns of rockfall deposits derived from geomorphological field maps. Furthermore, the rockfall velocities modelled by the three models are compared. It is found that the models produced rockfall runout zone maps with rather similar accuracies. However, the developed model performs best on forested hillslopes and it also produces velocities that match best with field estimates on both forested and nonforested hillslopes irrespective of the slope gradient.

4D monitoring of actively failing rockslopes

NASA Astrophysics Data System (ADS)

Rosser, Nick; Williams, Jack; Hardy, Richard; Brain, Matthew

2017-04-01

Assessing the conditions which promote rockfall to collapse relies upon detailed monitoring, ideally before, during and immediately after failure. With standard repeat surveys it is common that surveys do not coincide with or capture precursors, or that surveys are widely spaced relative to the timing and duration of driving forces such as storms. As a result gaining insight into the controls on failure and the timescales over which precursors operate remains difficult to establish with certainty, and establishing direct links between environmental conditions and rock-falls, or sequences of events prior to rockfall, remain difficult to define. To address this, we present analysis of a high-frequency 3D laser scan dataset captured using a new permanently installed system developed to constantly monitor actively failing rock slopes. The system is based around a time of flight laser scanner, integrated with and remotely controlled by dedicated controls and analysis software. The system is configured to capture data at 0.1 m spacing across > 22,000 m3 at up to 30 minute intervals. Here we present results captured with this system over a period of 9 months, spanning spring to winter 2015. Our analysis is focussed upon improving the understanding of the nature of small (< 1m^3) rockfalls falling from near vertical rock cliffs. We focus here on the development of a set of algorithms for differencing that trade-off the temporal resolution of frequent surveys (hourly) against high spatial resolution point clouds (< 0.05 m) to enhance the precision of change detection, allowing both deformation and detachments to be monitored through time. From this dataset we derive rockfall volume frequency distributions based upon short-interval surveys, and identify the presence and/or absence of precursors, in what we believe to be the first constant volumetric measurement of rock face erosion. The results hold implications for understanding of rockfall mechanics, but also for how actively eroding surfaces can be monitored at high temporal frequency. Whilst high frequency data is ideal for describing processes that evolve rapidly through time, the cumulative errors that accumulate when monitored changes are dominated by inverse power-law distributed volumes are significant. To conclude we consider the benefits of defining survey frequency on the basis of the changes being detected relative to the accumulation of errors that inevitably arises when comparing high numbers of sequential surveys.

Lava dome growth and mass wasting measured by a time series of ground-based radar and seismicity observations

NASA Astrophysics Data System (ADS)

Wadge, G.; Macfarlane, D. G.; Odbert, H. M.; James, M. R.; Hole, J. K.; Ryan, G.; Bass, V.; de Angelis, S.; Pinkerton, H.; Robertson, D. A.; Loughlin, S. C.

2008-08-01

Exogenous growth of Peléean lava domes involves the addition of lava from a central summit vent and mass wasting on the flanks as rockfalls and pyroclastic flows. These processes were investigated at the Soufrière Hills Volcano, Montserrat, between 30 March and 10 April 2006, using a ground-based imaging millimeter-wave radar, AVTIS, to measure the shape of the dome and talus surface and rockfall seismicity combined with camera observations to infer pyroclastic flow deposit volumes. The topographic evolution of the lava dome was recorded in a time series of radar range and intensity measurements from a distance of 6 km, recording a southeastward shift in the locus of talus deposition with time, and an average height increase for the talus surface of about 2 m a day. The AVTIS measurements show an acceleration in lava extrusion rate on 5 April, with a 2-day lag in the equivalent change in the rockfall seismicity record. The dense rock equivalent volumetric budget of lava added and dispersed, including the respective proportions of the total for each component, was calculated using: (1) AVTIS range and intensity measurements of the change in summit lava (˜1.5 × 106 m3, 22%), (2) AVTIS range measurements to measure the talus growth (˜3.9 × 106 m3, 57%), and (3) rockfall seismicity to measure the pyroclastic flow deposit volumes (˜1.4 × 106 m3, 21%), which gives an overall dense rock equivalent extrusion rate of about 7 m3·s-1. These figures demonstrate how efficient nonexplosive lava dome growth can be in generating large volumes of primary clastic deposits, a process that, by reducing the proportion of erupted lava stored in the summit region, will reduce the likelihood of large hazardous pyroclastic flows.

Slope failures in Northern Vermont, USA

USGS Publications Warehouse

Lee, F.T.; Odum, J.K.; Lee, J.D.

1997-01-01

Rockfalls and debris avalanches from steep hillslopes in northern Vermont are a continuing hazard for motorists, mountain climbers, and hikers. Huge blocks of massive schist and gneiss can reach the valley floor intact, whereas others may trigger debris avalanches on their downward travel. Block movement is facilitated by major joints both parallel and perpendicular to the glacially over-steepened valley walls. The slope failures occur most frequently in early spring, accompanying freeze/thaw cycles, and in the summer, following heavy rains. The study reported here began in August 1986 and ended in June 1989. Manual and automated measurements of temperature and displacement were made at two locations on opposing valley walls. Both cyclic-reversible and permanent displacements occurred during the 13-month monitoring period. The measurements indicate that freeze/thaw mechanisms produce small irreversible incremental movements, averaging 0.53 mm/yr, that displace massive blocks and produce rockfalls. The initial freeze/thaw weakening of the rock mass also makes slopes more susceptible to attrition by water, and heavy rains have triggered rockfalls and consequent debris flows and avalanches. Temperature changes on the rock surface produced time-dependent cyclic displacements of the rock blocks that were not instantaneous but lagged behind the temperature changes. Statistical analyses of the data were used to produce models of cyclic time-dependent rock block behavior. Predictions based solely on temperature changes gave poor results. A model using time and temperature and incorporating the lag effect predicts block displacement more accurately.

Geological hazard monitoring system in Georgia

NASA Astrophysics Data System (ADS)

Gaprindashvili, George

2017-04-01

Georgia belongs to one of world's most complex mountainous regions according to the scale and frequency of Geological processes and damage caused to population, farmlands, and Infrastructure facilities. Geological hazards (landslide, debrisflow/mudflow, rockfall, erosion and etc.) are affecting many populated areas, agricultural fields, roads, oil and gas pipes, high-voltage electric power transmission towers, hydraulic structures, and tourist complexes. Landslides occur almost in all geomorphological zones, resulting in wide differentiation in the failure types and mechanisms and in the size-frequency distribution. In Georgia, geological hazards triggered by: 1. Activation of highly intense earthquakes; 2. Meteorological events provoking the disaster processes on the background of global climatic change; 3. Large-scale Human impact on the environment. The prediction and monitoring of Geological Hazards is a very wide theme, which involves different researchers from different spheres. Geological hazard monitoring is essential to prevent and mitigate these hazards. In past years in Georgia several monitoring system, such as Ground-based geodetic techniques, Debrisflow Early Warning System (EWS) were installed on high sensitive landslide and debrisflow areas. This work presents description of Geological hazard monitoring system in Georgia.

Sampling of Stochastic Input Parameters for Rockfall Calculations and for Structural Response Calculations Under Vibratory Ground Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Gross

2004-09-01

The purpose of this scientific analysis is to define the sampled values of stochastic (random) input parameters for (1) rockfall calculations in the lithophysal and nonlithophysal zones under vibratory ground motions, and (2) structural response calculations for the drip shield and waste package under vibratory ground motions. This analysis supplies: (1) Sampled values of ground motion time history and synthetic fracture pattern for analysis of rockfall in emplacement drifts in nonlithophysal rock (Section 6.3 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (2) Sampled values of ground motion time history and rock mechanical properties category for analysis of rockfall inmore » emplacement drifts in lithophysal rock (Section 6.4 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (3) Sampled values of ground motion time history and metal to metal and metal to rock friction coefficient for analysis of waste package and drip shield damage to vibratory motion in ''Structural Calculations of Waste Package Exposed to Vibratory Ground Motion'' (BSC 2004 [DIRS 167083]) and in ''Structural Calculations of Drip Shield Exposed to Vibratory Ground Motion'' (BSC 2003 [DIRS 163425]). The sampled values are indices representing the number of ground motion time histories, number of fracture patterns and rock mass properties categories. These indices are translated into actual values within the respective analysis and model reports or calculations. This report identifies the uncertain parameters and documents the sampled values for these parameters. The sampled values are determined by GoldSim V6.04.007 [DIRS 151202] calculations using appropriate distribution types and parameter ranges. No software development or model development was required for these calculations. The calculation of the sampled values allows parameter uncertainty to be incorporated into the rockfall and structural response calculations that support development of the seismic scenario for the Total System Performance Assessment for the License Application (TSPA-LA). The results from this scientific analysis also address project requirements related to parameter uncertainty, as specified in the acceptance criteria in ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274]). This document was prepared under the direction of ''Technical Work Plan for: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 170528]) which directed the work identified in work package ARTM05. This document was prepared under procedure AP-SIII.9Q, ''Scientific Analyses''. There are no specific known limitations to this analysis.« less

The role of alpine rockfall aquifer systems in baseflow maintenance and flood attenuation

NASA Astrophysics Data System (ADS)

Lauber, Ute; Kotyla, Patrick; Morche, David; Goldscheider, Nico

2015-04-01

Rockfall masses are frequent in alpine valleys. Huge rockfalls (millions to billions m³) precipitated after the end of the last glaciation, but many large events (thousand to millions m³) have occurred in historical time, and increasingly during the past decades, as a result of glacier retreat and thawing of permafrost. Most hydrological research focuses on water as a cause or trigger of rockfalls, while much less research has been done on the hydrogeological properties and functions of rockfall masses in alpine valleys. We have studied a series of rockfall and alluvial aquifer systems in the Reintal valley, German Alps, where all surface water infiltrates underground and reemerges downgradient from the rockfall masses. The goal of the study was to characterize the role of this rockfall aquifer in baseflow maintenance and flood attenuation. Employed methods include geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements. Field observations have revealed that both the infiltration and exfiltration locations vary as a function of the hydrologic conditions. Underground flow path length range from 500 m during high flows to 2 km during low flows; measured groundwater flow velocities range between 13 and 30 m/h; lag times between upstream and downstream flood peaks are 5 to 101 hours. Flood peaks were dampened by a factor of 1.5 and the maximum discharge ratio (22) and peak recession coefficient (0.2/d) downstream are very low compared with other alpine catchments. These results indicate that rockfall aquifers can play an important role in the flow regime and flood attenuation in alpine regions.

Seismic Stability Evaluation of Ririe Dam and Reservoir Project. Report 2. Stability Calculations, Analysis, and Evaluations. Volume 1. Main Text

DTIC Science & Technology

1991-09-01

Army (i #Awleable) Engineer istrict. Walls Welli NPW-EN- GI _____________________ Bc DRSSW4~Sse.adZPa 10 SOURCE OF FUNDING NUMBERS Bldg. 602, City...cracks induced by ground motions. Z. Overtopping of dam due to seiches in reservoir. h. Overtopping of dam due to slides or rockfalls into reservoir. j...overtopping due to slides or rockfalls is not likely. Three potential modes of failure remain from the original list: (c) slope failures induced by

Link between surface temperature and documented rockfalls in the Mont Blanc massif rockwalls

NASA Astrophysics Data System (ADS)

Magnin, Florence; Deline, Philip; Ravanel, Ludovic

2014-05-01

Recent studies show that rockfall activity has increased along the three past decades in high mountain areas, and permafrost degradation is regarded as the main triggering factor. 433 rockfalls affecting the steep rockwalls of the Mont Blanc massif have been inventoried and documented (time and precise location, topographical and geological settings, volume, conditions, etc.) from 2007 to 2011. With the aim of better understanding geomorphic processes, we address questions about the thermal state of the unstable rockwalls within this study area. A statistical model of the Mean Annual Rock Surface Temperature (MARST) for the 1961-1990 period has been implemented on a 4-m-resolution DEM of the Mont Blanc massif. The model runs with Potential Incoming Solar radiation (PISR) calculated with GIS tools and air temperature parameters computed from Chamonix Météo France's records. 87 rockfalls are located at the geographical margins of the DEM, where the PISR calculation doesn't take account of the surrounding hillshading and biased MARST simulation. Thus, only 346 rockfalls were kept and linked to a MARST value after data sorting. Preliminary results show that rockfalls occurred over a modelled MARST range of -6°C to 5°C. MARSTs ranging from -2.5°C to 2.5°C encompass about 60% of the rockfalls. The mean MARST value for the 346 rockfalls is of -0.9°C. Simulated warm permafrost areas (> -2°C) are therefore appearing as the most affected by instabilities. These first observations reinforce the hypothesis that permafrost degradation is likely the dominant triggering factor of these rockfalls. The 1961-1990 period is supposed to be representative of the conditions at depth that are not affected by the recent climate warming. This means that the here presented results are mainly valuable for rockfalls related to pluri-decadal signal. But they also suggest that MARST model is an interesting tool to explore the link between rockwall instability and permafrost state. Simulations at various time scales would allow more precise reconstruction of the bedrock temperature during each year of rockfalls. Model possibilities and the related outcomings will be also presented.

Analysing rockfall processes on alpine rockfaces and the corresponding talus cones using Terrestrial Laserscanning

NASA Astrophysics Data System (ADS)

Haas, Florian; Heckmann, Tobias; Klein, Thomas; Becht, Michael

2010-05-01

In high mountain regions, rockfall plays a major role as a geomorphic process, both in terms of sediment budget and natural hazard. During the last two years, high-resolution Terrestrial Laserscanning (TLS) was applied to study (a) detachment zones and sizes of rock fall events within steep rockfaces, (b) characteristics of rockfall deposits such as surface roughness, size distribution and fragment morphology, and (c) their influence on rockfall run-out length. The investigations were carried out in three study areas located in the Northern, Central and Southern Alps (Val di Funes, Northern Dolomites/Italy; Horlachtal, Central Alps/Austria; Höllental, Northern Calcareous Alps/Germany). Within this project (funded by the German Science Foundation, DFG), rockfaces and corresponding talus cones were scanned twice a year with two scanning resolutions. Larger events were investigated by scanning large areas of rockfaces and talus cones from a great distance (~500 m). In contrast, detailed scans from shorter distances (<250m) were used to investigate the capability of the approach to detect smaller events. With this approach, it was possible to record three large and several smaller events in the three catchments. The largest event occurred in the Dolomite Alps (Val di Funes/Italy) with a volume of nearly 3300 cubic meters (8900 tons). Both the detachment zone and the depositional zones could be defined very well by a cut-and-fill analysis of the digital elevation models generated from the TLS data. In addition, ground based LIDAR data are also a very helpful tool to characterize the surface properties of talus cones and the runout distances of large boulders. The surface roughness of talus cones in all three catchments was derived from the TLS point clouds by a GIS approach according to the roughness-length method. The resulting detailed rougness maps of the talus cones will help in the future to improve existing process models which are able to model runout distances on the talus cones using friction parameters. It has often been mentioned that not only the surface roughness of the talus cone, but also the shape of the boulders itself have an influence on the runout distance. The interrelationship between rock fragment morphology (characterised by shape parameters) and runout distance was analysed at the site of a large rockfall event (>10 000 cubic meters) from the year 2003 in the northern Dolomite Alps. For these analyses, the axial ratio of 618 rocks (>50 cm long axis) in the depositional zone and their corresponding runout distance were measured using TLS data and the software RiscanPro. Results show a significant correlation between the axial ratio of the particles and their runout distance. Rocks with a "round" shape (axial ratio around 1) have a longer runout distance than elongated or irregularly shaped particles (axial ratio greater than 1).

Natural hazard fatalities in Switzerland from 1946 to 2015

NASA Astrophysics Data System (ADS)

Badoux, Alexandre; Andres, Norina; Techel, Frank; Hegg, Christoph

2016-12-01

A database of fatalities caused by natural hazard processes in Switzerland was compiled for the period between 1946 and 2015. Using information from the Swiss flood and landslide damage database and the Swiss destructive avalanche database, the data set was extended back in time and more hazard processes were added by conducting an in-depth search of newspaper reports. The new database now covers all natural hazards common in Switzerland, categorised into seven process types: flood, landslide, rockfall, lightning, windstorm, avalanche and other processes (e.g. ice avalanches, earthquakes). Included were all fatal accidents associated with natural hazard processes in which victims did not expose themselves to an important danger on purpose. The database contains information on 635 natural hazard events causing 1023 fatalities, which corresponds to a mean of 14.6 victims per year. The most common causes of death were snow avalanches (37 %), followed by lightning (16 %), floods (12 %), windstorms (10 %), rockfall (8 %), landslides (7 %) and other processes (9 %). About 50 % of all victims died in one of the 507 single-fatality events; the other half were killed in the 128 multi-fatality events. The number of natural hazard fatalities that occurred annually during our 70-year study period ranged from 2 to 112 and exhibited a distinct decrease over time. While the number of victims in the first three decades (until 1975) ranged from 191 to 269 per decade, it ranged from 47 to 109 in the four following decades. This overall decrease was mainly driven by a considerable decline in the number of avalanche and lightning fatalities. About 75 % of victims were males in all natural hazard events considered together, and this ratio was roughly maintained in all individual process categories except landslides (lower) and other processes (higher). The ratio of male to female victims was most likely to be balanced when deaths occurred at home (in or near a building), a situation that mainly occurred in association with landslides and avalanches. The average age of victims of natural hazards was 35.9 years and, accordingly, the age groups with the largest number of victims were the 20-29 and 30-39 year-old groups, which in combination represented 34 % of all fatalities. It appears that the overall natural hazard mortality rate in Switzerland over the past 70 years has been relatively low in comparison to rates in other countries or rates of other types of fatal accidents in Switzerland. However, a large variability in mortality rates was observed within the country with considerably higher rates in Alpine environments.

Specific analysis of the recent rockfall activity in the southeast face of the Piz Lischana (Engadin Valley, Graubünden, Switzerland)

NASA Astrophysics Data System (ADS)

Büsing, Susanna; Guerin, Antoine; Derron, Marc-Henri; Jaboyedoff, Michel; Phillips, Marcia

2016-04-01

The study of permafrost is now attracting more and more researchers because the warming observed in the Alps since the beginning of last century is causing changes in active layer depth and in the thermal state of this climate indicator. In mountain regions, permafrost degradation is becoming critical for the whole population since slopes and rock walls are being destabilized, thus increasing risk for infrastructure and inhabitants of mountain valleys. To anticipate the triggering of future events better, it is necessary to improve understanding on the relation between permafrost thaw and slope instabilities. A rockfall of about 7000 m3 occurred in the upper part of the southeast face of the Piz Lischana (3105 m), in the Engadin Valley (Graubünden, Switzerland) around noon on 31 July 2011. Luckily, this event was filmed and ice could be observed on the failure plane after analysis of the images. In September 2014 and in the same area, another rockfall of 2340 m3 occurred along a prominent open fracture which was apparent since the failure of the rock mass in 2011. In order to characterize and analyze these two events, three 3D high density point clouds have been made using Structure from Motion (SfM) and LiDAR, one before and two after the September 2014 rockfall. For this purpose, 120 photos were taken during a helicopter flight in July 2014 to produce the first SfM point cloud, and more than 400 terrestrial photos were taken at the end of September to produce the second SfM point cloud. In July 2015 a third point cloud was created from three LiDAR scans, taken from two different positions. The point clouds were georeferenced with a 2 m resolution digital elevation model and compared to each other in order to calculate the volume of the rockfalls. A detailed structural analysis of the two rockfalls was made and compared to the geological structures of the whole southeast face. The structural analysis also allowed to improve the understanding of the failure mechanisms of the past events and to better assess the probability of future rockfalls. Furthermore, valuable information about the velocity of the failure mechanisms could be extracted from the July 2011 video, using a Particle Image Velocimetry method (Matlab script developed by Thielicke and Stamhuis, 2014). These results, combined with analyses of potential triggering factors (permafrost, freeze-thaw cycles, thermomechanical processes, rainfall, radiation, glacier decompression and seismics) show that many of them contributed towards destabilization. It seems that the "special" structural situation led to the failure of Piz Lischana, but it also highlights the influence of permafrost. This study also provided the opportunity to perform a comparison of both LiDAR - SfM. The point clouds have been analyzed regarding their general quality, the quality of their meshes, the quantity of instrumental noise, the point density of different discontinuities, the structural analysis and kinematic tests. Results show the SfM also allows detailed structural analysis and that a good choice of the parameters allows to approach the quality of the LiDAR data. However, several factors (focal length, variation of distance to object, image resolution) may increase the uncertainty of the photo alignment. This study confirms that the coupling of the two techniques is possible and provides reliable results. This shows that SfM is one of the possible cheap methods to monitor rock summits that are subject to permafrost thaw.

Experiments and Dynamic Finite Element Analysis of a Wire-Rope Rockfall Protective Fence

NASA Astrophysics Data System (ADS)

Tran, Phuc Van; Maegawa, Koji; Fukada, Saiji

2013-09-01

The imperative need to protect structures in mountainous areas against rockfall has led to the development of various protection methods. This study introduces a new type of rockfall protection fence made of posts, wire ropes, wire netting and energy absorbers. The performance of this rock fence was verified in both experiments and dynamic finite element analysis. In collision tests, a reinforced-concrete block rolled down a natural slope and struck the rock fence at the end of the slope. A specialized system of measuring instruments was employed to accurately measure the acceleration of the block without cable connection. In particular, the performance of two energy absorbers, which contribute also to preventing wire ropes from breaking, was investigated to determine the best energy absorber. In numerical simulation, a commercial finite element code having explicit dynamic capabilities was employed to create models of the two full-scale tests. To facilitate simulation, certain simplifying assumptions for mechanical data of each individual component of the rock fence and geometrical data of the model were adopted. Good agreement between numerical simulation and experimental data validated the numerical simulation. Furthermore, the results of numerical simulation helped highlight limitations of the testing method. The results of numerical simulation thus provide a deeper understanding of the structural behavior of individual components of the rock fence during rockfall impact. More importantly, numerical simulations can be used not only as supplements to or substitutes for full-scale tests but also in parametric study and design.

Susceptibility analysis for slides and rockfall: an example from the Northern Calcareous Alps (Vorarlberg, Austria)

NASA Astrophysics Data System (ADS)

Ruff, Michael; Rohn, Joachim

2008-07-01

In this paper a tool for semi-quantitative susceptibility assessment at a regional scale is presented which is applicable at areas with complex geological setting. At a study area within the Northern Calcareous Alps geotechnical mappings were implemented into a Geographical Information System and analysed as grid data with a cell size of 25 m. The susceptibility to sliding and falling processes was considered according to five classes (very low, low, medium, high, very high). Susceptibility to sliding was analysed using an index method. The layers of lithology, bedding conditions, tectonic faults, slope angle, slope aspect, vegetation and erosion were combined iteratively. Dropout zones of rockfall material were determined with help of a Digital Elevation Model. The movement of rolling rock samples was modelled by a cost analysis of all potential rockfall trajectories. These trajectories were also divided into five susceptibility classes. The susceptibility maps are presented in a general way to be used by communities and spatial planners. Conflict areas of susceptibility and landuse were located and can be presented destinctively.

Search and rescue response to a large-scale rockfall disaster.

PubMed

Procter, Emily; Strapazzon, Giacomo; Balkenhol, Karla; Fop, Ernst; Faggionato, Alessandro; Mayr, Karl; Falk, Markus; Brugger, Hermann

2015-03-01

To describe the prehospital management and safety of search and rescue (SAR) teams involved in a large-scale rockfall disaster and monitor the acute and chronic health effects on personnel with severe dolomitic dust exposure. SAR personnel underwent on-site medical screening and lung function testing 3 months and 3 years after the event. The emergency dispatch center was responsible for central coordination of resources. One hundred fifty SAR members from multidisciplinary air- and ground-based teams as well as geotechnical experts were dispatched to a provisionary operation center. Acute exposure to dolomite dust with detectable silicon and magnesium concentrations was not associated with (sub)acute or chronic sequelae or a clinically significant impairment in lung function in exposed personnel. The risk for personnel involved in mountain SAR operations is rarely reported and not easily investigated or quantified. This case exemplifies the importance of a multiskilled team and additional considerations for prehospital management during natural hazard events. Safety plans should include compulsory protective measures and medical monitoring of personnel. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Reconstruction of the rock fall/avalanche frequency in the Mont Blanc massif since the Last Glacial Maximum. New results using 10Be cosmogenic dating and reflectance spectroscopy

NASA Astrophysics Data System (ADS)

Gallach, Xavi; Ogier, Christophe; Ravanel, Ludovic; Deline, Philip; Carcaillet, Julien

2017-04-01

Rockfalls and rock avalanches are active processes in the Mont Blanc massif, with infrastructure and alpinists at risk. Thanks to a network of observers (hut keepers, mountain guides, alpinists) set up in 2007 present rockfalls are well surveyed and documented. Rockfall frequency over the past 150 years has been studied by comparison of historical photographs, showing that it strongly increased during the three last decades, especially during hot periods like the summer of 2003 and 2015, due to permafrost degradation driven by the climate change. In order to decipher the possible relationship between rockfall occurrence and the warmest periods of the Lateglacial and the Holocene, we start to study the morphodynamics of some selected high-elevated (>3000 m a.s.l.) rockwalls of the massif on a long timescale. Contrary to low altitude, deglaciated sites where study of large rockfall deposits allows to quantify frequency and magnitude of the process, rockfalls that detached from high-elevated rockwalls are no more noticeable as debris were absorbed and evacuated by the glaciers. Therefore, our study focuses on the rockfall scars. Their 10Be dating gives us the rock surface exposure age from present to far beyond the Last Glacial Maximum, interpreted as the rockfall ages. TCN dating of rockfalls has been carried out at the Aiguille du Midi in 2007 (Boehlert et al., 2008), and three other sites in the Mont Blanc massif in 2011 (Gallach et al., submitted). Here we present a new data set of rockfall dating carried out in 2015 that improves the 2007 and 2011 data. Furthermore, a relationship between the colour of the Mont Blanc granite and its exposure age has been shown: fresh rock surface is light grey (e.g. in recent rockfall scars) whereas weathered rock surface is in the range grey to orange/red: the redder a rock surface, the older its age. Here, reflectance spectroscopy is used to quantify the granite surface colour. Böhlert, R., Gruber, S., Egli, M., Maisch, M., Brandová, D., Haeberli, W., Ivy-Ochs, S., Christl, M., Kubik, P.W., Deline, P. (2008). Comparison of exposure ages and spectral propierties of rock surfaces in steep, high alpine rock walls of Aiguille du Midi, France. Proceedings of the 9th International Conference on Permafrost, 143-148. Gallach, X. et al. (submitted). Timing of rockfalls in the Mont Blanc massif (western Alps). Evidences from surface exposure dating with cosmogenic 10Be. Landslides.

Rockfall hazard and risk assessment in the Yosemite Valley, California, USA

USGS Publications Warehouse

Guzzetti, F.; Reichenbach, P.; Wieczorek, G.F.

2003-01-01

Rock slides and rock falls are the most frequent types of slope movements in Yosemite National Park, California. In historical time (1857-2002) 392 rock falls and rock slides have been documented in the valley, and some of them have been mapped in detail. We present the results of an attempt to assess rock fall hazards in the Yosemite Valley. Spatial and temporal aspects of rock falls hazard are considered. A detailed inventory of slope movements covering the 145-year period from 1857 to 2002 is used to determine the frequency-volume statistics of rock falls and to estimate the annual frequency of rock falls, providing the temporal component of rock fall hazard. The extent of the areas potentially subject to rock fall hazards in the Yosemite Valley were obtained using STONE, a physically-based rock fall simulation computer program. The software computes 3-dimensional rock fall trajectories starting from a digital elevation model (DEM), the location of rock fall release points, and maps of the dynamic rolling friction coefficient and of the coefficients of normal and tangential energy restitution. For each DEM cell the software calculates the number of rock falls passing through the cell, the maximum rock fall velocity and the maximum flying height. For the Yosemite Valley, a DEM with a ground resolution of 10 ?? 10 m was prepared using topographic contour lines from the U.S. Geological Survey 1:24 000-scale maps. Rock fall release points were identified as DEM cells having a slope steeper than 60??, an assumption based on the location of historical rock falls. Maps of the normal and tangential energy restitution coefficients and of the rolling friction coefficient were produced from a surficial geologic map. The availability of historical rock falls mapped in detail allowed us to check the computer program performance and to calibrate the model parameters. Visual and statistical comparison of the model results with the mapped rock falls confirmed the accuracy of the model. The model results are compared with a previous map of rockfall talus and with a geomorphic assessment of rock fall hazard based on potential energy referred to as a shadow angle approach, recently completed for the Yosemite Valley. The model results are then used to identify the roads and trails more subject to rock fall hazard. Of the 166.5 km of roads and trails in the Yosemite Valley 31.2% were found to be potentially subject to rock fall hazard, of which 14% are subject to very high hazard. ?? European Geosciences Union 2003.

Time Series Radar Observations of a Growing Lava Dome

NASA Astrophysics Data System (ADS)

Wadge, G.; Macfarlane, D. G.; Odbert, H. M.; James, M. R.; Hole, J. K.; Ryan, G.; Bass, V.; de Angelis, S.; Pinkerton, H.; Robertson, D. A.; Loughlin, S. C.

2007-12-01

Exogenous growth of Peléean lava domes occurs by addition of lava from a central summit vent and mass wasting on the flanks as rockfalls and pyroclastic flows, forming an apron of talus. We observed this process at the Soufrière Hills Volcano, Montserrat between 30 March and 10 April 2006 using a ground-based imaging mm-wave radar, AVTIS, to measure the shape of the dome surface.From a time series of range and intensity measurements at a distance of six kilometres we measured the topographic evolution of the lava dome. The locus of talus deposition moved to the southeast with time and the talus surface grew upwards on average at about 2 metres per day. The AVTIS measurements show an acceleration in lava extrusion rate on 5 April, with a 2-day lag in the equivalent rockfall seismicity record. We account for the budget of lava addition and dispersal during the eleven days of measurements using: AVTIS range measurements to measure the talus growth (7.2 Mm3, 67%), AVTIS range and intensity measurements to measure the summit lava growth (1.7 Mm3, 16%), and rockfall seismicity and visual observations to measure the pyroclastic flow deposits (1.8 Mm3, 17%). This gives an overall dense rock equivalent extrusion rate of about 9.7 m3s-1. These figures demonstrate how efficient non-explosive lava dome growth can be in generating large volumes of primary clastic deposits, and how this process could also reduce the propensity for large hazardous pyroclastic flows. andrews.ac.uk/~mmwave/mmwave/avtis.shtml

Evaluation of the rockfall susceptibility of the Solà D'Andorra using the Matterock methodology

NASA Astrophysics Data System (ADS)

Mavrouli, O.; Pedrazzini, A.; Loye, A.; Jaboyedoff, M.; Corominas, J.

2010-05-01

The rockfall susceptibility of a slope is directly linked to the topographical relief and the presence of favorable discontinuities for the detachment of rock volumes from the slope face. In order to rank the rockfall susceptibility throughout a slope so as to localize the zones which are the most probable to produce rockfalls, these parameters have to be taken into consideration. In this context, the objective of this work was the identification of susceptible areas on the Solà de Andorra, in Andorra. The susceptibility is evaluated implementing a GIS platform and the Matterock methodology (Rouiller et al., 1998) by superposition of four criteria that are related to the topographical relief and the presence of discontinuities. The used parameters and the related analyses to obtain them are the following and they are briefly described in the continue: 1. Comparison of the slope angle with the threshold value defined by slope angle analysis. 2. Average number of unfavorable discontinuities per surface unit. 3. Number of kinematically permitted plane or wedge failures. 4. Value in cubic meters of the potentially instable volumes using the Slope Local Base Level, SLBL, method. The slope angle analysis is used for the determination of an angle value above which rockfalls are very probable. It is based on the decomposition of the histogram of the present slope angles to different families, using a Gaussian distribution. The families represent the existing geo-morphological structures. The threshold value is determined by the angle characterizing the steepest family. The unfavorable discontinuities are detected using the Matterock software. The input data is the DEM and the principal discontinuity sets. The output is the average number of discontinuities counted in every topographic facet. The kinematic tests are also performed using the Matterock software. For each unfavorable discontinuity set, the number of potential plane or wedge failures is calculated. The volumes above a base level that is determined by the topographical relief are calculated using the SLBL method, also on a GIS platform. For the application at a local scale to the Solà de Andorra, the four analyses are performed and their outputs are ranked using appropriate rating. The susceptibility index that is used is equal to the sum of the ranked outputs and it is expressed on an increasing scale from 0 to 8. Historical rockfall events are superimposed on the topographic map to check the consistency of the results. It is indicated that areas characterized by high values of the susceptibility index coincide with past events, thus may be considered prone to also produce rockfalls in the future. References Rouiller, J.-D., Jaboyedoff, M., Marro, C., Phlippossian, F. and Mamin, M. (1998): Pentes instables dans le Pennique valaisan. Rapport final PNR31. VDF, Zürich.

Roadway management plan based on rockfall modelling calibration and validation. Application along the Ma-10 road in Mallorca (Spain)

NASA Astrophysics Data System (ADS)

Mateos, Rosa Maria; Garcia, Inmaculada; Reichenbach, Paola; Herrera, Gerardo; Sarro, Roberto; Rius, Joan; Aguilo, Raul

2016-04-01

The Tramuntana range, in the northwestern sector of the island of Mallorca (Spain), is frequently affected by rockfalls which have caused significant damage, mainly along the road network. The Ma-10 road constitutes the main transportation corridor on the range with a heavy traffic estimated at 7,200 vehicles per day on average. With a length of 111 km and a tortuous path, the road is the connecting track for 12 municipalities and constitutes a strategic road on the island for many tourist resorts. For the period spanning from 1995 to current times, 63 rockfalls have affected the Ma-10 road with volumes ranging from 0.3m3 to 30,000 m3. Fortunately, no fatalities occurred but numerous blockages on the road took place which caused significant economic losses, valued of around 11 MEuro (Mateos el al., 2013). In this work we present the procedure we have applied to calibrate and validate rockfall modelling in the Tramuntana region, using 103 cases of the available detailed rockfall inventory (Mateos, 2006). We have exploited STONE (Guzzetti et al. 2002), a GIS based rockfall simulation software which computes 2D and 3D rockfall trajectories starting from a DTM and maps of the dynamic rolling friction coefficient and of the normal and tangential energy restitution coefficients. The appropriate identification of these parameters determines the accuracy of the simulation. To calibrate them, we have selected 40 rockfalls along the range which include a wide variety of outcropping lithologies. Coefficients values have been changed in numerous attempts in order to select those where the extent and shape of the simulation matched the field mapping. Best results were summarized with the average statistical values for each parameter and for each geotechnical unit, determining that mode values represent more precisely the data. Initially, for the validation stage, 10 well- known rockfalls exploited in the calibration phase have been selected. Confidence tests have been applied taking into account, not only the success, but also the mistakes. We have further validated the calibrated parameters along the Ma-road using the 63 rockfall recorded during the past 18 years along the road. 81.5% of the rockfalls are well represented by STONE modelling. Results have been exploited by the Road Maintenance Service of Mallorca for the design of the following road management plan: (1) Phase 1. Short-term. Design a specific plan for the road- sections where rockfalls were registered and modelling results were obtained. A large investment will be expended for implementation of retention and protection measures. (2) Phase 2. Medium-term. Design a specific plan for the road- sections where rockfalls were registered but no modelling results were obtained. For these cases, new studies at local scale are necessary as well as the application of other modelling software which include higher resolution input data. (3) Phase 3. Long-term. Design a specific plan for the road- sections where no rockfalls were registered but modelling results were obtained. These are potential rockfall areas and local and specific ground studies are necessaries. References Mateos RM (2006) Los movimientos de ladera en la Serra de Tramuntana (Mallorca). Caracterización geomecánica y análisis de peligrosidad. PhD. Servicio de Publicaciones de la Universidad Complutense de Madrid. Madrid, 299 p. Mateos RM, García-Moreno I, Herrera G, Mulas J (2013) Damage caused by recent mass-movements in Majorca (Spain), a region with a high risk due to tourism.Landslide Science and Practice.Claudio Margottini, Paolo Canuti and KyojiSassa (Editors). Volume 7: Social and Economic Impact and Policies. 105-113. Guzzetti F, Crosta G, Detti R, Agliardi F (2002) STONE: A computer program for the three-dimensional simulation of rock-falls. Computers Geosciences. Vol. 28:1079-1093.

Influence of tectonic folding on rockfall susceptibility, American Fork Canyon, Utah, USA

USGS Publications Warehouse

Coe, J.A.; Harp, E.L.

2007-01-01

We examine rockfall susceptibility of folded strata in the Sevier fold-thrust belt exposed in American Fork Canyon in north-central Utah. Large-scale geologic mapping, talus production data, rock-mass-quality measurements, and historical rockfall data indicate that rockfall susceptibility is correlated with limb dip and curvature of the folded, cliff-forming Mississippian limestones. On fold limbs, rockfall susceptibility increases as dip increases. This relation is controlled by several factors, including an increase in adverse dip conditions and apertures of discontinuities, and shearing by flexural slip during folding that has reduced the friction angles of discontinuities by smoothing surface asperities. Susceptibility is greater in fold hinge zones than on adjacent limbs primarily because there are greater numbers of discontinuities in hinge zones. We speculate that susceptibility increases in hinge zones as fold curvature becomes tighter.

Development of direct multi-hazard susceptibility assessment method for post-earthquake reconstruction planning in Nepal

NASA Astrophysics Data System (ADS)

Mavrouli, Olga; Rana, Sohel; van Westen, Cees; Zhang, Jianqiang

2017-04-01

After the devastating 2015 Gorkha earthquake in Nepal, reconstruction activities have been delayed considerably, due to many reasons, of a political, organizational and technical nature. Due to the widespread occurrence of co-seismic landslides, and the expectation that these may be aggravated or re-activated in future years during the intense monsoon periods, there is a need to evaluate for thousands of sites whether these are suited for reconstruction. In this evaluation multi-hazards, such as rockfall, landslides, debris flow, and flashfloods should be taken into account. The application of indirect knowledge-based, data-driven or physically-based approaches is not suitable due to several reasons. Physically-based models generally require a large number of parameters, for which data is not available. Data-driven, statistical methods, depend on historical information, which is less useful after the occurrence of a major event, such as an earthquake. Besides, they would lead to unacceptable levels of generalization, as the analysis is done based on rather general causal factor maps. The same holds for indirect knowledge-driven methods. However, location-specific hazards analysis is required using a simple method that can be used by many people at the local level. In this research, a direct scientific method was developed where local level technical people can easily and quickly assess the post-earthquake multi hazards following a decision tree approach, using an app on a smartphone or tablet. The methods assumes that a central organization, such as the Department of Soil Conservation and Watershed Management, generates spatial information beforehand that is used in the direct assessment at a certain location. Pre-earthquake, co-seismic and post-seismic landslide inventories are generated through the interpretation of Google Earth multi-temporal images, using anaglyph methods. Spatial data, such as Digital Elevation Models, land cover maps, and geological maps are used in a GIS to generate Terrain Units in a semi-automated manner, which are further edited using stereo-image interpretation. Source areas for rockfall and debris flows are outlined from the factor maps, and historical inventory, and regional scale empirical runout models are used to define areas that might be affected. This data is then used in the field in an application that guides the user through the decision tree by asking a number of questions, which can be answered by using the existing data, and by direct field observations. The method was applied in a part of Rasuwa district, which was seriously affected by co-seismic and post-seismic mass movements, leading to the evacuation of a number of village, and temporary closure of a number of hydropower construction projects.

Systematic analysis of natural hazards along infrastructure networks using a GIS-tool for risk assessment

NASA Astrophysics Data System (ADS)

Baruffini, Mirko

2010-05-01

Due to the topographical conditions in Switzerland, the highways and the railway lines are frequently exposed to natural hazards as rockfalls, debris flows, landslides, avalanches and others. With the rising incidence of those natural hazards, protection measures become an important political issue. However, they are costly, and maximal protection is most probably not economically feasible. Furthermore risks are distributed in space and time. Consequently, important decision problems to the public sector decision makers are derived. This asks for a high level of surveillance and preservation along the transalpine lines. Efficient protection alternatives can be obtained consequently considering the concept of integral risk management. Risk analysis, as the central part of risk management, has become gradually a generally accepted approach for the assessment of current and future scenarios (Loat & Zimmermann 2004). The procedure aims at risk reduction which can be reached by conventional mitigation on one hand and the implementation of land-use planning on the other hand: a combination of active and passive mitigation measures is applied to prevent damage to buildings, people and infrastructures. With a Geographical Information System adapted to run with a tool developed to manage Risk analysis it is possible to survey the data in time and space, obtaining an important system for managing natural risks. As a framework, we adopt the Swiss system for risk analysis of gravitational natural hazards (BUWAL 1999). It offers a complete framework for the analysis and assessment of risks due to natural hazards, ranging from hazard assessment for gravitational natural hazards, such as landslides, collapses, rockfalls, floodings, debris flows and avalanches, to vulnerability assessment and risk analysis, and the integration into land use planning at the cantonal and municipality level. The scheme is limited to the direct consequences of natural hazards. Thus, we develop a system which integrates the procedures for a complete risk analysis in a Geographic Information System (GIS) toolbox, in order to be applied to our testbed, the Alps-crossing corridor of St. Gotthard. The simulation environment is developed within ArcObjects, the development platform for ArcGIS. The topic of ArcObjects usually emerges when users realize that programming ArcObjects can actually reduce the amount of repetitive work, streamline the workflow, and even produce functionalities that are not easily available in ArcGIS. We have adopted Visual Basic for Applications (VBA) for programming ArcObjects. Because VBA is already embedded within ArcMap and ArcCatalog, it is convenient for ArcGIS users to program ArcObjects in VBA. Our tool visualises the obtained data by an analysis of historical data (aerial photo imagery, field surveys, documentation of past events) or an environmental modeling (estimations of the area affected by a given event), and event such as route number and route position and thematic maps. As a result of this step the record appears in WebGIS. The user can select a specific area to overview previous hazards in the region. After performing the analysis, a double click on the visualised infrastructures opens the corresponding results. The constantly updated risk maps show all sites that require more protection against natural hazards. The final goal of our work is to offer a versatile tool for risk analysis which can be applied to different situations. Today our GIS application mainly centralises the documentation of natural hazards. Additionally the system offers information about natural hazard at the Gotthard line. It is very flexible and can be used as a simple program to model the expansion of natural hazards, as a program of quantitatively estimate risks or as a detailed analysis at a municipality level. The tool is extensible and can be expanded with additional modules. The initial results of the experimental case study show how useful a GIS-based system can be for effective and efficient disaster response management. In the coming years our GIS application will be a data base containing all information needed for the evaluation of risk sites along the Gotthard line. Our GIS application can help the technical management to decide about protection measures because of, in addition to the visualisation, tools for spatial data analysis will be available. REFERENCES Bründl M. (Ed.) 2009 : Risikokonzept für Naturgefahren - Leitfaden. Nationale Plattform für Naturgefahren PLANAT, Bern. 416 S. BUWAL 1999: Risikoanalyse bei gravitativen Naturgefahren - Methode, Fallbeispiele und Daten (Risk analyses for gravitational natural hazards). Bundesamt für Umwelt, Wald und Landschaft (BUWAL). Umwelt-Materialen Nr. 107, 1-244. Loat, R. & Zimmermann, M. 2004: La gestion des risques en Suisse (Risk Management in Switzerland). In: Veyret, Y., Garry, G., Meschinet de Richemont, N. & Armand Colin (eds) 2002: Colloque Arche de la Défense 22-24 octobre 2002, dans Risques naturels et aménagement en Europe, 108-120. Maggi R. et al, 2009: Evaluation of the optimal resilience for vulnerable infrastructure networks. An interdisciplinary pilot study on the transalpine transportation corridors, NRP 54 "Sustainable Development of the Built Environment", Projekt Nr. 405 440, Final Scientific Report, Lugano

Block ground interaction of rockfalls

NASA Astrophysics Data System (ADS)

Volkwein, Axel; Gerber, Werner; Kummer, Peter

2016-04-01

During a rockfall the interaction of the falling block with the ground is one of the most important factors that define the evolution of a rockfall trajectory. It steers the rebound, the rotational movement, possibly brake effects, friction losses and damping effects. Therefore, if most reliable rockfall /trajectory simulation software is sought a good understanding of the block ground interaction is necessary. Today's rockfall codes enable the simulation of a fully 3D modelled block within a full 3D surface . However, the details during the contact, i.e. the contact duration, the penetration depth or the dimension of the marks in the ground are usually not part of the simulation. Recent field tests with rocks between 20 and 80 kg have been conducted on a grassy slope in 2014 [1]. A special rockfall sensor [2] within the blocks measured the rotational velocity and the acting accelerations during the tests. External video records and a so-called LocalPositioningSystem deliver information on the travel velocity. With these data not only the flight phases of the trajectories but also the contacts with the ground can be analysed. During the single jumps of a block the flight time, jump length, the velocity, and the rotation are known. During the single impacts their duration and the acting accelerations are visible. Further, the changes of rotational and translational velocity influence the next jump of the block. The change of the rotational velocity over the whole trajectory nicely visualizes the different phases of a rockfall regarding general acceleration and deceleration in respect to the inclination and the topography of the field. References: [1] Volkwein A, Krummenacher B, Gerber W, Lardon J, Gees F, Brügger L, Ott T (2015) Repeated controlled rockfall trajectory testing. [Abstract] Geophys. Res. Abstr. 17: EGU2015-9779. [2] Volkwein A, Klette J (2014) Semi-Automatic Determination of Rockfall Trajectories. Sensors 14: 18187-18210.

Calculation of the rockwall recession rate of a limestone cliff, affected by rockfalls, using cosmogenic chlorine-36. Case study of the Montsec Range (Eastern Pyrenees, Spain)

NASA Astrophysics Data System (ADS)

Domènech, Guillem; Corominas, Jordi; Mavrouli, Olga; Merchel, Silke; Abellán, Antonio; Pavetich, Stefan; Rugel, Georg

2018-04-01

Cliff erosion may be a major problem in settled areas affecting populations and producing economic and ecological losses. In this paper we present a procedure to calculate the long-term retreat rate of a cliff affected by rockfalls in the Montsec Range, Eastern Pyrenees (Spain). It is composed of low, densely fractured limestones; and the rockwall is affected by rockfalls of different sizes. The rockfall scars are clearly distinguishable by their regular boundaries and by their orange colour, which contrast with the greyish old reference surface (S0) of the cliff face. We have dated different stepped surfaces of the rockwall, including S0, using cosmogenic 36Cl. The total amount of material released by rockfall activity was calculated using a high definition point cloud of the slope face obtained with a terrestrial laser scanner (TLS). The present rockwall surface has been subtracted from the reconstructed old cliff surface. This has allowed the calculation of the total volume released by rockfalls and of the retreat rate. The latter ranges from 0.31 to 0.37 mm·a- 1. This value is of the same order of magnitude as that obtained by other researchers in neighbouring regions in Spain, having similar geology and affected by rockfalls.

Modeling the Rock Glacier Cycle

NASA Astrophysics Data System (ADS)

Anderson, R. S.; Anderson, L. S.

2016-12-01

Rock glaciers are common in many mountain ranges in which the ELA lies above the peaks. They represent some of the most identifiable components of today's cryosphere in these settings. Their oversteepened snouts pose often-overlooked hazards to travel in alpine terrain. Rock glaciers are supported by avalanches and by rockfall from steep headwalls. The winter's avalanche cone must be sufficiently thick not to melt entirely in the summer. The spatial distribution of rock glaciers reflects this dependence on avalanche sources; they are most common on lee sides of ridges where wind-blown snow augments the avalanche source. In the absence of rockfall, this would support a short, cirque glacier. Depending on the relationship between rockfall and avalanche patterns, "talus-derived" and "glacier-derived" rock glaciers are possible. Talus-derived: If the spatial distribution of rock delivery is similar to the avalanche pattern, the rock-ice mixture will travel an englacial path that is downward through the short accumulation zone before turning upward in the ablation zone. Advected debris is then delivered to the base of a growing surface debris layer that reduces the ice melt rate. The physics is identical to the debris-covered glacier case. Glacier-derived: If on the other hand rockfall from the headwall rolls beyond the avalanche cone, it is added directly to the ablation zone of the glacier. The avalanche accumulation zone then supports a pure ice core to the rock glacier. We have developed numerical models designed to capture the full range of glacier to debris-covered glacier to rock glacier behavior. The hundreds of meter lengths, tens of meters thicknesses, and meter per year speeds of rock glaciers are well described by the models. The model can capture both "talus-derived" and "glacier-derived" rock glaciers. We explore the dependence of glacier behavior on climate histories. As climate warms, a pure ice debris-covered glacier can transform to a much shorter rock glacier, leaving in its wake a thinning ice-cored moraine. Rock glaciers have much longer response times to climate change than their pure ice cousins.

Rockfall Modelling with Remedial Design and Measures along Part of a Mountainous Settlement Area, Southern Turkey

NASA Astrophysics Data System (ADS)

Güntel, Berna; Acar, Altay

2016-10-01

In June 2011, a heavy rainfall triggered a number of rockfalls from steep slopes and on slopes made of soft to loose soils capped by inhomogeneous hard rock blocks and masses in the Düziçi Town of Osmaniye Province in Turkey. Large rock blocks had damaged 15 prefabricated hotel rooms whereas the slope movement blocked the major road between Duzigi and hot spring facilities at numerous locations along 280 m. This paper describes remedial measures and design recommended according to the modelling process based on the collection of data and simulation of rockfall with Rocscience RockFall 5.0 software.

The rockfall observatory in the Reintal, Wetterstein Massif, German Alps

NASA Astrophysics Data System (ADS)

Schöpa, Anne; Turowski, Jens M.; Hovius, Niels

2017-04-01

The Reintal is an Alpine valley in the Wetterstein Massif close to the Zugspitze, Germany's highest mountain. Due to the variety of active geomorphic processes, including rockfalls off the steep limestone cliffs, debris flows, and snow avalanches, and the river Partnach, the Reintal has been the field area of many geomorphological and hydrological research campaigns over the last few decades. In 2014, the Geomorphology Section of the GFZ Potsdam started to install a monitoring network to detect and classify rockfalls in the Reintal. The network includes six seismic stations, optical and infrared cameras, and two weather stations measuring air and rock temperature, air pressure and relative humidity, precipitation, wind speed and direction, and solar radiation. The continuous observations of the network are supplemented by repeated field campaigns including terrestrial laser scans of a prominent rockfall niche at the Hochwanner mountain. The about 1,500 m high north face of the Hochwanner experienced the detachment of a 2.8 Mio m3 rockfall about 500 years ago that created the so-called Steingerümpel (German for rock debris deposit) and dammed the river Partnach. The cliff still shows high rockfall activity, and an 80,000 m3 block can be expected to fall in the near future. In this contribution, the layout of the observatory and details of the seismic network centered around the Hochwanner north face are described. Furthermore, the network data of a severe thunderstorm event in June 2016, that triggered many rockfalls and debris flows in the Reintal, is presented.

Impact of rockfalls on protection measures: an experimental approach

NASA Astrophysics Data System (ADS)

Yuan, J.; Li, Y.; Huang, R.; Pei, X.

2015-01-01

The determination of rockfall impact force is crucial in designing the protection measures. In the present study, laboratory tests are carried out by taking the weight and shape of the falling rock fragments, drop height, incident angle, platform on the slideway and cushion layer on the protection measures as factors to investigate their influences on the impact force. The test results indicate that the impact force is positively exponential to the weight of rockfall and the instantaneous impact velocity of the rockfall approaching the protection measures. The impact velocity is found to be dominated not only by the drop height but also by the shape of rockfall as well as the length of the platform on the slideway. A great drop height and/or a short platform produce a fast impact velocity. Spherical rockfalls experience a reater impact velocity than cubic and cylindrical ones. A layer of cushion on the protection measures may reduce the impact force to a greater extent. The reduction effects are dominated by the cushion material and the thickness of the cushion layer. The thicker the cushion layer, the greater the reduction effect and the less the impact force. The stiffer the buffer material, the less the buffering effect and the greater the impact force. The present study indicates that the current standard in China for designing protection measures may overestimate the impact force by taking no consideration for the rockfall shape, platform and cushion layer.

Genesis and geomorphic evolution of the Velké pinky stopes in the Zlatohorská Highlands, Eastern Sudetes

NASA Astrophysics Data System (ADS)

Lenart, Jan; Tichavský, Radek; Večeřa, Josef; Kapustová, Veronika; Šilhán, Karel

2017-11-01

Montanogenic landforms are commonly viewed as hazards by society, but they are also holders of specific and uncommon morphology with unique dynamics that act as remarks on landscape history. The Velké pinky stopes in the Zlatohorská Highlands, Eastern Sudetes, are naturally revitalized post-mining landforms with long-term geoecological succession. Their genetic origin is diverse but recent processes, such as deep-seated slope deformations, rockfalls and ground subsidence, have resulted in a distinct morphology dominated by rock walls and the accumulation of blocks and debris wedges. This morphology predisposes the stopes to become the core area of the most recent dynamic geomorphic activity within the wider, relatively homogenous area. By dendrogeomorphic techniques, we identified more than 20 rockfall events within three of the stopes with increased activity since the 1980s. Only the 1991 and 2006 events were identical for all three stopes. We obtained the years of exposures from 10 roots, revealing the ground subsidence and opening of tension cracks or even the lateral retreat of the flanks of minor depressions. The Schmidt hammer test revealed the most recent and fresh gravitational activity in one of the stopes. A relationship between the superficial morphology and underground structure was proven by electrical resistivity profiling. Compared to the previous studies engaged with the abandoned mines, we presented how complex their evolution can be. Our study brings new information about the historical development of anthropogenic relief forms. Moreover, our results suggest that standard research approaches can be successfully applied for development analysis of these specific forms.

The Sasso Pizzuto landslide dam and seismically induced rockfalls along the Nera River gorge (Central Italy).

NASA Astrophysics Data System (ADS)

Romeo, Saverio; Di Matteo, Lucio; Melelli, Laura; Cencetti, Corrado; Dragoni, Walter; Fredduzzi, Andrea; De Rosa, Pierluigi

2017-04-01

The seismically induced landslides are among the most destructive and dangerous effects of an earthquake. In the Italian contest, this is also documented by a national catalogue that collects data related to earthquake-induced ground failures in the last millennium (CEDIT database). In particular, Central Italy has been affected by several historical landslides triggered by significant earthquakes, the last of which occurred in August-October 2016, representing the Italian strongest event after the 1980 Irpinia earthquake (Mw 6.9). The study presents the effects of recent seismically induced rockfalls occurred within the Central Italy seismic sequence (October 30, 2016) along the Nera River gorge between Umbria and Marche. The study area is completely included in the Monti Sibillini National Park, where the highest mountain chain in the Umbrian-Marchean Apennine is located. Most of rockfalls have affected the "Maiolica" formation, a stratified and fractured pelagic limestone dating to the Early Cretaceous. The seismic sequence produced diffuse instabilities along the SP 209 road within the Nera River gorge: boulders, debris accumulations and diffuse rockfalls have been mapped. Most of boulders have size ranging from 0.3 to 2.0 m in diameter. Although several strong quakes (Mw > 5) occurred during the August-October sequence, only the main quake triggered the Sasso Pizzuto rockfall producing a landslide dam along the Nera River. The landslide appears to have originated as a wedge failure, which evolved to free fall when the rock block lost the contact with the stable rock mass. In other words, the quake produced the "explosion" of the rock wall allowing the rockfall process. Once the rock mass reached the toe of the slope, it was broken triggering a rock avalanche that obstructed both the Nera River and SP 209 road. With the aim to estimate the total volume of involved rock, a field survey was carried out by using a laser rangefinder. Remote measures were acquired taking into account the inclination, horizontal, vertical and slope distance. Through topographical calculations and GIS analysis, it has been possible to reconstruct the size and shape of debris accumulation estimating a volume of about 70000 m3 (±8000 m3 due to measurements accuracy). This agrees with qualitative measures independently performed. The maximum distance between the debris accumulation and rockfall source area is about 200 m; the altitude difference is 270 m. The landslide debris partially dammed the Nera River, generating a lake upstream: currently the stream is flowing on the road among debris.

Terrestrial Laser Scanner for assessing rockfall susceptibility in the Cilento rocky coast (Southern Italy)

NASA Astrophysics Data System (ADS)

Sorrentino, Valerio; Matasci, Battista; Abellan, Antonio; Jaboyedoff, Michel; Marino, Ermanno; Pignalosa, Antonio; Santo, Antonio

2016-04-01

Rockfalls and other types of landslides are the dominant processes causing a retreat of sea cliffs. The coastal areas constitute an important tourist attraction and a large number of people rest beneath the cliffs on a daily basis, considerably increasing the risk associated to rockfalls. We present an approach to assess rockfall susceptibility at the cliff scale based on terrestrial laser scanner (TLS) point clouds. The test area is a coastal cliff situated in the southern part of the Cilento (Centola Municipality, Campania Region), in which a natural arch was formed. This cliff is constituted by heavy fractured carbonate rock mass with a strong structural control. In June 2015 TLS data were acquired with long-range scanner RIEGL VZ1000®. The structural analysis of the cliff was performed in the field and using Coltop 3D software on the point cloud. As a result, 10 discontinuity sets (joint, faults and bedding planes) were individuated and the different characteristics such as orientation, spacing and persistence were measured. The kinematically unstable areas were highlighted using a script that computes an index of susceptibility to rockfalls based on the spatial distribution of failure mechanisms. The susceptibility index computation is based on the average surface that every joint set (or combinations of two joint sets in the case of wedge failure) forms on the topography according to its spacing, trace length, and incidence angle. This susceptibility index also depends on the steepness of the joint set (or of the intersection line in the case of wedge failure). As a result the most important discontinuity sets in terms of potential planar failure, wedge failure and toppling were individuated and an assessment of rockfall susceptibility at the cliff scale was achieved. Results show that the kinematically feasible failures are not equally distributed along the cliff but concentrated on certain areas. The most susceptible areas for planar failure are related to the discontinuity set K10 (71/097), whereas for toppling the highest susceptibility is reached with K1 (60/218). Concerning wedge failure, the combination of K10 and K1 yields the highest susceptibility values. It shows also clustering with higher density which is probably related to regional structures. More detailed investigations of the rockfall susceptibility and failure mechanisms will be performed during the forthcoming months. The relationship with regional structures will be also investigated in more detail. Perspectives also include using the methodology on the other side of the natural arch in order to provide a global susceptibility assessment of the area.

High morphogenic activity in the permafrost-affected rock walls of the Mont Blanc massif during the 2015 summer heat wave

NASA Astrophysics Data System (ADS)

Ravanel, Ludovic; Magnin, Florence; Deline, Philip

2016-04-01

In order to test the geomorphological hypothesis on the link between permafrost degradation and rock wall destabilisation, we survey all the rockfalls that occur in the central part of the Mont-Blanc massif using a network of observers since 2007. 511 rockfalls (100 < V < 45,000 m3) have been documented, year 2015 included. Between 2007 and 2014, the average number of destabilizations was 44 (from 17 in 2014 with a cold summer to 72 in 2009 with a relatively hot summer). In 2015, 160 events were recorded i.e. 4 times more than the annual average of the previous years. That makes the year 2015 similar to 2003 that was characterized by its summer heatwave triggering 152 rockfalls in the area currently covered by the network of observers, as shown by the analysis of a SPOT-5 image. Observations of 2015 are discussed and crossed with a statistical model of the Mean Annual Rock Surface Temperature (MARST) for the 1961-1990 period, implemented on a 4-m-resolution DEM of the Mont Blanc massif, and temperature measurements in three 10-m-deep boreholes at the Aiguille du Midi (3842 m a.s.l.), where the summer 2015 active layers have been the thickest since the start of measurements in 2009 (e.g. 3.6 m in the NE face against 2.9 m in average during the previous years). Before 2015, 90 % of the inventoried rockfalls occurred in areas where MARST is in the range -5 to 1°C, whereas only 50 % of the whole rock wall area above 2000 m a.s.l. covers this temperature range. With an air 0°C isotherm which sometimes exceeded the summit of Mont Blanc (4809 m a.s.l.) during the 2015 Summer, conditions were particularly unfavorable for mountaineering. Numerous rescues were carried out to climbers technically blocked by uncommon conditions or injured by rockfalls. On the normal route to the summit of Mont Blanc, two administrative closures of the Goûter hut (3835 m a.s.l.) were necessary to prevent climbers from the huge risk of rockfalls in the access couloir, known for its rockfall activity since its snow/ice cover thaws earlier and earlier in the hot season. This raises the question of the future of mountaineering in certain high altitude areas in the context of global warming.

Multicriteria Analysis model for the comparison of different rockfalls protection devices

NASA Astrophysics Data System (ADS)

Mignelli, C.; Pomarico, S.; Peila, D.

2012-04-01

In mountain regions roads and railways as well as urbanized areas, can often be endangered by rockfalls and need to be protected against the impact of falling blocks. The effects of rockfall events can be the damage of road, vehicles, injuries or death of drivers or passengers and economic loss due to road closure. The cost of a single car accident can be significant since it can involve the hospitalization of the driver and passengers, the repair of the vehicle, the legal costs and compensation. The public administrations must manage the roads in order to protect the areas at risk and therefore make choices that take into account both technical and social aspects. The fulfillment of safety requirements for routes in mountainside areas is therefore a multidimensional concept that includes socio-economic, environmental, technical and ethical perspectives and thus leads to issue that are characterized simultaneously by a high degree of conflict, complexity and uncertainty. Multicriteria Analysis (MCA) is an adequate approach that can deal with these kind of issues. It behaves as an umbrella term since it includes a large series of evaluation techniques able to take into explicit consideration simultaneously several criteria, in order to support the Decision Maker through a rational approach to make a comparative assessment of alternative projects. A very large and consolidated amount of MCA literature exists, in which it is possible to find a wide range of techniques and application fields such as waste management, transport infrastructures, strategic policy planning, environmental impact assessment of territorial transformations, market and logistics, economics and finance, industrial management and civil engineering. This paper address the problem of rockfall risk induced on a road using the Analytic Hierarchy Process (AHP), a Multicriteria Analysis technique suitable for dealing with complex problems related to making a choice from among several alternatives and which provides a comparison of the considered options. The developed model takes into account five different aspects of the decision-making process (economic, environmental, design, transport and social aspects) that have been organized according the hierarchical framework of the AHP technique. The criteria that were identified in the analysis and their weights, in the decision-making process, have been discussed and determined by means of specific focus groups with technical experts in the geo-engineering field. Three different protection devices, usually used for rockfall protection (embankment, shelter topped by rockfall barrier and tunnel), are compared through the AHP method, in a specific "geo" environment to show the feasibility of the method. The application of the AHP technique, which was performed using the Expert Choice software, allowed the most relevant aspects of the decision-making process to be highlighted and showing how the proposed method can be a valuable tool for public administration. Furthermore, in order to test the robustness of the proposed model a sensitivity analysis was carried out. The research has an originality value since it focuses on a participative methodological approach thus making the decision process more traceable and reliable.

Detection of Slope Instabilities Along the National Road 7, Mendoza Province, Argentina, Using Multi-Temporal InSAR

NASA Astrophysics Data System (ADS)

Michoud, Clément; Derron, Marc-Henri; Baumann, Valérie; Jaboyedoff, Michel; Rune Lauknes, Tom

2013-04-01

About 2'230 vehicles per day pass through the National Road 7 that link Buenos Aires to Santiago de Chile, crossing Andes Cordillera. This extremely important corridor, being the most important land pass between Argentina and Chile, is exposed to numerous natural hazards, such as snow avalanches, rockfalls and debris flows and remains closed by natural hazards several days per year. This goal of this study is to perform a regional mapping of geohazard susceptibilities along the Road 7 corridor, as started by Baumann et al. (2005), using modern remote sensing and numerical approaches with field checking. The area of interest is located in the Mendoza Province, between the villages Potrerillos and Las Cuevas near the Chilean border. The diversity of soil and rock conditions, the active geomorphological processes associated to post-glacial decompression, seasonal freeze and thaw and severe storms along the road corridor, increase the risk to natural hazard. With the support of the European Space Agency (ESA Category-1 Project 7154), we have in this study processed a large number of ERS and Envisat ASAR scenes, covering the period from 1995 to 2000. We applied both the small-baseline (SB) and the persistent scatterer (PSI) multi-temporal interferometric SAR (InSAR) techniques. The study area contains sparse vegetation, and the SB InSAR method is therefore well suited to map the area containing mainly distributed scatterers. Furthermore, PSI algorithms are also used for comparison for selected landslides in the inventory. Both approaches show a relatively good coherence within mountain areas, which is a good point for the landslide detections along the road. Indeed, the authors identified several large slope instabilities even active scree deposits. This inventory is finally compared with field observations and with existing susceptibility maps regarding snow avalanches, debris-flows and rockfalls. The final objective of this project is to develop a risk strategy that will help local authorities to manage the risk along this highway and also to provide guidelines.

Analysis of microseismic signals collected on an unstable rock face in the Italian Prealps

NASA Astrophysics Data System (ADS)

Arosio, Diego; Longoni, Laura; Papini, Monica; Boccolari, Mauro; Zanzi, Luigi

2018-04-01

In this work we present the analysis of more than 9000 signals collected from February 2013 to January 2016 by a microseismic monitoring network installed on a 300 m high limestone cliff in the Italian Prealps. The investigated area was affected by a major rockfall in 1969 and several other minor events up to nowadays. The network features five three-component geophones and a weather station and can be remotely accessed thanks to a dedicated radio link. We first manually classified all the recorded signals and found out that 95 per cent of them are impulsive broad-band disturbances, while about 2 per cent may be related to rockfalls or fracture propagation. Signal parameters in the time and frequency domains were computed during the classification procedure with the aim of developing an automatic classification routine based on linear discriminant analysis. The algorithm proved to have a hit rate higher than 95 per cent and a tolerable false alarm rate and it is now running on the field PC of the acquisition board to autonomously discard useless events. Analysis of lightning data sets provided by the Italian Lightning Detection Network revealed that the large majority of broad-band signals are caused by electromagnetic activity during thunderstorms. Cross-correlation between microseismic signals and meteorological parameters suggests that rainfalls influence the hydrodynamic conditions of the rock mass and can trigger rockfalls and fracture propagation very quickly since the start of a rainfall event. On the other hand, temperature seems to have no influence on the stability conditions of the monitored cliff. The only sensor deployed on the rock pillar next to the 1969 rockfall scarp typically recorded events with higher amplitude as well as energy. We deem that this is due to seismic amplification phenomena and we performed ambient noise recording sessions to validate this hypothesis. Results confirm that seismic amplification occurs, although we were not able to identify any spectral peak with confidence because the sensors used are not suitable for this task. In addition, we found out that there is a preferential polarization of the wave field along the EW direction and this is in agreement with the geological analysis according to which the pillar is overhanging towards the 1969 rockfall scarp and may preferentially evolve in a wedge failure. Event location was not possible because of the lack of a velocity model of the rock mass. We tried to distinguish between near and far events by analysing the covariance matrix of the three-component recordings. Although the parameters and the outcomes of this analysis should be evaluated very carefully, it seems that about 90 per cent of the considered microseismic signals are related to the stability conditions of the monitored area.

The 2012 Seti River flood disaster and alpine cryospheric hazards facing Pokhara, Nepal

NASA Astrophysics Data System (ADS)

Kargel, Jeffrey; Leonard, Gregory; Paudel, Lalu; Regmi, Dhananjay; Bajracharya, Samjwal; Fort, Monique; Joshi, Sharad; Poudel, Khagendra; Thapa, Bhabana; Watanabe, Teiji

2014-05-01

We have identified the likeliest cause of the Seti River disaster of May 5, 2012, in which a flash flood killed or left missing 72 people. A cascade of deadly physical Earth processes combined with imprudent habitation on the lowest flood terraces and floodplain. The process cascade started with rockfalls into the Seti River gorge (observed via repeat ASTER imaging). The last rockfall-one to several weeks prior to the disaster-affected a knickpoint in the Seti River gorge and impounded glacial meltwater and spring snowmelt. The trigger was a large rock/ice avalanche originating from cornice ice on Annapurna IV, where part of the mass was channeled into the impoundment reservoir. That violent ground-surge event, plus possibly an air blast caused by a violent gravity flow of airborne debris-then burst the rockfall dam. This was not a glacier lake outburst flood. Glaciers were involved in the disaster by supplying meltwater, which was impounded by the rockfall dam, by triggering the disaster with collapse of cornice ice, and by contributing ice to the landslide and outburst flood. Debuttressing of moraine debris and ancient glacial lake sediment by retreat and thinning of glaciers also may have played a role-this is the only possible indirect link of the disaster to climate change. The rockfall and avalanche mass movements occurred independently of climate change. The narrow and easily blocked Seti River gorge was a key factor in the 2012 disaster, and it remains a unique component of this physiographic setting. A similar flood in this area may happen by a different cascade of Earth surface processes. An enormous mass of ancient unconsolidated glaciolacustrine and moraine sediment-many cubic kilometers-was discovered and is vulnerable to production of debris flows and hyperconcentrated slurry flows. Some aggravating processes occurring in the Sabche Cirque are related to climate change. Glaciers in that area are melting, and small lakes are forming. Although the lakes were not implicated in the 2012 disaster, the possibility exists for a small glacial lake outburst flood to trigger a larger mass movement. Such a debris flow could reach Pokhara directly. More likely, a debris flow in the Sabche Cirque could form another temporary and potentially dangerous impoundment dam in the gorge. Furthermore, the type of rockfall blockage that produced 2012's natural impoundment reservoir is likely to happen repeatedly. Hence, there is a high capacity of the Earth system in this area to produce comparable or even bigger flash floods or mass flows. The likelihood of a further disaster is magnified by imprudent habitation of the river channel and lower floodplain. Of all the changes to the Pokhara Valley, human encroachment on the flood plain is the factor most related to increasing vulnerability, but it is also the one factor that could be remedied by a complete ban on construction on lower terraces, if that is politically feasible. Warning systems could help, but fairly relocating people in jeopardy would be more effective. Supported by NASA/USAID SERVIR Applied Sciences and USAID Climbers' Science.

Climate anomalies associated with the occurrence of rockfalls at high-elevation in the Italian Alps

NASA Astrophysics Data System (ADS)

Paranunzio, Roberta; Laio, Francesco; Chiarle, Marta; Nigrelli, Guido; Guzzetti, Fausto

2016-09-01

Climate change is seriously affecting the cryosphere in terms, for example, of permafrost thaw, alteration of rain / snow ratio, and glacier shrinkage. There is concern about the increasing number of rockfalls at high elevation in the last decades. Nevertheless, the exact role of climate parameters in slope instability at high elevation has not been fully explored yet. In this paper, we investigate 41 rockfalls listed in different sources (newspapers, technical reports, and CNR IRPI archive) in the elevation range 1500-4200 m a.s.l. in the Italian Alps between 1997 and 2013 in the absence of an evident trigger. We apply and improve an existing data-based statistical approach to detect the anomalies of climate parameters (temperature and precipitation) associated with rockfall occurrences. The identified climate anomalies have been related to the spatiotemporal distribution of the events. Rockfalls occurred in association with significant temperature anomalies in 83 % of our case studies. Temperature represents a key factor contributing to slope failure occurrence in different ways. As expected, warm temperatures accelerate snowmelt and permafrost thaw; however, surprisingly, negative anomalies are also often associated with slope failures. Interestingly, different regional patterns emerge from the data: higher-than-average temperatures are often associated with rockfalls in the Western Alps, while in the Eastern Alps slope failures are mainly associated with colder-than-average temperatures.

Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, J; Twilley, K; Murvosh, H

2003-03-03

For the purpose of proof-testing a system intended to remotely monitor rockfall inside a potential radioactive waste repository at Yucca Mountain, a system of seismic sub-arrays will be deployed and tested on the surface of the mountain. The goal is to identify and locate rockfall events remotely using automated data collecting and processing techniques. We install seismometers on the ground surface, generate seismic energy to simulate rockfall in underground space beneath the array, and interpret the surface response to discriminate and locate the event. Data will be analyzed using matched-field processing, a generalized beam forming method for localizing discrete signals.more » Software is being developed to facilitate the processing. To date, a three-component sub-array has been installed and successfully tested.« less

Potential of two submontane broadleaved species (Acer opalus, Quercus pubescens) to reveal spatiotemporal patterns of rockfall activity

NASA Astrophysics Data System (ADS)

Favillier, Adrien; Lopez-Saez, Jérôme; Corona, Christophe; Trappmann, Daniel; Toe, David; Stoffel, Markus; Rovéra, Georges; Berger, Frédéric

2015-10-01

Long-term records of rockfalls have proven to be scarce and typically incomplete, especially in increasingly urbanized areas where inventories are largely absent and the risk associated with rockfall events rises proportionally with urbanization. On forested slopes, tree-ring analyses may help to fill this gap, as they have been demonstrated to provide annually-resolved data on past rockfall activity over long periods. Yet, the reconstruction of rockfall chronologies has been hampered in the past by the paucity of studies that include broadleaved tree species, which are, in fact, quite common in various rockfall-prone environments. In this study, we test the sensitivity of two common, yet unstudied, broadleaved species - Quercus pubescens Willd. (Qp) and Acer opalus Mill. (Ao) - to record rockfall impacts. The approach is based on a systematic mapping of trees and the counting of visible scars on the stem surface of both species. Data are presented from a site in the Vercors massif (French Alps) where rocks are frequently detached from Valanginian limestone and marl cliffs. We compare recurrence interval maps obtained from both species and from two different sets of tree structures (i.e., single trees vs. coppice stands) based on Cohen's k coefficient and the mean absolute error. A total of 1230 scars were observed on the stem surface of 847 A. opalus and Q. pubescens trees. Both methods yield comparable results on the spatial distribution of relative rockfall activity with similar downslope decreasing recurrence intervals. Yet recurrence intervals vary significantly according to tree species and tree structure. The recurrence interval observed on the stem surface of Q. pubescens exceeds that of A. opalus by > 20 years in the lower part of the studied plot. Similarly, the recurrence interval map derived from A. opalus coppice stands, dominant at the stand scale, does not exhibit a clear spatial pattern. Differences between species may be explained by the bark thickness of Q. pubescens, which has been demonstrated to grow at twice the rate of A. opalus, thus constituting a mechanical barrier that is able to buffer low energy rockfalls and thus can avoid damage to the underlying tissues. The reasons for differences between tree structures are related to the clustered coppice-specific spatial stem distribution in clumps that could result on one hand in bigger gaps between clumps, which in turn decreases the probability of tree impacts for traveling blocks. On the other hand, data also indicate that several scars on the bark of coppice stands may stem from the same impact and thus may lead to an overestimation of rockfall activity.

RPAS application for estimating road exposition to rockfall

NASA Astrophysics Data System (ADS)

Santangelo, Michele; Alvioli, Massimiliano; Baldo, Marco; Giordan, Daniele; Guzzetti, Fausto; Marchesini, Ivan; Reichenbach, Paola

2017-04-01

The use of Remotely Piloted Aircraft Systems (RPASs) for landslide analysis and characterization is often aimed at the acquisition of DSMs and orthpohotos. One of the most interesting utilizations of RPASs to landslide studies consists in the production of data for rockfall risk assessment. A typical approach to study rockfalls consists in the application of numerical or stochastic models for the definition of possible trajectories of rock blocks to accurate DTMs of the source and runout areas. In this work, the case study of the rockfall of Vinnanova di Accumoli (Marche Region, central Italy) is presented and discussed. In this area, the earthquakes of the seismic sequence started on 24 August 2016 that struck central Italy caused several rockfalls that, in some cases damaged roads, and represented a threat to the population. In particular, the provincial road SP18 near Villanova di Accumoli was closed due to a 1 m3 rock block that fell down from the slope and crossed the SP20, partially damaging it. During the emergency, it was decided to apply a numerical model to estimate the trajectories of the remaining instable rock masses and to define the possible places where to set up protection measures to safely re-open the road. Therefore, a survey with a multicopter was carried out to obtain (i) an accurate DSM of the source area and the slope (ii) the identification and characterization of other instable blocks possibly not visible in the field. The 6,500 m2 area was covered by a total 161 photograms by a 34 Mpixel camera, obtaining a 1.5 cm/pixel Ground Sampling Distance (GSD). The final orthophoto has a resolution of 2.5 cm, whereas the DSM has a resolution of 20 cm. The DSM was then filtered by a three-step procedure including manual removal of sparse vegetation cover. In area covered by dense vegetation (the lower part of the slope) the DSM could not be manually filtered, which hampered to run the numerical model. This problem was addressed by a GPS RTK survey of the most vegetated area. A total of 73 points with less than 1m error were acquired and integrated in the DTM. The resulting integrated DTM has a resolution of 25 cm. The numerical model STONE was then applied to the source areas mapped in the field and by photo-interpretation of the RPAS orthophoto to get a 1m raster showing the potential trajectories of the mapped instable rock masses. Results showed that only the part of the road hit by the rockfall was actually exposed to rockfall trajectories. Therefore only limited protection measures were suggested to reduce the exposition of the road.

Multirisk analysis along the Road 7, Mendoza Province, Argentina

NASA Astrophysics Data System (ADS)

Wick, Emmanuel; Baumann, Valérie; Michoud, Clément; Derron, Marc-Henri; Jaboyedoff, Michel; Rune Lauknes, Tom; Marengo, Hugo; Rosas, Mario

2010-05-01

The National Road 7 crosses Argentina from East to West, linking Buenos Aires to the Chile border. This road is an extremely important corridor crossing the Andes Cordillera, but it is exposed to numerous natural hazards, such as rockfalls, debris flows and snow avalanches. The study area is located in the Mendoza Province, between Potrerillos and Las Cuevas in the Chilean border. This study has for main goals to achieve a regional mapping of geohazards susceptibility along the Road 7 corridor using modern remote sensing and numerical modelling techniques completed by field investigations. The main topics are: - Detection and monitoring of deep-seated gravitational slope deformations by time-series satellite radar interferometry (InSAR) methods. The area of interest is mountainous with almost no vegetation permitting an optimized InSAR processing. Our results are based on applying the small-baseline subset (SBAS) method to a time-series of Envisat ASAR images. - Rockfalls susceptibility mapping is realized using statistical analysis of the slope angle distribution, including external knowledge on the geology and land cover, to detect the potential source areas (quantitative DEM analysis). The run-outs are assessed with numerical methods based on the shallow angle method with Conefall. A second propagation is performed using the alpha-beta methodology (3D numerical modelling) with RAS and is compared to the first one. - Debris flow susceptibility mapping is realized using DF-IGAR to detect starting and spreading areas. Slope, flow accumulations, contributive surfaces, plan curvature, geological and land use dataset are used. The spreading is simulated by a multiple flow algorithm (rules the path that the debris flow will follow) coupled to a run-out distance calculation (energy-based). - Snow avalanches susceptibility mapping is realized using DF-IGAR to map sources areas and propagations. To detect the sources areas, slope, altitude, land-use and minimum surfaces are needed. DF-IGAR simulates the spreading by means of the "Perla" methodology. Furthermore, RAS performs the spreading based on the "alpha-beta" method. All these methods are based on Aster and SRTM DEM (grid 30 m) and observations of both optical and radar satellite imagery (Aster, Quickbird, Worldview, Ikonos, Envisat ASAR) and aerial photographs. Several field campaigns are performed to calibrate the regional models with adapted parameters. Susceptibility maps of the entire area for rockfalls, debris flows and snow avalanches at a scale of 1:100'000 are created. Those maps and the field investigations are cross-checked to identify and prioritize hotspots. It appears that numerous road sectors are subject to highly active phenomena. Some mitigation works already exist but they are often under-dimensioned, inadequate or neglected. Recommendations for priority and realistic mitigation measures along the endangered road sectors identified are proposed.

Application of dimensional analysis to predict the performance of rockfall barrier

NASA Astrophysics Data System (ADS)

Spadari, M.; Giacomini, A.; Buzzi, O.; Hambleton, J.

2012-04-01

Natural hazards involving rocks or rock slopes are responsible for loss of life and damage to infrastructure and are consequently widely studied. Rock fall barriers are a common type of protection structures that is usually designed on the basis of total impact energy. However, the systems are usually tested in free fall where the predominant component of energy is kinematic and it has been shown that there is not a unique relationship between the response of a barrier and the kinetic energy of the impacting block. In particular, recent studies have discussed the so called "bullet effect" i.e. relatively small blocks traveling at high speed can perforate the barriers yet having acceptable level of energy. This effect compromises the use of kinetic energy as an adequate design criterion since there is not a threshold value defining clearly acceptable and unacceptable values of energy. This issue can be addressed empirically by using different block sizes when it comes to test a system. However, the literature still lacks a characterization of a rockfall barrier performance regarding the bullet effect. This note presents the results of the application of dimensional analysis to the physical problem of the bullet effect. This latter has been formulated as a function involving eight key variables: v = f(ρ, K, σy, H, A, Db,Dw) where v is the minimum speed of a given block to break the barrier, ρgs the density of the block, Kis the stiffness of the system, σy is the strength of the wires, H is the height of the barrier, A is the aperture of the mesh, Db is the dimension of the block and Dw is the diameter of the wire. Applying the Buckingham Pi theorem allows reducing the equation above to a simpler problem involving only three dimensionless parameters: E*=F(S*, G*) Where E* is the performance parameter, S* is the strength-stiffness parameter and G* is the geometrical parameters defined as: E*= (ρ.v2.H)/K S*=K/(H.gσy) And G*=A-0.25.Db-0.75.Db F in the simplified equation is referred to as the Rockfall Barrier Performance, or RoBaP, Model. Results suggest that the dimensional analysis can satisfactorily be used to assess the performance of a barrier when impacted by variable block size. A calibration-prediction exercise has been conducted using data form the literature to assess the predictive capability of the RoBaP model. It has been found that the RoBaP model gives satisfactory results. In particular, the progressive loss of performance of the rock fall barrier as the block size diminishes has been well captured.

Rock falls landslides in Abruzzo (Central Italy) after recent earthquakes: morphostructural control

NASA Astrophysics Data System (ADS)

Piacentini, T.; Miccadei, E.; Di Michele, R.; Esposito, G.

2012-04-01

Recent earthquakes show that damages due to collateral effects could, in some cases exceed the economic and social losses directly connected to the seismic shaking. The earthquake heavily damaged urban areas and villages and induced several coseismic deformations and geomorphologic effects, including different types of instability such as: rock falls, debris falls, sink holes, ground collapses, liquefaction, etc. Among the effects induced by the seismic energy release, landslides are one of the most significant in terms of hazard and related risk, owing to the occurrence of exposed elements. This work analyzes the geomorphological effects, and particularly the rock falls, which occurred in the L'Aquila area during and immediately after the April 2009 earthquake. The analysis is focused mainly on the rock fall distribution related to the local morphostructural setting. Rock falls occurred mostly on calcareous bedrock slopes or on scarps developed on conglomerates and breccias of Quaternary continental deposits. Geological and geomorphological surveys have outlined different types of rock falls on different morpho-structural settings, which can be summarized as follow: 1)rock falls on calcareous faulted homoclinal ridges; 2)rock falls on calcareous rock slopes of karst landforms; 3)rock falls on structural scarps on conglomerates and breccias of Quaternary continental deposits. The first type of rockfall occurred particularly along main gorges carved on calcareous rocks and characterised by very steep fault slopes and structural slopes (i.e. San Venanzio Gorges, along the Aterno river). In these cases already unstable slopes due to lithological and structural control were triggered as rockfalls also at high distance from the epicentre area. These elements provide useful indications both at local scale, for seismic microzonation studies and seismic risk prevention, and at regional scale, for updating studies and inventory of landslides.

Rock slope design guide.

DOT National Transportation Integrated Search

2011-04-01

This Manual is intended to provide guidance for the design of rock cut slopes, rockfall catchment, and : rockfall controls. Recommendations presented in this manual are based on research presented in Shakoor : and Admassu (2010) entitled Rock Slop...

Tree-ring based reconstruction of rockfalls at Cofre de Perote volcano, Mexico

NASA Astrophysics Data System (ADS)

Franco-Ramos, Osvaldo; Stoffel, Markus; Vázquez-Selem, Lorenzo

2017-08-01

In this study, dendrogeomorphic techniques are employed to analyse the temporal frequency and spatial distribution of rockfalls on a talus slope of La Teta valley, located on the NW slopes of Cofre de Perote volcano at 4000 m above sea level. Based on the interpretation of disturbance signals in growth rings of old-growth Pinus hartwegii Lindl. trees, we identify 100 growth disturbances related with rockfall events dated between 1780 and 2011, with slightly more than half of these events being dated to the last 50 years. The sectors most susceptible to rockfall correspond with the young rock lobes located at the foot of scarps. Roughly three in ten events has been triggered by regional, M > 6 earthquakes, whereas half of the events activity coincides with periods characterized by severe, prolonged summer rainfalls such as the ones occurred in 1995, 1998, 2005 and 2011.

Detection of precursory deformation using a TLS. Application to spatial prediction of rockfalls.

NASA Astrophysics Data System (ADS)

Abellán, Antonio; Vilaplana, Joan Manuel; Calvet, Jaume; Rodriguez, Xavier

2010-05-01

Different applications on the use of Terrestrial Laser Scanner (TLS) on rock slopes are undergoing rapid development, mainly in the characterization of 3D discontinuities and the monitoring of rock slopes. The emphasis of this research is on detection of precursory deformation and its application to spatial prediction of rockfalls. The pilot study area corresponds to the main scarp of an old slide located at Puigcercós (Catalonia, Spain). 3D temporal variations of the terrain were analyzed by comparing sequential TLS datasets. Five areas characterized by centimetric precursory deformations were detected in the study area. Of these deformations, (a) growing deformation across three areas culminated in a rockfall occurrence; and (b) another growing deformation across two areas was detected, making a subsequent rockfall likely. The areas with precursory deformations detected in Puigcercós showed the following characteristics: (a) a sub-vertical fracture delimiting the moving part from the rest of the slope; (b) an increase in the horizontal displacement upwards, typical of a toppling failure mechanism (Muller 1968; Goodman and Bray, 1976). In addition, decimetric-scale rockfalls were observed in the upper part of the moving areas, which is consistent with the observations of Rosser et al., (2007). TLS ILRIS 3D technical characteristics are as follows: high accuracy (7.2 mm at a range of 50 meters), high angular resolution (e.g. 1 point every few cm), fast data acquisition: 2,500 points/second; broad coverage; high maximum range on natural slopes: ~600m. The single point distances between the surface of reference and the successive data point clouds were computed using a conventional methodology (data vs. reference comparison). The direction of comparison was defined as the normal vector of the rock face at its central part. We focused in the study of the small scale displacements towards the origin of coordinates, which reflect the pre-failure deformation on part of the slope. A nearest neighbour (NN) filtering technique was applied to the RAW datasets (Abellán et al., 2009), enabling the accurate detection of centimetric displacements. The parameters of the precursory deformation correlated with the failure mechanism, lithology and volume of the rockfall: higher values of length and duration of the precursory deformation were found in the toppling failure mechanism, ductile materials and rockfalls that involved considerable volumes. These results are consistent with observations in the literature regarding rockfalls of higher magnitude and lower frequency (e.g.: Zvelebil and Moser, 2001; Crosta and Agliardi, 2004; Hungr et al., 2007). It is also important to mention that no precursory indicators were detected prior to each rockfall that occurred in the study areas. This could simply be due to infrequent data acquisition or insufficient instrument accuracy. The application of TLS for the spatial prediction of rockfalls should be validated through: (a) the continuation of the TLS monitoring campaign at the areas which currently show ongoing deformation; (b) the selection of new case studies at different geomorphological sites with different lithologies; and (c) the selection of new case studies with different failure mechanisms (e.g. fall, slide). These tasks are of paramount importance to understand the pre-failure behaviour of rockfalls and to implement these findings in an early warning system.

Landslide and slope stability evaluation in the historical town of Kruja, Albania

NASA Astrophysics Data System (ADS)

Muceku, Y.; Korini, O.

2014-03-01

This paper describes landslides and slope stability evaluation in the urban area of Kruja, Albania. Kruja is a historical and heritage center, due to the existence of many important cultural monuments, including "Skanderbeg" castle and Bazaar square, etc. The urban area of Kruja has been affected by landslide effects, in the past and also the present. From this phenomenon many engineering objects such as buildings, roads, etc., are damaged and demolished. From engineering geological mapping at scale 1:5000 it is observed that many active landslides have dramatically increased in activity since the 1980s. The landslide types found in the studied area are earthslides, debris flow, as well as rockfall and rock rolling. Also, from field works and laboratory analysis, the slope stability of the whole urban area has been determined; for this purpose the studied zone is divided into stable and unstable areas, which helps to better understand mass movement activity as one of the most harmful hazards of geodynamic phenomena.

Estimation of the return period of rockfall blocks according to their size

NASA Astrophysics Data System (ADS)

De Biagi, Valerio; Lia Napoli, Maria; Barbero, Monica; Peila, Daniele

2017-01-01

With reference to the rockfall risk estimation and the planning of rockfall protection devices, one of the most critical and most discussed problems is the correct definition of the design block by taking into account its return period. In this paper, a methodology for the assessment of the design block linked with its return time is proposed and discussed, following a statistical approach. The procedure is based on the survey of the blocks that were already detached from the slope and had accumulated at the foot of the slope in addition to the available historical data.

A PROPOSAL FOR MAKING A RISK MAP OF ROCKFALL BY EVALUATING THE INFLUENCE TO RAILWAY TRACK

NASA Astrophysics Data System (ADS)

Fukata, Takahiro; Mori, Taiki; Shibuya, Satoru

An incident of rockfall may trigger serious damage to the safety as well as the after-the-event maintenance of railway transportation. In an attempt to minimize such damage caused by rockfall incident, the railway companies regularly in spect the concerned slopes along the railway, and take necessary measures. In the current practice, however, it is very difficult to make a full control of slopes in danger spreading over the wide area due to the limited human and financial resources. Accordingly, it is urgently needed for the railway firms to establish cost-effective as well as reliable system for the slope management. A risk map based on the impact statement of rockfall to railway track is of great use for not only enhancing the efficiency of slope inspection, but also planning the disaster prevention of railway. In this paper, a methodology for establishing a risk map by considering the impact statement to railway truck in a quantitative manner is proposed. In so doing, the rockfall movement on a slope was numerically simulated in match with each categorized type of slopes. The applicability of this proposed method for the slope management practice is examined based on a number of case histories.

Very long period conduit oscillations induced by rockfalls at Kilauea Volcano, Hawaii

USGS Publications Warehouse

Chouet, Bernard A.; Dawson, Phillip B.

2013-01-01

Eruptive activity at the summit of Kilauea Volcano, Hawaii, beginning in 2010 and continuing to the present time is characterized by transient outgassing bursts accompanied by very long period (VLP) seismic signals triggered by rockfalls from the vent walls impacting a lava lake in a pit within the Halemaumau pit crater. We use raw data recorded with an 11-station broadband network to model the source mechanism of signals accompanying two large rockfalls on 29 August 2012 and two smaller average rockfalls obtained by stacking over all events with similar waveforms to improve the signal-to-noise ratio. To determine the source centroid location and source mechanism, we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous medium that takes topography into account. We apply a new waveform inversion method that accounts for the contributions from both translation and tilt in horizontal seismograms through the use of Green's functions representing the seismometer response to translation and tilt ground motions. This method enables a robust description of the source mechanism over the period range 1–1000 s. The VLP signals associated with the rockfalls originate in a source region ∼1 km below the eastern perimeter of the Halemaumau pit crater. The observed waveforms are well explained by a simple volumetric source with geometry composed of two intersecting cracks including an east striking crack (dike) dipping 80° to the north, intersecting a north striking crack (another dike) dipping 65° to the east. Each rockfall is marked by a similar step-like inflation trailed by decaying oscillations of the volumetric source, attributed to the efficient coupling at the source centroid location of the pressure and momentum changes induced by the rock mass impacting the top of the lava column. Assuming a simple lumped parameter representation of the shallow magmatic system, the observed pressure and volume variations can be modeled with the following attributes: rockfall volume (200–4500 m3), length of magma column (120–210 m), diameter of pipe connecting the Halemaumau pit crater to the subjacent dike system (6 m), average thickness of the two underlying dikes (3–6 m), and effective magma viscosity (30–210 Pa s). Most rockfalls occur during episodes of sustained deflation of the Kilauea summit. The mass loss rate in the shallow magmatic system is estimated to be 1400–15,000 kg s−1 based on measurements of the temporal variation of VLP period in the two large rockfalls that occurred on 29 August 2012.

Assessing landslide susceptibility, hazards and sediment yield in the Río El Estado watershed, Pico de Orizaba volcano, Mexico

NASA Astrophysics Data System (ADS)

Legorreta Paulin, G.; Bursik, M. I.; Lugo Hubp, J.; Aceves Quesada, J. F.

2014-12-01

This work provides an overview of the on-going research project (Grant SEP-CONACYT # 167495) from the Institute of Geography at the National Autonomous University of Mexico (UNAM) that seeks to conduct a multi-temporal landslide inventory, analyze the distribution of landslides, and characterize landforms that are prone to slope instability by using Geographic Information Systems (GIS). The study area is the Río El Estado watershed that covers 5.2 km2 and lies on the southwestern flank of Pico de Orizaba volcano.The watershed was studied by using aerial photographs, fieldwork, and adaptation of the Landslide Hazard Zonation Protocol of the Washington State Department of Natural Resources, USA. 107 gravitational slope failures of six types were recognized: shallow landslides, debris-avalanches, deep-seated landslides, debris flows, earthflows, and rock falls. This analysis divided the watershed into 12 mass-wasting landforms on which gravitational processes occur: inner gorges, headwalls, active scarps of deep-seated landslides, meanders, plains, rockfalls, non-rule-identified inner gorges, non-rule-identified headwalls, non-rule-identified converging hillslopes and three types of hillslopes classified by their gradient: low, moderate, and high. For each landform the landslide area rate and the landslide frequency rate were calculated as well as the overall hazard rating. The slope-stability hazard rating has a range that goes from low to very high. The overall hazard rating for this watershed was very high. The shallow slide type landslide was selected and area and volume of individual landslides were retrieved from the watershed landslide inventory geo-database, to establish an empirical relationship between area and volume that takes the form of a power law. The relationship was used to estimate the total volume of landslides in the study area. The findings are important to understand the long-term evolution of the southwestern flank stream system of Pico de Orizaba, and may prove useful in the assessment of landslide susceptibility and hazard in volcanic terrains.

Explosive eruptions triggered by rockfalls at Kīlauea volcano, Hawaii

USGS Publications Warehouse

Orr, Tim R.; Thelen, Weston A.; Patrick, Matthew R.; Swanson, Donald A.; Wilson, David C.

2012-01-01

Ongoing eruptive activity at Kīlauea volcano’s (Hawai‘i) summit has been controlled in part by the evolution of its vent from a 35-m-diameter opening into a collapse crater 150 m across. Geologic observations, in particular from a network of webcams, have provided an unprecedented look at collapse crater development, lava lake dynamics, and shallow outgassing processes. These observations show unequivocally that the hundreds of transient outgassing bursts and weak explosive eruptions that have punctuated the vent’s otherwise nearly steady-state behavior, and that are associated with composite seismic events, were triggered by rockfalls from the vent walls onto the top of the lava column. While the process by which rockfalls drive the explosive bursts is not fully understood, we believe that it is initiated by the generation of a rebound splash, or Worthington jet, which then undergoes fragmentation. The external triggering of low-energy outgassing events by rockfalls represents a new class of small transient explosive eruptions.

Integrated risk management and communication: case study of Canton Vaud (Switzerland)

NASA Astrophysics Data System (ADS)

Artigue, Veronica; Aye, Zar Chi; Gerber, Christian; Derron, Marc-Henri; Jaboyedoff, Michel

2017-04-01

Canton Vaud's history is marked by events that remind us that any territory may have to cope with natural hazards such as devastating floods of the Baye and the Veraye rivers in Montreux (1927), the overflowing of the Rhône by dam failure (1935), the mud flow of Pissot (1995) and avalanches in the Prealps (1999). All of these examples have caused significant damage, and sometimes even fatalities, in the regions of Canton Vaud. In response to these new issues, the Swiss Confederation and the local authorities of the Canton decided to implement an integrated management policy of natural risks. The realization of natural hazards maps was the first step of the integrated management process. This work resulted in more than 10'000 maps and related documents for 94% of the municipalities of the Canton, covering 17% of its total surface. From this significant amount of data, the main issue is to propose a relevant communication and to build an integrated risk management structure. To make this available information relevant for end users, the implied teams worked to realize documents and tools for a better understanding of these data by all stakeholders. The first step of this process was to carry out a statistical and geographical analysis of hazard maps that allows identifying the most exposed areas to natural hazards. An atlas could thus be created. Then, continued under this framework, several topics have been discussed for each identified risk. The results show that 88 of 318 municipalities in Canton Vaud have at least a high hazard level on their territory, 108 with a moderate hazard level, 41 with a low level and 8 with a residual level. Only 73 of 318 municipalities remain with a minimum or zero hazard level. Concerning the type of hazard considered, 16% of the building zones are exposed to floods, 18% to mud flow, 16% to deep landslides, 14% to spontaneous surface landslides, 6% to rockfall, 55% to rock collapses and less than 5% to avalanches. As the national policies require to take into account the risk at the building scale, further analysis on the buildings have been made. 1'154 buildings are exposed to a high hazard level, while 8409, 21'130 and 14'980 buildings are exposed to a moderate, low and residual hazard level respectively. This paper addresses the complexity of the realization of the hazard map products of the Canton Vaud, particularly through the statistical analysis and the difficulties encountered for data availability and quality at the building scale. The authors highlight the necessary processes to build a robust communication for all the implied stakeholders of risk management in a dynamic and changing area through the example of the Canton Vaud.

Titan2D simulations of dome-collapse pyroclastic flows for crisis assessments on Montserrat

NASA Astrophysics Data System (ADS)

Widiwijayanti, C.; Voight, B.; Hidayat, D.; Patra, A.; Pitman, E.

2010-12-01

The Soufriere Hills Volcano (SHV), Montserrat, has experienced numerous episodes of lava dome collapses since 1995. Collapse volumes range from small rockfalls to major dome collapses (as much as ~200 M m3). Problems arise in hazards mitigation, particularly in zoning for populated areas. Determining the likely extent of flowage deposits in various scenarios is important for hazards zonation, provision of advice by scientists, and decision making by public officials. Towards resolution of this issue we have tested the TITAN2D code, calibrated parameters for an SHV database, and using updated topography have provided flowage maps for various scenarios and volume classes from SHV, for use in hazards assessments. TITAN2D is a map plane (depth averaged) simulator of granular flow and yields mass distributions over a DEM. Two Coulomb frictional parameters (basal and internal frictions) and initial source conditions (volume, source location, and source geometry) of single or multiple pulses in a dome-collapse type event control behavior of the flow. Flow kinematics are captured, so that the dynamics of flow can be examined spatially from frame to frame, or as a movie. Our hazard maps include not only the final deposit, but also areas inundated by moving debris prior to deposition. Simulations from TITAN2D were important for analysis of crises in the period 2007-2010. They showed that any very large mass released on the north slope would be strongly partitioned by local topography, and thus it was doubtful that flows of very large size (>20 M m3) could be generated in the Belham River drainage. This partitioning effect limited runout toward populated areas. These effects were interpreted to greatly reduce the down-valley risk of ash-cloud surges.

Analysis of High Resolution Satellite imagery to acsees Glacier Mass Balance and Lake Hazards in Sikkim Himalayas

NASA Astrophysics Data System (ADS)

Bhushan, S.; Shean, D. E.; Haritashya, U. K.; Arendt, A. A.; Syed, T. H.; Setiawan, L.

2017-12-01

Glacial lake outburst floods can impact downstream communities due to the sudden outflux of huge quantities of stored water. In this study, we develop a hazard assessment of the moraine dammed glacial lakes in Sikkim Himalayas by analyzing the morphometry of proglacial features, and the surface velocity and mass balance of glaciers. We generated high-resolution digital elevation models (DEMs) using the open-source NASA Ames Stereo Pipeline (ASP) and use other open-source tools to calculate surface velocity and patterns of glacier downwasting over time. Geodetic glacier mass balance is obtained for three periods using high-resolution WorldView/GeoEye stereo DEMs (8 m posting, 2014-2016), Cartosat-1 stereo DEMs (10 m, 2006-2008) and SRTM (30 m, 2000). Initial results reveal a region-wide mass balance of -0.31±0.13 m w.eq.a-1 for the 2007-2015 period, with some debris covered glaciers showing a very low mass loss rate. Additionally, 12 annual glacier velocity fields spanning from 1991 to 2017.derived from Landsat imagery are used to explore the relationship between glacier dynamics and changes in proglacial lakes. Multi-temporal glacial lake mapping is conducted using Landsat and Cartosat imagery. Avalanche and rockfall modeling are combined with morphometric analysis of the proglacial lake area to assess the likelihood of glacial lake dam failure. The above parameters are integrated into a decision tree approach enabling categorization of moraine-dammed lakes according to their potential for outburst events.

Geologic map of the eastern half of the Vail 30' x 60' quadrangle, Eagle, Summit, and Grand Counties, Colorado

USGS Publications Warehouse

Kellogg, Karl S.; Shroba, Ralph R.; Premo, Wayne R.; Bryant, Bruce

2011-01-01

The map is intended as a database for a variety of land-use and scientific purposes, including (1) assessment of geologically stable building sites, (2) planning for road and highway construction, (3) assessment of groundwater resources, (4) assessment of mineral resources, (5) determining geologic-hazard potential (flooding, landslide, rockfall, and seismic risk), (6) evaluating the structure of the northern Rio Grande rift in the Blue River valley, (7) improvement in understanding of the sedimentary section, which spans the period from the Cambrian to the Holocene, and (8) new insights into the geologic history of the Proterozoic basement rocks, including a number of new radiometric dates.

Landslide hazard assessment of the Black sea coastline (Caucasus, Russia) via drones

NASA Astrophysics Data System (ADS)

Kazeev, Andrey; Postoev, German; Fedotova, Ksenia

2017-04-01

Landslide hazard assessment of slopes of Sochi was performed along the railway between the cities Tuapse and Adler (total length 103 km). The railway passes through the territory with active development of hazardous geological processes such as landslides, rock falls and debris-flows. By the beginning of 2016, 36 landslide sites were discovered along the railway (total length 34 km), 48 rock-fall sites (length 31 km), and 5 debris-flow sites (length 0.14 km). In recent years the intensification of deformations was observed. For instance, during previous 10 years (1996¬¬-2005) 28 sudden deformations occurred due to slope processes, which caused interruptions in traffic. And in the present decade (2006-2015), 72 deformations were recorded. High landslide activity and economic loss determined the necessity of complex investigations of engineering geological conditions of landslides development and causes of its intensification. The protection strategy development was needed to minimize negative consequences. Thus, the investigations of landslide situation along the railway "Tuapse - Adler" included the categorization of landslide sites by level of hazard, with risk assessment based on numerical criteria. Preliminary evaluation of landslide hazard for the railway was conducted via the analysis of archived engineering-geological documents. 13 of 36 landslide sites (total length 13 km) were selected, reflecting the variety and peculiarities of landslide displacements on slopes (both active and inactive sites). Visual field observations of landslide slopes using drone "DJI Phantom 4" were completed during the second stage of this investigation. High-resolution photographs of landslide cirques, cracks, scarp walls, vegetation features were obtained via drone, which would have been impossible to obtain from the ground in conditions of dense subtropical vegetation cover. Possible approaches to the landslide activity and hazard assessment were evaluated: slope stability analysis, geophysical monitoring methods, analysis of critical deformations and critical velocities of displacement, the analysis of changes of conditions of landslide development during its displacement, as well as scoring approaches to landslide hazard and risk assessment. As the result, the method of probabilistic estimation of landslide activity and hazard has been proposed, based on selection and analysis of main factors, influencing landslide displacements. Slope steepness, landslide thickness, slope length, bedrock dip, slope relief, cracks, vegetation patterns and other factors were used for assessment of activity of landslide sites. The investigation was based on the proposed probabilistic method of assessment of landslide activity and hazard. The considered landslide sites were ranked by the rate of activity as inactive, potentially active and active. The most active sites were used to identify potentially the most hazardous sites. Furthermore, the following factors were additionally considered: the damage of railroad facilities due to landslide, landslide activity, thickness of landslide at the toe of the slope, bedrock stratification, the conditions for the cirque development, the position of the sliding surface relatively to the railway, the involvement of bedrock into displaced mass. As the result, the investigated railroad sites were divided into three categories: non-hazardous, potentially hazardous and hazardous. The research was supported by Russian Scientific Foundation (Project № 16-17-00125).

Qualitative landslide susceptibility assessment by multicriteria analysis: A case study from San Antonio del Sur, Guantánamo, Cuba

NASA Astrophysics Data System (ADS)

Castellanos Abella, Enrique A.; Van Westen, Cees J.

Geomorphological information can be combined with decision-support tools to assess landslide hazard and risk. A heuristic model was applied to a rural municipality in eastern Cuba. The study is based on a terrain mapping units (TMU) map, generated at 1:50,000 scale by interpretation of aerial photos, satellite images and field data. Information describing 603 terrain units was collected in a database. Landslide areas were mapped in detail to classify the different failure types and parts. Three major landslide regions are recognized in the study area: coastal hills with rockfalls, shallow debris flows and old rotational rockslides denudational slopes in limestone, with very large deep-seated rockslides related to tectonic activity and the Sierra de Caujerí scarp, with large rockslides. The Caujerí scarp presents the highest hazard, with recent landslides and various signs of active processes. The different landforms and the causative factors for landslides were analyzed and used to develop the heuristic model. The model is based on weights assigned by expert judgment and organized in a number of components such as slope angle, internal relief, slope shape, geological formation, active faults, distance to drainage, distance to springs, geomorphological subunits and existing landslide zones. From these variables a hierarchical heuristic model was applied in which three levels of weights were designed for classes, variables, and criteria. The model combines all weights into a single hazard value for each pixel of the landslide hazard map. The hazard map was then divided by two scales, one with three classes for disaster managers and one with 10 detailed hazard classes for technical staff. The range of weight values and the number of existing landslides is registered for each class. The resulting increasing landslide density with higher hazard classes indicates that the output map is reliable. The landslide hazard map was used in combination with existing information on buildings and infrastructure to prepare a qualitative risk map. The complete lack of historical landslide information and geotechnical data precludes the development of quantitative deterministic or probabilistic models.

Rockfall catchment area design guide : metric edition : appendices.

DOT National Transportation Integrated Search

2001-12-01

The appendices belong to "Rockfall catchment area design guide : metric edition". : The data gathered from an exhaustive research project consisting of rolling a total of approximately 11,250 rocks off vertical; 4V:1H;2V;1H;1.33V:1H;1.0V:1.0H slopes ...

Rockfalls and Avalanches from Little Tahoma Peak on Mount Rainier, Washington

USGS Publications Warehouse

Crandell, Dwight Raymond; Fahnestock, Robert K.

1965-01-01

In December 1963 rockfalls from Little Tahoma Peak on the east side of Mount Rainier volcano fell onto Emmons Glacier and formed avalanches of rock debris that traveled about 4 miles down the glacier and the White River valley. In this distance, the rock debris descended as much as 6,200 feet in altitude. Minor lithologic differences and crosscutting relations indicate that the rockfalls caused at least seven separate avalanches, having an estimated total volume of 14 million cubic yards. The initial rockfall may have been caused by a small steam explosion near the base of Little Tahoma Peak. During movement, some of the avalanches were deflected from one side of the valley to the other. Calculations based on the height to which the avalanches rose on the valley walls suggest that their velocity reached at least 80 or 90 miles per hour. The unusually long distance some of the avalanches were transported is attributed to a cushion of trapped and compressed air at their base, which buoyed them up amid reduced friction.

Monitoring of a steep rockfall area experiencing fast displacements in Kåfjord, Northern Norway

NASA Astrophysics Data System (ADS)

Dreiås Majala, Gudrun; Harald Blikra, Lars; Skrede, Ingrid; Kristensen, Lene

2016-04-01

An unstable rockfall area in Kåfjord, Northern Norway, was recognized during periodic monitoring campaigns in July and early September 2015. The LiSALab ground based Interferometric Synthethic Aperture Radar (GB InSAR) from Ellegi were used. A relatively sharply defined steep area of 1200 m2 (6.000 - 12.000 m3) was documented to be in movement. Norwegian Water Resources and Energy Directorate (NVE) was at this point performing mitigation work in terms of an embarkment within the rockfall run-out area. The monitoring system was reinstalled and adjusted to perform continuous monitoring with an early-warning aim. The section for rockslide management in NVE was responsible for the monitoring and the warning to the municipality and Police. The displacements increased from about 1 mm/day in July to 3 cm/day in mid September. People were evalcuated due to increased velocities the 16th of September. The displacements continued to increase in several stages, and with a distinct accelleration the 2nd of October. The velocity peaked in a short window to more than 200 cm/day, and it ended with a partly frontal and sideway collapse of the unstable area. However, large parts of the area stabilized again, and the run-out lengths from the small rockfalls were limited. The GB InSAR system operated exceptionally well during the event, and were able to follow continuously the displacements during the accelleration stage until collapse as the processing time window was frequently adjusted to the changes in velocity. We were also able to follow inidividual rockfalls from the images - primarily as the rockfall impact points on the slope below showed up clearly on the radar images. The area continued to stabilize due to falling temperatures, and the mitigation work were finished during the fall. The displacements seem to be correlated to the increasing temperatures in late summer and precipitation events.

Toward a better integration of roughness in rockfall simulations - a sensitivity study with the RockyFor3D model

NASA Astrophysics Data System (ADS)

Monnet, Jean-Matthieu; Bourrier, Franck; Milenkovic, Milutin

2017-04-01

Advances in numerical simulation and analysis of real-size field experiments have supported the development of process-based rockfall simulation models. Availability of high resolution remote sensing data and high-performance computing now make it possible to implement them for operational applications, e.g. risk zoning and protection structure design. One key parameter regarding rock propagation is the surface roughness, sometimes defined as the variation in height perpendicular to the slope (Pfeiffer and Bowen, 1989). Roughness-related input parameters for rockfall models are usually determined by experts on the field. In the RockyFor3D model (Dorren, 2015), three values related to the distribution of obstacles (deposited rocks, stumps, fallen trees,... as seen from the incoming rock) relatively to the average slope are estimated. The use of high resolution digital terrain models (DTMs) questions both the scale usually adopted by experts for roughness assessment and the relevance of modeling hypotheses regarding the rock / ground interaction. Indeed, experts interpret the surrounding terrain as obstacles or ground depending on the overall visibility and on the nature of objects. Digital models represent the terrain with a certain amount of smoothing, depending on the sensor capacities. Besides, the rock rebound on the ground is modeled by changes in the velocities of the gravity center of the block due to impact. Thus, the use of a DTM with resolution smaller than the block size might have little relevance while increasing computational burden. The objective of this work is to investigate the issue of scale relevance with simulations based on RockyFor3D in order to derive guidelines for roughness estimation by field experts. First a sensitivity analysis is performed to identify the combinations of parameters (slope, soil roughness parameter, rock size) where the roughness values have a critical effect on rock propagation on a regular hillside. Second, a more complex hillside is simulated by combining three components: a) a global trend (planar surface), b) local systematic components (sine waves), c) random roughness (Gaussian, zero-mean noise). The parameters for simulating these components are estimated for three typical scenarios of rockfall terrains: soft soil, fine scree and coarse scree, based on expert knowledge and available airborne and terrestrial laser scanning data. For each scenario, the reference terrain is created and used to compute input data for RockyFor3D simulations at different scales, i.e. DTMs with resolutions from 0.5 m to 20 m and associated roughness parameters. Subsequent analysis mainly focuses on the sensitivity of simulations both in terms of run-out envelope and kinetic energy distribution. Guidelines drawn from the results are expected to help experts handle the scale issue while integrating remote sensing data and field measurements of roughness in rockfall simulations.

Historical analysis of rainfall-triggered rockfalls: the case study of the disaster of the ancient hydrothermal Sclafani Spa (Madonie Mts, northern-central Sicily, Italy) in 1851

NASA Astrophysics Data System (ADS)

Contino, Antonio; Bova, Patrizia; Esposito, Giuseppe; Giuffré, Ignazio; Monteleone, Salvatore

2017-12-01

In 1851, the region of Sicily experienced many rainstorm-induced landslides. On 13 March 1851, a rainstorm brought about a severe rockfall disaster near the small town of Sclafani (Madonie Mountains, northern-central Sicily, Italy). Rocks detached from the carbonate crest of Mt Sclafani (813 m above sea level) and fell downslope, causing the collapse of the ancient hydrothermal spa (about 430 m above sea level) and burying it. Fortunately, there were no injuries or victims. Given its geological, geomorphological and tectonic features, the calcareous-dolomitic and carbonate-siliciclastic relief of Mt Sclafani is extremely prone to landsliding. This study combines the findings of detailed geological and geomorphological field surveys and of a critical review of documentary data. A thorough analysis of documentary sources and historical maps made it possible to identify the location (previously unknown) of the ancient spa. The rockfall dynamics was reconstructed by comparing field reconnaissance data and documentary sources. The 1851 event reconstruction is an example of the application of an integrated methodological approach, which can yield a propaedeutic, yet meaningful picture of a natural disaster, paving the way for further research (e.g. slope failure susceptibility, future land-use planning, protection of thermal springs and mitigation of the impact of similar disasters in this area). Indeed, the intensification of extreme weather events, caused by global warming induced by climate change, has increased the risk of recurrence of a catastrophic event, like that of the ancient Sclafani spa, which is always a potential threat.

MONTE GENEROSO ROCKFALL FIELD TEST (SWITZERLAND): Real size experiment to constraint 2D and 3D rockfall simulations

NASA Astrophysics Data System (ADS)

Humair, F.; Matasci, B.; Carrea, D.; Pedrazzini, A.; Loye, A.; Pedrozzi, G.; Nicolet, P.; Jaboyedoff, M.

2012-04-01

In numerical rockfall simulation, the runout of rockfall is highly dependent of the restitution coefficients which are one of the key parameters to estimate the energy and simulate the rebounds of the blocks during their travel. Restitution coefficients values derived from literature may however not be adapted to every rockfall area as they do not integrate some of the influencing parameters as, among others, block shape rock size, soil cover… The aim is to illustrate how real size rockfall experiment can improve the reliability of computational trajectory simulations of rockfall propagation by calibrating these latter with experiment extracted results. Experimental rockfall tests were performed in the slopes of Monte Generoso area (lat 720850/ long 84830) which is located in the canton of Ticino in south Switzerland above a highway. The field site is a forested area with a thin soil cover on a bedrock characterized by massive carbonates. The elevation ranges between 894m and 322m above see level with a slope of 35 to 40° in the upper part, 60 to 89° in the medium part and 28 to 38° in the lower part. 22 blocks with different size and shape were manually released down, imparting little or no initial velocity. The failing blocks were coloured to make the impacts easier to recognize. The paths of the failing blocks are recorded using two high speed cameras and the impacts of the blocks were sampled using dGNSS. The rockfall trajectories were analysed based on the movies. As the movies have to be referenced in x and y direction, the distance between two known point in the terrain as well as the position of the cameras were measured prior to the blocks throws. Measurements of bounce height, angular and translational velocity (as well as energy) and restitution coefficients (normal kn and tangential kt) were attempt to be deduced from the movies. First, a-priori simulations are compared with the real size experiment throw. Then a-fortiori simulations taking into account the results of the experimental testing are performed and compared with the a-priori simulations. 3D simulations were performed using a software that takes into account the effect of the forest cover in the blocky trajectory (RockyFor 3D) and an other that neglects this aspect (Rotomap; geo&soft international). 2D simulation (RocFall; Rocscience) profiles were located in the blocks paths deduced from 3D simulations. The preliminary results show that: (1) high speed movies are promising and allow us to track the blocks using video software, (2) the a-priori simulations tend to overestimate the runout distance which is certainly due to an underestimation of the obstacles as well as the breaking of the failing rocks which is not taken into account in the models, (3) the trajectories deduced from both a-priori simulation and real size experiment highlights the major influence of the channelized slope morphology on rock paths as it tends to follow the flow direction. This indicates that the 2D simulation have to be performed along the line of flow direction.

Rock-fall hazard in the Etruscan archaeological site of Norchia (Central Italy)

NASA Astrophysics Data System (ADS)

Margottini, Claudio; Spizzichino, Daniele; Argento, Alessia; Russo, Alfonsina

2016-04-01

The ancient Etruscan town of Norchia (Central Italy, 80 km North of Rome) is situated on a long volcanic plateau surrounded by steep slopes, at the confluence of rivers Pile and Acqua Alta into the river Biedano. It has been constructed along the ancient Via Clodia, a short-range route intended for commercial traffic between Rome and the colonies in Etruscan lands. The flourishing of the town, evidenced by the beautiful necropolis, is placed between the end of the fourth and half of the second century BC. With its necropolis Norchia is the most significant example of funerary architecture rock Hellenistic period (IV-II century BC.). Its rock-cut tombs, are among the most important archaeological sites of Etruscan civilisation. They are an important and rare example of rock architecture and one of the few preserved in Italy. Also, the necropolis, with an extension of more than 100 hectares, is composed of rock-cut tombs of various types (façade, half-cube, false-cube and temple type) and dimensions (4-10 m in height), exhibiting a remarkable similarity with Asian tombs. From geological point of view, the area is exhibiting the overly of rigid volcanic products from both Vico and Volsini volcanic apparatus; as a bedrock, a plastic clay formation is positioned. The rock-cut tombs were excavated on two main volcanic levels, following the natural profile of tuff outcrops. The tombs located in the upper part of the necropolis have been excavated in a Red Tuff from Vico volcanic district, while those in lower level are dug in a grey tuff (Nenfro) from Vulsini volcanic apparatus. Recent investigations revealed the presence of many threats affecting the conservation of the site, that are including: surface rock weathering, water percolation and infiltration, surface vegetation and biological colonisation, instability and collapse of the cliff. The purpose of this study is mainly focused to verify whether the geological, geomorphological and geomechanical processes that have allowed the creation of a typical "butte" landscape, later inhabited by Etruscans, are still active. Field survey and historical data collection revealed the presence of many rock slope instabilities that have affected the site. Particularly meaningful is the presence of a large debris fan, just at the toe of the most relevant archaeological place, where the half-cube rock-cut tombs are positioned, testifying important rock-falls after the excavation of the necropolis. The preliminary investigation is revealing the importance of rock-fall hazard as well as the other environmental threats for the future conservation of the site. An integrated approach among different experts is now required, to define processes and causative factors and then to establish priorities for conservation

Endurance of rockfall protection fences

NASA Astrophysics Data System (ADS)

Gerber, W.; Meyer, M.

2009-04-01

Research on rockfall protection systems usually focuses on the performance of flexible barriers regarding their limit or design energy retention capacity. This research increased the maximum retention by a factor 15 within the last 15-20 years. Today rockfall energies up to 5'000 kJ can be retained. But this is relevant only for actual projects and newly erected barriers. However, the majority of all barriers installed in the alpine area were built many years ago and there is little knowledge on their long-term performance. Among others this includes not only the consideration of maintenance works such as man and machine power as well as yearly costs, but also the endurance of such barriers over the years. Such information normally stays at the authority or institution that initiated the construction of a protection system and/or is responsible for the maintenance of the object. But even if an institution maintains a large number of barriers, there mostly does not exist a general inventory because the barriers were installed over a time period of sometimes more than 30 years enduring many changes in the inventory procedures, drawings and documentations. Therefore, an actual investigation of all rockfall barriers protecting a sector of the Swiss railways (SBB) was performed in order to obtain an overview of their conditions. This project delivers both a detailed analysis of more than 100 single barriers and a statistically evaluable overview. It also allows a comparison between different generations of barrier types, independently from the different producers of the barriers. In a first step existing catalogues and data belonging to the relevant barriers were evaluated, summarized and mapped into topographic maps using GIS allowing a proper planning of the field trip, optimised regarding route, time consumption and possibly necessary closures of rail tracks. During the field investigations each barrier was inspected and all details regarding structural system, geometry, age, retained rockfall volume, probable remaining load capacity, damages, mistakes during erection, sufficient distance to rail tracks for the stopping process of the falling rock etc. were logged and photographically documented. The posterior analyses then lead to an overall classification of the single barriers into the three groups good/sufficent/insufficent resulting in different priority levels regarding the next suggested maintenance steps. The classification depends on whether a barrier can stop a frequent and a medium-sized rockfall event or not. The analysis gives a general overview of all barriers as well as a separate describtion of all criticised barriers to enable a proper planning of the repair tasks. The final summary over all barriers within the investigated sector can also be used to predict the expenditure on repairs for other areas assuming that the investigated barriers reflect the average of barriers installed in other areas. It also revealed that the barriers can be divided into two main groups older and younger than 1990. Around this date the rockfall retention techniques changed completely from more or less rigid fences towards full dynamically operating systems with net curtain effects along support ropes and special energy absorbing devices. For the first time, such an extensive inventory has been compiled and revealed its necessity to now have a unified data basis. The investigation also showed - and this will be shown more closely in the presentation - an in general good status of the protection systems after many years of operation. Although most of the modern flexible barriers are general in a good status, too, it has to be pointed out, that they are not necessarily appropriate to protect the railway infrastructure if they are erected to close to the tracks. The required stopping distance of the barriers has to be taken into account.

Air blasts generated by rockfall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park

USGS Publications Warehouse

Morrissey, M.M.; Savage, W.Z.; Wieczorek, G.F.

1999-01-01

The July 10, 1996, Happy Isles rockfall in Yosemite National Park, California, released 23,000 to 38,000 m3 of granite in four separate events. The impacts of the first two events which involved a 550-m free fall, generated seismic waves and atmospheric pressure waves (air blasts). We focus on the dynamic behavior of the second air blast that downed over 1000 trees, destroyed a bridge, demolished a snack bar, and caused one fatality and several injuries. Calculated velocities for the air blast from a two-phase, finite difference model are compared to velocities estimated from tree damage. From tornadic studies of tree damage, the air blast is estimated to have traveled <108-120 m/s within 50 m from the impact and decreased to <10-20 m/s within 500 m from the impact. The numerical model simulates the two-dimensional propagation of an air blast through a dusty atmosphere with initial conditions defined by the impact velocity and pressure. The impact velocity (105-107 m/s) is estimated from the Colorado Rockfall Simulation Program that simulates rockfall trajectories. The impact pressure (0.5 MPa) is constrained by the kinetic energy of the impact (1010-1012 J) estimated from the seismic energy generated by the impact. Results from the air blast simulations indicate that the second Happy Isles air blast (weak shock wave) traveled with an initial velocity above the local sound speed. The size and location of the first impact are thought to have injected <50 wt % dust into the atmosphere. This amount of dust lowered the local atmospheric sound speed to ???220 m/s. The discrepancy between calculated velocity data and field estimated velocity data (???220 m/s versus ???110 m/s) is attributed to energy dissipated by the downing of trees and additional entrainment of debris into the atmosphere not included in the calculations. Copyright 1999 by the American Geophysical Union.

Air blasts generated by rockfall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park

NASA Astrophysics Data System (ADS)

Morrissey, M. M.; Savage, W. Z.; Wieczorek, G. F.

1999-10-01

The July 10, 1996, Happy Isles rockfall in Yosemite National Park, California, released 23,000 to 38,000 m3 of granite in four separate events. The impacts of the first two events which involved a 550-m free fall, generated seismic waves and atmospheric pressure waves (air blasts). We focus on the dynamic behavior of the second air blast that downed over 1000 trees, destroyed a bridge, demolished a snack bar, and caused one fatality and several injuries. Calculated velocities for the air blast from a two-phase, finite difference model are compared to velocities estimated from tree damage. From tornadic studies of tree damage, the air blast is estimated to have traveled <108-120 m/s within 50 m from the impact and decreased to <10-20 m/s within 500 m from the impact. The numerical model simulates the two-dimensional propagation of an air blast through a dusty atmosphere with initial conditions defined by the impact velocity and pressure. The impact velocity (105-107 m/s) is estimated from the Colorado Rockfall Simulation Program that simulates rockfall trajectories. The impact pressure (0.5 MPa) is constrained by the kinetic energy of the impact (1010-1012 J) estimated from the seismic energy generated by the impact. Results from the air blast simulations indicate that the second Happy Isles air blast (weak shock wave) traveled with an initial velocity above the local sound speed. The size and location of the first impact are thought to have injected <50 wt% dust into the atmosphere. This amount of dust lowered the local atmospheric sound speed to ˜220 m/s. The discrepancy between calculated velocity data and field estimated velocity data (˜220 m/s versus ˜110 m/s) is attributed to energy dissipated by the downing of trees and additional entrainment of debris into the atmosphere not included in the calculations.

A new testing station about full-scale testing for rockfall protection systems

NASA Astrophysics Data System (ADS)

Bost, Marion; Dubois, Laurent; Rocher-Lacoste, Frédéric

2010-05-01

Rock blocks which detach from slopes overhanging urban areas, roads, railways and other infrastructures create one of the most frequent hazards in mountainous areas. Some of protection systems against rockfalls are designed to mitigate the effects of a foreseen movement by intercepting and stopping falling rock blocks. Despite the worldwide application of this kind of protections, the global behaviour of such a system has been poorly investigated, for the time being, and only at a reduced scale. The behaviour of these protection systems at real scale has been widely extrapolated, however these theories have still not been investigated by performing relating test at scale 1. The French Public Work Laboratory (LCPC) has decided to build a new testing station to work on that topic. This new testing station located in French Alps is able to drop heavy loads (up to 20 tons) from the top of a cliff down to structural systems in order to test their resistance to big shocks and study their dynamical behaviour at this high energy level. As the fall height can reach near 70m, the impact velocity can actually reach 35 metres per second and the energy released during the impact can be as large as 13 500 kilojoules. The experimental area at the bottom of the cliff which can be impacted by a block is 12 metres wide. This allows to test not only rockfall protection systems at scale 1 but also some parts of building structures too. To avoid damaging test-structure during a block drop due to dynamical effects, the dropping hook was designed with a special system. This one consists of a reversed mass which can be adapted to the dropped block and dropped together with the block. Moreover, it is very important to pay attention on repeatability of results concerning new devices for experiments. Whatever fall height the impact point is hit so with a precision of 50 centimetres. Such an experimental facility needs to be equipped with a relevant instrumentation. High capacity stress sensors, accelerometers and high speed cameras are available for experiments. They have been chosen for their capacity to work with an important length of cables. The monitoring with these experimental devices is performed at a high sample frequency suitable and for a very short load like an impact. A radio controlled system allows triggering monitoring and dropping at the same time. Due to bounce risk with the dropped block the safety of personal is ensured by strict operating rules. An observation platform has been located on an embankment along the test-site in order to follow experiments without risk. Two years were necessary for the test-site construction and its equipment. First tests on rockfall nets fences were performed at the end of 2009.

A quality assessment of 3D video analysis for full scale rockfall experiments

NASA Astrophysics Data System (ADS)

Volkwein, A.; Glover, J.; Bourrier, F.; Gerber, W.

2012-04-01

Main goal of full scale rockfall experiments is to retrieve a 3D trajectory of a boulder along the slope. Such trajectories then can be used to calibrate rockfall simulation models. This contribution presents the application of video analysis techniques capturing rock fall velocity of some free fall full scale rockfall experiments along a rock face with an inclination of about 50 degrees. Different scaling methodologies have been evaluated. They mainly differ in the way the scaling factors between the movie frames and the reality and are determined. For this purpose some scale bars and targets with known dimensions have been distributed in advance along the slope. The single scaling approaches are briefly described as follows: (i) Image raster is scaled to the distant fixed scale bar then recalibrated to the plane of the passing rock boulder by taking the measured position of the nearest impact as the distance to the camera. The distance between the camera, scale bar, and passing boulder are surveyed. (ii) The image raster was scaled using the four nearest targets (identified using frontal video) from the trajectory to be analyzed. The average of the scaling factors was finally taken as scaling factor. (iii) The image raster was scaled using the four nearest targets from the trajectory to be analyzed. The scaling factor for one trajectory was calculated by balancing the mean scaling factors associated with the two nearest and the two farthest targets in relation to their mean distance to the analyzed trajectory. (iv) Same as previous method but with varying scaling factors during along the trajectory. It has shown that a direct measure of the scaling target and nearest impact zone is the most accurate. If constant plane is assumed it doesn't account for the lateral deviations of the rock boulder from the fall line consequently adding error into the analysis. Thus a combination of scaling methods (i) and (iv) are considered to give the best results. For best results regarding the lateral rough positioning along the slope, the frontal video must also be scaled. The error in scaling the video images can be evaluated by comparing the data by additional combination of the vertical trajectory component over time with the theoretical polynomial trend according to gravity. The different tracking techniques used to plot the position of the boulder's center of gravity all generated positional data with minimal error acceptable for trajectory analysis. However, when calculating instantaneous velocities an amplification of this error becomes un acceptable. A regression analysis of the data is helpful to optimize trajectory and velocity, respectively.

Energy Dissipating Devices in Falling Rock Protection Barriers

NASA Astrophysics Data System (ADS)

Castanon-Jano, L.; Blanco-Fernandez, E.; Castro-Fresno, D.; Ballester-Muñoz, F.

2017-03-01

Rockfall is a phenomenon which, when uncontrolled, may cause extensive material damage and personal injury. One of the structures used to avoid accidents caused by debris flows or rockfalls is flexible barriers. The energy dissipating devices which absorb the energy generated by rock impact and reduce the mechanical stresses in the rest of the elements of the structure are an essential part of these kinds of structures. This document proposes an overview of the performance of energy dissipating devices, as well as of the role that they fulfil in the barrier. Furthermore, a compilation and a description of the dissipating elements found in the literature are proposed. Additionally, an analysis has been performed of the aspects taken into account in the design, such as experimental (quasi-static and dynamic) tests observing the variation of the behaviour curve depending on the test speed and numerical simulations by means of several finite element software packages.

Development of a 3D rockfall simulation model for point cloud topography

NASA Astrophysics Data System (ADS)

Noël, François; Wyser, Emmanuel; Jaboyedoff, Michel; Clouthier, Catherine; Locat, Jacques

2017-04-01

Rockfall simulations are generally used, for example, as input data to generate rockfall susceptibility map, to evaluate the reach probability of an infrastructure or to define input parameter values for mitigation designs. During the simulations, the lateral and vertical deviations of the particle and the change of velocity happening during the impacts have to be evaluated. Numerous factors control rockfall paths and velocities, like the particle's and terrain's shapes and compositions. Some models, especially the ones using discrete element methods, can consider a lot of physical factors. However, a compromise often has to be done between the time needed to produce a sufficient amount of 2D or 3D rockfall trajectories and the level of complexity of the model. In this presentation, the current version of our rockfall model in development is detailed and the compromises that were made are explained. For example, it is hard to predict the sizes and shapes of the components that could fall from a developing rock instability, or if they will break after the first impact or stay as massive blocks. For this reason, we decided for now to simplify the particle's shape to a sphere which can vary in size and to use a cubical shape to compute the 3D rotational inertia. In contrast to the particle's characteristics, the terrain's shape is known and can be acquired in detail using current topographical acquisition methods, e.g. airborne and terrestrial laser scans and aerial based structure from motion. We made no sacrifice on that side and developed our model so it can simulate rockfalls directly on 3D point clouds topographical data. It is also been shown that calibrating velocity weighting factors, often called restitution coefficients, is not an easy task. Divergent results could be obtained by different users using the same simulation program simply because they use different weighting factors, which are hard to evaluate and quantify from field work. Moreover, the normal velocity weighting factor does not seems to be constant as the impact conditions change, even if the terrain composition does not change. It could be correlated with the incident angle. We then decided for now to let impact characteristics control velocity changes with some variability and to use the detailed topographic representation to control the direction after a rebound. As a high topographical level of detail is used, less random variability is needed. Therefore, it would be easier for different users working on the same study area to get similar results as long as detailed enough topographical data are used. Some applications cases are also shown. Further development should focus on more calibration with known rockfall events, taking into account impact against trees and fragmentation of rock blocks, and improving the impact model by studying impacts on different terrain compositions from a mechanical approach using discrete element method based simulations.

Seismic and mechanical studies of the artificially triggered rockfall at the Mount Néron (French Alps, December 2011)

NASA Astrophysics Data System (ADS)

Bottelin, P.; Jongmans, D.; Daudon, D.; Mathy, A.; Helmstetter, A.; Bonilla-Sierra, V.; Cadet, H.; Amitrano, D.; Richefeu, V.; Lorier, L.; Baillet, L.; Villard, P.; Donzé, F.

2014-02-01

The eastern limestone cliff of Mount Néron (French Alps) was the theatre of two medium-size rockfalls between summer and winter 2011. On 14 August 2011, a ~ 2000 m3 rock compartment detached from the cliff, fell 100 m below and propagated down the slope. Although most of the fallen rocks deposited in the upper part of the slope, about 15 meter-size blocks were stopped by a ditch and an earthen barrier after a runout of 800 m. An unstable overhanging ~ 2600 m3 compartment remained attached to the cliff and was blasted on 13 December 2011. During this artificially triggered event, 7 blocks reached the same ditch, with volumes ranging from 0.8 to 12 m3. A semi-permanent seismic array located about 2.5 km from the site recorded the two events, providing a unique opportunity to understand and to compare the seismic phases generated during natural and artificially triggered rockfalls. Both events have signal duration of ~ 100 s with comparable maximum amplitudes recorded at large distances (computed local magnitude of 1.14 and 1.05, respectively), most of the energy lying below 20 Hz. Remote sensing techniques (photogrammetry and LiDAR) were employed before and after the provoked rockfall, allowing the volume and fracturing to be characterized. This event was filmed by two video cameras and the generated ground motions were recorded using two temporary 3C seismic sensors and 3 seismic arrays deployed at the slope toe. Movie and seismogram processing provided estimates of the propagation velocity during the successive rockfall phases, which ranges from 12 m s-1 to 30 m s-1. The main seismic phases were obtained from combined video and seismic signal analyses. The two most energetic phases are related to the ground impact of fallen material after free-fall, and to individual rock block impacts into the ditch and the earthen barrier. These two phases are characterized by similar low-frequency content but show very different particle motions. The discrete element technique allowed reproducing the key features of the rockfall dynamics, yielding propagation velocities compatible with experimental observations.

Load Measurement on Foundations of Rockfall Protection Systems

PubMed Central

Volkwein, Axel; Kummer, Peter; Bitnel, Hueseyin; Campana, Lorenzo

2016-01-01

Rockfall protection barriers are connected to the ground using steel cables fixed with anchors and foundations for the steel posts. It is common practice to measure the forces in the cables, while to date measurements of forces in the foundations have been inadequately resolved. An overview is presented of existing methods to measure the loads on the post foundations of rockfall protection barriers. Addressing some of the inadequacies of existing approaches, a novel sensor unit is presented that is able to capture the forces acting on post foundations in all six degrees of freedom. The sensor unit consists of four triaxial force sensors placed between two steel plates. To correctly convert the measurements into the directional forces acting on the foundation a special in-situ calibration procedure is proposed that delivers a corresponding conversion matrix. PMID:26840315

Hydrogeology of an alpine rockfall aquifer system and its role in flood attenuation and maintaining baseflow

NASA Astrophysics Data System (ADS)

Lauber, U.; Kotyla, P.; Morche, D.; Goldscheider, N.

2014-06-01

The frequency and intensity of extreme hydrological events in alpine regions is projected to increase with climate change. The goal of this study was to better understand the functioning of aquifers composed of complex alluvial and rockfall deposits in alpine valleys and to quantify the role of these natural storage spaces in flood attenuation and baseflow maintenance. Geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements were conducted in the Reintal valley (German Alps), where runoff from a karst spring infiltrates into a series of postglacial alluvial/rockfall aquifers. During high-flow conditions, groundwater velocities of 30 m h-1 were determined along 500 m; hydrograph analyses revealed short lag times (5 h) between discharge peaks upstream and downstream from the aquifer series; the maximum discharge ratio downstream (22) and the peak recession coefficient (0.196 d-1) are low compared with other alpine catchments. During low-flow conditions, the underground flow path length increased to 2 km and groundwater velocities decreased to 13 m h-1. Downstream hydrographs revealed a delayed discharge response after 101 h and peaks dampened by a factor of 1.5. These results indicate that alluvial/rockfall aquifers might play an important role in the flow regime and attenuation of floods in alpine regions.

Hydrogeology of an Alpine rockfall aquifer system and its role in flood attenuation and maintaining baseflow

NASA Astrophysics Data System (ADS)

Lauber, U.; Kotyla, P.; Morche, D.; Goldscheider, N.

2014-11-01

The frequency and intensity of extreme hydrological events in Alpine regions is projected to increase with climate change. The goal of this study is to better understand the functioning of aquifers composed of complex alluvial and rockfall deposits in Alpine valleys and to quantify the role of these natural storage spaces in flood attenuation and baseflow maintenance. Geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements were conducted in the Reintal (German Alps), where runoff from a karst spring infiltrates a series of postglacial alluvial/rockfall aquifers. During high-flow conditions, groundwater velocities of 30 m h-1 were determined along 500 m; hydrograph analyses revealed short lag times (5 h) between discharge peaks upstream and downstream from the aquifer series; the maximum discharge ratio downstream (22) and the peak recession coefficient (0.196 d-1) are low compared with other Alpine catchments. During low-flow conditions, the underground flow path length increased to 2 km and groundwater velocities decreased to 13 m h-1. Downstream hydrographs revealed a delayed discharge response after 101 h and peaks damped by a factor of 1.5. These results indicate that alluvial/rockfall aquifers might play an important role in the flow regime and attenuation of floods in Alpine regions.

Seismic and acoustic recordings of an unusually large rockfall at Mount St. Helens, Washington

USGS Publications Warehouse

Moran, Seth C.; Matoza, R.S.; Garces, M.A.; Hedlin, M.A.H.; Bowers, D.; Scott, William E.; Sherrod, David R.; Vallance, James W.

2008-01-01

On 29 May 2006 a large rockfall off the Mount St. Helens lava dome produced an atmospheric plume that was reported by airplane pilots to have risen to 6,000 m above sea level and interpreted to be a result of an explosive event. However, subsequent field reconnaissance found no evidence of a ballistic field, indicating that there was no explosive component. The rockfall produced complex seismic and infrasonic signals, with the latter recorded at sites 0.6 and 13.4 km from the source. An unusual, very long-period (50 s) infrasonic signal was recorded, a signal we model as the result of air displacement. Two high-frequency infrasonic signals are inferred to result from the initial contact of a rock slab with the ground and from interaction of displaced air with a depression at the base of the active lava dome.

Statistical Interpretation of Natural and Technological Hazards in China

NASA Astrophysics Data System (ADS)

Borthwick, Alistair, ,, Prof.; Ni, Jinren, ,, Prof.

2010-05-01

China is prone to catastrophic natural hazards from floods, droughts, earthquakes, storms, cyclones, landslides, epidemics, extreme temperatures, forest fires, avalanches, and even tsunami. This paper will list statistics related to the six worst natural disasters in China over the past 100 or so years, ranked according to number of fatalities. The corresponding data for the six worst natural disasters in China over the past decade will also be considered. [The data are abstracted from the International Disaster Database, Centre for Research on the Epidemiology of Disasters (CRED), Université Catholique de Louvain, Brussels, Belgium, http://www.cred.be/ where a disaster is defined as occurring if one of the following criteria is fulfilled: 10 or more people reported killed; 100 or more people reported affected; a call for international assistance; or declaration of a state of emergency.] The statistics include the number of occurrences of each type of natural disaster, the number of deaths, the number of people affected, and the cost in billions of US dollars. Over the past hundred years, the largest disasters may be related to the overabundance or scarcity of water, and to earthquake damage. However, there has been a substantial relative reduction in fatalities due to water related disasters over the past decade, even though the overall numbers of people affected remain huge, as does the economic damage. This change is largely due to the efforts put in by China's water authorities to establish effective early warning systems, the construction of engineering countermeasures for flood protection, the implementation of water pricing and other measures for reducing excessive consumption during times of drought. It should be noted that the dreadful death toll due to the Sichuan Earthquake dominates recent data. Joint research has been undertaken between the Department of Environmental Engineering at Peking University and the Department of Engineering Science at Oxford University on the production of zonation maps of certain natural hazards in China. Data at city and county level have been interpreted using a hierarchical system of indices, which are then ranked according to severity. Zonation maps will be presented for debris flows, landslide and rockfall hazards, flood risk in mainland China, and for soil erosion processes in the Yellow River basin. The worst debris flow hazards are to be found in southwest China as the land begins to become mountainous. Just over 20% of the land area is at high or very high risk of landslide and rockfall hazards, especially Yunnan, Sichuan, Gansu and Shannxi provinces. Flood risk is concentrated towards the eastern part of China, where the major rivers meet the sea. The paper will also consider data on technological disasters in China from 1900 to 2010, using data supplied by CRED. In terms of fatalities, industrial accidents appear to be dominated by explosion events. However, gas leaks have affected the largest number of people. Transport accidents are ranked in terms of fatalities as follows: water - road - rail - air. Fire is a major cause of loss of life, whereas chemical spills and poisoning seem to lead to fewer deaths.

Rockfall monitoring of a poorly consolidated marly sandstone cliff by TLS and IR thermography

NASA Astrophysics Data System (ADS)

Lefeuvre, Caroline; Guérin, Antoine; Carrea, Dario; Derron, Marc-Henri; Jaboyedoff, Michel

2017-04-01

The study area of La Cornalle (Vaud, Switzerland) is a 40 m high south-west facing cliff which is also part of a larger landslide (Bersier 1975 ; Parriaux, 1998). The cliff is formed by an alternation of marls and sandstones. The thicknesses of sandstone layers range from 0.5 to 4 meters. The rockfall activity of this cliff is high, with an average of one event per day. The aim of this study is to better understand the links between rockfall activity, cliff's structures, and weather and thermal conditions. The 3D surface evolution of the Cornalle cliff is monitored approximately every month since September 2012 using a Terrestrial Laser Scanning (TLS) data in order to get a monthly inventory of rockfall events. Since November 2013, a weather station located 150 meters away from the cliff collects data such as temperature, humidity, atmospheric pressure, rain and solar radiation every 15 minutes. Furthermore, we also fixed a thermic probe in the sandstone at 10 cm deep which measures temperature every 10 minutes. A detailed analysis has been performed during a short period (01/29/2016-04/08/2016) and pointed out a correlation between daily rainfall and rockfall. We found that a fall occurred the day or the day after a cumulative daily rainfall of at least 10 mm/day.In parallel to this monthly monitoring, the northwest part of La Cornalle cliff (the most active part) was monitored for 24 consecutive hours in July 2016 (from 12:30 to 12:30) using infrared thermography and crackmeters with a precision of 0.01mm. We collected a series of thermal pictures every 20 minutes, and measured the opening of a crack in sandstone layers every hour. We observed that marls are more affected by external changes of temperature than sandstones. Their surface temperature rises (resp. falls) more with an increase (resp. decrease) of external temperature than sandstones. Crackmeters measured an opening of the crack with an increase of the rock temperature and the opposite displacement (crack closing) happened with a decrease of temperature. The maximal amplitude of cumulated displacements measured is 0.15 mm. In terms of uncertainty, note that until 30% of the measured displacement can be related to instrument thermal dilatation. Finally, a multilayer model of daily thermal variations, including air temperature, solar radiation, rock temperature and thermal imaging is in development to assess the effect of temperature on unstable blocks and fracture opening, as demonstrated recently by Collins and Stock (2016). References Bersier A., Blanc P., Weidmann M. (1975). Le glissement de terrain de La Cornalle-Les Luges (Epesses, Vaud, Suisse). Bulletin de la société vaudoise des sciences naturelles, 72, fasc. 4 Collins B. D., Stock G. M. (2016). Rockfall triggering by cyclic thermal stressing of exfoliation fractures. Nature Geoscience. Published online March 28, 2016. Doi 10.1038/NGEO2686 Parriaux A. (1998): Glissement de la Cornalle: Bull. Géol. appl.,3 (1), 49-56

Geologic and seismic investigation for southeast expressway, stations 600-603 in Quincy, Mass.

USGS Publications Warehouse

May, James E.

1954-01-01

At this site the southbound lane of the proposed highway will be located approximately 75 feet to the left (south) of the base line. This will place it close to the base of a mound of granite quarry waste with very steep slopes. As a cut of considerable depth will be required for the road, the mound of waste with its unstable slope constitutes a very hazardous condition, especially with respect to the possibility of rock-falls and slides. Seismic work was performed at the site with the two aims in view; firstly, to obtain information on depths to bedrock that would aid in estimating the quantities of materials to be removed from the proposed cut, secondly, to obtain data that might aid in estimating the quantity of material in the mound of quarry waste with the object of obtaining estimates for its removal. Transverses A-13 and C-D were made for this latter purpose. Additional transverses would have been of value, but they were not made because of the possibility of starting rock-falls or slides, a situation that would have exposed personnel to unwarranted danger, and equipment to avoidable risk. Mr. M. E. Chandler and Me. W. L. Carney, Massachusetts Department of Public Works' Engineers, performed pertinent survey work required for this project, and prepared the essential plans and profiles. Mr. Chandler also operated the seismic equipment and assisted in the preparation of the seismic velocity data. The work was performed in June 1953 as part of a cooperative program of the Massachusetts Department of Public Works and the United States Geological Survey.

Procedure for assessing the performance of a rockfall fragmentation model

NASA Astrophysics Data System (ADS)

Matas, Gerard; Lantada, Nieves; Corominas, Jordi; Gili, Josep Antoni; Ruiz-Carulla, Roger; Prades, Albert

2017-04-01

A Rockfall is a mass instability process frequently observed in road cuts, open pit mines and quarries, steep slopes and cliffs. It is frequently observed that the detached rock mass becomes fragmented when it impacts with the slope surface. The consideration of the fragmentation of the rockfall mass is critical for the calculation of block's trajectories and their impact energies, to further assess their potential to cause damage and design adequate preventive structures. We present here the performance of the RockGIS model. It is a GIS-Based tool that simulates stochastically the fragmentation of the rockfalls, based on a lumped mass approach. In RockGIS, the fragmentation initiates by the disaggregation of the detached rock mass through the pre-existing discontinuities just before the impact with the ground. An energy threshold is defined in order to determine whether the impacting blocks break or not. The distribution of the initial mass between a set of newly generated rock fragments is carried out stochastically following a power law. The trajectories of the new rock fragments are distributed within a cone. The model requires the calibration of both the runout of the resultant blocks and the spatial distribution of the volumes of fragments generated by breakage during their propagation. As this is a coupled process which is controlled by several parameters, a set of performance criteria to be met by the simulation have been defined. The criteria includes: position of the centre of gravity of the whole block distribution, histogram of the runout of the blocks, extent and boundaries of the young debris cover over the slope surface, lateral dispersion of trajectories, total number of blocks generated after fragmentation, volume distribution of the generated fragments, the number of blocks and volume passages past a reference line and the maximum runout distance Since the number of parameters to fit increases significantly when considering fragmentation, the final parameters selected after the calibration process are a compromise which meet all considered criteria. This methodology has been tested in some recent rockfall where high fragmentation was observed. The RockGIS tool and the fragmentation laws using data collected from recent rockfall have been developed within the RockRisk project (2014-2016, BIA2013-42582-P). This project was funded by the Spanish Ministerio de Economía y Competitividad.

Rockfall monitoring by Terrestrial Laser Scanning - case study of the basaltic rock face at Castellfollit de la Roca (Catalonia, Spain)

NASA Astrophysics Data System (ADS)

Abellán, A.; Vilaplana, J. M.; Calvet, J.; García-Sellés, D.; Asensio, E.

2011-03-01

This case study deals with a rock face monitoring in urban areas using a Terrestrial Laser Scanner. The pilot study area is an almost vertical, fifty meter high cliff, on top of which the village of Castellfollit de la Roca is located. Rockfall activity is currently causing a retreat of the rock face, which may endanger the houses located at its edge. TLS datasets consist of high density 3-D point clouds acquired from five stations, nine times in a time span of 22 months (from March 2006 to January 2008). The change detection, i.e. rockfalls, was performed through a sequential comparison of datasets. Two types of mass movement were detected in the monitoring period: (a) detachment of single basaltic columns, with magnitudes below 1.5 m3 and (b) detachment of groups of columns, with magnitudes of 1.5 to 150 m3. Furthermore, the historical record revealed (c) the occurrence of slab failures with magnitudes higher than 150 m3. Displacements of a likely slab failure were measured, suggesting an apparent stationary stage. Even failures are clearly episodic, our results, together with the study of the historical record, enabled us to estimate a mean detachment of material from 46 to 91.5 m3 year-1. The application of TLS considerably improved our understanding of rockfall phenomena in the study area.

The 2010-2011 Canterbury Earthquake Sequence: Environmental effects, seismic triggering thresholds and geologic legacy

NASA Astrophysics Data System (ADS)

Quigley, Mark C.; Hughes, Matthew W.; Bradley, Brendon A.; van Ballegooy, Sjoerd; Reid, Catherine; Morgenroth, Justin; Horton, Travis; Duffy, Brendan; Pettinga, Jarg R.

2016-03-01

Seismic shaking and tectonic deformation during strong earthquakes can trigger widespread environmental effects. The severity and extent of a given effect relates to the characteristics of the causative earthquake and the intrinsic properties of the affected media. Documentation of earthquake environmental effects in well-instrumented, historical earthquakes can enable seismologic triggering thresholds to be estimated across a spectrum of geologic, topographic and hydrologic site conditions, and implemented into seismic hazard assessments, geotechnical engineering designs, palaeoseismic interpretations, and forecasts of the impacts of future earthquakes. The 2010-2011 Canterbury Earthquake Sequence (CES), including the moment magnitude (Mw) 7.1 Darfield earthquake and Mw 6.2, 6.0, 5.9, and 5.8 aftershocks, occurred on a suite of previously unidentified, primarily blind, active faults in the eastern South Island of New Zealand. The CES is one of Earth's best recorded historical earthquake sequences. The location of the CES proximal to and beneath a major urban centre enabled rapid and detailed collection of vast amounts of field, geospatial, geotechnical, hydrologic, biologic, and seismologic data, and allowed incremental and cumulative environmental responses to seismic forcing to be documented throughout a protracted earthquake sequence. The CES caused multiple instances of tectonic surface deformation (≥ 3 events), surface manifestations of liquefaction (≥ 11 events), lateral spreading (≥ 6 events), rockfall (≥ 6 events), cliff collapse (≥ 3 events), subsidence (≥ 4 events), and hydrological (10s of events) and biological shifts (≥ 3 events). The terrestrial area affected by strong shaking (e.g. peak ground acceleration (PGA) ≥ 0.1-0.3 g), and the maximum distances between earthquake rupture and environmental response (Rrup), both generally increased with increased earthquake Mw, but were also influenced by earthquake location and source characteristics. However, the severity of a given environmental response at any given site related predominantly to ground shaking characteristics (PGA, peak ground velocities) and site conditions (water table depth, soil type, geomorphic and topographic setting) rather than earthquake Mw. In most cases, the most severe liquefaction, rockfall, cliff collapse, subsidence, flooding, tree damage, and biologic habitat changes were triggered by proximal, moderate magnitude (Mw ≤ 6.2) earthquakes on blind faults. CES environmental effects will be incompletely preserved in the geologic record and variably diagnostic of spatial and temporal earthquake clustering. Liquefaction feeder dikes in areas of severe and recurrent liquefaction will provide the best preserved and potentially most diagnostic CES features. Rockfall talus deposits and boulders will be well preserved and potentially diagnostic of the strong intensity of CES shaking, but challenging to decipher in terms of single versus multiple events. Most other phenomena will be transient (e.g., distal groundwater responses), not uniquely diagnostic of earthquakes (e.g., flooding), or more ambiguous (e.g. biologic changes). Preliminary palaeoseismic investigations in the CES region indicate recurrence of liquefaction in susceptible sediments of 100 to 300 yr, recurrence of severe rockfall event(s) of ca. 6000 to 8000 yr, and recurrence of surface rupturing on the largest CES source fault of ca. 20,000 to 30,000 yr. These data highlight the importance of utilising multiple proxy datasets in palaeoearthquake studies. The severity of environmental effects triggered during the strongest CES earthquakes was as great as or equivalent to any historic or prehistoric effects recorded in the geologic record. We suggest that the shaking caused by rupture of local blind faults in the CES comprised a 'worst case' seismic shaking scenario for parts of the Christchurch urban area. Moderate Mw blind fault earthquakes may contribute the highest proportion of seismic hazard, be the most important drivers of landscape evolution, and dominate the palaeoseismic record in some locations on Earth, including locations distal from any identified active faults. A high scientific priority should be placed on improving the spatial extent and quality of 'off-fault' shaking records of strong earthquakes, particularly near major urban centres.

Rockfall vulnerability assessment for masonry buildings

NASA Astrophysics Data System (ADS)

Mavrouli, Olga

2015-04-01

The methodologies for the quantitative risk assessment vary in function of the application scale and the available data. For fragmental rockfalls, risk calculation requires data for the expected damage of the exposed elements due to potential rock block impacts with a range of trajectories, magnitudes and intensities. Although the procedures for the quantification of the rock block characteristics in terms of magnitude-frequency relationships are well established, there are few methodologies for the calculation of the vulnerability, and these are usually empirical or judgmental. The response of buildings to rock block impacts using analytical methods has been mainly realised so far for reinforced concrete buildings, and some fragility curves have been calculated with the results, indicating the potential damage for a range of rock block characteristics. Masonry buildings, as a common structural typology in mountainous areas, are in many cases impacted by rock blocks during rockfalls. Their response presents some peculiarities in comparison with reinforced-concrete structures given the non-homogeneity and variability of the compound materials (blocks and mortar), their orthotropy, low strength in tension, the statically indeterminate load-bearing system and the non-monolithic connections. To this purpose, analytical procedures which are specifically adapted to masonry structures should be used for the evaluation of the expected damage due to rock impacts. In this contribution we discuss the application of the analytical approach for the assessment of the expected damage in rockfall prone areas and the simulation assumptions that can be made concerning the materials, geometry, loading and the relevant simplifications. The amount of uncertainties introduced during their analytical simulation is high due to the dispersion of the data for material mechanical properties and the construction techniques and quality and thus a probabilistic assessment is suggested. The random nature of the rockfall as far as it concerns the magnitude and the intensity of the rock blocks can also be introduced using parametric analyses.

Site-specific landslide assessment in Alpine area using a reliable integrated monitoring system

NASA Astrophysics Data System (ADS)

Romeo, Saverio; Di Matteo, Lucio; Kieffer, Daniel Scott

2016-04-01

Rockfalls are one of major cause of landslide fatalities around the world. The present work discusses the reliability of integrated monitoring of displacements in a rockfall within the Alpine region (Salzburg Land - Austria), taking into account also the effect of the ongoing climate change. Due to the unpredictability of the frequency and magnitude, that threatens human lives and infrastructure, frequently it is necessary to implement an efficient monitoring system. For this reason, during the last decades, integrated monitoring systems of unstable slopes were widely developed and used (e.g., extensometers, cameras, remote sensing, etc.). In this framework, Remote Sensing techniques, such as GBInSAR technique (Groung-Based Interferometric Synthetic Aperture Radar), have emerged as efficient and powerful tools for deformation monitoring. GBInSAR measurements can be useful to achieve an early warning system using surface deformation parameters as ground displacement or inverse velocity (for semi-empirical forecasting methods). In order to check the reliability of GBInSAR and to monitor the evolution of landslide, it is very important to integrate different techniques. Indeed, a multi-instrumental approach is essential to investigate movements both in surface and in depth and the use of different monitoring techniques allows to perform a cross analysis of the data and to minimize errors, to check the data quality and to improve the monitoring system. During 2013, an intense and complete monitoring campaign has been conducted on the Ingelsberg landslide. By analyzing both historical temperature series (HISTALP) recorded during the last century and those from local weather stations, temperature values (Autumn-Winter, Winter and Spring) are clearly increased in Bad Hofgastein area as well as in Alpine region. As consequence, in the last decades the rockfall events have been shifted from spring to summer due to warmer winters. It is interesting to point out that temperature values recorded in the valley and on the slope show a good relationship indicating that the climatic monitoring is reliable. In addition, the landslide displacement monitoring is reliable as well: the comparison between displacements in depth by extensometers and in surface by GBInSAR - referred to March-December 2013 - shows ad high reliability as confirmed by the inter-rater reliability analysis (Pearson correlation coefficient higher than 0.9). In conclusion, the reliability of the monitoring system confirms that data can be useful to improve the knowledge on rockfall kinematic and to develop an accurate early warning system useful for civil protection issues.

Landslide monitoring and early warning systems in Lower Austria - current situation and new developments

NASA Astrophysics Data System (ADS)

Thiebes, Benni; Glade, Thomas; Schweigl, Joachim; Jäger, Stefan; Canli, Ekrem

2014-05-01

Landslides represent significant hazards in the mountainous areas of Austria. The Regional Geological Surveys are responsible to inform and protect the population, and to mitigate damage to infrastructure. Efforts of the Regional Geological Survey of Lower Austria include detailed site investigations, the planning and installation of protective structures (e.g. rock fall nets) as well as preventive measures such as regional scale landslide susceptibility assessments. For potentially endangered areas, where protection works are not feasible or would simply be too costly, monitoring systems have been installed. However, these systems are dominantly not automatic and require regular field visits to take measurements. Therefore, it is difficult to establish any relation between initiating and controlling factors, thus to fully understand the underlying process mechanism which is essential for any early warning system. Consequently, the implementation of new state-of-the-art monitoring and early warning systems has been started. In this presentation, the design of four landslide monitoring and early warning systems is introduced. The investigated landslide process types include a deep-seated landslide, a rock fall site, a complex earth flow, and a debris flow catchment. The monitoring equipment was chosen depending on the landslide processes and their activity. It aims to allow for a detailed investigation of process mechanisms in relation to its triggers and for reliable prediction of future landslide activities. The deep-seated landslide will be investigated by manual and automatic inclinometers to get detailed insights into subsurface displacements. In addition, TDR sensors and a weather station will be employed to get a better understanding on the influence of rainfall on sub-surface hydrology. For the rockfall site, a wireless sensor network will be installed to get real-time information on acceleration and inclination of potentially unstable blocks. The movement of the earth flow site will be monitored by differential GPS to get high precision information on displacements of marked points. Photogrammtetry based on octocopter surveys will provide spatial information on movement patterns. A similar approach will be followed for the debris flow catchment. Here, the focus lies on a monitoring of the landslide failures in the source area which prepares the material for subsequent debris flow transport. In addition to the methods already mentioned, repeated terrestrial laserscanning campaigns will be used to monitor geomorphological changes at all sites. All important data, which can be single measurements, episodic or continuous monitoring data for a given point (e.g. rainfall, inclination) or of spatial character (e.g. LiDAR measurements), are collected and analysed on an external server. Automatic data analysis methods, such as progressive failure analysis, are carried out automatically based on field measurements. The data and results from all monitoring sites are visualised on a web-based platform which enables registered users to analyse the respective information in near-real-time. Moreover, thresholds can be determined which trigger automated warning messages to the involved scientists if thresholds are exceeded by field measurements. The described system will enable scientists and decision-makers to access the latest data from the monitoring systems. Automatic alarms are raised when thresholds are exceeded to inform them about potentially hazardous changes. Thereby, a more efficient hazard management and early warning can be achieved. Keywords: landslide, rockfall, debris flow, earth flow, monitoring, early warning system.

True 3D kinematic analysis for slope instability assessment in the Siq of Petra (Jordan), from high resolution TLS

NASA Astrophysics Data System (ADS)

Gigli, Giovanni; Margottini, Claudio; Spizzichino, Daniele; Ruther, Heinz; Casagli, Nicola

2016-04-01

Most classifications of mass movements in rock slopes use relatively simple, idealized geometries for the basal sliding surface, like planar sliding, wedge sliding, toppling or columnar failures. For small volumes, the real sliding surface can be often well described by such simple geometries. Extended and complex rock surfaces, however, can exhibit a large number of mass movements, also showing various kind of kinematisms. As a consequence, the real situation in large rock surfaces with a complicate geometry is generally very complex and a site depending analysis, such as fieldwork and compass, cannot be comprehensive of the real situation. Since the outstanding development of terrestrial laser scanner (TLS) in recent years, rock slopes can now be investigated and mapped through high resolution point clouds, reaching the resolution of few mm's and accuracy less than a cm in most advanced instruments, even from remote surveying. The availability of slope surface digital data can offer a unique chance to determine potential kinematisms in a wide distributed area for all the investigated geomorphological processes. More in detail the proposed method is based on the definition of least squares fitting planes on clusters of points extracted by moving a sampling cube on the point cloud. If the associated standard deviation is below a defined threshold, the cluster is considered valid. By applying geometric criteria it is possible to join all the clusters lying on the same surface; in this way discontinuity planes can be reconstructed, rock mass geometrical properties are calculated and, finally, potential kinematisms established. The Siq of Petra (Jordan), is a 1.2 km naturally formed gorge, with an irregular horizontal shape and a complex vertical slope, that represents the main entrance to Nabatean archaeological site. In the Siq, discontinuities of various type (bedding, joints, faults), mainly related to geomorphological evolution of the slope, lateral stress released, stratigraphic setting and tectonic activity can be recognized. As a consequence, rock-falls have been occurring, even recently, with unstable rock mass volumes ranging from 0.1 m3 up to over some hundreds m3. Slope instability, acceleration of crack deformation and consequent increasing of rock-fall hazard conditions, could threaten the safety of tourist as well as the integrity of the heritage. 3D surface model coming from Terrestrial Laser Scanner acquisitions was developed almost all over the site of Petra, including the Siq. Comprehensively, a point cloud of five billion points was generated making the site of Petra likely the largest scanned archaeological site in the word. As far as the Siq, the scanner was positioned on the path floor at intervals of not more than 10 meters from each station. The total number of scans in the Siq was 220 with an average point cloud interval of approximately 3 cm. Subsequently, for the definition of the main rockfall source areas, a spatial kinematic analysis for the whole Siq has been performed, by using discontinuity orientation data extracted from the point cloud by means of the software Diana. Orientation, number of sets, spacing/frequency, persistence, block size and scale dependent roughness was obtained combining fieldwork and automatic analysis. This kind of analysis is able to establish where a particular instability mechanism is kinematically feasible, given the geometry of the slope, the orientation of discontinuities and shear strength of the rock. The final outcome of this project was a detail landslide kinematic index map, reporting main potential instability mechanisms for a given area. The kinematic index was finally calibrated for each instability mechanism (plane failure; wedge failure; block toppling; flexural toppling) surveyed in the site. The latter is including the collapse occurred in May 2015, likely not producing any victim, in a sector clearly identified by the susceptibility maps produced by the analysis.

Calibration and validation of rockfall models

NASA Astrophysics Data System (ADS)

Frattini, Paolo; Valagussa, Andrea; Zenoni, Stefania; Crosta, Giovanni B.

2013-04-01

Calibrating and validating landslide models is extremely difficult due to the particular characteristic of landslides: limited recurrence in time, relatively low frequency of the events, short durability of post-event traces, poor availability of continuous monitoring data, especially for small landslide and rockfalls. For this reason, most of the rockfall models presented in literature completely lack calibration and validation of the results. In this contribution, we explore different strategies for rockfall model calibration and validation starting from both an historical event and a full-scale field test. The event occurred in 2012 in Courmayeur (Western Alps, Italy), and caused serious damages to quarrying facilities. This event has been studied soon after the occurrence through a field campaign aimed at mapping the blocks arrested along the slope, the shape and location of the detachment area, and the traces of scars associated to impacts of blocks on the slope. The full-scale field test was performed by Geovert Ltd in the Christchurch area (New Zealand) after the 2011 earthquake. During the test, a number of large blocks have been mobilized from the upper part of the slope and filmed with high velocity cameras from different viewpoints. The movies of each released block were analysed to identify the block shape, the propagation path, the location of impacts, the height of the trajectory and the velocity of the block along the path. Both calibration and validation of rockfall models should be based on the optimization of the agreement between the actual trajectories or location of arrested blocks and the simulated ones. A measure that describe this agreement is therefore needed. For calibration purpose, this measure should simple enough to allow trial and error repetitions of the model for parameter optimization. In this contribution we explore different calibration/validation measures: (1) the percentage of simulated blocks arresting within a buffer of the actual blocks, (2) the percentage of trajectories passing through the buffer of the actual rockfall path, (3) the mean distance between the location of arrest of each simulated blocks and the location of the nearest actual blocks; (4) the mean distance between the location of detachment of each simulated block and the location of detachment of the actual block located closer to the arrest position. By applying the four measures to the case studies, we observed that all measures are able to represent the model performance for validation purposes. However, the third measure is more simple and reliable than the others, and seems to be optimal for model calibration, especially when using a parameter estimation and optimization modelling software for automated calibration.

Experiences from full-scale rockfall testing of protection gallery

NASA Astrophysics Data System (ADS)

Volkwein, Axel; Fergg, Daniel; Hess, Reto; Schellenberg, Kristian

2017-04-01

Vertical drop tests have been performed at the Swiss Oberalppass road. The planned deconstruction of two avalanche protection galleries enabled a precedent evaluation of one gallery (Parde 1} regarding its capacity against rockfall. The background for this evaluation was also to evaluate an existing model for predicting the protection capacity of a rockfall gallery. Based on this model existing galleries can be evaluated whether their residual capacity is sufficient or if it is necessary to strengthen the structureaccording to the current guidelines. This contribution focusses the conduction of the experiments and the experiences obtained from. The presentation gives details on experimental setup, impact characterization, gallery performance, weather implications, data retrieval and data analysis.According to the limited time span for testing and the resources available, a compact testing series has been setup. Three fields of the gallery were tested with drop weights of 800, 1600 and 3200 kg falling from up to 25 m height. The blocks were lifted by a mobil crane. The concrete roof is supported by columns on the valley side and on the mountainside simply supported on the retention wall. The roof slabspans approximately 6x5 m with a thickness of about 0.60 m and is covered by a soil cushion, which has been unified to 0.40 m thickness previous to the test. Additional wooden columns have been installed at the roof's valleyside to avoid a failure of the concrete columns and to favorize a failure of the roof itself due to bending or punching. The measurements performed consist of high speed video records, accelerations within the impactors and on the bottom surface of the gallery roof.

Assessing the interaction between mountain forests and snow avalanches at Nevados de Chillán, Chile and its implications for ecosystem-based disaster risk reduction

NASA Astrophysics Data System (ADS)

Casteller, Alejandro; Häfelfinger, Thomas; Cortés Donoso, Erika; Podvin, Karen; Kulakowski, Dominik; Bebi, Peter

2018-04-01

Gravitational natural hazards such as snow avalanches, rockfalls, shallow landslides and volcanic activity represent a risk to mountain communities around the world. In particular, where documentary records about these processes are rare, decisions on risk management and land-use planning have to be based on a variety of other sources including vegetation, tree-ring data and natural hazard process models. We used a combination of these methods in order to evaluate dynamics of natural hazards with a focus on snow avalanches at Valle Las Trancas, in the Biobío region in Chile. Along this valley, natural hazards threaten not only the local human population, but also the numerous tourists attracted by outdoor recreational activities. Given the regional scarcity of documentary records, tree-ring methods were applied in order to reconstruct the local history of snow avalanches and debris flow events, which are the most important weather-related processes at respective tracks. A recent version of the model Rapid Mass MovementS (RAMMS), which includes influences of forest structure, was used to calculate different avalanche parameters such as runout distances and maximum pressures, taking into consideration the presence or absence of forest along the tracks as well as different modeled return periods. Our results show that local Nothofagus broadleaf forests contribute to a reduction of avalanche runout distances as well as impact pressure on present infrastructure, thus constituting a valuable ecosystem disaster risk reduction measure that can substitute or complement other traditional measures such as snow sheds.

Mobility of pyroclastic flows and surges at the Soufriere Hills Volcano, Montserrat

USGS Publications Warehouse

Calder, E.S.; Cole, P.D.; Dade, W.B.; Druitt, T.H.; Hoblitt, R.P.; Huppert, H.E.; Ritchie, L.; Sparks, R.S.J.; Young, S.R.

1999-01-01

The Soufriere Hills Volcano on Montserrat has produced avalanche-like pyroclastic flows formed by collapse of the unstable lava dome or explosive activity. Pyroclastic flows associated with dome collapse generate overlying dilute surges which detach from and travel beyond their parent flows. The largest surges partially transform by rapid sedimentation into dense secondary pyroclastic flows that pose significant hazards to distal areas. Different kinds of pyroclastic density currents display contrasting mobilities indicated by ratios of total height of fall H, run-out distance L, area inundated A and volume transported V. Dome-collapse flow mobilities (characterised by either L/H or A/V 2/3) resemble those of terrestrial and extraterrestrial cold-rockfalls (Dade and Huppert, 1998). In contrast, fountain-fed pumice flows and fine-grained, secondary pyroclastic flows travel slower but, for comparable initial volumes and heights, can inundate greater areas.

Developing effective rockfall protection barriers for low energy impacts

NASA Astrophysics Data System (ADS)

Mentani, Alessio; Giacomini, Anna; Buzzi, Olivier; Govoni, Laura; Gottardi, Guido; Fityus, Stephen

2016-04-01

Recently, important progresses have been made towards the development of high capacity rockfall barriers (100 kJ - 8000 kJ). The interest of researchers and practitioners is now turning to the development of fences of minor capacity, whose use becomes essential in areas where rockfall events generally have low intensity and the use of high capacity barriers would be accompanied by excessive costs and high environmental impact. Low energy barriers can also provide a cost-effective solution even in areas where high energies events are expected. Results of full-scale tests are vital to any investigation on the behaviour of these structures. An experimental set-up has been developed at The University of Newcastle (AUS), to investigate the response of low energy rockfall barrier prototypes to low energy impacts. The Australian territory, and in particular New South Wales, is in fact characterised by rockfall events of low-to-medium intensity (50 kJ - 500 kJ) and the need of protection structures working within such energy range, is particularly felt [1]. The experiments involved the impact of a test block onto three spans, low energy barrier prototypes, made of steel structural posts, fully fixed at the base, side cables and a steel meshwork constituted by a double twist hexagonal wire net [2]. Test data enabled the development, calibration and assessment of FE models [3], on which non-linear and dynamic analyses have been performed addressing the effect of the block size. Results have shown that the response of the structure is strongly governed by the net. Data from tests conducted on the sole net and on the entire barrier showed in fact a similar trend, different to what typically observed for high capacity barriers, whose behaviour is also led by the presence of uphill cables and brakes. In particular, the numerical analyses have demonstrated a dependence of the net performance on the block size. In particular, a loss of capacity in the order of 50% occurred as the block size dropped from 1000 to 450 mm, with a realistic velocity observed to get the perforation of the net. The results of the study provide an important insight on the behaviour of low energy barriers. Data also shed an important light on the testing procedures which should be followed when full-scale experiments are performed on these structures, highlighting the need of considering the whole spectrum of potential block sizes. References [1] Spadari M, Kardani M, De Carteret R, Giacomini A, Buzzi O, Fityus S, Sloan S W (2013) Statistical evaluation of rockfall energy ranges for different geological settings of New South Wales, Australia. Eng Geol 158:57-65. [2] Thoeni K, Lambert C, Giacomini A, Sloan S W (2013) Discrete modelling of hexagonal wire meshes with a stochastically distorted contact model. Comp Geotech 49: 158-169. [3] Mentani A, Giacomini A, Buzzi O, Govoni L, Gottardi G, Fityus S (2015) Numerical Modelling of a Low-Energy Rockfall Barrier: New Insight into the Bullet Effect, Rock Mech Rock Eng, DOI10.1007/s00603-015-0803-1

The Rockfall Buzzsaw: Quantifying the role of frost processes on mountain evolution

NASA Astrophysics Data System (ADS)

Hales, T.; Roering, J. J.

2006-12-01

The height and relief of high mountains reflects a balance between uplift, caused by tectonic and isostatic forces, and erosion, by fluvial, glacial, periglacial, and hillslope processes. Recently, models of mountain evolution have focused on the importance of glaciers in eroding deep valleys, a process referred to as the "glacial buzzsaw". Little attention has been paid to the role of periglacial processes, despite large scree slopes and rubble-covered glaciers being common in mountains. Frost cracking induced rockfall erosion has wide acceptance in the literature and a number of local studies have calculated high rockfall erosion rates in cold environments; but the question remains, how important is frost cracking in eroding bedrock in mountainous environments? We quantify how and where ice-driven mechanical erosion occurs in cold, bedrock-dominated landscapes using a simple one-dimensional numerical heat flow model. In our model, ice grows by water migration to colder regions in shallow rock by the reduction in chemical potential associated with intermolecular forces between ice and mineral surfaces, a process called segregation ice growth. Positive MAT sites are characterized by intense cracking in the top meter of the rock mass and a maximum frost penetration of ~4m. In contrast, negative MAT areas have an order of magnitude less intense cracking that primarily occurs at depths between 50 and 800 cm. This suggests that periglacial erosion may be concentrated in a narrow elevation range (corresponding to areas with a MAT between 0 and 2°C). At higher MATs ice growth is limited to very shallow depths. As MATs dip below zero, frost cracking intensity is reduced considerably resulting in a high and frozen condition. These results suggest that rocks with a fracture spacing of less than 400cm provide more sites for the nucleation and growth of segregation ice, and are therefore more susceptible to frost-induced bedrock weathering. To quantify the effect of ice weathering, we compared the elevation, rock fracture spacing, and the rockfall erosion rate for three areas, the eastern Southern Alps, New Zealand (fracture spacing of <10cm), rock outcrops in Utah (variable fracture spacing), and Mt. Whitney, Sierra Nevada (fracture spacing of ~400 cm). The eastern Southern Alps are characterized by large (km scale) scree slopes, rapid rockfall erosion rates (~0.1 mm/yr), and rounded peaks whose maximum elevation corresponds with the ~0°C isotherm. The eastern Sierra Nevada has small scree slopes and steep pinnacled ridges and peaks above the -5°C isotherm, consistent with the high and frozen scenario. In Utah the highest rockfall frequencies occur in coincidence with the 0.5°C isotherm. These results hint at an interplay between mountain height and rock fracture spacing, such that the height of mountains with highly fractured rocks may be limited by the intense frost processes coincident with the 1°C isotherm. In this case, mountain elevations may be limited by a rockfall buzzsaw, which efficiently erodes bedrock within a narrow elevation band, the location of which is controlled by glacial- interglacial climate cycles.

Rockfalls in cliffs surrounding waterfall revealed by high-definition topographic measurements

NASA Astrophysics Data System (ADS)

Hayakawa, Y. S.; Obanawa, H.

2017-12-01

Bedrock rivers of volcanic terrain often comprise numerous knickpoints. Erosion of bedrock at knickpoints is an essential process of fluvial dissection of volcanic landforms, which also affects the deformations of surrounding slopes. However, short term (less than decadal) changes in bedrock landforms have often been limited to examine in a spatiotemporal framework. Here we use terrestrial laser scanning and SfM-MVS photogrammetry to detect recent annual changes in the morphology of cliffs surrounding a waterfall (Kegon Falls) on jointed andesite lava and conglomerates. The amount of bedrock deformation caused by small rockfalls and surface lowering are assessed in volume, which often appears in a relatively lower portion of the cliff. Such the changes are supposed to be affected by the enhanced supply of water and weathering following the latest major rockfall in 1986 which caused 8-m recession of the waterfall lip. The three-dimensional point cloud data is also utilized to construct a 3D model using cardboards, which is useful for understanding the topography and its changes of the waterfall as educational resources.

National Program for Inspection of Non-Federal Dams. Winsor Dam (MA 00588), Quabbin Spillway (MA 00589), Goodnough Dike (MA 00590), Connecticut River Basin, Ware, Massachusetts. Phase I Inspection Report.

DTIC Science & Technology

1978-09-01

at the en- trance to the channel. Another rockfall occurs along the right side of the channel, about 280 ft. downstream from the channel entrance. The...new level survey on seven settlement observation points at Goodnough Dike, in particular to check the 1973 data at * 27 ,nn lnmnnnm u u ~ l I • lI gI ...Spillway weir masonry to maintain the structure in good condition. 3. Periodically remove brush, saplings and rockfalls from the I spiliway discharge

Is rock slope instability in high-mountain systems driven by topo-climatic, paraglacial or rock mechanical factors? - A question of scale!

NASA Astrophysics Data System (ADS)

Messenzehl, Karoline; Dikau, Richard

2016-04-01

Due to the emergent and (often non-linear) complex nature of mountain systems the key small-scale system properties responsible for rock slope instability contrast to those being dominant at larger spatial scales. This geomorphic system behaviour has major epistemological consequences for the study of rockfalls and associated form-process-relationships. As each scale requires its own scientific explanation, we cannot simply upscale bedrock-scale findings and, in turn, we cannot downscale the valley-scale knowledge to smaller phenomena. Here, we present a multi-scale study from the Turtmann Valley (Swiss Alps), that addresses rock slope properties at three different geomorphic levels: (i) regional valley scale, (ii) the hillslope scale and (iii) the bedrock scale. Using this hierarchical approach, we aim to understand the key properties of high-mountain systems responsible for rockfall initiation with respect to the resulting form-process-relationship at each scale. (i) At the valley scale (110 km2) rock slope instability was evaluated using a GIS-based modelling approach. Topo-climatic parameters, i.e. the permafrost distribution and the time since deglaciation after LGM were found to be the key variables causative for the regional-scale bedrock erosion and the storage of 62.3 - 65.3 x 106 m3 rockfall sediments in the hanging valleys (Messenzehl et al. 2015). (ii) At the hillslope scale (0.03 km2) geotechnical scanline surveys of 16 rock slopes and one-year rock temperature data of 25 ibuttons reveal that the local rockfall activity and the resulting deposition of individual talus slope landforms is mainly controlled by the specific rock mass strength with respect to the slope aspect, than being a paraglacial reaction. Permafrost might be only of secondary importance for the present-day rock mechanical state as geophysical surveys disprove the existence of frozen bedrock below 2600 m asl. (Messenzehl & Draebing 2015). (iii) At the bedrock scale (0.01 mm - 10 m) the spacing, persistence and orientation of joints turned out to be the most causative bedrock properties for the higher-scale rock mass strength. Rock temperature data suggest that high-frequent, surficial thermal processes, daily freeze-thaw cycles and seasonal ice segregation coupled with a winter snow cover are the major rock breakdown mechanisms. By linking the rockwalls' joint geometric pattern to the size and shape of rockfall blocks lying on the corresponding talus slopes, different rockfall magnitudes and frequencies were identified. Here we show, that the decrease in spatial scale is linked with a shift in variable importance, from topo-climatic and paraglacial factors at the largest scale to rock mechanical parameters at the smallest scale. Therefore, to understand the key destabilising factors of rock slopes in mountain systems and the resulting landforms, a holistic research approach is needed which considers the nested, hierarchical structure of geomorphic systems. Messenzehl, K., Meyer, H., Otto, J.-C., Hoffmann, T., Dikau, R., 2015. Regional-scale controls on the spatial activity of rockfalls. (Turtmann valley, Swiss Alps) - A multivariate modelling approach. In: Geomorphology. Messenzehl, K., Draebing, D., 2015. Multidisciplinary investigations on coupled rockwall talus-systems (Turtmann valley, Swiss Alps). Geophysical Research Abstracts, 17 (EGU2015-1935, 2015).

Joint analysis of epistemic and aleatory uncertainty in stability analysis for geo-hazard assessments

NASA Astrophysics Data System (ADS)

Rohmer, Jeremy; Verdel, Thierry

2017-04-01

Uncertainty analysis is an unavoidable task of stability analysis of any geotechnical systems. Such analysis usually relies on the safety factor SF (if SF is below some specified threshold), the failure is possible). The objective of the stability analysis is then to estimate the failure probability P for SF to be below the specified threshold. When dealing with uncertainties, two facets should be considered as outlined by several authors in the domain of geotechnics, namely "aleatoric uncertainty" (also named "randomness" or "intrinsic variability") and "epistemic uncertainty" (i.e. when facing "vague, incomplete or imprecise information" such as limited databases and observations or "imperfect" modelling). The benefits of separating both facets of uncertainty can be seen from a risk management perspective because: - Aleatoric uncertainty, being a property of the system under study, cannot be reduced. However, practical actions can be taken to circumvent the potentially dangerous effects of such variability; - Epistemic uncertainty, being due to the incomplete/imprecise nature of available information, can be reduced by e.g., increasing the number of tests (lab or in site survey), improving the measurement methods or evaluating calculation procedure with model tests, confronting more information sources (expert opinions, data from literature, etc.). Uncertainty treatment in stability analysis usually restricts to the probabilistic framework to represent both facets of uncertainty. Yet, in the domain of geo-hazard assessments (like landslides, mine pillar collapse, rockfalls, etc.), the validity of this approach can be debatable. In the present communication, we propose to review the major criticisms available in the literature against the systematic use of probability in situations of high degree of uncertainty. On this basis, the feasibility of using a more flexible uncertainty representation tool is then investigated, namely Possibility distributions (e.g., Baudrit et al., 2007) for geo-hazard assessments. A graphical tool is then developed to explore: 1. the contribution of both types of uncertainty, aleatoric and epistemic; 2. the regions of the imprecise or random parameters which contribute the most to the imprecision on the failure probability P. The method is applied on two case studies (a mine pillar and a steep slope stability analysis, Rohmer and Verdel, 2014) to investigate the necessity for extra data acquisition on parameters whose imprecision can hardly be modelled by probabilities due to the scarcity of the available information (respectively the extraction ratio and the cliff geometry). References Baudrit, C., Couso, I., & Dubois, D. (2007). Joint propagation of probability and possibility in risk analysis: Towards a formal framework. International Journal of Approximate Reasoning, 45(1), 82-105. Rohmer, J., & Verdel, T. (2014). Joint exploration of regional importance of possibilistic and probabilistic uncertainty in stability analysis. Computers and Geotechnics, 61, 308-315.

The altitudinal temperature lapse rates applied to high elevation rockfalls studies in the Western European Alps

NASA Astrophysics Data System (ADS)

Nigrelli, Guido; Fratianni, Simona; Zampollo, Arianna; Turconi, Laura; Chiarle, Marta

2018-02-01

Temperature is one of the most important aspects of mountain climates. The relationships between air temperature and rockfalls at high-elevation sites are very important to know, but are also very difficult to study. In relation to this, a reliable method to estimate air temperatures at high-elevation sites is to apply the altitudinal temperature lapse rates (ATLR). The aims of this work are to quantify the values and the variability of the hourly ATLR and to apply this to estimated temperatures at high-elevation sites for rockfalls studies. To calculate ATLR prior the rockfalls, we used data acquired from two automatic weather stations that are located at an elevation above 2500 m. The sensors/instruments of these two stations are reliable because subjected to an accurate control and calibration once for year and the raw data have passed two automatic quality controls. Our study has yielded the following main results: (i) hourly ATLR increases slightly with increasing altitude, (ii) it is possible to estimate temperature at high-elevation sites with a good level of accuracy using ATLR, and (iii) temperature plays an important role on slope failures that occur at high-elevation sites and its importance is much more evident if the values oscillate around 0 °C with an amplitude of ±5 °C during the previous time-period. For these studies, it is not enough to improve the knowledge on air temperature, but it is necessary to develop an integrated knowledge of the thermal conditions of different materials involved in these processes (rock, debris, ice, water). Moreover, this integrated knowledge must be acquired by means of sensors and acquisition chains with known metrological traceability and uncertainty of measurements.

Characterization of past landslides and slope susceptibility analysis for Lima and Callao provinces, Peru

NASA Astrophysics Data System (ADS)

Tatard, Lucile; Villacorta, Sandra; Metzger, Pascale

2013-04-01

85% of people exposed to earthquakes, hurricanes, floods and drought live in developing countries (IPU, 2010). This population is also exposed to the landslide risk as this phenomenon is mainly triggered by earthquakes and rainfall. There is an urgent need to propose methods to evaluate and mitigate the landslide risk for developing countries, where few studies were undergone and data, and information on data, are scarce. In this study, we characterize a landslide inventory set up for the megalopolis of Lima, Peru, by the local geological bureau (INGEMMET). This inventory was set up using satellite images and includes landslides of all ages. It is composed of two landslide types: rockfalls and debris flows (huaycos) that we investigate together and separately. First, we describe qualitatively the landslide occurrences in terms of geology, slope steepness, altitude, etc. We notably find that debris flows occur at altitudes larger than the ones of the rockfalls, probably due to the climatic conditions. Then we find that the rockfalls and debris flows area distributions follow a power law when investigated separately whereas it does not follow a power law when investigated together. This highlights a logical difference of mechanics between the two landslide types. Then, using the dimension of correlation D (Grassberger and Procaccia, 1983) we show that the event spatial occurrences are not uniformly distributed but clustered. It supports the existence of controlling parameters on the spatial occurrence of landslides and the research to identify them. Last, we investigate the relationships between different landslide parameters (geology, altitude, slope steepness, ...) using the linear correlation coefficient r, and we find that all these parameters are independent to each other. This allows us to investigate each parameter separately in terms of landslide susceptibility and to define values for which the landslide susceptibility is low, medium or high for each parameter. The characterization of the landslide database is a necessary step to assess the good quality of the data. It then allows us to pursue our investigation and set up a robust landslide susceptibility analysis using our good-quality inventory.

Temporal variation of mass-wasting activity in Mount St. Helens crater, Washington, U. S. A. indicated by seismic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mills, H.H.

1991-11-01

In the crater of Mount St. Helens, formed during the eruption of 18 May 1980, thousands of rockfalls may occur in a single day, and some rock and dirty-snow avalanches have traveled more than 1 km from their source. Because most seismic activity in the crater is produced by mass wasting, the former can be used to monitor the latter. The number and amplitude of seismic events per unit time provide a generalized measure of mass-wasting activity. In this study 1-min averages of seismic amplitudes were used as an index of rockfall activity during summer and early fall. Plots ofmore » this index show the diurnal cycle of rockfall activity and establish that the peak in activity occurs in mid to late afternoon. A correlation coefficient of 0.61 was found between daily maximum temperature and average seismic amplitude, although this value increases to 0.72 if a composite temperature variable that includes the maximum temperature of 1 to 3 preceding days as well as the present day is used. Correlation with precipitation is much weaker.« less

A landslide susceptibility map of Africa

NASA Astrophysics Data System (ADS)

Broeckx, Jente; Vanmaercke, Matthias; Duchateau, Rica; Poesen, Jean

2017-04-01

Studies on landslide risks and fatalities indicate that landslides are a global threat to humans, infrastructure and the environment, certainly in Africa. Nonetheless our understanding of the spatial patterns of landslides and rockfalls on this continent is very limited. Also in global landslide susceptibility maps, Africa is mostly underrepresented in the inventories used to construct these maps. As a result, predicted landslide susceptibilities remain subject to very large uncertainties. This research aims to produce a first continent-wide landslide susceptibility map for Africa, calibrated with a well-distributed landslide dataset. As a first step, we compiled all available landslide inventories for Africa. This data was supplemented by additional landslide mapping with Google Earth in underrepresented regions. This way, we compiled 60 landslide inventories from the literature (ca. 11000 landslides) and an additional 6500 landslides through mapping in Google Earth (including 1500 rockfalls). Various environmental variables such as slope, lithology, soil characteristics, land use, precipitation and seismic activity, were investigated for their significance in explaining the observed spatial patterns of landslides. To account for potential mapping biases in our dataset, we used Monte Carlo simulations that selected different subsets of mapped landslides, tested the significance of the considered environmental variables and evaluated the performance of the fitted multiple logistic regression model against another subset of mapped landslides. Based on these analyses, we constructed two landslide susceptibility maps for Africa: one for all landslide types and one excluding rockfalls. In both maps, topography, lithology and seismic activity were the most significant variables. The latter factor may be surprising, given the overall limited degree of seismicity in Africa. However, its significance indicates that frequent seismic events may serve as in important preparatory factor for landslides. This finding concurs with several other recent studies. Rainfall explains a significant, but limited part of the observed landslide pattern and becomes insignificant when also rockfalls are considered. This may be explained by the fact that a significant fraction of the mapped rockfalls occurred in the Sahara desert. Overall, both maps perform well in predicting intra-continental patterns of mass movements in Africa and explain about 80% of the observed variance in landslide occurrence. As a result, these maps may be a valuable tool for planning and risk reduction strategies.

A tool for the calculation of rockfall fragility curves for masonry buildings

NASA Astrophysics Data System (ADS)

Mavrouli, Olga

2017-04-01

Masonries are common structures in mountainous and coastal areas and they exhibit substantial vulnerability to rockfalls. For big rockfall events or precarious structures the damage is very high and the repair is not cost-effective. Nonetheless, for small or moderate rockfalls, the damage may vary in function of the characteristics of the impacting rock blocks and of the buildings. The evaluation of the expected damage for masonry buildings, and for different small and moderate rockfall scenarios, is useful for assessing the expected direct loss at constructed areas, and its implications for life safety. A tool for the calculation of fragility curves for masonry buildings which are impacted by rock blocks is presented. The fragility curves provide the probability of exceeding a given damage state (low, moderate and high) for increasing impact energies of the rock blocks on the walls. The damage states are defined according to a damage index equal to the percentage of the damaged area of a wall, as being proportional to the repair cost. Aleatoric and epistemic uncertainties are incorporated with respect to the (i) rock block velocity, (ii) rock block size, (iii) masonry width, and (iv) masonry resistance. The calculation of the fragility curves is applied using a Monte Carlo simulation. Given user-defined data for the average value of these four parameters and their variability, random scenarios are developed, the respective damage index is assessed for each scenario, and the probability of exceedance of each damage state is calculated. For the assessment of the damage index, a database developed by the results of 576 analytical simulations is used. The variables range is: wall width 0.4 - 1.0 m, wall tensile strength 0.1 - 0.6 MPa, rock velocity 1-20 m/s, rock size 1-20 m3. Nonetheless this tool permits the use of alternative databases, on the condition that they contain data that correlate the damage with the four aforementioned variables. The fragility curves can be calculated using this tool either for single or for groups of buildings, as long as their characteristics are properly reflected in the variability of the input parameters. Selected examples of fragility curves sets are presented demonstrating the effect of the input parameters on the calculated probability of exceeding a given damage state, for different masonry typologies (stone and brick).

Geological hazards, vulnerability, and risk assessment using GIS: model for Glenwood Springs, Colorado

NASA Astrophysics Data System (ADS)

Mejía-Navarro, Mario; Wohl, Ellen E.; Oaks, Sherry D.

1994-08-01

Glenwood Springs, Colorado, lies at the junction of the Roaring Fork and Colorado Rivers, surrounded by the steep peaks of the Colorado Rocky Mountains. Large parts of the region have had intensive sheet erosion, debris flows, and hyperconcentrated floods triggered by landslides and slumps. The latter come from unstable slopes in the many tributary channels on the mountainsides, causing concentration of debris in channels and a large accumulation of sediment in colluvial wedges and debris fans that line the river valleys. Many of the landslide and debris-flow deposits exist in a state resembling suspended animation, ready to be destabilized by intense precipitation and/or seismic activity. During this century urban development in the Roaring Fork River valley has increased rapidly. The city of Glenwood Springs continues to expand over unstable debris fans without any construction of hazard mitigation structures. Since 1900, Glenwood Springs has had at least 21 damaging debris flows and floods; on July 24, 1977 a heavy thunderstorm spread a debris flow over more than 80 ha of the city. This paper presents a method that uses Geographic Information Systems (GIS) to assess geological hazards, vulnerability, and risk in the Glenwood Springs area. The hazards evaluated include subsidence, rockfall, debris flows, and floods, and in this paper we focus on debris flows and subsidence. Information on topography, hydrology, precipitation, geomorphic processes, bedrock and surficial geology, structural geology, soils, vegetation, and land use, was processed for hazard assessment using a series of algorithms. ARC/INFO and GRASS GIS softwares were used to produce maps and tables in a format accessible to urban planners. After geological hazards were defined for the study area, we estimated the vulnerability ( Ve) of various elements for an event of intensity i. Risk is assessed as a function of hazard and vulnerability. We categorized the study area in 14 classes for planning procedures; 7 classes defined as areas suitable for human settlement, and 7 classes defined as unsuitable for building, and most effectively reserved for parks and forests.

A generalized model for stability of trees under impact conditions

NASA Astrophysics Data System (ADS)

Dattola, Giuseppe; Crosta, Giovanni; Castellanza, Riccardo; di Prisco, Claudio; Canepa, Davide

2016-04-01

Stability of trees to external actions involve the combined effects of stem and tree root systems. A block impacting on the stem or an applied force pulling the stem can cause a tree instability involving stem bending or failure and tree root rotation. So different contributions are involved in the stability of the system. The rockfalls are common natural phenomena that can be unpredictable in terms of frequency and magnitude characteristics, and this makes difficult the estimate of potential hazard and risk for human lives and activities. In mountain areas a natural form of protection from rockfalls is provided by forest growing. The difficulties in the assessment of the real capability of this natural barrier by means of models is an open problem. Nevertheless, a large amount of experimental data are now available which provides support for the development of advanced theoretical framework and corresponding models. The aim of this contribution consists in presenting a model developed to predict the behavior of trees during a block impact. This model describes the tree stem by means of a linear elastic beam system consisting of two beams connected in series and with an equivalent geometry. The tree root system is described via an equivalent foundation, whose behavior is modelled through an elasto-plastic macro-element model. In order to calibrate the model parameters, simulations reproducing a series of winching tests, are performed. These numerical simulations confirm the capability of the model to predict the mechanical behavior of the stem-root system in terms of displacement vs force curves. Finally, numerical simulations of the impact of a boulder with a tree stem are carried out. These simulations, done under dynamic regime and with the model parameters obtained from the previous set of simulations, confirm the capability of the model to reproduce the effects on the stem-roots system generated by impulsive loads.

High-resolution seismic monitoring of rockslide activity in the Illgraben, Switzerland

NASA Astrophysics Data System (ADS)

Burtin, Arnaud; Hovius, Niels; Dietze, Michael; McArdell, Brian

2014-05-01

Rockfalls and rockslides are important geomorphic processes in landscape dynamics. They contribute to the evolution of slopes and supply rock materials to channels, enabling fluvial incision. Hillslope processes are also a natural hazard that we need to quantify and, if possible, predict. For these reasons, it is necessary to determine the triggering conditions and mechanisms involved in rockfalls. Rainfall is a well-known contributor since water, through soil moisture or pore pressure, may lead to the inception and propagation of cracks and can induce slope failure. Water can also affect slope stability through effects of climatic conditions such as the fluctuations of temperature around the freezing point. During the winter of 2012, we have recorded with a seismic array of 8 instruments substantial rockslide activity that affected a gully in the Illgraben catchment in the Swiss Alps. Three stations were positioned directly around the gully with a nearest distance of 400 m. The period of intense activity did not start during a rainstorm as it is common in summer but during a period of oscillation of temperatures around the freezing point. The activity did not occur in a single event but lasted about a week with a decay in time of the event frequency. Many individual events had two distinct seismic signals, with first, a short duration phase of about 10 s at frequencies below 5 Hz that we interpret as a slope failure signature, followed by a second long duration signal of > 60 s at frequencies above 10 Hz that we attribute to the propagation of rock debris down the slope. Thanks to the array of seismic sensors, we can study the fine details of this rockslide sequence by locating the different events, determining their distribution in time, and systematic quantification of seismic metrics (energy, duration, intensity...). These observations are compared to independent meteorological constrains and laser scan data to obtain an estimate of the volume mobilized by the event.

Landslide database dominated by rainfall triggered events

NASA Astrophysics Data System (ADS)

Devoli, G.; Strauch, W.; Álvarez, A.

2009-04-01

A digital landslide database has been created for Nicaragua to provide the scientific community and national authorities with a tool for landslide hazard assessment. Valuable information on landslide events has been obtained from a great variety of sources. On the basis of the data stored in the database, preliminary analyses performed at national scale aimed to characterize landslides in terms of spatial and temporal distribution, types of slope movements, triggering mechanisms, number of casualties and damage to infrastructure. A total of about 17000 events spatially distributed in mountainous and volcanic terrains have been collected in the database. The events are temporally distributed between 1826 and 2003, but a large number of the records (62% of the total number) occurred during the disastrous Hurricane Mitch in October 1998. The results showed that debris flows are the most common types of landslides recorded in the database (66% of the total amount), but other types, including rockfalls and slides, have also been identified. Rainfall, also associated with tropical cyclones, is the most frequent triggering mechanism of landslides in Nicaragua, but also seismic and volcanic activities are important triggers or, especially, the combination of one of them with rainfall. Rainfall has caused all types of failures, but debris flows and translational shallow slides are more frequent types. Earthquakes have most frequently triggered rockfalls and slides, while volcanic eruptions rockfalls and debris flows. Landslides triggered by rainfall were limited in time to the wet season that lasts from May to October and an increase in the number of events is observed during the months of September and October, which is in accord with the period of the rainy season in the Pacific and Northern and Central regions and when the country has the highest probability of being impacted by hurricanes. Both Atlantic and Pacific tropical cyclones have triggered landslides. At the medium scale, the influence of topographic and lithologic parameters on the occurrence of landslides was also analyzed and the physical characterization of landslides was done to better understand the landslide dynamics and run-out distances in both volcanic and non-volcanic areas. Data from fairly well documented events in Nicaragua were compared with other similar events in Central America and elsewhere and treated statistically to search for possible correlations and empirical relationships to predict run-out distances for different types of landslides, knowing the height of fall or the volume. The empirical relationships showed that debris flows and debris avalanches at volcanoes have the highest mobility and reach longer distances compared to other types of landslides. Because of their characteristics and downstream behaviour (long run-out distances and large volumes) both types of landslides have produced the highest number of victims in the country being the most dangerous to life and property.

Was The 01.09.2001 Etarpas Rockfall Detectable? Answer Using A Gis Approach

NASA Astrophysics Data System (ADS)

Baillifard, F.; Jaboyedoff, M.; Rouiller, J.-D.; Sartori, M.

As a general rule, "a posteriori" studies of rock slope instabilities show that rock- falls don't occur in casual locations. First, many geomorphologic arguments allow to identify the rupture zone as sensitive; secondly, external factors such as groundwa- ter circulations, freezing and thaw cycles, etc., induce long-term solicitations of the rock mass, and thus the diminution of the resistance along the discontinuities and the probably progressive rupture of the thrust. Once the sensitive zones are detected, the global activity induced by the external factors must be assessed, and the probability of rupture may be evaluated. Taking the opportunity of a 2'000 m3 rockfall that occurred on January, 9th, 2001, along a mountain road near Sion (Switzerland), a simple method to detect rock slope instabilities was tested. In order to locate sensitive areas, a set of five criterions was chosen, using available GIS formatted data such as vectorized topographic and geological maps, and a 25 m grid DTM. The chosen criterions are: the presence of faults and screes within a short distance, the presence of a rock face, a steep slope and a road. This scaling leads to a linear rating from 0 to 5. The location of the 01.09.01 rockfall obtains a score of 5. Once applied to the entire length of the road (4 km), the present method indicates two others areas which are highly sensitive to rupture, allowing to detect the main instabilities along this road. Such methods based on rough available parameters have now to be applied to larger areas. They also must be calibrated using a survey of past events. The studied rockfall area is affected by a high probability of rupture, as far as some necessary criteria are respected: first, the structural pattern has to be unfavorable; sec- ondly, the morphological conditions have to be favorable to the action of external factors.

Detection of morphological changes in cliff face surrounding a waterfall using terrestrial laser scanning and unmanned aerial system

NASA Astrophysics Data System (ADS)

Hayakawa, Yuichi S.; Obanawa, Hiroyuki

2015-04-01

Waterfall or bedrock knickpoint appears as an erosional front in bedrock rivers forming deep v-shaped valley downstream. Following the rapid fluvial erosion of waterfall, rockfalls and gravita-tional collapses often occur in surrounding steep cliffs. Although morphological changes of such steep cliffs are sometimes visually observed, quantitative and precise measurements of their spatio-temporal distribution have been limited due to the difficulties in direct access to such cliffs if with classical measurement methods. However, for the clarification of geomorphological processes oc-curring in the cliffs, multi-temporal mapping of the cliff face at a high resolution is necessary. Re-mote sensing approaches are therefore suitable for the topographic measurements and detection of changes in such inaccessible cliffs. To achieve accurate topographic mapping of cliffs around a wa-terfall, here we perform multi-temporal terrestrial laser scanning (TLS), as well as structure-from-motion multi-view stereo (SfM-MVS) photogrammetry based on unmanned aerial system (UAS). The study site is Kegon Falls in central Japan, having a vertical drop of surface water from top of its overhanging cliff, as well as groundwater outflows from its lower portions. The bedrock is composed of alternate layers of andesite lava and conglomerates. Minor rockfalls in the cliffs are often ob-served by local people. The latest major rockfall occurred in 1986, causing ca. 8-m upstream propa-gation of the waterfall lip. This provides a good opportunity to examine the changes in the surround-ing cliffs following the waterfall recession. Multi-time point clouds were obtained by TLS measure-ment over years, and the three-dimensional changes of the rock surface were detected, uncovering the locus of small rockfalls and gully developments. Erosion seems particularly frequent in relatively weak the conglomerates layer, whereas small rockfalls seems to have occurred in the andesite layers. Also, shadows in the TLS point clouds are effectively filled by complementary data of UAS-based SfM-MVS photogrammetry, which can improve the mapping quality of the cliff morphology. The point clouds are also projected on a vertical plane to generate a digital elevation model (DEM). Cross-sectional profiles extracted from the DEM show the presence of a distinct, 5-10-m depression at the mid of the cliff (bottom of the upper andesite layer), which appears to have been formed by freeze-thaw and/or wet-dry weathering following the waterfall recession in 1986.

Rock Slope Monitoring from 4D Time-Lapse Structure from Motion Analysis

NASA Astrophysics Data System (ADS)

Kromer, Ryan; Abellan, Antonio; Chyz, Alex; Hutchinson, Jean

2017-04-01

Structure from Motion (SfM) photogrammetry has become an important tool for studying earth surface processes because of its flexibility, ease of use, low cost and its capability of producing high quality 3-D surface models. A major benefit of SfM is that model accuracy is fit for purpose and surveys can be designed to meet a large range of spatial and temporal scales. In the Earth sciences, research in time-lapse SfM photogrammetry or videogrammetry is an area that is difficult to undertake due to complexities in acquiring, processing and managing large 4D datasets and represents an area with significant advancement potential (Eltner et al. 2016). In this study, we investigate the potential of 4D time-lapse SfM to monitor unstable rock slopes. We tested an array of statically mounted cameras collecting time-lapse photos of a limestone rock slope located along a highway in Canada. Our setup consisted of 8 DSLR cameras with 50 mm prime lenses spaced 2-3 m apart at a distance of 10 m from the slope. The portion of the rock slope monitored was 20 m wide and 6 m high. We collected data in four phases, each having 50 photographs taken simultaneously by each camera. The first phase of photographs was taken of the stable slope. In each successive phase, we gradually moved small, discrete blocks within the rock slope by 5-15 mm, simulating pre-failure deformation of rockfall. During the last phase we also removed discrete rock blocks, simulating rockfall. We used Agisoft Photoscan's 4D processing functionality and timeline tools to create 3D point clouds from the time-lapse photographs. These tools have the benefit of attaining better accuracy photo alignments as a greater number of photos are used. For change detection, we used the 4D filtering and calibration technique proposed by Kromer et al. (2015), which takes advantage of high degrees of spatial and temporal point redundancy to decrease measurement uncertainty. Preliminary results show that it is possible to attain more accurate 3D models using time-lapse photos taken from an array of cameras than photos taken from a single camera from multiple positions. For this survey setup, it was possible to detect mm to cm level of changes, which is of sufficient accuracy to detect the pre-failure stage of rockfalls, as well as small rockfall events. Additionally, cameras mounted in a static array can be operated remotely and automatically. Time-lapse SfM photogrammetry can be a cost effective alternative to terrestrial laser scanning for rockfall prone areas and facilitates the study of surface processes with high spatial and temporal detail. We gratefully acknowledge support from the NSERC collaborative research and development grant. References Eltner, A., Kaiser, A., Castillo, C.; Rock, G., Neugirg, F., Abellán, A. Image-based surface reconstruction in geomorphometry—Merits, limits and developments. Earth Surf. Dyn. 2016, 4, 359-389. Kromer, R. A., Abellán, A., Hutchinson, D. J., Lato, M., Edwards, T., & Jaboyedoff, M. A 4D filtering and calibration technique for small-scale point cloud change detection with a terrestrial laser scanner. Remote Sensing 2015, 7(10), 13029-13052.

A new Geo-Information Architecture for Risk Management in the Alps

NASA Astrophysics Data System (ADS)

Baruffini, Mi.; Thuering, M.

2009-04-01

During the last decades land-use increased significantly in the Swiss (and European) mountain regions. Due to the scarceness of areas suitable for development, anthropic activities were extended into areas prone to natural hazards such as avalanches, debris flows and rockfalls (Smith 2001). Furthermore, the transalpine transport system necessity to develop effective links in an important area collides with the need to ensure the safety of travelers and the health of the population. Consequently, an increase in losses due to hazards can be observed. To mitigate these associated losses, both traditional protective measures and land-use planning policies are to be developed and implemented to optimize future investments. Efficient protection alternatives can be obtained considering the concept of integral risk management. Risk analysis, as the central part of risk management, has become gradually a generally accepted approach for the assessment of current and future scenarios (Loat & Zimmermann 2004). The procedure aims at risk reduction which can be reached by conventional mitigation on one hand and the implementation of land-use planning on the other hand: a combination of active and passive mitigation measures is applied to prevent damage to buildings, people and infrastructures. As part of the Swiss National Science Foundation Project 54 "Evaluation of the optimal resilience for vulnerable infrastructure networks - An interdisciplinary pilot study on the transalpine transportation corridors" we study the vulnerability of infrastructures due to natural hazards. The project aims to study various natural hazards (and later, even man-made) and to obtain an evaluation of the resilience according to an interdisciplinary approach, considering the possible damage by means of risk criteria and pointing out the feasibility of conceivable measures to reduce potential damage. The project consists of a geoscientific part and an application. The fist part consists in studying the dangers (natural) and related risks in terms of infrastructure vulnerability. The application considers different types of danger (logically intersected with the transport infrastructure) and compares them with fixed values to obtain a so-called deficit. As framework we adopt The Swiss system for risk analysis of gravitational natural hazards (BUWAL 1999). In this way the project develops a methodology that makes possible a risk analysis aiming to optimize the infrastructure vulnerability and therefore allows to obtain a model designed to optimize the functionality of the network infrastructure. A simulation environment, RiskBox, is developed within the open-source GIS environment GRASS (Geographic Resources Analysis Support System) and a database (PostgreSQL) in order to manage a infrastructure data catalog. The targeted simulation environment includes the elements that identify the consecutive steps of risk analysis: hazard - vulnerability - risk. The initial results of the experimental case study show how useful a GIS-based system, which identify the risk of any single vulnerable element in the corridor and to assess the risk to the global system on the basis of priorities of the actors involved, can be for effective and efficient disaster response management, as explained in (ARMONIA Project 2007). In our work we wanted to highlight the complexity of the risk analysis methodology, difficulty that is amplified by many peculiarities in the mountain areas. In particular, the illustrative performed process can give an overview of the interests and the need to act to reduce vulnerability and the hazardous nature of the Gotthard corridor. We present the concept and current state of development of our project and our application to the testbed, the Alps-crossing corridor of St. Gotthard. REFERENCES ARMONIA Project 2007: Land use plans in Risky areas fro Unwise to Wise Practices - Materials 2nd conference. Politecnico di Milano. BUWAL 1999: Risikoanalyse bei gravitativen Naturgefahren - Methode, Fallbeispiele und Daten (Risk analyses for gravitational natural hazards). Bundesamt für Umwelt, Wald und Landschaft (BUWAL). Umwelt-Materialen Nr. 107, 1-244. Loat, R. & Zimmermann, M. 2004 : La gestion des risques en Suisse (Risk Management in Switzerland). In: Veyret, Y., Garry, G., Meschinet de Richemont, N. & Armand Colin (eds) 2002: Colloque Arche de la Défense 22-24 octobre 2002, dans Risques naturels et aménagement en Europe, 108-120. Smith, K. 2001: Environmental hazards. Assessing the risk and reducing disaster. Third edition. London

Landslide Hazard in Georgia

NASA Astrophysics Data System (ADS)

Gaprindashvili, G.; Tsereteli, E.; Gaprindashvili, M.

2013-12-01

In the last decades of the XX century, protect the population from geological hazards, to maintain land and safe operation of the engineering facilities has become the most important social - economic, demographic, political and environmental problems for the whole world. Georgia, with its scales of origination of the natural-catastrophic processes (landslide, mudflow, rockfall, erosion and etc.), their re-occurrence and with the negative results inflicted by these processes to the population, agricultural lands and engineering objects, is one of the most complex mountainous region. The extremely sensitive conditions were conditioned by: 1. Activation of highly intense earthquakes; 2. Activation of the negative meteorological events provoking the disaster processes on the background of global climatic changes and their abnormally frequent occurrence (mostly increased atmospheric precipitations, temperature and humidity); 3. Large-scale Human impact on the environment. Following the problem urgency, a number of departmental and research institutions have made their operations more intense in the given direction within the limits of their competence. First of all, the activity of the Department of Geology of Georgia (which is at present included in the National Environmental Agency of the Ministry of Environment and Natural Resources Protection), which mapped, identified and cataloged the hazardous processes on the territory of the country and identified the spatial limits and developmental regularities of these processes for tens of years. The increased risk of Geological catastrophes in Georgia first of all is caused by insufficient information between society and responsible persons toward this event. The existed situation needs the base assessment of natural disasters level, the identification of events, to determine their caused reasons, to develop special maps in GIS system, and continuous functioning of geo monitoring researches for develop safety early warning system.

Landslide Hazard in Georgia

NASA Astrophysics Data System (ADS)

Gaprindashvili, George; Tsereteli, Emil; Gaprindashvili, Merab

2014-05-01

In the last decades of the XX century, protect the population from geological hazards, to maintain land and safe operation of the engineering facilities has become the most important social - economic, demographic, political and environmental problems for the whole world. Georgia, with its scales of origination of the natural-catastrophic processes (landslide, mudflow, rockfall, erosion and etc.), their re-occurrence and with the negative results inflicted by these processes to the population, agricultural lands and engineering objects, is one of the most complex mountainous region. The extremely sensitive conditions were conditioned by: 1. Activation of highly intense earthquakes; 2. Activation of the negative meteorological events provoking the disaster processes on the background of global climatic changes and their abnormally frequent occurrence (mostly increased atmospheric precipitations, temperature and humidity); 3. Large-scale Human impact on the environment. Following the problem urgency, a number of departmental and research institutions have made their operations more intense in the given direction within the limits of their competence. First of all, the activity of the Department of Geology of Georgia (which is at present included in the National Environmental Agency of the Ministry of Environment and Natural Resources Protection), which mapped, identified and cataloged the hazardous processes on the territory of the country and identified the spatial limits and developmental regularities of these processes for tens of years. The increased risk of Geological catastrophes in Georgia first of all is caused by insufficient information between society and responsible persons toward this event. The existed situation needs the base assessment of natural disasters level, the identification of events, to determine their caused reasons, to develop special maps in GIS system, and continuous functioning of geo monitoring researches for develop safety early warning system.

Historical rock falls in Yosemite National Park, California (1857-2011)

USGS Publications Warehouse

Stock, Greg M.; Collins, Brian D.; Santaniello, David J.; Zimmer, Valerie L.; Wieczorek, Gerald F.; Snyder, James B.

2013-01-01

Inventories of rock falls and other types of landslides are valuable tools for improving understanding of these events. For example, detailed information on rock falls is critical for identifying mechanisms that trigger rock falls, for quantifying the susceptibility of different cliffs to rock falls, and for developing magnitude-frequency relations. Further, inventories can assist in quantifying the relative hazard and risk posed by these events over both short and long time scales. This report describes and presents the accompanying rock fall inventory database for Yosemite National Park, California. The inventory database documents 925 events spanning the period 1857–2011. Rock falls, rock slides, and other forms of slope movement represent a serious natural hazard in Yosemite National Park. Rock-fall hazard and risk are particularly relevant in Yosemite Valley, where glacially steepened granitic cliffs approach 1 km in height and where the majority of the approximately 4 million yearly visitors to the park congregate. In addition to damaging roads, trails, and other facilities, rock falls and other slope movement events have killed 15 people and injured at least 85 people in the park since the first documented rock fall in 1857. The accompanying report describes each of the organizational categories in the database, including event location, type of slope movement, date, volume, relative size, probable trigger, impact to humans, narrative description, references, and environmental conditions. The inventory database itself is contained in a Microsoft Excel spreadsheet (Yosemite_rock_fall_database_1857-2011.xlsx). Narrative descriptions of events are contained in the database, but are also provided in a more readable Adobe portable document format (pdf) file (Yosemite_rock_fall_database_narratives_1857-2011.pdf) available for download separate from the database.

Assessment of indirect losses and costs of emergency for project planning of alpine hazard mitigation

NASA Astrophysics Data System (ADS)

Amenda, Lisa; Pfurtscheller, Clemens

2013-04-01

By virtue of augmented settling in hazardous areas and increased asset values, natural disasters such as floods, landslides and rockfalls cause high economic losses in Alpine lateral valleys. Especially in small municipalities, indirect losses, mainly stemming from a breakdown of transport networks, and costs of emergency can reach critical levels. A quantification of these losses is necessary to estimate the worthiness of mitigation measures, to determine the appropriate level of disaster assistance and to improve risk management strategies. There are comprehensive approaches available for assessing direct losses. However, indirect losses and costs of emergency are widely not assessed and the empirical basis for estimating these costs is weak. To address the resulting uncertainties of project appraisals, a standardized methodology has been developed dealing with issues of local economic effects and emergency efforts needed. In our approach, the cost-benefit-analysis for technical mitigation of the Austrian Torrent and Avalanche Control (TAC) will be optimized and extended using the 2005-debris flow as a design event, which struggled a small town in the upper Inn valley in southwest Tyrol (Austria). Thereby, 84 buildings were affected, 430 people were evacuated and due to this, the TAC implemented protection measures for 3.75 million Euros. Upgrading the method of the TAC and analyzing to what extent the cost-benefit-ratio is about to change, is one of the main objectives of this study. For estimating short-run indirect effects and costs of emergency on the local level, data was collected via questionnaires, field mapping, guided interviews, as well as intense literature research. According to this, up-to-date calculation methods were evolved and the cost-benefit-analysis of TAC was recalculated with these new-implemented results. The cost-benefit-ratio will be more precise and specific and hence, the decision, which mitigation alternative will be carried out. Based on this, the worthiness of the mitigation measures can be determined in more detail and the proper level of emergency assistance can be calculated more adequately. By dint of this study, a better data basis will be created evaluating technical and non-technical mitigation measures, which is useful for government agencies, insurance companies and research.

Rockslide susceptibility and hazard assessment for mitigation works design along vertical rocky cliffs: workflow proposal based on a real case-study conducted in Sacco (Campania), Italy

NASA Astrophysics Data System (ADS)

Pignalosa, Antonio; Di Crescenzo, Giuseppe; Marino, Ermanno; Terracciano, Rosario; Santo, Antonio

2015-04-01

The work here presented concerns a case study in which a complete multidisciplinary workflow has been applied for an extensive assessment of the rockslide susceptibility and hazard in a common scenario such as a vertical and fractured rocky cliffs. The studied area is located in a high-relief zone in Southern Italy (Sacco, Salerno, Campania), characterized by wide vertical rocky cliffs formed by tectonized thick successions of shallow-water limestones. The study concerned the following phases: a) topographic surveying integrating of 3d laser scanning, photogrammetry and GNSS; b) gelogical surveying, characterization of single instabilities and geomecanichal surveying, conducted by geologists rock climbers; c) processing of 3d data and reconstruction of high resolution geometrical models; d) structural and geomechanical analyses; e) data filing in a GIS-based spatial database; f) geo-statistical and spatial analyses and mapping of the whole set of data; g) 3D rockfall analysis; The main goals of the study have been a) to set-up an investigation method to achieve a complete and thorough characterization of the slope stability conditions and b) to provide a detailed base for an accurate definition of the reinforcement and mitigation systems. For this purposes the most up-to-date methods of field surveying, remote sensing, 3d modelling and geospatial data analysis have been integrated in a systematic workflow, accounting of the economic sustainability of the whole project. A novel integrated approach have been applied both fusing deterministic and statistical surveying methods. This approach enabled to deal with the wide extension of the studied area (near to 200.000 m2), without compromising an high accuracy of the results. The deterministic phase, based on a field characterization of single instabilities and their further analyses on 3d models, has been applied for delineating the peculiarity of each single feature. The statistical approach, based on geostructural field mapping and on punctual geomechanical data from scan-line surveying, allowed the rock mass partitioning in homogeneous geomechanical sectors and data interpolation through bounded geostatistical analyses on 3d models. All data, resulting from both approaches, have been referenced and filed in a single spatial database and considered in global geo-statistical analyses for deriving a fully modelled and comprehensive evaluation of the rockslide susceptibility. The described workflow yielded the following innovative results: a) a detailed census of single potential instabilities, through a spatial database recording the geometrical, geological and mechanical features, along with the expected failure modes; b) an high resolution characterization of the whole slope rockslide susceptibility, based on the partitioning of the area according to the stability and mechanical conditions which can be directly related to specific hazard mitigation systems; c) the exact extension of the area exposed to the rockslide hazard, along with the dynamic parameters of expected phenomena; d) an intervention design for hazard mitigation.

Slope instability in a historical and architectural interest site: the Agrigento hill (Sicily-Italy)

NASA Astrophysics Data System (ADS)

Liguori, Vincenzo; Manno, Giorgio

2014-05-01

The impact of landslides are an issue for many urban cities and their cultural heritage, especially where both natural factors and human actions are join. Indeed in these cases, both the geological-geomorphological area predisposition and the continuous human actions increase the possibility occurrence of a landslide. In order to study these landslides and their natural hazard, a multi-disciplinary approach is necessary. Agrigento (37°19'18''N; 13°35'22''E), founded around 580 b.C. along the Sicilian southern coast, is an example of a possible impacts of landslides on cultural heritage. This work discusses the geological, geomorphological and hydrological data results, performed in order to study and the monitoring the landslide on the north side of the Agrigento hill (335 m a.s.l.), on which is localized the antique cathedral (sixteenth century) and the old city. The hill geology is a typical regressive Plio-Pleistocene succession and their lithology are clays (Monte Narbone formation) , calcarenites , sands and silts of the Agrigento formation. The landslide phenomena, current since 1315, involves a calcarenitic pack (Pleistocene), weakly cemented, highly porous, fractured and fissured (E-W). This phenomena from 1924, at different times, have produced various types of instability such as: falls, flows and complex movements. From 7 March 2005 have been reactivated fractures of the calcarenitic pack, already highlighted by studies in 1966. These fractures have triggered slope movements damaging the cathedral and the various historic buildings. In order to reduce the risk and thus safeguard the monuments and the activity in this area, carried out the several studies. Since 2005, the landslide is the subject both geological-geomorphological studies and a continuous monitoring, which have used different techniques of different disciplines: interferometric analysis, interpretation of aerial and satellite imagery, geophysical investigations, stratigraphic survey, etc. The results of this studies carried out the landslide kinematics and the lithology involved, in this way it was possible to suggest targeted intervention. Keywords: rotational landslide, rockfall, hazard, architectural heritage.

Assessment of landslide hazards induced by extreme rainfall event in Jammu and Kashmir Himalaya, northwest India

NASA Astrophysics Data System (ADS)

Kumar, Amit; Asthana, AKL; Priyanka, Rao Singh; Jayangondaperumal, R.; Gupta, Anil K.; Bhakuni, SS

2017-05-01

In the Indian Himalayan region (IHR), landslide-driven hazards have intensified over the past several decades primarily caused by the occurrence of heavy and extreme rainfall. However, little attention has been given to determining the cause of events triggered during pre- and post-Indian Summer Monsoon (ISM) seasons. In the present research, detailed geological, meteorological, and remote sensing investigations have been carried out on an extreme rainfall landslide event that occurred in Sadal village, Udhampur district, Jammu and Kashmir Himalaya, during September 2014. Toward the receding phase of the ISM (i.e., in the month of September 2014), an unusual rainfall event of 488.2 mm rainfall in 24 h took place in Jammu and Kashmir Himalaya in contrast to the normal rainfall occurrence. Geological investigations suggest that a planar weakness in the affected region is caused by bedding planes that consist of an alternate sequence of hard, compact sandstone and weak claystone. During this extreme rainfall event, the Sadal village was completely buried under the rock slides, as failure occurred along the planar weakness that dips toward the valley slope. Rainfall data analysis from the Tropical Rainfall Measuring Mission (TRMM) for the preceding years homogeneous time series (July-September) indicates that the years 2005, 2009, 2011, 2012, and 2014 (i.e., closely spaced and clustering heavy rainfall events) received heavy rainfalls during the withdrawal of the ISM; whereas the heaviest rainfall was received in the years 2003 and 2013 at the onset of the ISM in the study region. This suggests that no characteristic cyclicity exists for extreme rainfall events. However, we observe that either toward the onset of the ISM or its retreat, the extreme rainfall facilitates landslides, rockfall, and slope failures in northwestern Himalaya. The spatiotemporal distribution of landslides caused by extreme rainfall events suggests its confinement toward the windward side of the Himalayan front.

Modelling rock fragmentation of Extremely Energetic Rockfalls

NASA Astrophysics Data System (ADS)

De Blasio, Fabio; Dattola, Giuseppe; Battista Crosta, Giovanni

2017-04-01

Extremely energetic rockfalls (EER) are phenomena for which the combination of a large volume (at least some thousands of m ) and a free fall height of hundreds of metres, results in a large released energy. We fix a threshold value of around 1/50 of kilotons to define such a type of events. Documented examples include several events with dif-ferent size in the Alps (Dru, 2005, 2011, 265,000, 59,200 m3; val Fiscalina - Cima Una, 2007, 40,000 m3; Thurwieser 2004, ca 2 Mm3; Cengalo, 2011, 1.5*105 m3 in 2016, in Switzerland; Civetta, 2013, ca 50,000 m3;), in the Apennines (Gran Sasso, 2006, 30,000 m3), Rocky Mountains (Yosemite, Happy Isles, 38,000 m3), and Himalaya. EERs may become more frequent on steep and sharp mountain peaks as a consequence of permafrost thawing at higher altitudes. In contrast to low energy rockfalls where block disintegration is limited, in EERs the impact after free fall causes an immediate and efficient release of energy much like an explosion. The severe disintegration of the rock and the corresponding air blast are capable of snapping trees many hundreds of metres ahead of the fall area. Pulverized rock at high speed can abrade tree logs, and the resulting suspension flow may travel much further the impact zone, blanketing vast surrounding areas. Using both published accounts of some of these events and collecting direct data for some of them, we present some basic models to describe the involved processes based on analogies with explosions and explosive fragmentation. Of the initial energy, one part is used up in the rock disintegration, and the rest is shared between the shock wave and air blast. The fragmentation energy is calculated based on the fitting of the dust size spectrum by using different proba-bilistic distribution laws and the definition of a surface energy and by considering the involved strain rate. We find the fragmentation is around one third of the initial boulder energy. Finally, we evaluate the velocity of the corresponding cloud generated by the powder suspension and compare with the information available in literature. keywords: EER, Rockfalls, Disintegration number, Omographic distribution

Automatic Processing and Interpretation of Long Records of Endogenous Micro-Seismicity: the Case of the Super-Sauze Soft-Rock Landslide.

NASA Astrophysics Data System (ADS)

Provost, F.; Malet, J. P.; Hibert, C.; Doubre, C.

2017-12-01

The Super-Sauze landslide is a clay-rich landslide located the Southern French Alps. The landslide exhibits a complex pattern of deformation: a large number of rockfalls are observed in the 100 m height main scarp while the deformation of the upper part of the accumulated material is mainly affected by material shearing along stable in-situ crests. Several fissures are locally observed. The shallowest layer of the accumulated material tends to behave in a brittle manner but may undergo fluidization and/or rapid acceleration. Previous studies have demonstrated the presence of a rich endogenous micro-seismicity associated to the deformation of the landslide. However, the lack of long-term seismic records and suitable processing chains prevented a full interpretation of the links between the external forcings, the deformation and the recorded seismic signals. Since 2013, two permanent seismic arrays are installed in the upper part of the landslide. We here present the methodology adopted to process this dataset. The processing chain consists of a set of automated methods for automatic and robust detection, classification and location of the recorded seismicity. Thousands of events are detected and further automatically classified. The classification method is based on the description of the signal through attributes (e.g. waveform, spectral content properties). These attributes are used as inputs to classify the signal using a Random Forest machine-learning algorithm in four classes: endogenous micro-quakes, rockfalls, regional earthquakes and natural/anthropogenic noises. The endogenous landslide sources (i.e. micro-quake and rockfall) are further located. The location method is adapted to the type of event. The micro-quakes are located with a 3D velocity model derived from a seismic tomography campaign and an optimization of the first arrival picking with the inter-trace correlation of the P-wave arrivals. The rockfalls are located by optimizing the inter-trace correlation of the whole signal. We analyze the temporal relationships of the endogenous seismic events with rainfall and landslide displacements. Sub-families of landslide micro-quakes are also identified and an interpretation of their source mechanism is proposed from their signal properties and spatial location.

Development of Waterfall Cliff Face: An Implication from Multitemporal High-definition Topographic Data

NASA Astrophysics Data System (ADS)

Hayakawa, Y. S.; Obanawa, H.

2015-12-01

Bedrock knickpoints (waterfalls) often act as erosional front in bedrock rivers, whose geomorphological processes are various. In waterfalls with vertical cliffs, both fluvial erosion and mass movement are feasible to form the landscape. Although morphological changes of such steep cliffs are sometimes visually observed, quantitative and precise measurements of their spatiotemporal distribution have been limited due to poor accessibility to such cliffs. For the clarification of geomorphological processes in such cliffs, multi-temporal mapping of the cliff face at a high resolution can be advantaged by short-range remote sensing approaches. Here we carry out multi-temporal terrestrial laser scanning (TLS), as well as structure-from-motion multi-view stereo (SfM-MVS) photogrammetry based on unmanned aerial system (UAS) for accurate topographic mapping of cliffs around a waterfall. The study site is Kegon Falls in central Japan, having a vertical drop of surface water from top of its overhanging cliff and groundwater outflows from its lower portions. The bedrock consists of alternate layers of jointed andesite lava and conglomerates. The latest major rockfall in 1986 caused approximately 8-m recession of the waterfall lip. Three-dimensional changes of the rock surface were detected by multi-temporal measurements by TLS over years, showing the portions of small rockfalls and surface lowering in the bedrock. Erosion was frequently observed in relatively weak the conglomerates layer, whereas small rockfalls were often found in the andesite layers. Wider areas of the waterfall and cliff were also measured by UAS-based SfM-MVS photogrammetry, improving the mapping quality of the cliff morphology. Point clouds are also projected on a vertical plane to generate a digital elevation model (DEM), and cross-sectional profiles extracted from the DEM indicate the presence of a distinct, 5-10-m deep depression in the cliff face. This appears to have been formed by freeze-thaw and/or wet-dry weathering following the recession in 1986. The long-term development of the waterfall cliff face is then discussed comprising various processes of rockfalls, water pressure and weathering.

Identification of stable areas in unreferenced laser scans for automated geomorphometric monitoring

NASA Astrophysics Data System (ADS)

Wujanz, Daniel; Avian, Michael; Krueger, Daniel; Neitzel, Frank

2018-04-01

Current research questions in the field of geomorphology focus on the impact of climate change on several processes subsequently causing natural hazards. Geodetic deformation measurements are a suitable tool to document such geomorphic mechanisms, e.g. by capturing a region of interest with terrestrial laser scanners which results in a so-called 3-D point cloud. The main problem in deformation monitoring is the transformation of 3-D point clouds captured at different points in time (epochs) into a stable reference coordinate system. In this contribution, a surface-based registration methodology is applied, termed the iterative closest proximity algorithm (ICProx), that solely uses point cloud data as input, similar to the iterative closest point algorithm (ICP). The aim of this study is to automatically classify deformations that occurred at a rock glacier and an ice glacier, as well as in a rockfall area. For every case study, two epochs were processed, while the datasets notably differ in terms of geometric characteristics, distribution and magnitude of deformation. In summary, the ICProx algorithm's classification accuracy is 70 % on average in comparison to reference data.

Stability of Molasse: TLS for structural analysis in the valley of Gotteron-Fribourg, Switzerland

NASA Astrophysics Data System (ADS)

Ben Hammouda, Mariam; Jaboyedoff, Michel; Derron, Marc Henri; Bouaziz, Samir; Mazotti, Benoit

2016-04-01

The marine molasses of Fribourg (Switzerland) is an area where the cliff collapses and rockfalls are quite frequent and difficult to predict due to this particular lithology, a poorly consolidated greywacke. Because of some recent rockfall events, the situation became critical especially in the valley of Gotteron where a big block has slightly moved down and might destroy a house in case of rupture. The cliff made of jointed sandstone and thin layers of clay and siltstone presents many fractures, joints and massive cross bedding surfaces which increases the possibility of slab failure. This paper presents a detailed structural analysis of the cliff and the identification of the potential failure mechanisms. The methodology is about combining field observation and terrestrial LiDAR scanning point cloud in order to assess the stability of potential slope instabilities of molasses. Three LiDAR scans were done i) to extract discontinuity families depending to the dip and the dip direction of joints and ii) to run kinematic tests in order to identify responsible sets for each potential failure mechanisms. Raw point clouds were processed using IMAlign module of Polyworks and CloudCompare software. The structural analysis based on COLTOP 3D (Jaboyedoff et al. 2007) allowed the identification of four discontinuity sets that were not measured in the field. Two different failure mechanisms have been identified as critical: i) planar sliding which is the main responsible mechanism of the present fallen block and ii) wedge sliding. The planar sliding is defined by the discontinuity sets J1 and J5 with a direction parallel to the slope and with a steep dip angle. The wedges, defined by couples of discontinuity sets, contribute to increase cracks' opening and to the detachment of slabs. The use of TLS combined with field survey provides us a first interpretation of instabilities and a very promising structural analysis.

Landslide susceptibility mapping in three selected target zones in Afghanistan

NASA Astrophysics Data System (ADS)

Schwanghart, Wolfgang; Seegers, Joe; Zeilinger, Gerold

2015-04-01

In May 2014, a large and mobile landslide destroyed the village Ab Barek, a village in Badakshan Province, Afghanistan. The landslide caused several hundred fatalities and once again demonstrated the vulnerability of Afghanistan's population to extreme natural events following more than 30 years of civil war and violent conflict. Increasing the capacity of Afghanistan's population by strengthening the disaster preparedness and management of responsible government authorities and institutions is thus a major component of international cooperation and development strategies. Afghanistan is characterized by high relief and widely varying rock types that largely determine the spatial distribution as well as emplacement modes of mass movements. The major aim of our study is to characterize this variability by conducting a landslide susceptibility analysis in three selected target zones: Greater Kabul Area, Badakhshan Province and Takhar Province. We expand on an existing landslide database by mapping landforms diagnostic for landslides (e.g. head scarps, normal faults and tension cracks), and historical landslide scars and landslide deposits by visual interpretation of high-resolution satellite imagery. We conduct magnitude frequency analysis within subregional physiogeographic classes based on geological maps, climatological and topographic data to identify regional parameters influencing landslide magnitude and frequency. In addition, we prepare a landslide susceptibility map for each area using the Weight-of-Evidence model. Preliminary results show that the three selected target zones vastly differ in modes of landsliding. Low magnitude but frequent rockfall events are a major hazard in the Greater Kabul Area threatening buildings and infrastructure encroaching steep terrain in the city's outskirts. Mass movements in loess covered areas of Badakshan are characterized by medium to large magnitudes. This spatial variability of characteristic landslide magnitudes and modes of emplacement necessitates different strategies to assess, mitigate, and prepare for landslides in the three different target zones.

Use of Bedrock and Geomorphic Mapping Compilations in Assessing Geologic Hazards at Recreation Sites on National Forests in NW California

NASA Astrophysics Data System (ADS)

de La Fuente, J. A.; Bell, A.; Elder, D.; Mowery, R.; Mikulovsky, R.; Klingel, H.; Stevens, M.

2010-12-01

Geologic hazards on US Forest Service lands have a long history of producing catastrophic events. In 1890 (prior to the establishment of the Forest Service), the China Mine landslide buried a miner’s camp along the Trinity River in NW California, killing a number of miners. An earthquake in southwestern Montana triggered a massive landslide which killed 28 people in a US Forest Service campground in 1959. In 1980, Mount St. Helens erupted in Oregon, killing 57 people. Debris flows from a winter storm in 2003 on the burned hillslopes of the San Bernardino National Forest in California killed 14 people at the St. Sophia youth Camp. A rockfall in the summer of 2009 in Lassen National Park killed a 9 year old boy. The most recent catastrophe occurred on June 11, 2010 when 20 people died in a flash flood at the Albert Pike Campground on the Ouachita National Forest. These and other disasters point out the need for geologic hazard mapping and assessments on the National Forests. The US Forest Service (USFS) is currently assessing geologic hazards in the Northern Province of USFS Region 5 (Pacific Southwest Region), which includes the Klamath, Mendocino, Shasta-Trinity, and Six Rivers National Forests. The most common geologic hazards (relatively short return intervals) in this area include landslides, rock falls, debris flows, flooding, temporary dam failures (landslide or woody debris), naturally occurring hazardous materials, (asbestos radon, etc), and rarely, karst subsidence. Seismic and volcanic hazards are also important at longer return intervals. This assessment will be conducted in three phases, and is patterned after a process developed by Region 8 of the US Forest Service. The first phase is a reconnaissance level assessment based on existing information such as spatial databases, aerial photos, Digital Elevation Models, State of California Alquist-Priolo Earthquake Fault Zone maps, previous investigations and anecdotal accounts of past events. The bedrock coverage is a compilation of the best available mapping for all National Forests in California. The geomorphic coverage includes features such as active and dormant landslides, alluvial fans, headwall basins, glacial features, and valley inner gorge. Criteria will be developed which utilize elements of this data to evaluate geologic hazards in the vicinity of developed recreation sites. The second phase will be conducted later and involves site specific analyses focusing on areas identified as higher hazard in the first phase, along with verification and updating of phase 1 findings. The third phase will complete any site level geologic or hydrologic investigations, and wrap up the hazard assessment process. A summary report with hazard maps and recommendations will be prepared at the end of each phase. The overriding goal of this project is to provide sound geologic information to managers so they can use a science-based approach in recognizing and managing geologic hazards at recreation sites.

Simulation of rockfalls triggered by earthquakes

USGS Publications Warehouse

Kobayashi, Y.; Harp, E.L.; Kagawa, T.

1990-01-01

A computer program to simulate the downslope movement of boulders in rolling or bouncing modes has been developed and applied to actual rockfalls triggered by the Mammoth Lakes, California, earthquake sequence in 1980 and the Central Idaho earthquake in 1983. In order to reproduce a movement mode where bouncing predominated, we introduced an artificial unevenness to the slope surface by adding a small random number to the interpolated value of the mid-points between the adjacent surveyed points. Three hundred simulations were computed for each site by changing the random number series, which determined distances and bouncing intervals. The movement of the boulders was, in general, rather erratic depending on the random numbers employed, and the results could not be seen as deterministic but stochastic. The closest agreement between calculated and actual movements was obtained at the site with the most detailed and accurate topographic measurements. ?? 1990 Springer-Verlag.

Historical and Paleo Events as an input for Seismic And Associated Natural Hazard Assessment of Javakheti highland (South Georgia)

NASA Astrophysics Data System (ADS)

Elashvili, M.; Javakhishvili, Z.; Godoladze, T.; Karakhanyan, A.; Sukhishvili, L.; Nikolaeva, E.; Sokhadze, G.; Avanesyan, M.

2012-12-01

Current study concerns Javakheti area in the Lesser Caucasus. This area comprises a volcanic plateau with more than 20 volcanoes, several of them dated as having erupted during the Holocene. In the region the upper part of Lava complex is represented by Middle-Upper Quaternary formations. The region is an area of young deformations in the Alpine belt. Formation of relief began at the neotectonic stage (Sarmatian) and continues at present. Javakheti is one of the most seismically active regions in the Caucasus, earthquakes of 1899 and 1986 with magnitudes up to 6.0, causing severe damage and hundreds of casualties, occurred there. Historical data on earthquakes in 1088 and 1899 locate them in the same region, highlighting the importance on learning about the location and characteristics of their seismic sources. Javakheti highland seems to be actively populated at least from the Bronze Age period, forming a local culture to be strongly affected by Natural catastrophes and significant changes in Landscapes and climate. Study of potential seismic and associated natural hazards, such as landslide and rockfalls, possible volcanic activity in the region, including paleo and historical evidences, were addressed by number of International Projects (ISTC A-1418, NATO SFP # 983284 ) and multidisciplinary studies carried out by the Institute of Earth Sciences. Data gathered after the Installation of local GPS and Seismic networks have provided new look on seismicity pattern of the region and major seismic sources, while field studies (Geophysical survey, Paleo trenching, Archaeological studies, etc.) have provided new information on the dramatic Natural disasters which occurred in the region and probably played a vital role in its history. Remote sensing techniques became widely used in geological investigations during the decades. Interferometric synthetic aperture radar (InSAR), aerial and optical data analysis have contributed to the development of this work.. Case studies of historical earthquakes of 1899 and 1089, as well as Archaeo-Seismological site along the Javakheti seismic fault will be presented. History on Natural Disasters in the region can be complemented by Bertakana Paleo-Landslide, to be discussed separately as one of the mega events in the Area. The mentioned events are considered as an important input for Seismic Hazard Assessment of Javakheti Region.

Three-dimensional analysis of the anatomical growth response of European conifers to mechanical disturbance.

PubMed

Schneuwly, Dominique M; Stoffel, Markus; Dorren, Luuk K A; Berger, Frédéric

2009-10-01

Studies on tree reaction after wounding were so far based on artificial wounding or chemical treatment. For the first time, type, spread and intensity of anatomical responses were analyzed and quantified in naturally disturbed Larix decidua Mill., Picea abies (L.) Karst. and Abies alba Mill. trees. The consequences of rockfall impacts on increment growth were assessed at the height of the wounds, as well as above and below the injuries. A total of 16 trees were selected on rockfall slopes, and growth responses following 54 wounding events were analyzed on 820 cross-sections. Anatomical analysis focused on the occurrence of tangential rows of traumatic resin ducts (TRD) and on the formation of reaction wood. Following mechanical disturbance, TRD production was observed in 100% of L. decidua and P. abies wounds. The radial extension of TRD was largest at wound height, and they occurred more commonly above, rather than below, the wounds. For all species, an intra-annual radial shift of TRD was observed with increasing axial distance from wounds. Reaction wood was formed in 87.5% of A. alba following wounding, but such cases occurred only in 7.7% of L. decidua. The results demonstrate that anatomical growth responses following natural mechanical disturbance differ significantly from the reactions induced by artificial stimuli or by decapitation. While the types of reactions remain comparable between the species, their intensity, spread and persistence disagree considerably. We also illustrate that the external appearance of wounds does not reflect an internal response intensity. This study reveals that disturbance induced under natural conditions triggers more intense and more widespread anatomical responses than that induced under artificial stimuli, and that experimental laboratory tests considerably underestimate tree response.

An analysis of three new infrasound arrays around Kīlauea Volcano

USGS Publications Warehouse

Thelen, Weston A.; Cooper, Jennifer

2015-01-01

A network of three new infrasound station arrays was installed around Kīlauea Volcano between July 2012 and September 2012, and a preliminary analysis of open-vent monitoring has been completed by Hawaiian Volcano Observatory (HVO). Infrasound is an emerging monitoring method in volcanology that detects perturbations in atmospheric pressure at frequencies below 20 Hz, which can result from volcanic events that are not always observed optically or thermally. Each array has the capability to detect various infrasound events as small as 0.05 Pa as measured at the array site. The infrasound monitoring network capabilities are demonstrated through case studies of rockfalls, pit collapses, and rise-fall cycles at Halema'uma'u Crater and Pu'u 'Ōʻō.

Guide for Preparation of Waterways Experiment Station Technical Information Reports

DTIC Science & Technology

1993-01-01

Printing .......................... F1 Appendix G: Index .................................... GI SF 298 List of Figures Figure 1. Distribution statements...dimensional R rainwater riverside Ramm river wall Range 5 roadbed rattail rockbound (adj) real-time rockfall (n) reentrants rock-fill (adj

Hazard maps of Colima volcano, Mexico

NASA Astrophysics Data System (ADS)

Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Escudero Ayala, C. R.

2011-12-01

Colima volcano, also known as Volcan de Fuego (19° 30.696 N, 103° 37.026 W), is located on the border between the states of Jalisco and Colima and is the most active volcano in Mexico. Began its current eruptive process in February 1991, in February 10, 1999 the biggest explosion since 1913 occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching attitudes between 4,500 and 9,000 m.a.s.l., further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events ash emissions were generated in all directions reaching distances up to 100 km, slightly affected nearby villages as Tuxpan, Tonila, Zapotlán, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During the 2005 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano due to low population density and low socio-economic activities at the time. Shows the updating of the volcanic hazard maps published in 2001, where we identify whit SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano, the population inhabiting the area is approximately 517,000 people, and growing at an annual rate of 4.77%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by the construction of highways, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. The update the hazard maps are: a) Exclusion areas and moderate hazard for explosive events (rockfall) and pyroclastic flows, b) Hazard map of lahars and debris flow, and c) Hazard map of ash-fall. The cartographic and database information obtained will be the basis for updating the Operational Plan of the Colima Volcano by the State Civil & Fire Protection Unit of Jalisco, Mexico, and the urban development plans of surrounding municipalities, in order to reduce their vulnerability to the hazards of the volcanic activity.

Quantification of rock slope terrain properties

NASA Astrophysics Data System (ADS)

Volkwein, Axel; Gerber, Werner

2017-04-01

Rockfall trajectory simulation codes need information on the terrain properties to formulate appropriate rebound models. Usually, the manuals of rockfall simulation codes give sketches or photographs of terrain samples [1,2]. Based on these the user can select suitable terrains for the simulation area. We now would like to start a discussion whether it is possible to numerically quantify the terrain properties which would make the ground assignment more objective. Different ground properties play a role for the interaction between a falling rock and the ground: • Elastic deformation • plastic deformation • Energy absorption • friction • hardness • roughness • surface vs. underground • etc. The question is now whether it is possible to quantify above parameters and to finally provide tables that contain appropriate simulation parameters. In a first attempt we suggest different methods or parameters that might be evaluated in situ: • Small scale drop tests • Light weight deflectometer (LWD) • Particle sizes • Sliding angle • Particle distribution • Soil cover • Water content Of course, above measurements will never perfectly fit to different mountain slopes. However, if a number of measurements has been made their spreading will give an idea on the natural variability of the ground properties. As an example, the following table gives an idea on how the ME and Evd values vary for different soils. Table 1: LWD measurements on different soil types [3] Ground type Soil layer Soil humidityEvd (median)σ (median)Evd (average) Humus-carb. < 10cm dry 17.4 6.8 15.6 Regosol 10 - 30cm dry 8.6 3.9 9.4 Brownish 30 - 50cm dry 12.1 3.2 11.7 Calcaric 30 - 50cm dry 7.5 3.3 7.0 Acid brownish70 - 100cmdry 7.8 2.1 7.7 Fahlgley 10 - 30cm dry 9.2 4.0 7.7 References [1] Bartelt P et al (2016) RAMMS::rockfall user manual v1.6. SLF, Davos. [2] Dorren L.K.A., 2015. Rockyfor3D (v5.2) revealed - Transparent description of the complete 3D rockfall model. ecorisQ paper (www.ecorisq.org): 32 p. [3] Hoffmann P. (2015) Härte von Böden. Bsc thesis, ZHAW Waedenswil.

What's the Point of a Raster ? Advantages of 3D Point Cloud Processing over Raster Based Methods for Accurate Geomorphic Analysis of High Resolution Topography.

NASA Astrophysics Data System (ADS)

Lague, D.

2014-12-01

High Resolution Topographic (HRT) datasets are predominantly stored and analyzed as 2D raster grids of elevations (i.e., Digital Elevation Models). Raster grid processing is common in GIS software and benefits from a large library of fast algorithms dedicated to geometrical analysis, drainage network computation and topographic change measurement. Yet, all instruments or methods currently generating HRT datasets (e.g., ALS, TLS, SFM, stereo satellite imagery) output natively 3D unstructured point clouds that are (i) non-regularly sampled, (ii) incomplete (e.g., submerged parts of river channels are rarely measured), and (iii) include 3D elements (e.g., vegetation, vertical features such as river banks or cliffs) that cannot be accurately described in a DEM. Interpolating the raw point cloud onto a 2D grid generally results in a loss of position accuracy, spatial resolution and in more or less controlled interpolation. Here I demonstrate how studying earth surface topography and processes directly on native 3D point cloud datasets offers several advantages over raster based methods: point cloud methods preserve the accuracy of the original data, can better handle the evaluation of uncertainty associated to topographic change measurements and are more suitable to study vegetation characteristics and steep features of the landscape. In this presentation, I will illustrate and compare Point Cloud based and Raster based workflows with various examples involving ALS, TLS and SFM for the analysis of bank erosion processes in bedrock and alluvial rivers, rockfall statistics (including rockfall volume estimate directly from point clouds) and the interaction of vegetation/hydraulics and sedimentation in salt marshes. These workflows use 2 recently published algorithms for point cloud classification (CANUPO) and point cloud comparison (M3C2) now implemented in the open source software CloudCompare.

Three consecutive years of road closures due to natural hazards in the Weisstannen valley, Canton of St-Gallen, Switzerland

NASA Astrophysics Data System (ADS)

Voumard, Jérémie; Derron, Marc-Henri; Jaboyedoff, Michel

2017-04-01

The Weisstannen small alpine valley located in the Canton of St-Gallen, Switzerland, has been affected by four different natural hazards these three last years. Its unique access road has been cut off height times during this period: by an earth slide in January 2014, by three debris flows in August 2015, by one debris flow in September 2016, by two floods in June and July 2016 and by a rockfall in May 2016. Although the valley is sparsely populated, 240 people have been affected by the height road closures due to these events. In addition to road damages, several buildings, of which a restaurant (with EUR 190'000 damages) and an animal shelter, have been damaged. In Switzerland, some roads of 15 communes have been affected by natural hazards at least three times in five years (2012-2016). Then the Weisstannen valley is not an exception at the communal level. However, it is the only valley whose unique access was cut off three consecutive years. With these repeated events, the population of the valley does not understand how possible it is to end up in such a situation in a country accustomed to natural hazards. In the media and social media, people do not hide their irritation regarding to this situation: "Have the authorities failed to take into account natural dangers despite of the 4.7 million Euro allocated for a flood protection project? Who is responsible of those repeated damages? Why the situation did not improve after the events of the first year and then the second year? ". In the present work, we try to shed the light on this peculiar case analysing the causes of road closures, studying meteorological, topographical, hydrological and geological data for each events. The effectiveness of the new protective measures built between the events are assessed, as the future planned protectives measures. Road closures consequences on the population and the economy are also estimated. Finally, we estimate the probability of having new road closures in the Weisstannen valley during the next years. Data about the events were documented during field visit, or obtained from the media and official reports.

RUPOK - a web-map application for assessment of impacts of natural hazards on the transportation infrastructure

NASA Astrophysics Data System (ADS)

Bíl, Michal; Kubeček, Jan; Andrášik, Richard; Bílová, Martina; Sedoník, Jiří

2016-04-01

We present a web-map application (www.rupok.cz) designed for visualization of losses caused by natural hazards to the transportation infrastructure. This application is an output of a project in which we analyzed direct, indirect and network-wide impacts of major natural disasters which hit the CZ as of 1997. When natural disasters hit a road network the results are often a number of closed road sections. Certain roads may be, however, destroyed, whereas the majority of them are usually only closed and can be reopened after a short period of time. While the computation of direct losses (the cost of remedial works) is fairly simple, the evaluation of indirect and network-wide costs is much more difficult. We created a database of interrupted road and highway sections due to natural processes which includes data since 1997 and which is automatically updated. 6,828 records concerning interrupted communications located on 2,879 road sections are included in the database for the 1997 - 2014 time period. Flooding caused 37 % of the traffic interruptions, followed by fallen trees (22 %), landsliding (5 %) and rockfalls (2 %). The RUPOK webpage contains information on the probabilities of transportation section interruptions due to natural processes as well as the impacts of possible interruptions. The direct losses are depicted as monetary values per road section unit. The values are calculated on the basis of official tables including the prices for construction works. The indirect losses were calculated on the basis of the best alternative route expenses and as traffic intensities affected by a road section interruption.

The Gravitational Process Path (GPP) model (v1.0) - a GIS-based simulation framework for gravitational processes

NASA Astrophysics Data System (ADS)

Wichmann, Volker

2017-09-01

The Gravitational Process Path (GPP) model can be used to simulate the process path and run-out area of gravitational processes based on a digital terrain model (DTM). The conceptual model combines several components (process path, run-out length, sink filling and material deposition) to simulate the movement of a mass point from an initiation site to the deposition area. For each component several modeling approaches are provided, which makes the tool configurable for different processes such as rockfall, debris flows or snow avalanches. The tool can be applied to regional-scale studies such as natural hazard susceptibility mapping but also contains components for scenario-based modeling of single events. Both the modeling approaches and precursor implementations of the tool have proven their applicability in numerous studies, also including geomorphological research questions such as the delineation of sediment cascades or the study of process connectivity. This is the first open-source implementation, completely re-written, extended and improved in many ways. The tool has been committed to the main repository of the System for Automated Geoscientific Analyses (SAGA) and thus will be available with every SAGA release.

Modified rockfall catch fence Mayflower Creek - Detroit Dam : final report.

DOT National Transportation Integrated Search

1988-08-08

The experimental features project is located on the North Santiam Highway (#162) between Mayflower Creek and Detroit Dam, approximately 40 miles east of Salem. Here access is limited and the slope is nonuniform. To deal with the constant problem of f...

Modified rockfall catch fence Mayflower Creek - Detroit Dam : interim Report.

DOT National Transportation Integrated Search

1986-07-01

This experimental features project is located on the North Santiam Highway (#162) between Mayflower Creek and Detroit Dam, approximately 40 miles east of Salem. Here access is limited and the slope is non-uniform. To deal with the problem of falling ...

Rockfall hazard assessment of nearly vertical rhyolite tuff cliff faces by using terrestrial laser scanner, UAV and FEM analyses

NASA Astrophysics Data System (ADS)

Török, Ákos; Barsi, Árpád; Görög, Péter; Lovas, Tamás; Bögöly, Gyula; Czinder, Balázs; Vásárhelyi, Balázs; Molnár, Bence; József Somogyi, Árpád

2017-04-01

Nearly vertical rhyolite tuff cliff faces are located in NE-Hungary representing rock fall hazard in the touristic region of Sirok. Larger blocks of the cliff have fallen in recent years menacing tourists and human lives. The rhyolite tuff, that forms the Castle Hill was formed during Miocene volcanism and comprises of brecciated lapilli tuffs and tuffs with intercalating ignimbritic horizons. The paper focuses on the 3D mapping of cliff faces and modeling of rock fall hazard. The topography and 3D model of the cliff was obtained by using GNSS supported terrestrial laser scanner and UAV. With imaging techniques of UAV a Triangulated Irregular Network (TIN) model was developed that contained triangles with 5-10 cm side lengths. GNSS supported terrestrial laser scanning allowed the observation with a resolution 1-5 cm of point spacing. The point clouds were further processed and with the combination of laser scanner and UAV data a 3D model of the studied cliff faces were obtained. Geological parameters for rock fall analyses included both field observations and laboratory tests. The lithotypes were identified on the field and were sampled for rock mechanical laboratory analyses. Joint- and fault system was mapped and visualized by using Rocscience Dip. EN test methods were used to obtain the density properties of various lithotypes of rhyolite tuff. Other standardized EN tests included ultrasonic pulse velocity, water absorption, indirect tensile strength (Brasilian), uniaxial compressive strength and modulus of elasticity of air dry and of water saturated samples. GSI values were denoted based on filed observations and rock mass properties. The stability analyses of cliff faces were made by using 2D FEM software (Phase 2). Cross sections were evaluated and global factor of safety was also calculated. The modeled displacements were in the order of few centimeters; however several locations were pinpointed where wedge failure and planar slip surfaces were identified as major cliff stability hazards. These were associated with the major joint systems dissecting cliff faces. This research have proved that the combined methods of field surveying, imaging techniques, data processing and FEM modelling with rock mechanical laboratory analyses allowed the identification of major rock fall hazards even at areas which are difficult to access.

Five years database of landslides and floods affecting Swiss transportation networks

NASA Astrophysics Data System (ADS)

Voumard, Jérémie; Derron, Marc-Henri; Jaboyedoff, Michel

2017-04-01

Switzerland is a country threatened by a lot of natural hazards. Many events occur in built environment, affecting infrastructures, buildings or transportation networks and producing occasionally expensive damages. This is the reason why large landslides are generally well studied and monitored in Switzerland to reduce the financial and human risks. However, we have noticed a lack of data on small events which have impacted roads and railways these last years. This is why we have collect all the reported natural hazard events which have affected the Swiss transportation networks since 2012 in a database. More than 800 roads and railways closures have been recorded in five years from 2012 to 2016. These event are classified into six classes: earth flow, debris flow, rockfall, flood, avalanche and others. Data come from Swiss online press articles sorted by Google Alerts. The search is based on more than thirty keywords, in three languages (Italian, French, German). After verifying that the article relates indeed an event which has affected a road or a railways track, it is studied in details. We get finally information on about sixty attributes by event about event date, event type, event localisation, meteorological conditions as well as impacts and damages on the track and human damages. From this database, many trends over the five years of data collection can be outlined: in particular, the spatial and temporal distributions of the events, as well as their consequences in term of traffic (closure duration, deviation, etc.). Even if the database is imperfect (by the way it was built and because of the short time period considered), it highlights the not negligible impact of small natural hazard events on roads and railways in Switzerland at a national level. This database helps to better understand and quantify this events, to better integrate them in risk assessment.

Automated terrestrial laser scanning with near-real-time change detection - monitoring of the Séchilienne landslide

NASA Astrophysics Data System (ADS)

Kromer, Ryan A.; Abellán, Antonio; Hutchinson, D. Jean; Lato, Matt; Chanut, Marie-Aurelie; Dubois, Laurent; Jaboyedoff, Michel

2017-05-01

We present an automated terrestrial laser scanning (ATLS) system with automatic near-real-time change detection processing. The ATLS system was tested on the Séchilienne landslide in France for a 6-week period with data collected at 30 min intervals. The purpose of developing the system was to fill the gap of high-temporal-resolution TLS monitoring studies of earth surface processes and to offer a cost-effective, light, portable alternative to ground-based interferometric synthetic aperture radar (GB-InSAR) deformation monitoring. During the study, we detected the flux of talus, displacement of the landslide and pre-failure deformation of discrete rockfall events. Additionally, we found the ATLS system to be an effective tool in monitoring landslide and rockfall processes despite missing points due to poor atmospheric conditions or rainfall. Furthermore, such a system has the potential to help us better understand a wide variety of slope processes at high levels of temporal detail.

Recent advances in analysis and prediction of Rock Falls, Rock Slides, and Rock Avalanches using 3D point clouds

NASA Astrophysics Data System (ADS)

Abellan, A.; Carrea, D.; Jaboyedoff, M.; Riquelme, A.; Tomas, R.; Royan, M. J.; Vilaplana, J. M.; Gauvin, N.

2014-12-01

The acquisition of dense terrain information using well-established 3D techniques (e.g. LiDAR, photogrammetry) and the use of new mobile platforms (e.g. Unmanned Aerial Vehicles) together with the increasingly efficient post-processing workflows for image treatment (e.g. Structure From Motion) are opening up new possibilities for analysing, modeling and predicting rock slope failures. Examples of applications at different scales ranging from the monitoring of small changes at unprecedented level of detail (e.g. sub millimeter-scale deformation under lab-scale conditions) to the detection of slope deformation at regional scale. In this communication we will show the main accomplishments of the Swiss National Foundation project "Characterizing and analysing 3D temporal slope evolution" carried out at Risk Analysis group (Univ. of Lausanne) in close collaboration with the RISKNAT and INTERES groups (Univ. of Barcelona and Univ. of Alicante, respectively). We have recently developed a series of innovative approaches for rock slope analysis using 3D point clouds, some examples include: the development of semi-automatic methodologies for the identification and extraction of rock-slope features such as discontinuities, type of material, rockfalls occurrence and deformation. Moreover, we have been improving our knowledge in progressive rupture characterization thanks to several algorithms, some examples include the computing of 3D deformation, the use of filtering techniques on permanently based TLS, the use of rock slope failure analogies at different scales (laboratory simulations, monitoring at glacier's front, etc.), the modelling of the influence of external forces such as precipitation on the acceleration of the deformation rate, etc. We have also been interested on the analysis of rock slope deformation prior to the occurrence of fragmental rockfalls and the interaction of this deformation with the spatial location of future events. In spite of these recent advances, a great challenge still remains in the development of new algorithms for more accurate techniques for 3D point cloud treatment (e.g. filtering, segmentation, etc.) aiming to improve rock slope characterization and monitoring, a series of exciting research findings are expected in the forthcoming years.

Report of Accomplishments Under the Airport Improvement Program.

DTIC Science & Technology

1986-01-01

CONTINUED) STERLING ROCKFALLS 04 $540,800 OVERLAY RUNWAY, TAXIWAY AND APRON; WHITESIDE CO ARPT-JOS H BITTORF FLD REHABILITATE TAXIWAY LIGHTING; INSTALL...PLACED UNDER GRANT AGREEMENT - FISCAL YEAR 1986 LOCATION AND PROJECT FLDERAL NAME OF AIRPORT NUMBER FUNDS DESCRIPTION OF WORK WEST v !R GI NIA

Numerical and analytical investigation towards performance enhancement of a newly developed rockfall protective cable-net structure

NASA Astrophysics Data System (ADS)

Dhakal, S.; Bhandary, N. P.; Yatabe, R.; Kinoshita, N.

2012-04-01

In a previous companion paper, we presented a three-tier modelling of a particular type of rockfall protective cable-net structure (barrier), developed newly in Japan. Therein, we developed a three-dimensional, Finite Element based, nonlinear numerical model having been calibrated/back-calculated and verified with the element- and structure-level physical tests. Moreover, using a very simple, lumped-mass, single-degree-of-freedom, equivalently linear analytical model, a global-displacement-predictive correlation was devised by modifying the basic equation - obtained by combining the principles of conservation of linear momentum and energy - based on the back-analysis of the tests on the numerical model. In this paper, we use the developed models to explore the performance enhancement potential of the structure in terms of (a) the control of global displacement - possibly the major performance criterion for the proposed structure owing to a narrow space available in the targeted site, and (b) the increase in energy dissipation by the existing U-bolt-type Friction-brake Devices - which are identified to have performed weakly when integrated into the structure. A set of parametric investigations have revealed correlations to achieve the first objective in terms of the structure's mass, particularly by manipulating the wire-net's characteristics, and has additionally disclosed the effects of the impacting-block's parameters. Towards achieving the second objective, another set of parametric investigations have led to a proposal of a few innovative improvements in the constitutive behaviour (model) of the studied brake device (dissipator), in addition to an important recommendation of careful handling of the device based on the identified potential flaw.

Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

USGS Publications Warehouse

Carrara, Paul E.

2012-01-01

Mesa Verde National Park in southwestern Colorado was established in 1906 to preserve and protect the artifacts and dwelling sites, including the famous cliff dwellings, of the Ancestral Puebloan people who lived in the area from about A.D. 550 to A.D. 1300. In 1978, the United Nations designated the park as a World Heritage Site. The geology of the park played a key role in the lives of these ancient people. For example, the numerous (approximately 600) cliff dwellings are closely associated with the Cliff House Sandstone of Late Cretaceous age, which weathers to form deep alcoves. In addition, the ancient people farmed the thick, red loess (wind-blown dust) deposits on the mesa tops, which because of its particle size distribution has good moisture retention properties. The soil in this loess cover and the seasonal rains allowed these people to grow their crops (corn, beans, and squash) on the broad mesa tops. Today, geology is still an important concern in the Mesa Verde area because the landscape is susceptible to various forms of mass movement (landslides, debris flows, rockfalls), swelling soils, and flash floods that affect the park's archeological sites and its infrastructure (roads, septic systems, utilities, and building sites). The map, which encompasses an area of about 100 mi2 (260 km2), includes all of Mesa Verde National Park, a small part of the Ute Mountain Indian Reservation that borders the park on its southern and western sides, and some Bureau of Land Management and privately owned land to the north and east. Surficial deposits depicted on the map include: artificial fills, alluvium of small ephemeral streams, alluvium deposited by the Mancos River, residual gravel on high mesas, a combination of alluvial and colluvial deposits, fan deposits, colluvial deposits derived from the Menefee Formation, colluvial deposits derived from the Mancos Shale, rockfall deposits, debris flow deposits, earthflow deposits, translational and rotational landslide deposits, rock rubble deposits, and loess. Bedrock units depicted on the map include the Cliff House Sandstone, Menefee Formation, Point Lookout Sandstone, and Mancos Shale all of Late Cretaceous age. In addition, minette dikes, of Oligocene age, found at several locations in the park are depicted on the map. Descriptions, including associated hazards and resources as used by the Ancestral Puebloans, are given for all map units.

Landslides and the weathering of granitic rocks

Treesearch

Philip B. Durgin

1977-01-01

Abstract - Granitic batholiths around the Pacific Ocean basin provide examples of landslide types that characterize progressive stages of weathering. The stages include (1) fresh rock, (2) corestones, (3) decomposed granitoid, and (4) saprolite. Fresh granitoid is subject to rockfalls, rockslides, and block glides. They are all controlled by factors related to...

Unusual July 10, 1996, rock fall at Happy Isles, Yosemite National Park, California

USGS Publications Warehouse

Wieczorek, G.F.; Snyder, J.B.; Waitt, R.B.; Morrissey, M.M.; Uhrhammer, R.A.; Harp, E.L.; Norris, R.D.; Bursik, M.I.; Finewood, L.G.

2000-01-01

Effects of the July 10, 1996, rock fall at Happy Isles in Yosemite National Park, California, were unusual compared to most rock falls. Two main rock masses fell about 14 s apart from a 665-m-high cliff southeast of Glacier Point onto a talus slope above Happy Isles in the eastern part of Yosemite Valley. The two impacts were recorded by seismographs as much as 200 km away. Although the impact area of the rock falls was not particularly large, the falls generated an airblast and an abrasive dense sandy cloud that devastated a larger area downslope of the impact sites toward the Happy Isles Nature Center. Immediately downslope of the impacts, the airblast had velocities exceeding 110 m/s and toppled or snapped about 1000 trees. Even at distances of 0.5 km from impact, wind velocities snapped or toppled large trees, causing one fatality and several serious injuries beyond the Happy Isles Nature Center. A dense sandy cloud trailed the airblast and abraded fallen trunks and trees left standing. The Happy Isles rock fall is one of the few known worldwide to have generated an airblast and abrasive dense sandy cloud. The relatively high velocity of the rock fall at impact, estimated to be 110-120 m/s, influenced the severity and areal extent of the airblast at Happy Isles. Specific geologic and topographic conditions, typical of steep glaciated valleys and mountainous terrain, contributed to the rock-fall release and determined its travel path, resulting in a high velocity at impact that generated the devastating airblast and sandy cloud. The unusual effects of this rock fall emphasize the importance of considering collateral geologic hazards, such as airblasts from rock falls, in hazard assessment and planning development of mountainous areas.

Rockfall catchment area design guide : final report.

DOT National Transportation Integrated Search

2001-11-01

The data gathered from an extensive research project consisting of rolling approximately 11,250 rocks off vertical; 0.25H:1V; 0.5H:1V; 0.75H:1V; and 1.0H:1.0V slopes of three different heights (40, 60 and 80 feet) into three differently inclined catc...

Rockfall catchment area design guide : final report : appendices.

DOT National Transportation Integrated Search

2001-11-01

The data gathered from an extensive research project consisting of rolling approximately 11,250 rocks off vertical; 0.25H:1V; 0.5H:1V; 0.75H:1V; and 1.0H:1.0V slopes of three different heights (40, 60 and 80 feet) into three differently inclined catc...

Rockfall catchment area design guide : final report

DOT National Transportation Integrated Search

2001-12-01

The data gathered from an exhaustive research project consisting of rolling a total of approximately 11,250 rocks off vertical; 4V:1H;2V;1H;1.33V:1H;1.0V:1.0H slopes of three different heights (12.2, 18.3, and 24.4 meters) into three differently incl...

A comparison of artifical and natural slope failures: the Santa Barbara earthquake of August 13, 1978.

USGS Publications Warehouse

Harp, E.L.; Keefer, D.K.; Wilson, R.C.

1980-01-01

The earthquake triggered rockfalls and rockslides from steep road cuts and coastal cliffs. The landslide reconnaissance survey which was carried out is described, with separate comments on each landslide site recorded. The general regional slope response to the earthquake is briefly considered. -R. House

GIS- and field based mapping of geomorphological changes in a glacier retreat area: A case study from the Kromer valley, Silvretta Alps (Austria)

NASA Astrophysics Data System (ADS)

Guttmann, Markus; Pöppl, Ronald

2017-04-01

Global warming results in an ongoing retreat of Alpine glaciers, leaving behind large amounts of easily erodible sediments. As a consequence processes like rockfalls, landslides and debris flows as well as fluvial processes occur more frequently in pro- and paraglacial areas, often involving catastrophic consequences for humans and infrastructure in the affected valleys. The main objective of the presented work was to map and spatially quantify glacier retreat and geomorphological changes in the Kromer valley, Silvretta Alps (Austria) by applying GIS- and field-based geomorphological mapping. In total six geomorphological maps (1950s, 1970s, 2001, 2006, 2012, and 2016) were produced and analyzed in the light of the study aim. First results have shown a significant decrease of total glaciated area from 96 ha to 53 ha which was accompanied by increased proglacial geomorphic activity (i.e. fluvial processes, rockfalls, debris flows, shallow landslides) in the last 15 years. More detailed results will be presented at the EGU General Assembly 2017.

Characterization of Fluid Oscillations at Kilauea Volcano Through Time-Dependent Modeling of Seismic Displacements from Rockfall Events

NASA Astrophysics Data System (ADS)

Karlstrom, L.; Dunham, E. M.; Thelen, W. A.; Patrick, M. R.; Liang, C.; Prochnow, B. N.

2015-12-01

Beginning with the opening of a summit vent in 2008, Kilauea's (Hawaíi) summit eruption has exhibited frequent rockfalls from the crater walls into the active lava lake. These events perturb the lake surface, causing vigorous outgassing and sometimes explosions. A network of broadband seismometers records these events as a combination of high-frequency, long-period, and very long period (VLP) oscillations. The VLP portion of the signal has varied in period from 20-40 s since the summit vent opened and has a duration of 10-15 min. These seismic signals reflect the coupling of fluid motion in the conduit to elastic wall rocks. Oscillatory flow can be quantified in terms of the eigenmodes of a magma-filled conduit. Wave motion is affected by conduit geometry, multiphase fluid compressibility, viscosity, and pressure dependent H2O and CO2 solubility. Background stratification and a large impedance contrast at the depth where volatiles first exsolve gives rise to spatially localized families of conduit eigenmodes. The longest period modes are sensitive to properties of bubbly magma and to the length of the conduit above exsolution (which is set by total volatile content). To study the VLP events, we linearize the conduit flow equations assuming small perturbations to an initially magmastatic column, accounting for non-equilibrium multiphase fluid properties, stratification and buoyancy, and conduit width changes. We solve for conduit eigenmodes and associated eigenfrequencies, as well as for the time-domain conduit response to forces applied to the surface of the lava lake. We use broadband records of rockfalls from 2011-2015 that exhibit consistent periods along with lake level measurements to estimate conduit parameters. Preliminary results suggest that VLP periods can be matched with volatile contents similar to those inferred from melt inclusions from Halemaumau explosions. We are currently conducting a more thorough exploration of the parameter space to investigate this further.

Reality of Risk of Natural Disasters in Georgia and a Management Policy

NASA Astrophysics Data System (ADS)

Gaprindashvili, George; Tsereteli, Emil; Gobejishvili, Ramin; King, Lorenz; Gaprindashvili, Merab

2013-04-01

In the last decades of the 20th century, the protection of the population from natural disasters, the preservation of land resources and the safe operation of a complex infrastructure and costly engineering facilities have become the primary socio-economic, demographic, political and environmental problems worldwide. This problem has become more acute in recent years when the natural cataclysms in terms of a population increase, progressive urbanization and use of vulnerable technologies have acquired even larger scales. This holds true especially for mountainous countries as Georgia, too. Natural-catastrophic processes as landslides, mudflows, rockfalls and erosion, and their frequent reoccurrence with harmful impacts to population, agricultural lands and engineering objects form a demanding challenge for the responsible authorities. Thousands of settlements, roads, oil and gas pipelines, high-voltage power transmission lines and other infrastructure may be severely damaged. Respective studies prove that the origin and activation of landslide-gravitational and mudflow processes increase year by year, and this holds true for almost all landscapes and geomorphological zones of Georgia. Catastrophic events may be triggered by (1) intense earthquakes, (2) extreme hydro-meteorological events, probably on the background of global climatic changes (3) large-scale human impacts on the environment. Societies with a low level of preparedness concerning these hazards are especially hit hard. In view of this urgent task, many departmental and research institutions have increased their efforts within the limits of their competence. First of all, it is the activity of the Geological Survey of Georgia (at present included in the National Environmental Agency of the Ministry of Environment Protection of Georgia) which mapped, identified and catalogued the hazardous processes on the territory of the country and identified the spatial limits and occurrences of hazardous processes for tens of years. Moreover, the scientific research institutes of geography, geophysics at several universities and at the Georgian Academy of Sciences have accomplished other significant studies on natural hazards. In Georgia, an increased risk of catastrophes is caused by insufficient information between society and the authorities and persons responsible for mitigation. Urgent research tasks are the basic assessment of natural disasters level, the identification of events, the determination of their cause, and the development of special risk maps in GIS systems. This forms the base for developing a sustainable functioning monitoring and early warning system by the respective authorities.

Progressive failure of sheeted rock slopes: the 2009–2010 Rhombus Wall rock falls in Yosemite Valley, California, USA

USGS Publications Warehouse

Stock, Greg M.; Martel, Stephen J.; Collins, Brian D.; Harp, Edwin L.

2012-01-01

Progressive rock-fall failures in natural rock slopes are common in many environments, but often elude detailed quantitative documentation and analysis. Here we present high-resolution photography, video, and laser scanning data that document spatial and temporal patterns of a 15-month-long sequence of at least 14 rock falls from the Rhombus Wall, a sheeted granitic cliff in Yosemite Valley, California. The rock-fall sequence began on 26 August 2009 with a small failure at the tip of an overhanging rock slab. Several hours later, a series of five rock falls totaling 736 m3progressed upward along a sheeting joint behind the overhanging slab. Over the next 3 weeks, audible cracking occurred on the Rhombus Wall, suggesting crack propagation, while visual monitoring revealed opening of a sheeting joint adjacent to the previous failure surface. On 14 September 2009 a 110 m3 slab detached along this sheeting joint. Additional rock falls between 30 August and 20 November 2010, totaling 187 m3, radiated outward from the initial failure area along cliff (sub)parallel sheeting joints. We suggest that these progressive failures might have been related to stress redistributions accompanying propagation of sheeting joints behind the cliff face. Mechanical analyses indicate that tensile stresses should occur perpendicular to the cliff face and open sheeting joints, and that sheeting joints should propagate parallel to a cliff face from areas of stress concentrations. The analyses also account for how sheeting joints can propagate to lengths many times greater than their depths behind cliff faces. We posit that as a region of failure spreads across a cliff face, stress concentrations along its margin will spread with it, promoting further crack propagation and rock falls.

Interesting insights into instability of slopes and rock fall in the morphodynamic Himalayan terrane

NASA Astrophysics Data System (ADS)

Singh, T. N.; Vishal, V.; Pradhan, S. P.

2015-12-01

Himalayan mountain ranges are tectonically and seismically very active and experience many disastrous events with time due to slope failure. Frequent failures of rock cut slopes cause obstruction in traffic and often lead to fatalities. In recent years, the number of tragedies has increased when associated with regional phenomena such at the Kedarnath tragedy of 2013 and the Gorkha earthquake of 2015. The influence of such phenomena on the stability of slopes along important national highways and key settlement areas only raise the risk to lives and property. We conducted a multi-approach investigation for some key slopes along the National Highway 58 in Uttarakhand Himalaya, India. A very detailed field work was conducted to identify the unstable slopes and those with some history of failure. The pertinent geomechanical characteristics of the representative rock samples were determined in the laboratory. Based on the structural data, kinematic analysis was carried out. Finally the slopes were simulated using FDM based simulator, Flac/Slope for analysing the health of the slopes and Rockfall 4.0 to investigate the phenomenon of rockfall along the Highway. It was found that few slopes were weak due to the inherent weak rock materials while few slopes made up of high strength rocks were effectively weak due to prone-to-failure orientation of the joints. Quantification of bounce-height of rock blocks during fall, their energy, velocity and displacement along the slope was also done. Using 3-D simulations, few critically-stable slopes that appear to be stable, were identified. Little ground movement could be capable of triggering a large scale failure in the area. Slopes in the studied region are under threat to failure and need immediate proper planning using the suggested remedial measures.

Rockfall catchment area design guide : final report : metric edition.

DOT National Transportation Integrated Search

2001-12-01

The data gathered from an exhaustive research project consisting of rolling a total of approximately 11,250 rocks off vertical; 4V:1H;2V;1H;1.33V:1H;1.0V:1.0H slopes of three different heights (12.2, 18.3, and 24.4 meters) into three differently incl...

Rockfall Milepoint 49 Monitoring Plan for Check Dams on Mt. Hood Highway (US 26) (M.P. 49.10 to M.P. 49.23)

DOT National Transportation Integrated Search

2003-07-31

This Stormwater BMP Monitoring Plan details the approach to be used for monitoring : roadside ditch sediment traps located on Highway 26 in the Mt. Hood National Forest. : These sediment traps were designed and installed by ODOT for the capture of se...

High-Precision, Continuous GPS Data Reveals Seasonal Groundwater Influence on the Deformation of the Salmon Falls Landslide, a Slow-Moving, Rotational Feature in Central Idaho

NASA Astrophysics Data System (ADS)

Lauer, I. H.; Crosby, B. T.

2017-12-01

The development of predictive tools for landslide initiation and deformation serve both the natural hazard and geomorphic communities. Founded on both field observations and physical laws, these tools require a mechanistic understanding of the connection between forcing and response. Water has a well-documented influence on slope stability, impacting both soil plasticity and pore water pressure. High precision, high frequency GPS measurements of deformation paired with similar frequency water table measurements enable new insight into the lag and sensitivity present in the coupled hillslope-groundwater system, especially in the rotational domain, which is underrepresented in current literature. Our study explores the influence of groundwater on a slow-moving, deep-seated, rotational slide in southern Idaho using daily, mm precision GPS positions and contemporaneous groundwater levels measurements in adjacent wells, lakes, and streams. Seven semi-permanent GPS stations are spatially distributed across the slide and record three-dimensional velocities up to 11 cm/yr, which compare well with historical measurements from the early 2000's. Water level loggers are located in a rough cross-section through the study area and documents rises in water level during spring 2017 and a subsequent 1.5m drop in the following summer. We hypothesize a correlation of groundwater levels and landslide velocity, which varies seasonally and spatially across the body of the slide. We will present whether deformation is spatially contemporaneous or initiate in one region and propagates down-feature. We will also discuss whether temporal lag exists between water level change and deformation and if hysteresis complicates correlation between forcing and response. Results will bolster the breadth of case-studies available for this landslide morphology and provide regional land managers with predictors for increased landslide activity and associated hazards, such as rockfall or landslide dam outburst events. The data from this study will also be integrated into a newly developed field-education module under the GETSI curriculum project. Our project provides a core dataset for how how-precision GPS positioning can be applied to solve societally relevant issues such as hazard prediction or early warning systems.

Evaluation of Commercially Available Open Circuit Scuba Regulators

DTIC Science & Technology

1987-08-01

ANNEX B LIST OF MANUFACTURERS 1. AGA/IISIERSPIRO U.S. Distributor Intersiro AB AGA/INTERSPIRO S-181 81 Lidingo Sweden Pistol Shop Road Rockfall ...RWV--*-- 40.0 RWV DACOR PACER XLE360 --G- 2.5 OW 600 80 1000 psig Supply Pressure -=70 -- 500 6050 7040 . GI "C - 300 , 𔄃° 4O- 30 200 0100 1030 0 0 0

The nature of rockfall as the basis for a new fallout area design criteria for 0.25:1 slopes.

DOT National Transportation Integrated Search

1994-09-01

The data gathered from rolling nearly 2800 rocks off several 0.25H:1V slopes into three differently shaped ditches (flat, 6H:1V and 4H:1V) was used to develop 12 design charts for rock fallout areas. The data were analyzed using simple statistical an...

Anomalous concentrations of seismically triggered rock falls in Pacoima Canyon: Are they caused by highly susceptible slopes or local amplification of seismic shaking?

USGS Publications Warehouse

Harp, Edwin L.; Jibson, Randall W.

2002-01-01

Anomalously high concentrations of rock falls were triggered in Pacoima Canyon (Los Angeles, California) during the 1994 Northridge earthquake. Similar concentrations were also documented from the 1971 San Fernando earthquake. Using an engineering rock-mass classification that evaluates the susceptibility of rock slopes to seismic failure based on the fracture properties of a rock mass (in terms of a numerical "Q-value" that describes rock quality), the rock slopes in Pacoima Canyon were compared with rock slopes in sorrounding areas where topography and lithology are similar, but rock-fall concentrations from the earthquakes were much lower. A statistical comparison of Q-values from five sites surrounding Pacoima Canyon indicates that seismic susceptibilities are similar to those within Pacoima Canyon; differences in the characteristics of rock slopes between these sites are not sufficient to account for the relatively high concentrations of rock falls within Pacoima Canyon as compared to low concentrations elsewhere. By eliminating susceptibility differences as a cause, the most likely explanations for the differences in rock-fall concentrations is anomalously high shaking levels in Pacoima Canyon, possibly resulting from topographic amplification within the canyon.

Natural and anthropogenic multi-type hazards for loess territories

NASA Astrophysics Data System (ADS)

Mavlyanova, Nadira; Zakirova, Zulfiya

2013-04-01

Central Asia (CA) is an extremely large region of varied geography from plains to high, rugged mountains (the region belongs to the Tien-Shan and Pamirs mountain system), vast deserts (Kara Kum, Kyzyl Kum, Taklamakan). The area of the CA region is including the territories of following countries: of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan. CA is particularly exposed to natural hazards like earthquakes, landslide, rockfalls, avalanches, mudflows, flooding, high mountains lakes, sub flooding, and debris flow. This region is one of the most seismically active in the world. In XX century almost in each of five countries have occurred strong earthquakes with magnitude more than 7, led to human victims. Loess soils are widespread in this region in foothills, foothill plains and intermountain depressions. Loess can cause a number of engineering problems because loess undergoes structural collapse and subsidence due to saturation when both the initial dry density and initial water content are low. By comparison of the map of seismic zoning to a map of distribution of loess soils it is easy to be convinced that the territory of the majority of seismic areas are covering by collapsible loess soils with significant thickness (50-150 m). The natural hazards leads to a disaster, if it develops in an urbanized or industrial areas and directly affects people and economic objects. In this case, risk takes place with all its consequences especially on loess soil. In the past a formation of natural hazards was connected generally with two main groups of factors: geological structure and climatic conditions. Now to them the third factor - of human made influence was added. Intensive influence of human activity to the loess territories in CA for last 60 years is destruction of nature balance and changing in environment of loess land in zone with high seismic hazard. This processes primarily associated with following: 1) irrigation of new lands; 2) the developing of mining manufactures and their waste located in the foothill areas with high seismic risk and where manifested of dangerous geological processes as landslide, collapse, mud stream, rock falls and toxic contamination; 3) development of urbanization with manifestation of difference engineering geological processes in loess soil on the based of constructions in cities (collapse, liquefaction). That example of cascade effects when natural and anthropogenic multi type hazards in loess was the Gissar earthquake (1989) in Tajikistan when the earthquake of rather moderate intensity (M=5.2; H=5-7 km; I=7 - MSK scale) was triggered several landslides and mudslides connected with liquefaction of wetted loess and can cause a large number of human victims. In the pre 20 years steady irrigation of the slope area occurred for cotton field. This moistening has increase and the water content of the soil to wet 24-28%, up to a depth of 20-30 m that increased the vulnerability of this territory. The interactions between different natural hazards, include triggered, especially earthquakes, landslides, collapses, liquefaction in loess soil with taking account of anthropogenic hazard influence was investigate.

Incidence of mass movement processes after an historical episode of heavy snowfall in the Asturian Massif (Northern Spain)

NASA Astrophysics Data System (ADS)

Garcia-Hernandez, Cristina; Ruiz-Fernández, Jesús; Gallinar, David

2015-04-01

This research examines a mass movement event caused in the context of the Great Blizzard of 1888, one of the most severe recorded blizzards in the history of Europe, whose implications go far beyond. In the Asturian Massif the episode consisted in four linked and consecutive snowstorms that took place between the 14th of February 1888 and the 8th of April 1888, creating snow covers with a depth ranging between 5 and 7 m, snow avalanches and flooding, causing dozens of deaths and large material damage. The Asturian Massif belongs to the Atlantic-climate area and is composed mainly by sedimentary and metamorphic paleozoic rocks. Many sectors of the Massif are between 1.000 and 2.000 m a.s.l., and its topography is characterized by a great height difference and steep slopes. Because of the lack of deep soils suitable for farming, the main traditional activity has been livestock keeping, and goods traffic. We have devised a method that enables the reconstruction of this event on the basis of nivo-meteorogical conditions, geographical location and socio-economic impact. The mass movement episode has been studied through the issues of 6 newspapers published in Asturias between the 20th of January and 30th of May 1888, the ancient meteorological station data of the University of Oviedo, and field work. A logical database structure has been designed with the aim to store and cross the information for statistical analysis. Thirty six mass movement worthy of consideration were documented, 28 of them causing material damage (six homes destroyed and at least 22 interruptions with the traffic flow on roads, highways and railways). Ten high- and mid-elevation mountain municipalities were affected by mass movement. We must consider that only the most important events, or those that happened in crowded places, have been considered by the newspapers, so the total number of mass movements should be considered as a minimum figure. We have got to identify and classify 27 of them; 16 as landslides, 5 as rockfalls, 4 as mixed typology of rockfalls with a big amount of mud, and 2 as debris flow. One person died as a consecuence of a rockfall. Thirty out of thirty six events anthropic intervention is proved. It acted as a prior conditioning where the previous topography has been modified (in 29 cases), either as a direct triggering mechanism at least in one landslide episode. The sequence analysis of the events shows that their number and frequency increases with episodes of snow melting during the snowstorm breaks, announcing the highest instabilities on 10th and 11th of March, coinciding with a rainfall peak. However the connection with the rainfall episode seems weak compared with the one than can be settled with the rise of temperatures and the resulting melting intensification. It caused the progressive water saturation of surface formations, that reached a maximum during the second break, triggering 20 events during the 11th of March 1888.

Arguing for a multi-hazard mapping program in Newfoundland and Labrador, Canada

NASA Astrophysics Data System (ADS)

Batterson, Martin; Neil, Stapleton

2010-05-01

This poster describes efforts to implement a Provincial multi-hazard mapping program, and will explore the challenges associated with this process. Newfoundland and Labrador is on the eastern edge of North America, has a large land area (405,212 km2) and a small population (510,000; 2009 estimate). The province currently has no legislative framework to control development in hazardous areas, but recent landslides in the communities of Daniel's Harbour and Trout River, both of which forced the relocation of residents, emphasize the need for action. There are two factors which confirm the need for a natural hazard mapping program: the documented history of natural disasters, and the future potential impacts of climate change. Despite being relatively far removed from the impacts of earthquake and volcanic activity, Newfoundland and Labrador has a long history of natural disasters. Rockfall, landslide, avalanche and flood events have killed at least 176 people over the past 225 years, many in their own homes. Some of the fatalities resulted from the adjacency of homes to places of employment, and of communities and roads to steep slopes. Others were likely the result of chance, and were thus unavoidable. Still others were the result of poor planning, albeit unwitting. Increasingly however, aesthetics have replaced pragmatism as a selection criterion for housing developments, with residential construction being contemplated for many coastal areas. The issue is exacerbated by the impacts of climate change, which while not a universal bane for the Province, will likely result in rising sea level and enhanced coastal erosion. Much of the Province's coastline is receding at up to 30 cm (and locally higher) per year. Sea level is anticipated to rise by 70cm to over 100 cm by 2099, based on IPCC predictions, plus the effects of enhanced ice sheet melting, plus (or minus) continued local isostatic adjustment. The history of geological disasters, coupled with pressures on development and the threat of rising sea levels, has prompted the initiation of a Provincial multi-hazard mapping program. Initial focus is on the north-east Avalon Peninsula, where the majority of the Province's residents are located and where most development is occurring. A regional land-use plan is being initiated for this area. While there are few, if any, standard protocols in literature for determining variables/data to be included in a hazard assessment, three important factors require consideration: the characteristics and detail of the study area, the availability of digital datasets, and the scale of data. For the north-east Avalon Peninsula hazard mapping will combine slope models generated from DEMs, bedrock/surficial geology mapping at 1:50,000 scale, Provincial flood risk mapping and municipal digital topographic data at 1:2500 scale, and historical research and field work, to produce a ‘traffic-light' designation of potentially hazardous areas. Data will be presented in an ArcGIS environment. Sea-level rise scenarios will also be incorporated into the mapping. Following the experience of flood risk mapping in the Province, which identified hazardous areas for development which nevertheless continued to experience urban expansion, subsequently ensuring the utilization of these maps in future land-use planning will likely require entrenchment in legislation.

Landslide susceptibility modeling applying machine learning methods: A case study from Longju in the Three Gorges Reservoir area, China

NASA Astrophysics Data System (ADS)

Zhou, Chao; Yin, Kunlong; Cao, Ying; Ahmed, Bayes; Li, Yuanyao; Catani, Filippo; Pourghasemi, Hamid Reza

2018-03-01

Landslide is a common natural hazard and responsible for extensive damage and losses in mountainous areas. In this study, Longju in the Three Gorges Reservoir area in China was taken as a case study for landslide susceptibility assessment in order to develop effective risk prevention and mitigation strategies. To begin, 202 landslides were identified, including 95 colluvial landslides and 107 rockfalls. Twelve landslide causal factor maps were prepared initially, and the relationship between these factors and each landslide type was analyzed using the information value model. Later, the unimportant factors were selected and eliminated using the information gain ratio technique. The landslide locations were randomly divided into two groups: 70% for training and 30% for verifying. Two machine learning models: the support vector machine (SVM) and artificial neural network (ANN), and a multivariate statistical model: the logistic regression (LR), were applied for landslide susceptibility modeling (LSM) for each type. The LSM index maps, obtained from combining the assessment results of the two landslide types, were classified into five levels. The performance of the LSMs was evaluated using the receiver operating characteristics curve and Friedman test. Results show that the elimination of noise-generating factors and the separated modeling of each landslide type have significantly increased the prediction accuracy. The machine learning models outperformed the multivariate statistical model and SVM model was found ideal for the case study area.

A custom acoustic emission monitoring system for harsh environments: application to freezing-induced damage in alpine rock-walls

NASA Astrophysics Data System (ADS)

Girard, L.; Beutel, J.; Gruber, S.; Hunziker, J.; Lim, R.; Weber, S.

2012-06-01

We present a custom acoustic emission (AE) monitoring system designed to perform long-term measurements on high-alpine rock-walls. AE monitoring is a common technique for characterizing damage evolution in solid materials. The system is based on a two-channel AE sensor node (AE-node) integrated into a Wireless Sensor Network (WSN) customized for operation in harsh environments. This wireless architecture offers flexibility in the deployment of AE-nodes at any position of the rock-wall that needs to be monitored, within a range of a few hundred meters from a core station connected to the internet. The system achieves near real-time data delivery and allows the user to remotely control the AE detection threshold. In order to protect AE sensors and capture acoustic signals from specific depths of the rock-wall, a special casing was developed. The monitoring system is completed by two probes that measure rock temperature and liquid water content, both probes being also integrated into the WSN. We report a first deployment of the monitoring system on a rock-wall at Jungfraujoch, 3500 m a.s.l., Switzerland. While this first deployment of the monitoring system aims to support fundamental research on processes that damage rock under cold climate, the system could serve a number of other applications, including rock-fall hazard surveillance or structural monitoring of concrete structures.

Post-disaster Risk Assessment for Hilly Terrain exposed to Seismic Loading

NASA Astrophysics Data System (ADS)

Yates, Katherine; Villeneuve, Marlene; Wilson, Thomas

2013-04-01

The 2010-present Canterbury earthquake sequence in the central South Island of New Zealand has identified and highlighted the value of practical, standardised and coordinated geotechnical risk assessment guidelines for inhabited structures in the aftermath of a geotechnical disaster. The lack of such guidelines and provisions to enforce risk assessments was a major gap which hindered coordinated, timely and transparent management of geotechnical risk. The earthquake sequence initiated a series of rockfall, cliff collapse and landslide events around the Port Hills southeast of Christchurch. This was particularly the case with the 22 February 2011 earthquakes, which put thousands of people inhabiting the area at risk. Lives were lost and thousands of houses and critical infrastructure were damaged. Given the highly seismic environment in New Zealand and a significant number of active faults near population centres, it is prudent to develop such guidelines to ensure response mechanisms and geotechnical risk assessment is effective following an earthquake rupture in a largely populated urban environment. For response and associated risk assessments to be effective, the mechanisms of the geotechnical failure should be taken into consideration as part of the life safety assessment. This is to ensure that the hazard's potential risk is fully assessed and encompassed in decisions regarding life safety. This paper examines the event sequence, slope failure mechanisms and the geotechnical risk management approach that developed immediately post-earthquake. It highlights experiences from key municipal, management and operational stakeholders who were involved in geotechnical risk assessment during the Canterbury earthquake sequence, and sheds light on the evolution of information needed through time during the emergency response and identify the hard won lessons. It then discusses what is needed for life safety assessment post-earthquake and create awareness of potential geotechnical hazards. This is not only important to New Zealand but has international implications as there are many other regions of the world also subject to high seismic risk.

Slope, Scarp and Sea Cliff Instability Susceptibility Mapping for Planning Regulations in Almada County, Portugal

NASA Astrophysics Data System (ADS)

Marques, Fernando; Queiroz, Sónia; Gouveia, Luís; Vasconcelos, Manuel

2017-12-01

In Portugal, the modifications introduced in 2008 and 2012 in the National Ecological Reserve law (REN) included the mandatory study of slope instability, including slopes, natural scarps, and sea cliffs, at municipal or regional scale, with the purpose of avoiding the use of hazardous zones with buildings and other structures. The law also indicates specific methods to perform these studies, with different approaches for slope instability, natural scarps and sea cliffs. The methods used to produce the maps required by REN law, with modifications and improvements to the law specified methods, were applied to the 71 km2 territory of Almada County, and included: 1) Slope instability mapping using the statistically based Information Value method validated with the landslide inventory using ROC curves, which provided an AAC=0.964, with the higher susceptibility zones which cover at least 80% of the landslides of the inventory to be included in REN map. The map was object of a generalization process to overcome the inconveniences of the use of a pixel based approach. 2) Natural scarp mapping including setback areas near the top, defined according to the law and setback areas near the toe defined by the application of the shadow angle calibrated with the major rockfalls which occurred in the study area; 3) Sea cliffs mapping including two levels of setback zones near the top, and one setback zone at the cliffs toe, which were based on systematic inventories of cliff failures occurred between 1947 and 2010 in a large scale regional littoral monitoring project. In the paper are described the methods used and the results obtained in this study, which correspond to the final maps of areas to include in REN. The results obtained in this study may be considered as an example of good practice of the municipal authorities in terms of solid, technical and scientifically supported regulation definitions, hazard prevention and safe and sustainable land use management.

Completion of Embankment, Spillway and Outlet Works

DTIC Science & Technology

1990-08-01

Protection Against Slides and Rockfalls 42 5 PILE DRIVING AND SPECIAL FOUNDATIONS 42 6 TUNNELS, SHAFTS, AND UNDERGROUND STRUCTURES 42 7 FOUNDATION ANCHOR TEST...TW r tyVs.. l ti rs 80 .S0.90 R 4oeS . 14.0-..19.01 Noe 2ale 3" 0 34. lattafro14 600.0j 33.0’ S. 38.0-.39.01 631.0 for gi . x 0% WI APnbdcE

Interpretation and misinterpretation of warning signage: perceptions of rockfalls in a naturalistic setting.

PubMed

Aucote, Helen M; Miner, Anthony; Dahlhaus, Peter

2012-01-01

The aim of the present study was to investigate the factors relating to non-adherence to warning signs about falling rocks from coastal cliff faces. Face-to-face interviews (n = 62) in a naturalistic setting (in the vicinity of a high-risk rockfall area) were conducted to investigate attention to and comprehension of warning signs, as well as beliefs relating to non-adherence of the signage. It was found that, while most participants could correctly identify the danger in the area and had noticed the warning signage, less than half of the participants could correctly interpret the signage. The perception of danger did not differ significantly between the participants who had, or had not, entered the high-risk zone. Differences in knowledge and beliefs between local residents and visitors to the area were identified. It was concluded that the warning signs did not provide enough detail for people to make informed decisions about safe behaviours. Comprehension of the signage may have been hampered by a lack of prior-knowledge of the particular risk, a failure to think carefully about the situation (i.e. low-effort processing), and the pictorial representation on the signs misleading the participants as to the true danger.

Spatial distribution of sediment storage types and quantification of valley fill deposits in an alpine basin, Reintal, Bavarian Alps, Germany

NASA Astrophysics Data System (ADS)

Schrott, Lothar; Hufschmidt, Gabi; Hankammer, Martin; Hoffmann, Thomas; Dikau, Richard

2003-09-01

Spatial patterns of sediment storage types and associated volumes using a novel approach for quantifying valley fill deposits are presented for a small alpine catchment (17 km 2) in the Bavarian Alps. The different sediment storage types were analysed with respect to geomorphic coupling and sediment flux activity. The most landforms in the valley in terms of surface area were found to be talus slopes (sheets and cones) followed by rockfall deposits and alluvial fans and plains. More than two-thirds of the talus slopes are relict landforms, completely decoupled from the geomorphic system. Notable sediment transport is limited to avalanche tracks, debris flows, and along floodplains. Sediment volumes were calculated using a combination of polynomial functions of cross sections, seismic refraction, and GIS modelling. A total of, 66 seismic refraction profiles were carried out throughout the valley for a more precise determination of sediment thicknesses and to check the bedrock data generated from geomorphometric analysis. We calculated the overall sediment volume of the valley fill deposits to be 0.07 km 3. This corresponds to a mean sediment thickness of 23.3 m. The seismic refraction data showed that large floodplains and sedimentation areas, which have been developed through damming effects from large rockfalls, are in general characterised by shallow sediment thicknesses (<20 m). By contrast, the thickness of several talus slopes is more than twice as much. For some locations (e.g., narrow sections of valley), the polynomial-generated cross sections resulted in overestimations of up to one order of magnitude; whereas in sections with a moderate valley shape, the modelled cross sections are in good accordance with the obtained seismic data. For the quantification of valley fill deposits, a combined application of bedrock data derived from polynomials and geophysical prospecting is highly recommended.

Himalayan/Karakoram Disaster After Disaster: The Pain Will Not Be Ending Anytime Soon

NASA Astrophysics Data System (ADS)

Kargel, J. S.; Leonard, G. J.

2013-12-01

Are recent natural disasters in the Himalaya/Karakoram partly human-caused? Will disasters diminish or increase in frequency? Natural disasters in this region are nothing new. Earthquakes, floods, landslides, avalanches, and debris flows have occurred in the Himalaya/Karakoram since the mountains first grew from the sea. Simply put, the Himalaya/Karakoram, being South Asia's 'water tower' and an active plate tectonic collision zone, must shed water and debris to the lowlands and the sea. When this activity occurs swiftly and with high intensity at or near human settlements, the results are often deadly. Remote sensing analysis of recent disasters coupled with demography, news accounts, and field studies indicate that there is a component of human responsibility. Two overarching human elements include (1) settlement and infrastructure encroachment into hazardous mountain areas and (2) aggravation of climate change. Both are substantially responsible--separately or together--for most of the recent tragedies. These conclusions provide the answer to when the disasters will end: not soon. Unfortunately, disasters will almost surely increase. Whether natural disasters have increased in frequency over the region's long historical record may be debated and must be researched. This expected link is a challenge to assess due to the stochastic nature of disasters and their triggering events (e.g., earthquakes and extreme weather events). While Himalayan tectonism, rock mechanics, glaciation, and climate are fundamental causes of the disasters, so are human land uses. Encroaching development into ever-hazardous zones is a paramount cause of much human tragedy. Climate change is harder to pin down specifically as a cause of some of these disasters, because some disasters are linked to rare extreme weather events and mass movements, which may be statistically but not individually attributable in part to climate change. Nevertheless, evidence supports a major role of climate change for some natural disasters, and little if any role in others. I select a few recent disaster examples (Attabad rockfall, Gayari avalanche, Seti River flood, and Uttarakhand floods) and summarize their relationships to geology and geomorphology, weather, climate change, habitation, and infrastructure development. Disasters are apt to increase in frequency, effects, and geographic spread due to increased habitation and infrastructure development and changing climate. Whether climate change causes glacier shrinkage or growth, glacier-related hazards are affected. Some of these disasters have international cross-cultural, political, economic, and security components and could spiral into further human catastrophes related to international tensions. Improved international cooperation could ease the chances for disasters to trigger additional unintended consequences between nations. Not all development and human uses of the Himalaya/Karakoram are unwise. Furthermore, some people committed to living in risky places have nowhere else to go. Climate change and shifting mountain processes may have winners and losers. All current and future uses of the region should be weighed against the rapidly changing climate and shifting natural hazard landscape. Acknowledgements: Support from NASA/USAID SERVIR Applied Science Team, NASA Science of Terra & Aqua, and USAID Climbers' Science.

Assessment of impact of mass movements on the upper Tayyah valley's bridge along Shear escarpment highway, Asir region (Saudi Arabia) using remote sensing data and field investigation

NASA Astrophysics Data System (ADS)

Youssef, A. M.; Al-Kathery, M.; Pradhan, B.

2015-01-01

Escarpment highways, roads and mountainous areas in Saudi Arabia are facing landslide hazards that are frequently occurring from time to time causing considerable damage to these areas. Shear escarpment highway is located in the north of the Abha city. It is the most important escarpment highway in the area, where all the light and heavy trucks and vehicle used it as the only corridor that connects the coastal areas in the western part of the Saudi Arabia with the Asir and Najran Regions. More than 10 000 heavy trucks and vehicles use this highway every day. In the upper portion of Tayyah valley of Shear escarpment highway, there are several landslide and erosion potential zones that affect the bridges between tunnel 7 and 8 along the Shear escarpment Highway. In this study, different types of landslides and erosion problems were considered to access their impacts on the upper Tayyah valley's bridge along Shear escarpment highway using remote sensing data and field investigation. These landslides and erosion problems have a negative impact on this section of the highway. Results indicate that the areas above the highway and bridge level between bridge 7 and 8 have different landslides including planar, circular, rockfall failures and debris flows. In addition, running water through the gullies cause different erosional (scour) features between and surrounding the bridge piles and culverts. A detailed landslides and erosion features map was created based on intensive field investigation (geological, geomorphological, and structural analysis), and interpretation of Landsat image 15 m and high resolution satellite image (QuickBird 0.61 m), shuttle radar topography mission (SRTM 90 m), geological and topographic maps. The landslides and erosion problems could exhibit serious problems that affect the stability of the bridge. Different mitigation and remediation strategies have been suggested to these critical sites to minimize and/or avoid these problems in the future.

Towards a Comprehensive Catalog of Volcanic Seismicity

NASA Astrophysics Data System (ADS)

Thompson, G.

2014-12-01

Catalogs of earthquakes located using differential travel-time techniques are a core product of volcano observatories, and while vital, they represent an incomplete perspective of volcanic seismicity. Many (often most) earthquakes are too small to locate accurately, and are omitted from available catalogs. Low frequency events, tremor and signals related to rockfalls, pyroclastic flows and lahars are not systematically catalogued, and yet from a hazard management perspective are exceedingly important. Because STA/LTA detection schemes break down in the presence of high amplitude tremor, swarms or dome collapses, catalogs may suggest low seismicity when seismicity peaks. We propose to develop a workflow and underlying software toolbox that can be applied to near-real-time and offline waveform data to produce comprehensive catalogs of volcanic seismicity. Existing tools to detect and locate phaseless signals will be adapted to fit within this framework. For this proof of concept the toolbox will be developed in MATLAB, extending the existing GISMO toolbox (an object-oriented MATLAB toolbox for seismic data analysis). Existing database schemas such as the CSS 3.0 will need to be extended to describe this wider range of volcano-seismic signals. WOVOdat may already incorporate many of the additional tables needed. Thus our framework may act as an interface between volcano observatories (or campaign-style research projects) and WOVOdat. We aim to take the further step of reducing volcano-seismic catalogs to sets of continuous metrics that are useful for recognizing data trends, and for feeding alarm systems and forecasting techniques. Previous experience has shown that frequency index, peak frequency, mean frequency, mean event rate, median event rate, and cumulative magnitude (or energy) are potentially useful metrics to generate for all catalogs at a 1-minute sample rate (directly comparable with RSAM and similar metrics derived from continuous data). Our framework includes tools to plot these metrics in a consistent manner. We work with data from unrest at Redoubt volcano and Soufriere Hills volcano to develop our framework.

NASA Hazard Analysis Process

NASA Technical Reports Server (NTRS)

Deckert, George

2010-01-01

This viewgraph presentation reviews The NASA Hazard Analysis process. The contents include: 1) Significant Incidents and Close Calls in Human Spaceflight; 2) Subsystem Safety Engineering Through the Project Life Cycle; 3) The Risk Informed Design Process; 4) Types of NASA Hazard Analysis; 5) Preliminary Hazard Analysis (PHA); 6) Hazard Analysis Process; 7) Identify Hazardous Conditions; 8) Consider All Interfaces; 9) Work a Preliminary Hazard List; 10) NASA Generic Hazards List; and 11) Final Thoughts

Risk assessment of mountain infrastructure destabilization in the French Alps

NASA Astrophysics Data System (ADS)

Duvillard, Pierre-Allain; Ravanel, Ludovic; Deline, Philip

2015-04-01

In the current context of imbalance of geosystems in connection with the rising air temperature for several decades, high mountain environments are especially affected by the shrinkage of glaciers and the permafrost degradation which can trigger slope movements in the rock slopes (rockfall, rock avalanches) or in superficial deposits (slides, rock glacier rupture, thermokarst). These processes generate a risk of direct destabilization for high mountain infrastructure (huts, cable-cars...) in addition to indirect risks for people and infrastructure located on the path of moving rock masses. We here focus on the direct risk of infrastructure destabilization due to permafrost degradation and/or glacier shrinkage in the French Alps. To help preventing these risks, an inventory of all the infrastructure was carried out with a GIS using different data layers among which the Alpine Permafrost Index Map and inventories of the French Alps glaciers in 2006-2009, 1967-1971 and at the end of the Little Ice Age. 1769 infrastructures have been identified in areas likely characterized by permafrost and/or possibly affected by glacier shrinkage. An index of risk of destabilization has been built to identify and to rank infrastructure at risk. This theoretical risk index includes a characterization of hazards and a diagnosis of the vulnerability. The value of hazard is dependent on passive factors (topography, lithology, geomorphological context...) and on so-considered active factors (thermal state of the permafrost, and changing constraints on slopes related to glacier shrinkage). The diagnosis of vulnerability has meanwhile been established by combining the level of potential damage to the exposed elements with their operational and financial values. The combination of hazard and vulnerability determines a degree of risk of infrastructure destabilization (from low to very high). Field work and several inventories of infrastructure damages were used to validate it. The application of this risk index for infrastructure in the French Alps indicates 999 infrastructures potentially at risk, among 0.2 % are characterized by a very high risk and 4.4 % by a high risk of destabilization. The risk unequally affects massifs: 55 % of the infrastructure at risk are in the Vanoise massif (Savoie) due to the large number of high-altitude ski resorts in this area. The Mont-Blanc massif (Haute-Savoie) includes only 6.5 % of the infrastructure at risk. Furthermore, 71 % of the exposed infrastructure are ski-lifts.

Initiation and Frequency of Debris Flows in Grand Canyon, Arizona

DTIC Science & Technology

1996-01-01

illustrations. Ed Holroyd, U.S. Bureau of Reclamation in Denver, Colorado, gave extensive technical help and advice with the GIS software. Steve Sutley, of the...value. Drainage-basin boundaries were drawn by hand on topographic maps, digitized, and entered into a GIS , which calculated drainage areas and centroids...overlying cliffs of more indurated sandstones and limestones. These processes result in rockfalls and rock avalanches that occur in all seasons, and under a

Changes in Mass Flux of Tephra from the Lava Lake in Overlook Crater, Kīlauea Volcano, Hawai`i

NASA Astrophysics Data System (ADS)

Swanson, D. A.; Orr, T. R.; Patrick, M. R.

2016-12-01

The mass flux of tephra (mostly Pele's hair and tears, hollow spherules, and lithic clasts) from the lava lake in Overlook crater varies on short (seconds-minutes), intermediate (hours-days), and long (months) time scales. The tephra is collected almost daily from a network of 10 buckets within 400 m of, and 100-150 m above, the lava lake; bucket locations have not changed during the eruption. A mass accumulation rate (AR) is calculated for the network; since April 2008, the AR averages 0.17 g/m2/h ( 5×10-8 kg/m2/s). The tephra forms during almost constant spattering at the SE sink (the main downwelling site) and ephemeral sites along the crater wall, as well as from sporadic, rockfall-induced violent outgassing that can eject decimeter-size spatter clots onto the crater rim; the average AR excludes these violent events. The rockfalls, and nearly constant raveling from the crater wall, introduce lithic clasts into the tephra. The lithic content of the tephra has decreased with time, reflecting both greater wall stability and higher lake level, and was usually <10 mass percent in 2014-2015 and <5 percent in 2016. At short time scales, juvenile AR increases during episodic gas-piston events, rockfalls, and strong winds (>7 m/s). At intermediate and long time scales, juvenile AR shows no correlation with measured SO2 output and only weak or no correlation with wind speed, but it often tracks the elevation of the lake surface—higher when lava is nearer the buckets. For example, both lava level and juvenile AR were unusually high in January-July 2016. Before 2016, however, 7-9 periods of heightened juvenile production (see figure below), each lasting several months, show no correlation with other monitored parameters—lake level, SO2, wind speed and direction, or downwelling location. Often AR gradually increased to a peak before falling off, sometimes to nearly zero. We speculate that such long-term variations result from changes in magma supply rate, gas concentration, or rise frequency of decoupled gas slugs. These changes may be too small or slow to detect by current geodetic and gas monitoring. They suggest a slowly pulsing rate of gas delivery or magma supply on a several-month time scale at Kīlauea.

21 CFR 120.7 - Hazard analysis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Hazard analysis. 120.7 Section 120.7 Food and... hazards. The written hazard analysis shall consist of at least the following: (1) Identification of food..., including food hazards that can occur before, during, and after harvest. The hazard analysis shall be...

21 CFR 120.7 - Hazard analysis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Hazard analysis. 120.7 Section 120.7 Food and... hazards. The written hazard analysis shall consist of at least the following: (1) Identification of food..., including food hazards that can occur before, during, and after harvest. The hazard analysis shall be...

21 CFR 120.7 - Hazard analysis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Hazard analysis. 120.7 Section 120.7 Food and... hazards. The written hazard analysis shall consist of at least the following: (1) Identification of food..., including food hazards that can occur before, during, and after harvest. The hazard analysis shall be...

21 CFR 120.7 - Hazard analysis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Hazard analysis. 120.7 Section 120.7 Food and... hazards. The written hazard analysis shall consist of at least the following: (1) Identification of food..., including food hazards that can occur before, during, and after harvest. The hazard analysis shall be...

Canister Storage Building (CSB) Hazard Analysis Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

POWERS, T.B.

2000-03-16

This report describes the methodology used in conducting the Canister Storage Building (CSB) Hazard Analysis to support the final CSB Safety Analysis Report and documents the results. This report describes the methodology used in conducting the Canister Storage Building (CSB) hazard analysis to support the CSB final safety analysis report (FSAR) and documents the results. The hazard analysis process identified hazardous conditions and material-at-risk, determined causes for potential accidents, identified preventive and mitigative features, and qualitatively estimated the frequencies and consequences of specific occurrences. The hazard analysis was performed by a team of cognizant CSB operations and design personnel, safetymore » analysts familiar with the CSB, and technical experts in specialty areas. The material included in this report documents the final state of a nearly two-year long process. Attachment A provides two lists of hazard analysis team members and describes the background and experience of each. The first list is a complete list of the hazard analysis team members that have been involved over the two-year long process. The second list is a subset of the first list and consists of those hazard analysis team members that reviewed and agreed to the final hazard analysis documentation. The material included in this report documents the final state of a nearly two-year long process involving formal facilitated group sessions and independent hazard and accident analysis work. The hazard analysis process led to the selection of candidate accidents for further quantitative analysis. New information relative to the hazards, discovered during the accident analysis, was incorporated into the hazard analysis data in order to compile a complete profile of facility hazards. Through this process, the results of the hazard and accident analyses led directly to the identification of safety structures, systems, and components, technical safety requirements, and other controls required to protect the public, workers, and environment.« less

National Dam Inspection Program. Locklin Pond Dam (NDI ID Number PA-00139, DER ID Number 64-31), Delaware River Basin, Lakeville Creek, Wayne County, Pennsylvania. Phase I Inspection Report.

DTIC Science & Technology

1980-07-01

3 - C-L lz - gI Ado 00 V.,nw e. 232 "is. BRUSH, DEBRIS, AND SOIL COVERING CREST, CREST IS SHORTER THAN ~DELN AUXILIARY SPILLWAY -~Z Z KNOLL LOCKLIN...some rockfall from vertical and high-angle cut slopes. Bedrock is entirely overlain by glacial till of Late Wisconsin Age. This till is an unsorted

Glaciohydrologic and Glaciohydraulic Effects on Runoff and Sediment Yield in Glacierized Basins

DTIC Science & Technology

1993-11-01

3 (17) wateron ice layers(Colbeck 1979). These complex- ities can be somewhat simplified by considering where (x = a constant = p, gi ...debris is reworked and modified ited on the ice by mass movements- rockfalls , by weathering, especially freeze-thaw, and by avalanches, slushflows (e.g...hydrological and glaciological studies have been supported by Grande Dixence over the last 40 where gi is the viscosity of water. As stated in an years at

The Prehistory and Paleoenvironment of Hominy Creek Valley. 1979 Field Season,

DTIC Science & Technology

1982-01-01

study of Hiominy Creek Valley (Henry, 1977a:1-5). The program focuses on the definition of adaptive strate- gies throughout the prehistoric occupation...area of the shelter is estimated 75m 2 with approximately one-fifth of this area covered by rockfall . The cellng is generally level with a height...greater rates of deposition than fewer numbers Gi occupants. These open floodplain sites may LW -98- well have represented alternative encampments to the

Summary of geologic effects of the Boxcar event, Nevada Test Site

USGS Publications Warehouse

Dickey, Dayton Delbert; McKeown, F.A.; Ellis, William L.

1969-01-01

A high-yield underground nuclear explosion at the U20i site, formed a sink 1,000 feet in diameter above the explosion point. Fractures opened as far as 20,000 feet from the explosion and rock-falls occurred as far as 15 miles. Most fractures were coincidental with north-trending naturally occurring faults. Maximum displacement along a fault was 3 feet vertically with the downthrown side the same as that on the original fault.

Hydrothermal Liquefaction Treatment Preliminary Hazard Analysis Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowry, Peter P.; Wagner, Katie A.

A preliminary hazard assessment was completed during February 2015 to evaluate the conceptual design of the modular hydrothermal liquefaction treatment system. The hazard assessment was performed in 2 stages. An initial assessment utilizing Hazard Identification and Preliminary Hazards Analysis (PHA) techniques identified areas with significant or unique hazards (process safety-related hazards) that fall outside of the normal operating envelope of PNNL and warranted additional analysis. The subsequent assessment was based on a qualitative What-If analysis. This analysis was augmented, as necessary, by additional quantitative analysis for scenarios involving a release of hazardous material or energy with the potential for affectingmore » the public.« less

INTERNAL HAZARDS ANALYSIS FOR LICENSE APPLICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

R.J. Garrett

2005-02-17

The purpose of this internal hazards analysis is to identify and document the internal hazards and potential initiating events associated with preclosure operations of the repository at Yucca Mountain. Internal hazards are those hazards presented by the operation of the facility and by its associated processes that can potentially lead to a radioactive release or cause a radiological hazard. In contrast to external hazards, internal hazards do not involve natural phenomena and external man-made hazards. This internal hazards analysis was performed in support of the preclosure safety analysis and the License Application for the Yucca Mountain Project. The methodology formore » this analysis provides a systematic means to identify internal hazards and potential initiating events that may result in a radiological hazard or radiological release during the repository preclosure period. These hazards are documented in tables of potential internal hazards and potential initiating events (Section 6.6) for input to the repository event sequence categorization process. The results of this analysis will undergo further screening and analysis based on the criteria that apply to the performance of event sequence analyses for the repository preclosure period. The evolving design of the repository will be re-evaluated periodically to ensure that internal hazards that have not been previously evaluated are identified.« less

Characterization of the deformation and thermal behavior of granitic exfoliation sheets with LiDAR and infrared thermography (Yosemite Valley, USA)

NASA Astrophysics Data System (ADS)

Guerin, Antoine; Derron, Marc-Henri; Jaboyedoff, Michel; Collins, Brian D.; Stock, Greg M.

2017-04-01

Yosemite Valley is a long (11 km) and deep ( 1 km) glacier-carved valley, bounded by steep granitic cliffs cutting the western slope of the central Sierra Nevada mountain range (California, USA). These cliffs produce numerous rockfalls every year (925 events reported between 1857 and 2011) and this rockfall activity is often linked to the presence of sheeting joints (Stock et al., 2013), also called exfoliation joints, formed in response to stress changes associated with changes in the topography (Martel, 2011). Furthermore, the historical rockfall inventory indicates that many events occurred without recognized triggers (Austin et al., 2014), in summer time, and on sunny days in particular. This suggests that thermal stress changes are involved in triggering of rockfalls (Collins and Stock, 2016). To further characterize the relationship between thermal stresses and rock face deformation, we carried out three experiments in Yosemite Valley during October 2015: (i) monitoring of a sub-vertical granodiorite exfoliation sheet on the Rhombus Wall for 24 consecutive hours (from 8:00 p.m. to 8:00 p.m.) using terrestrial LiDAR, crackmeters and infrared thermal sensors; (ii) monitoring the El Capitan rockwall composed of tens of exfoliation sheets for 8 consecutive hours (from 5:30 p.m. to 1:30 a.m.) with terrestrial LiDAR and thermal imaging; (iii) collecting several sequences of thermal GigaPan panoramas during periods of rock cooling on both cliffs (Rhombus Wall and El Capitan). In parallel to these experiments, we also developed a method for calibrating and correcting the raw apparent temperature measured by our thermal imager (a FLIR T660 infrared camera) from thermoresistances, reflective and black papers and by using some information given by the LiDAR point clouds (range, dip and dip direction). LiDAR monitoring of experiments (i) and (ii) allowed us to detect millimetric deformations for the exfoliations sheets whose crack aperture is persistent, deep and greater than 9 cm, confirming the results of Collins and Stock (2016). Then, the LiDAR - infrared thermography coupling allowed us to establish a link between the contraction - expansion cycles observed and daily thermal variations: the cycles of contraction (crack closure) occur between 3:00 p.m. and 8:00 a.m. and are associated with cooling, whereas the opposite is true for the expansion cycles (crack opening). In addition, in the case of experiment (i), we observe a delay of about 40 minutes between the time when surface temperatures are minimum and the maximum closure of the crack (-5.33 +/- 0.01 mm), which occurs a little before 8:00 a.m. Concerning the thermal behavior of the exfoliation sheets, the experiments (i) and (ii) show that the exfoliation sheets are almost always colder than surrounding stable areas, except during the hottest hours of the day when the temperatures are similar. At the end of the night, the temperature deviation between an exfoliation sheet and a stable part can reach 5 to 6 Celsius degrees (values valid for October) and this thermal contrast makes it possible to remotely detect the presence of exfoliation sheets in a rockwall. This result was then confirmed by the experiment (iii) which shows that a whole series of exfoliation sheets could be detected at a distance of 1 km, by means of thermal comparisons. Coupled to the LiDAR, infrared thermography can thus be useful for drawing a 3D map of exfoliation sheets in a cliff of several hundred meters high.

Hazard Analysis Guidelines for Transit Projects

DOT National Transportation Integrated Search

2000-01-01

These hazard analysis guidelines discuss safety critical systems and subsystems, types of hazard analyses, when hazard analyses should be performed, and the hazard analysis philosophy. These guidelines are published by FTA to assist the transit indus...

14 CFR 437.29 - Hazard analysis.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Hazard analysis. 437.29 Section 437.29... Documentation § 437.29 Hazard analysis. (a) An applicant must perform a hazard analysis that complies with § 437.55(a). (b) An applicant must provide to the FAA all the results of each step of the hazard analysis...

14 CFR 437.29 - Hazard analysis.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Hazard analysis. 437.29 Section 437.29... Documentation § 437.29 Hazard analysis. (a) An applicant must perform a hazard analysis that complies with § 437.55(a). (b) An applicant must provide to the FAA all the results of each step of the hazard analysis...

Lunar mission safety and rescue: Hazards analysis and safety requirements

NASA Technical Reports Server (NTRS)

1971-01-01

The results are presented of the hazards analysis which was concerned only with hazards to personnel and not with loss of equipment or property. Hazards characterization includes the definition of a hazard, the hazard levels, and the hazard groups. The analysis methodology is described in detail. The methodology was used to prepare the top level functional flow diagrams, to perform the first level hazards assessment, and to develop a list of conditions and situations requiring individual hazard studies. The 39 individual hazard study results are presented in total.

National Dam Inspection Program. Freethy Dam (NDI ID Number PA-00171, DER ID Number 64-160), Delaware River Basin, Carley Brook, Wayne County, Pennsylvania. Phase I Inspection Report,

DTIC Science & Technology

1981-03-01

Rignt; End of Damn. P. sp LI Tway Stah. "’nt.. - -JZIL E. e efz Abutment. of’ Damn. 74". I I~ 1t 1 1 of Darnm Downstream Side. ~ 4L Gi Ex ir End~ of...susceptible to slope failure; however, the presence of well-developed bedding and Joint planes will result in some rockfall from vertical and high

National Dam Safety Program. Garnerville Dam (Inventory Number N.Y. 744), Hudson River Basin, Rockland County, New York. Phase I Inspection Report,

DTIC Science & Technology

1980-08-01

drain and the 8-inch pipeline are in good operating condition and appear to be well maintained. e. Reservoir Area There are neither slides, rockfalls ...Stability fOpcrc c- ,k- I p. Miscellaneous 1 1I I L Project ._Dheet___ _.. Subject ABy Gi ___ A _ A _Chk. by I 0 Q I 40 CiQI /" e6dn-r-f/aa /Ortf e / 7, 4 o

21 CFR 123.6 - Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan. 123.6 Section 123.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... processor shall have and implement a written HACCP plan whenever a hazard analysis reveals one or more food...

21 CFR 123.6 - Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan. 123.6 Section 123.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... processor shall have and implement a written HACCP plan whenever a hazard analysis reveals one or more food...

A hazard and risk classification system for catastrophic rock slope failures in Norway

NASA Astrophysics Data System (ADS)

Hermanns, R.; Oppikofer, T.; Anda, E.; Blikra, L. H.; Böhme, M.; Bunkholt, H.; Dahle, H.; Devoli, G.; Eikenæs, O.; Fischer, L.; Harbitz, C. B.; Jaboyedoff, M.; Loew, S.; Yugsi Molina, F. X.

2012-04-01

The Geological Survey of Norway carries out systematic geologic mapping of potentially unstable rock slopes in Norway that can cause a catastrophic failure. As catastrophic failure we describe failures that involve substantial fragmentation of the rock mass during run-out and that impact an area larger than that of a rock fall (shadow angle of ca. 28-32° for rock falls). This includes therefore rock slope failures that lead to secondary effects, such as a displacement wave when impacting a water body or damming of a narrow valley. Our systematic mapping revealed more than 280 rock slopes with significant postglacial deformation, which might represent localities of large future rock slope failures. This large number necessitates prioritization of follow-up activities, such as more detailed investigations, periodic monitoring and permanent monitoring and early-warning. In the past hazard and risk were assessed qualitatively for some sites, however, in order to compare sites so that political and financial decisions can be taken, it was necessary to develop a quantitative hazard and risk classification system. A preliminary classification system was presented and discussed with an expert group of Norwegian and international experts and afterwards adapted following their recommendations. This contribution presents the concept of this final hazard and risk classification that should be used in Norway in the upcoming years. Historical experience and possible future rockslide scenarios in Norway indicate that hazard assessment of large rock slope failures must be scenario-based, because intensity of deformation and present displacement rates, as well as the geological structures activated by the sliding rock mass can vary significantly on a given slope. In addition, for each scenario the run-out of the rock mass has to be evaluated. This includes the secondary effects such as generation of displacement waves or landslide damming of valleys with the potential of later outburst floods. It became obvious that large rock slope failures cannot be evaluated on a slope scale with frequency analyses of historical and prehistorical events only, as multiple rockslides have occurred within one century on a single slope that prior to the recent failures had been inactive for several thousand years. In addition, a systematic analysis on temporal distribution indicates that rockslide activity following deglaciation after the Last Glacial Maximum has been much higher than throughout the Holocene. Therefore the classification system has to be based primarily on the geological conditions on the deforming slope and on the deformation rates and only to a lesser weight on a frequency analyses. Our hazard classification therefore is primarily based on several criteria: 1) Development of the back-scarp, 2) development of the lateral release surfaces, 3) development of the potential basal sliding surface, 4) morphologic expression of the basal sliding surface, 5) kinematic feasibility tests for different displacement mechanisms, 6) landslide displacement rates, 7) change of displacement rates (acceleration), 8) increase of rockfall activity on the unstable rock slope, 9) Presence post-glacial events of similar size along the affected slope and its vicinity. For each of these criteria several conditions are possible to choose from (e.g. different velocity classes for the displacement rate criterion). A score is assigned to each condition and the sum of all scores gives the total susceptibility score. Since many of these observations are somewhat uncertain, the classification system is organized in a decision tree where probabilities can be assigned to each condition. All possibilities in the decision tree are computed and the individual probabilities giving the same total score are summed. Basic statistics show the minimum and maximum total scores of a scenario, as well as the mean and modal value. The final output is a cumulative frequency distribution of the susceptibility scores that can be divided into several classes, which are interpreted as susceptibility classes (very high, high, medium, low, and very low). Today the Norwegian Planning and Building Act uses hazard classes with annual probabilities of impact on buildings producing damages (<1/100, <1/1000, <1/5000 and zero for critical buildings). However, up to now there is not enough scientific knowledge to predict large rock slope failures in these strict classes. Therefore, the susceptibility classes will be matched with the hazard classes from the Norwegian Building Act (e.g. very high susceptibility represents the hazard class with annual probability >1/100). The risk analysis focuses on the potential fatalities of a worst case rock slide scenario and its secondary effects only and is done in consequence classes with a decimal logarithmic scale. However we recommend for all high risk objects that municipalities carry out detailed risk analyses. Finally, the hazard and risk classification system will give recommendations where surveillance in form of continuous 24/7 monitoring systems coupled with early-warning systems (high risk class) or periodic monitoring (medium risk class) should be carried out. These measures are understood as to reduce the risk of life loss due to a rock slope failure close to 0 as population can be evacuated on time if a change of stability situation occurs. The final hazard and risk classification for all potentially unstable rock slopes in Norway, including all data used for its classification will be published within the national landslide database (available on www.skrednett.no).

A novel hazard assessment method for biomass gasification stations based on extended set pair analysis

PubMed Central

Yan, Fang; Xu, Kaili; Li, Deshun; Cui, Zhikai

2017-01-01

Biomass gasification stations are facing many hazard factors, therefore, it is necessary to make hazard assessment for them. In this study, a novel hazard assessment method called extended set pair analysis (ESPA) is proposed based on set pair analysis (SPA). However, the calculation of the connection degree (CD) requires the classification of hazard grades and their corresponding thresholds using SPA for the hazard assessment. In regard to the hazard assessment using ESPA, a novel calculation algorithm of the CD is worked out when hazard grades and their corresponding thresholds are unknown. Then the CD can be converted into Euclidean distance (ED) by a simple and concise calculation, and the hazard of each sample will be ranked based on the value of ED. In this paper, six biomass gasification stations are introduced to make hazard assessment using ESPA and general set pair analysis (GSPA), respectively. By the comparison of hazard assessment results obtained from ESPA and GSPA, the availability and validity of ESPA can be proved in the hazard assessment for biomass gasification stations. Meanwhile, the reasonability of ESPA is also justified by the sensitivity analysis of hazard assessment results obtained by ESPA and GSPA. PMID:28938011

14 CFR 437.55 - Hazard analysis.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Hazard analysis. 437.55 Section 437.55... TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.55 Hazard analysis. (a) A permittee must... safety of property resulting from each permitted flight. This hazard analysis must— (1) Identify and...

14 CFR 437.55 - Hazard analysis.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Hazard analysis. 437.55 Section 437.55... TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.55 Hazard analysis. (a) A permittee must... safety of property resulting from each permitted flight. This hazard analysis must— (1) Identify and...

Hydrotreater/Distillation Column Hazard Analysis Report Rev. 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowry, Peter P.; Wagner, Katie A.

This project Hazard and Risk Analysis Report contains the results of several hazard analyses and risk assessments. An initial assessment was conducted in 2012, which included a multi-step approach ranging from design reviews to a formal What-If hazard analysis. A second What-If hazard analysis was completed during February 2013 to evaluate the operation of the hydrotreater/distillation column processes to be installed in a process enclosure within the Process Development Laboratory West (PDL-West) facility located on the PNNL campus. The qualitative analysis included participation of project and operations personnel and applicable subject matter experts. The analysis identified potential hazardous scenarios, eachmore » based on an initiating event coupled with a postulated upset condition. The unmitigated consequences of each hazardous scenario were generally characterized as a process upset; the exposure of personnel to steam, vapors or hazardous material; a spray or spill of hazardous material; the creation of a flammable atmosphere; or an energetic release from a pressure boundary.« less

Automated Hazard Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riddle, F. J.

2003-06-26

The Automated Hazard Analysis (AHA) application is a software tool used to conduct job hazard screening and analysis of tasks to be performed in Savannah River Site facilities. The AHA application provides a systematic approach to the assessment of safety and environmental hazards associated with specific tasks, and the identification of controls regulations, and other requirements needed to perform those tasks safely. AHA is to be integrated into existing Savannah River site work control and job hazard analysis processes. Utilization of AHA will improve the consistency and completeness of hazard screening and analysis, and increase the effectiveness of the workmore » planning process.« less

Hydrothermal Liquefaction Treatment Hazard Analysis Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowry, Peter P.; Wagner, Katie A.

Hazard analyses were performed to evaluate the modular hydrothermal liquefaction treatment system. The hazard assessment process was performed in 2 stages. An initial assessment utilizing Hazard Identification and Preliminary Hazards Analysis (PHA) techniques identified areas with significant or unique hazards (process safety-related hazards) that fall outside of the normal operating envelope of PNNL and warranted additional analysis. The subsequent assessment was based on a qualitative What-If analysis. The analysis was augmented, as necessary, by additional quantitative analysis for scenarios involving a release of hazardous material or energy with the potential for affecting the public. The following selected hazardous scenarios receivedmore » increased attention: •Scenarios involving a release of hazardous material or energy, controls were identified in the What-If analysis table that prevent the occurrence or mitigate the effects of the release. •Scenarios with significant consequences that could impact personnel outside the immediate operations area, quantitative analyses were performed to determine the potential magnitude of the scenario. The set of “critical controls” were identified for these scenarios (see Section 4) which prevent the occurrence or mitigate the effects of the release of events with significant consequences.« less

Hazard Analysis for Building 34 Vacuum Glove Box Assembly

NASA Technical Reports Server (NTRS)

Meginnis, Ian

2014-01-01

One of the characteristics of an effective safety program is the recognition and control of hazards before mishaps or failures occur. Conducting potentially hazardous tests necessitates a thorough hazard analysis in order to prevent injury to personnel, and to prevent damage to facilities and equipment. The primary purpose of this hazard analysis is to define and address the potential hazards and controls associated with the Building 34 Vacuum Glove Box Assembly, and to provide the applicable team of personnel with the documented results. It is imperative that each member of the team be familiar with the hazards and controls associated with his/her particular tasks, assignments and activities while interfacing with facility test systems, equipment and hardware. In fulfillment of the stated purposes, the goal of this hazard analysis is to identify all hazards that have the potential to harm personnel, damage the facility or its test systems or equipment, test articles, Government or personal property, or the environment. This analysis may also assess the significance and risk, when applicable, of lost test objectives when substantial monetary value is involved. The hazards, causes, controls, verifications, and risk assessment codes have been documented on the hazard analysis work sheets in Appendix A of this document. The preparation and development of this report is in accordance with JPR 1700.1, "JSC Safety and Health Handbook" and JSC 17773 Rev D "Instructions for Preparation of Hazard Analysis for JSC Ground Operations".

Seismic monitoring of effusive-explosive activity and large lava dome collapses during 2013-2015 at Volcán de Colima, Mexico

NASA Astrophysics Data System (ADS)

Arámbula-Mendoza, Raúl; Reyes-Dávila, Gabriel; Vargas-Bracamontes Dulce, M.; González-Amezcua, Miguel; Navarro-Ochoa, Carlos; Martínez-Fierros, Alejandro; Ramírez-Vázquez, Ariel

2018-02-01

Volcán de Colima, the most active volcano in Mexico, started a new eruptive cycle in January 2013. Since this date, the volcano has presented effusive and explosive activity. The beginning of the cycle was marked by a moderate Vulcanian explosion which had hyperbolical behavior in its precursory seismicity, possibly related to a shallow rupture process. Then, during the whole eruptive stage, the effusive activity was accompanied by low to moderate explosions. The explosions had energies mainly of 106 joules and were located between 0 and 1600 m below the crater, whereas the locations of tremor sources were found to be deeper, reaching up to 3800 m beneath the crater. Very-long-period signals (VLPs) have been observed with Vulcanian explosions that produce pyroclastic flows. A few number of volcano-tectonic events (VTs) were recognized during the studied period (2013-2015), indicating that the volcano is an open system. This was particularly evidenced in July 2015, when a new batch of magma rose rapidly without large precursors, only an accelerated increase in the number of rockfalls and associated RSEM. This event generated two large lava dome collapses with several pulses of material and pyroclastic flows that travelled up to 10.3 km from the summit. The seismic monitoring of Volcán de Colima is currently the only tool in real-time employed to assess the state of the volcanic activity. It is thus necessary to integrate new seismic methods as well as other geophysical monitoring techniques able to detect precursory signals of an impending hazardous event.

Frequency-dependent seismic attenuation in the eastern United States as observed from the 2011 central Virginia earthquake and aftershock sequence

USGS Publications Warehouse

McNamara, Daniel E.; Gee, Lind; Benz, Harley M.; Chapman, Martin

2014-01-01

Ground shaking due to earthquakes in the eastern United States (EUS) is felt at significantly greater distances than in the western United States (WUS) and for some earthquakes it has been shown to display a strong preferential direction. Shaking intensity variation can be due to propagation path effects, source directivity, and/or site amplification. In this paper, we use S and Lg waves recorded from the 2011 central Virginia earthquake and aftershock sequence, in the Central Virginia Seismic Zone, to quantify attenuation as frequency‐dependent Q(f). In support of observations based on shaking intensity, we observe high Q values in the EUS relative to previous studies in the WUS with especially efficient propagation along the structural trend of the Appalachian mountains. Our analysis of Q(f) quantifies the path effects of the northeast‐trending felt distribution previously inferred from the U.S. Geological Survey (USGS) “Did You Feel It” data, historic intensity data, and the asymmetrical distribution of rockfalls and landslides.

78 FR 69604 - Current Good Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-20

... Manufacturing Practice and Hazard Analysis and Risk- Based Preventive Controls for Human Food; Extension of... Hazard Analysis and Risk- Based Preventive Controls for Human Food'' and its information collection... Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for Human Food.'' IV. How To...

Hazard Analysis for Pneumatic Flipper Suitport/Z-1 Manned Evaluation, Chamber B, Building 32. Revision: Basic

NASA Technical Reports Server (NTRS)

2012-01-01

One of the characteristics of an effective safety program is the recognition and control of hazards before mishaps or failures occur. Conducting potentially hazardous tests necessitates a thorough hazard analysis in order to protect our personnel from injury and our equipment from damage. The purpose of this hazard analysis is to define and address the potential hazards and controls associated with the Z1 Suit Port Test in Chamber B located in building 32, and to provide the applicable team of personnel with the documented results. It is imperative that each member of the team be familiar with the hazards and controls associated with his/her particular tasks, assignments, and activities while interfacing with facility test systems, equipment, and hardware. The goal of this hazard analysis is to identify all hazards that have the potential to harm personnel and/or damage facility equipment, flight hardware, property, or harm the environment. This analysis may also assess the significance and risk, when applicable, of lost test objectives when substantial monetary value is involved. The hazards, causes, controls, verifications, and risk assessment codes have been documented on the hazard analysis work sheets in appendix A of this document. The preparation and development of this report is in accordance with JPR 1700.1, JSC Safety and Health Handbook.

[Hazard function and life table: an introduction to the failure time analysis].

PubMed

Matsushita, K; Inaba, H

1987-04-01

Failure time analysis has become popular in demographic studies. It can be viewed as a part of regression analysis with limited dependent variables as well as a special case of event history analysis and multistate demography. The idea of hazard function and failure time analysis, however, has not been properly introduced to nor commonly discussed by demographers in Japan. The concept of hazard function in comparison with life tables is briefly described, where the force of mortality is interchangeable with the hazard rate. The basic idea of failure time analysis is summarized for the cases of exponential distribution, normal distribution, and proportional hazard models. The multiple decrement life table is also introduced as an example of lifetime data analysis with cause-specific hazard rates.

78 FR 24691 - Current Good Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-26

... Manufacturing Practice and Hazard Analysis and Risk- Based Preventive Controls for Human Food; Extension of... Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for Human Food'' that appeared in... Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for Human Food'' with a 120-day...

Sequential dome-collapse nuées ardentes analyzed from broadband seismic data, Merapi Volcano, Indonesia

USGS Publications Warehouse

Brodscholl, A.; Kirbani, S.B.; Voight, B.

2000-01-01

The broadband data were evaluated using the assumption that avalanches with the same source areas and descent paths exhibit a linear relation between source volume and recorded seismic-amplitude envelope area. A result of the analysis is the determination of the volume of selected individual events. From the field surveys, the total volume of the collapsed dome lava is 2.6 Mm3. Discounting the volumetric influence of rockfalls, the average size of the 44 nuées ardentes is therefore about 60,000 m3. The largest collapse event at 10:54 is estimated to involve 260,000 m3, based on an analysis of the seismicity. The remaining 23 phase I events averaged 60,000 m3, with the total volume of all phase I events accounting for 63% of the unstable dome. The 20 phase II events comprised 37% of the total volume and averaged 47,000 m3. The methods described here can be put to practical use in real-time monitoring situations. Broadband data were essential in this study primarily because of the wide dynamic range.

Multiple remote-sensing assessment of the catastrophic collapse in Langtang Valley induced by the 2015 Gorkha earthquake

NASA Astrophysics Data System (ADS)

Nagai, Hiroto; Watanabe, Manabu; Tomii, Naoya; Tadono, Takeo; Suzuki, Shinichi

2017-11-01

The main shock of the 2015 Gorkha Earthquake in Nepal induced numerous avalanches, rockfalls, and landslides in Himalayan mountain regions. A major village in the Langtang Valley was destroyed and numerous people were victims of a catastrophic avalanche event, which consisted of snow, ice, rock, and blast wind. Understanding the hazard process mainly depends on limited witness accounts, interviews, and an in situ survey after a monsoon season. To record the immediate situation and to understand the deposition process, we performed an assessment by means of satellite-based observations carried out no later than 2 weeks after the event. The avalanche-induced sediment deposition was delineated with the calculation of decreasing coherence and visual interpretation of amplitude images acquired from the Phased Array-type L-band Synthetic Aperture Radar-2 (PALSAR-2). These outline areas are highly consistent with that delineated from a high-resolution optical image of WorldView-3 (WV-3). The delineated sediment areas were estimated as 0.63 km2 (PALSAR-2 coherence calculation), 0.73 km2 (PALSAR-2 visual interpretation), and 0.88 km2 (WV-3). In the WV-3 image, surface features were classified into 10 groups. Our analysis suggests that the avalanche event contained a sequence of (1) a fast splashing body with an air blast, (2) a huge, flowing muddy mass, (3) less mass flowing from another source, (4) a smaller amount of splashing and flowing mass, and (5) splashing mass without flowing on the east and west sides. By means of satellite-derived pre- and post-event digital surface models, differences in the surface altitudes of the collapse events estimated the total volume of the sediments as 5.51 ± 0.09 × 106 m3, the largest mass of which are distributed along the river floor and a tributary water stream. These findings contribute to detailed numerical simulation of the avalanche sequences and source identification; furthermore, altitude measurements after ice and snow melting would reveal a contained volume of melting ice and snow.

Towards a debris-flow warning system based on hydrological measurements of the triggering conditions. A study of El Rebaixader catchment (Central Pyrenees, Spain)

NASA Astrophysics Data System (ADS)

Abancó, Clàudia; Hürlimann, Marcel; Moya, José

2014-05-01

Debris flows represent a risk to the society due to their high destructive power. Rainfall is the main debris-flow triggering factor. Rainfall thresholds are generally used for warning of debris flow occurrence in susceptible catchments. However, the efficiency of such thresholds for real time hazard assessment is often conditioned by many factors, such as: the location and number of the rain gauges used (both to define the thresholds, and for setting off warnings); the temporal and spatial evolution of rainfall's convective cells or the effect of snow cover melting. These factors affect the length of the warning time, which is of crucial importance for issuing alert messages or alarms to the people and infrastructures at risk. The Rebaixader catchment (Central Pyrenees, Spain) is being monitored since 2009 by six stations recording information on initiation (4 stations) and flow detection and cinematic behaviour (2 stations). Until December 2013, 7 debris flows, 17 debris floods and 4 rockfalls have been recorded. The objectives of this work were: a) the definition of rainfall thresholds at two different rain gauges; b) the analysis of the infiltration patterns in order to define their potential use for warning systems and c) preliminary testing of rainfall thresholds' efficiency in terms of warning time, in this catchment. This last goal consisted in the comparison of the time elapsed between the rainfall threshold was exceeded and the event occurrence was detected by the stations at the channel area. The results suggest that the intensity-duration rainfall thresholds sometimes provide warning times which would be too short for an adequate reaction in the Rebaixader catchment (less than 10 minutes). The combination of such rainfall thresholds with infiltration measurements is useful to increase the warning time. This occurs especially in the events triggered in spring, when the snowmelt plays an important role in the event's triggering conditions. However, the effects of infiltration associated to the summer convective rainfalls are almost imperceptible; therefore their importance in warning systems decreases.

77 FR 55371 - System Safety Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-07

...-based rule and FRA seeks comments on all aspects of the proposed rule. An SSP would be implemented by a... SSP would be the risk-based hazard management program and risk-based hazard analysis. A properly implemented risk-based hazard management program and risk-based hazard analysis would identify the hazards and...

9 CFR 417.2 - Hazard Analysis and HACCP Plan.

Code of Federal Regulations, 2012 CFR

2012-01-01

... more food safety hazards that are reasonably likely to occur, based on the hazard analysis conducted in... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Hazard Analysis and HACCP Plan. 417.2 Section 417.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

9 CFR 417.2 - Hazard Analysis and HACCP Plan.

Code of Federal Regulations, 2014 CFR

2014-01-01

... more food safety hazards that are reasonably likely to occur, based on the hazard analysis conducted in... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Hazard Analysis and HACCP Plan. 417.2 Section 417.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

9 CFR 417.2 - Hazard Analysis and HACCP Plan.

Code of Federal Regulations, 2011 CFR

2011-01-01

... more food safety hazards that are reasonably likely to occur, based on the hazard analysis conducted in... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Hazard Analysis and HACCP Plan. 417.2 Section 417.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

9 CFR 417.2 - Hazard Analysis and HACCP Plan.

Code of Federal Regulations, 2013 CFR

2013-01-01

... more food safety hazards that are reasonably likely to occur, based on the hazard analysis conducted in... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Hazard Analysis and HACCP Plan. 417.2 Section 417.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

9 CFR 417.2 - Hazard Analysis and HACCP Plan.

Code of Federal Regulations, 2010 CFR

2010-01-01

... more food safety hazards that are reasonably likely to occur, based on the hazard analysis conducted in... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Hazard Analysis and HACCP Plan. 417.2 Section 417.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

Externally triggered renewed bubble nucleation in basaltic magma: the 12 October 2008 eruption at Halema‘uma‘u Overlook vent, Kīlauea, Hawai‘i, USA

USGS Publications Warehouse

Carey, Rebecca J.; Manga, Michael; Degruyter, Wim; Swanson, Donald; Houghton, Bruce F.; Orr, Tim R.; Patrick, Matthew R.

2012-01-01

From October 2008 until present, dozens of small impulsive explosive eruptions occurred from the Overlook vent on the southeast side of Halema‘uma‘u Crater, at Kīlauea volcano, USA. These eruptions were triggered by rockfalls from the walls of the volcanic vent and conduit onto the top of the lava column. Here we use microtextural observations and data from clasts erupted during the well-characterized 12 October 2008 explosive eruption at Halema‘uma‘u to extend existing models of eruption triggering. We present a potential mechanism for this eruption by combining microtextural observations with existing geophysical and visual data sets. We measure the size and number density of bubbles preserved in juvenile ejecta using 2D images and X-ray microtomography. Our data suggest that accumulations of large bubbles with diameters of >50μm to at least millimeters existed at shallow levels within the conduit prior to the 12 October 2008 explosion. Furthermore, a high number density of small bubbles <50 μm is measured in the clasts, implying very rapid nucleation of bubbles. Visual observations, combined with preexisting geophysical data, suggest that the impact of rockfalls onto the magma free surface induces pressure changes over short timescales that (1) nucleated new additional bubbles in the shallow conduit leading to high number densities of small bubbles and (2) expanded the preexisting bubbles driving upward acceleration. The trigger of eruption and bubble nucleation is thus external to the degassing system.

14 CFR 417.227 - Toxic release hazard analysis.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Toxic release hazard analysis. 417.227..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.227 Toxic release hazard analysis. A flight safety analysis must establish flight commit criteria that protect the public from any...

Mobile Laser Scanning along Dieppe coastal cliffs: reliability of the acquired point clouds applied to rockfall assessments

NASA Astrophysics Data System (ADS)

Michoud, Clément; Carrea, Dario; Augereau, Emmanuel; Cancouët, Romain; Costa, Stéphane; Davidson, Robert; Delacourt, Chirstophe; Derron, Marc-Henri; Jaboyedoff, Michel; Letortu, Pauline; Maquaire, Olivier

2013-04-01

Dieppe coastal cliffs, in Normandy, France, are mainly formed by sub-horizontal deposits of chalk and flintstone. Largely destabilized by an intense weathering and the Channel sea erosion, small and large rockfalls are regularly observed and contribute to retrogressive cliff processes. During autumn 2012, cliff and intertidal topographies have been acquired with a Terrestrial Laser Scanner (TLS) and a Mobile Laser Scanner (MLS), coupled with seafloor bathymetries realized with a multibeam echosounder (MBES). MLS is a recent development of laser scanning based on the same theoretical principles of aerial LiDAR, but using smaller, cheaper and portable devices. The MLS system, which is composed by an accurate dynamic positioning and orientation (INS) devices and a long range LiDAR, is mounted on a marine vessel; it is then possible to quickly acquire in motion georeferenced LiDAR point clouds with a resolution of about 15 cm. For example, it takes about 1 h to scan of shoreline of 2 km long. MLS is becoming a promising technique supporting erosion and rockfall assessments along the shores of lakes, fjords or seas. In this study, the MLS system used to acquire cliffs and intertidal areas of the Cap d'Ailly was composed by the INS Applanix POS-MV 320 V4 and the LiDAR Optech Ilirs LR. On the same day, three MLS scans with large overlaps (J1, J21 and J3) have been performed at ranges from 600 m at 4 knots (low tide) up to 200 m at 2.2 knots (up tide) with a calm sea at 2.5 Beaufort (small wavelets). Mean scan resolutions go from 26 cm for far scan (J1) to about 8.1 cm for close scan (J3). Moreover, one TLS point cloud on this test site has been acquired with a mean resolution of about 2.3 cm, using a Riegl LMS Z390i. In order to quantify the reliability of the methodology, comparisons between scans have been realized with the software Polyworks™, calculating shortest distances between points of one cloud and the interpolated surface of the reference point cloud. A MatLab™ routine was also written to extract interesting statistics. First, mean distances between points of the reference point clouds (J21) and its interpolated surface are about 0.35 cm with a standard deviation of 15 cm; errors introduced during the surface interpolation step, especially in vegetated areas, may explain those differences. Then, mean distances between J1's points (resp. J3) and the J21's reference surface are about 4 cm (resp. -17 cm) with a standard deviation of 53 cm (resp. 55 cm). After a best fit alignment of J1 and J3 on J21, mean distances between J1 (resp. J3) and the J21's reference surface decrease to about 0.15 cm (resp. 1.6 cm) with a standard deviation of 41 cm (resp. 21 cm). Finally, mean distances between the TLS point clouds and the J21's reference surface are about 3.2 cm with a standard deviation of 26 cm. In conclusion, MLS devices are able to quickly scan long shoreline with a resolution up to about 10 cm. The precision of the acquired data is relatively small enough to investigate on geomorphological features of coastal cliffs. The ability of the MLS technique to detect and monitor small and large rockfalls will be investigated thanks to new acquisitions of the Dieppe cliffs in a close future and enhanced adapted post-processing steps.

Alpine Cliff Backwearing Rates Derived From Cosmogenic 10-Be in Active Medial Moraines

NASA Astrophysics Data System (ADS)

Ward, D. J.; Anderson, R. S.

2008-12-01

We use cosmogenic 10Be concentrations in rock samples from an active, ice-cored medial moraine to constrain glacial valley sidewall backwearing rates in the Kichatna Mountains, Alaska Range, Alaska. Kilometer-tall granite walls that tower over active glaciers are some of the most dramatic landscape features of the Alaska Range. The sheer scale of the relief speaks to the relative rates of valley incision by glaciers and rockwall retreat, but these rates are difficult to determine independently of one another. We present a method that uses cosmogenic nuclides to measure rockwall backwearing rates in glaciated settings on timescales of 103 yr, with a straightforward sampling strategy that exploits active medial moraines. Ablation-dominated medial moraines form by exhumation of debris-rich ice in the ablation zone of a glacier. Exhumed debris insulates the underlying ice and reduces its ablation rate relative to bare ice, promoting formation of a ridge-like, ice cored moraine. The rock debris is primarily derived from supraglacial rockfalls, which become incorporated in the ice along the glacier margins in the accumulation area. These lateral bands of debris-rich ice merge to form a medial debris band when glacial tributaries converge. The debris is minimally mixed until it is exhumed on the moraine crest. In the simplest case, such a system serves as a conveyor belt, bringing material from a specific part of the ablation zone valley wall to a specific point on a medial moraine in the ablation zone. We collected 5 grab samples, each consisting of ~30 2-10 cm rock fragments of the same lithology, from a 4.5 km longitudinal transect on the crest of the medial moraine of the Shadows glacier. We sampled the crest to minimize the amount of post-exhumation transport and mixing that may have occurred; each sample probably contains rocks from only one to a few rockfall events. Measured 10Be concentrations range from 1.5x104 to 3x104 at/g-qtz and are higher downvalley. First-order interpretation of these results yields minimum erosion rates of 0.2 to 0.5 mm/yr, consistent with erosion rates measured by various means in other glacial environments. This interpretation assumes a simple source area geometry and 10Be production rate scaling. To interpret these measurements in their full geological and topographic context, we present numerical models to describe how the expected distribution of 10Be concentrations should vary with erosion rate. This relationship is affected by source area hypsography and the distributions of size and recurrence interval of rockfall events. We randomly sample events based on a power-law size-recurrence relationship (constrained by field observations) from a numerical grid of production rates derived from a DEM of the source area. This yields the expected probability distribution of 10Be concentrations in the rockfall debris for a given mean erosion rate, weighted by event volume and source hypsography. The measured 10Be concentrations are low enough that accumulation during burial, exhumation, and transport in the medial moraine could account for up to ~1/4 of the signal, given our best estimates of glacier's surface speed (~30 m/yr). The slight downvalley increase in the concentrations supports a component of exposure in the moraine during transport. The amount of exposure depends on factors such as the entry and exit points of debris incorporated into the glacial ice, and the glacial mass balance pattern, and downvalley surface speed. We assess these effects with analytical and numerical models of debris transport in medial moraines, following Anderson (2000).

Development of a Probabilistic Tsunami Hazard Analysis in Japan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toshiaki Sakai; Tomoyoshi Takeda; Hiroshi Soraoka

2006-07-01

It is meaningful for tsunami assessment to evaluate phenomena beyond the design basis as well as seismic design. Because once we set the design basis tsunami height, we still have possibilities tsunami height may exceeds the determined design tsunami height due to uncertainties regarding the tsunami phenomena. Probabilistic tsunami risk assessment consists of estimating for tsunami hazard and fragility of structures and executing system analysis. In this report, we apply a method for probabilistic tsunami hazard analysis (PTHA). We introduce a logic tree approach to estimate tsunami hazard curves (relationships between tsunami height and probability of excess) and present anmore » example for Japan. Examples of tsunami hazard curves are illustrated, and uncertainty in the tsunami hazard is displayed by 5-, 16-, 50-, 84- and 95-percentile and mean hazard curves. The result of PTHA will be used for quantitative assessment of the tsunami risk for important facilities located on coastal area. Tsunami hazard curves are the reasonable input data for structures and system analysis. However the evaluation method for estimating fragility of structures and the procedure of system analysis is now being developed. (authors)« less

A critical analysis of hazard resilience measures within sustainability assessment frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, Elizabeth C., E-mail: echiso1@lsu.edu; Sattler, Meredith, E-mail: msattler@lsu.edu; Friedland, Carol J., E-mail: friedland@lsu.edu

Today, numerous sustainability assessment frameworks (SAFs) exist to guide designers in achieving sustainable performance in the design of structures and communities. SAFs are beneficial in educating users and are useful tools for incorporating sustainability strategies into planning, design, and construction; however, there is currently a substantial gap in the ability of existing SAFs to incorporate hazard resistance and hazard mitigation in the broader context of sustainable design. This paper analyzes the incorporation of hazard resistant design and hazard mitigation strategies within SAFs via a multi-level analysis of eleven SAFs. The SAFs analyzed range in scale of application (i.e. building, site,more » community). Three levels of analysis are presented: (1) macro-level analysis comparing the number of measures strictly addressing resilience versus sustainability, (2) meso-level analysis of the coverage of types of hazards within SAFs (e.g. flood, fire), and (3) micro-level analysis of SAF measures connected to flood-related hazard resilience. The results demonstrate that hazard resistance and hazard mitigation do not figure prominently in the intent of SAFs and that weaknesses in resilience coverage exist that have the potential to lead to the design of structures and communities that are still highly vulnerable to the impacts of extreme events. - Highlights: • Sustainability assessment frameworks (SAFs) were analyzed for resilience coverage • Hazard resistance and mitigation do not figure prominently in the intent of SAFs • Approximately 75% of SAFs analyzed address three or fewer hazards • Lack of economic measures within SAFs could impact resilience and sustainability • Resilience measures for flood hazards are not consistently included in SAFs.« less

Enhancement of archaeological heritage. El Risco de las Cuevas at Perales de Tajuña, Madrid (Spain)

NASA Astrophysics Data System (ADS)

Freire-Lista, David Martin; Alvarez de Buergo, Mónica; Fort, Rafael

2016-04-01

Heritage conservation has a great impact on the economy of a country. The enhancement of archaeological sites is an investment that promotes tourism and culture. The interdisciplinary knowledge of heritage should be the basis of its management. Preventive actions, non-destructive analytical techniques and monitoring for the conservation of these assets should be promoted. "El Risco de las Cuevas" is a highly decayed and nearly vertical gypsum escarpment which contains a series of dwellings excavated during the Chalcolithic and much more recent times. It is located at Perales de Tajuña, 40 km southeast of Madrid, Spain. This monument is approximately 70 metres high and 500 metres wide. It was listed as a cultural and monumental heritage site by the regional government of Madrid in 1998. The gypsum escarpment housing the dwellings forms part of a lower Miocene unit (Madrid Basin). Debris cones with a mixture of debris from the lower, medium and upper units are found at the bottom of the rockwall. The vulnerability of this monument to atmospheric agents has been studied using "in situ" monitoring techniques of humidity, temperature and rate of rockfalls. Drones have been used for aerial photography in the highest areas of the escarpment and have provided an information network of fractures likely to cause rockfall. Gypsum artificial accelerated ageing has been carried out in the laboratory, including freeze/thaw, wet/dry, thermal shock and dissolution tests. To determine the response of these accelerated ageing processes, density, micro-roughness, ultrasound velocities (Vp and Vs), air permeability and microscopy measurements were made before, during and after ageing tests. Geomorphological studies, rates of decay, material characteristics and durability tests indicate that the decay is controlled by the mineralogy, clay content and porosity of the gypsum rock, as well as microclimate, temperature changes and rock fractures. Rockfalls are particularly relevant in the safety of the monument and visitors. The enhancement of El Risco de las Cuevas has involved both local government (City council of Perales de Tajuña) and regional one (General Directorate of Historical Heritage of the Community of Madrid), besides the Institute of Geosciences IGEO (CSIC-UCM). Thanks to the collaboration of these agencies an interpretation centre has been created, preserving El Risco de las Cuevas in an educational and user-friendly manner. By conducting tours during the Science week of Madrid this promotes citizen participation, dissemination and social transfer, which are essential to preserve heritage. A project has been designed to monitor and ensure control and stability of the monument Acknowledgements: Community of Madrid for financing Geomateriales2 program (P2013/MIT2914), CEI-Moncloa UCM-UPM, Applied Petrology for Heritage Stone Materials Conservation Research Group and local government of Perales de Tajuña.

K Basin Hazard Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

PECH, S.H.

This report describes the methodology used in conducting the K Basins Hazard Analysis, which provides the foundation for the K Basins Final Safety Analysis Report. This hazard analysis was performed in accordance with guidance provided by DOE-STD-3009-94, Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports and implements the requirements of DOE Order 5480.23, Nuclear Safety Analysis Report.

Scenario earthquake hazards for the Long Valley Caldera-Mono Lake area, east-central California (ver. 2.0, January 2018)

USGS Publications Warehouse

Chen, Rui; Branum, David M.; Wills, Chris J.; Hill, David P.

2014-06-30

As part of the U.S. Geological Survey’s (USGS) multi-hazards project in the Long Valley Caldera-Mono Lake area, the California Geological Survey (CGS) developed several earthquake scenarios and evaluated potential seismic hazards, including ground shaking, surface fault rupture, liquefaction, and landslide hazards associated with these earthquake scenarios. The results of these analyses can be useful in estimating the extent of potential damage and economic losses because of potential earthquakes and also for preparing emergency response plans.The Long Valley Caldera-Mono Lake area has numerous active faults. Five of these faults or fault zones are considered capable of producing magnitude ≥6.7 earthquakes according to the Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2) developed by the 2007 Working Group on California Earthquake Probabilities (WGCEP) and the USGS National Seismic Hazard Mapping Program. These five faults are the Fish Slough, Hartley Springs, Hilton Creek, Mono Lake, and Round Valley Faults. CGS developed earthquake scenarios for these five faults in the study area and for the White Mountains Fault Zone to the east of the study area.In this report, an earthquake scenario is intended to depict the potential consequences of significant earthquakes. A scenario earthquake is not necessarily the largest or most damaging earthquake possible on a recognized fault. Rather it is both large enough and likely enough that emergency planners should consider it in regional emergency response plans. In particular, the ground motion predicted for a given scenario earthquake does not represent a full probabilistic hazard assessment, and thus it does not provide the basis for hazard zoning and earthquake-resistant building design.Earthquake scenarios presented here are based on fault geometry and activity data developed by the WGCEP, and are consistent with the 2008 Update of the United States National Seismic Hazard Maps (NSHM). Alternatives to the NSHM scenario were developed for the Hilton Creek and Hartley Springs Faults to account for different opinions in how far these two faults extend into Long Valley Caldera. For each scenario, ground motions were calculated using the current standard practice: the deterministic seismic hazard analysis program developed by Art Frankel of USGS and three Next Generation Ground Motion Attenuation (NGA) models. Ground motion calculations incorporated the potential amplification of seismic shaking by near-surface soils defined by a map of the average shear wave velocity in the uppermost 30 m (VS30) developed by CGS.In addition to ground shaking and shaking-related ground failure such as liquefaction and earthquake induced landslides, earthquakes cause surface rupture displacement, which can lead to severe damage of buildings and lifelines. For each earthquake scenario, potential surface fault displacements are estimated using deterministic and probabilistic approaches. Liquefaction occurs when saturated sediments lose their strength because of ground shaking. Zones of potential liquefaction are mapped by incorporating areas where loose sandy sediments, shallow groundwater, and strong earthquake shaking coincide in the earthquake scenario. The process for defining zones of potential landslide and rockfall incorporates rock strength, surface slope, and existing landslides, with ground motions caused by the scenario earthquake.Each scenario is illustrated with maps of seismic shaking potential and fault displacement, liquefaction, and landslide potential. Seismic shaking is depicted by the distribution of shaking intensity, peak ground acceleration, and 1.0-second spectral acceleration. One-second spectral acceleration correlates well with structural damage to surface facilities. Acceleration greater than 0.2 g is often associated with strong ground shaking and may cause moderate to heavy damage. The extent of strong shaking is influenced by subsurface fault dip and near surface materials. Strong shaking is more widespread in the hanging wall regions of a normal fault. Larger ground motions also occur where young alluvial sediments amplify the shaking. Both of these effects can lead to strong shaking that extends farther from the fault on the valley side than on the hill side.The effect of fault rupture displacements may be localized along the surface trace of the mapped earthquake fault if fault geometry is simple and the fault traces are accurately located. However, surface displacement hazards can spread over a few hundred meters to a few kilometers if the earthquake fault has numerous splays or branches, such as the Hilton Creek Fault. Faulting displacements are estimated to be about 1 meter along normal faults in the study area and close to 2 meters along the White Mountains Fault Zone.All scenarios show the possibility of widespread ground failure. Liquefaction damage would likely occur in the areas of higher ground shaking near the faults where there are sandy/silty sediments and the depth to groundwater is 6.1 meters (20 feet) or less. Generally, this means damage is most common near lakes and streams in the areas of strongest shaking. Landslide potential exists throughout the study region. All steep slopes (>30 degrees) present a potential hazard at any level of shaking. Lesser slopes may have landslides within the areas of the higher ground shaking. The landslide hazard zones also are likely sources for snow avalanches during winter months and for large boulders that can be shaken loose and roll hundreds of feet down hill, which happened during the 1980 Mammoth Lakes earthquakes.Whereas methodologies used in estimating ground shaking, liquefaction, and landslides are well developed and have been applied in published hazard maps; methodologies used in estimating surface fault displacement are still being developed. Therefore, this report provides a more in-depth and detailed discussion of methodologies used for deterministic and probabilistic fault displacement hazard analyses for this project.

New early warning system for gravity-driven ruptures based on codetection of acoustic signal

NASA Astrophysics Data System (ADS)

Faillettaz, J.

2016-12-01

Gravity-driven rupture phenomena in natural media - e.g. landslide, rockfalls, snow or ice avalanches - represent an important class of natural hazards in mountainous regions. To protect the population against such events, a timely evacuation often constitutes the only effective way to secure the potentially endangered area. However, reliable prediction of imminence of such failure events remains challenging due to the nonlinear and complex nature of geological material failure hampered by inherent heterogeneity, unknown initial mechanical state, and complex load application (rainfall, temperature, etc.). Here, a simple method for real-time early warning that considers both the heterogeneity of natural media and characteristics of acoustic emissions attenuation is proposed. This new method capitalizes on codetection of elastic waves emanating from microcracks by multiple and spatially separated sensors. Event-codetection is considered as surrogate for large event size with more frequent codetected events (i.e., detected concurrently on more than one sensor) marking imminence of catastrophic failure. Simple numerical model based on a Fiber Bundle Model considering signal attenuation and hypothetical arrays of sensors confirms the early warning potential of codetection principles. Results suggest that although statistical properties of attenuated signal amplitude could lead to misleading results, monitoring the emergence of large events announcing impeding failure is possible even with attenuated signals depending on sensor network geometry and detection threshold. Preliminary application of the proposed method to acoustic emissions during failure of snow samples has confirmed the potential use of codetection as indicator for imminent failure at lab scale. The applicability of such simple and cheap early warning system is now investigated at a larger scale (hillslope). First results of such a pilot field experiment are presented and analysed.

PREFACE: International Symposium on Geohazards and Geomechanics (ISGG2015)

NASA Astrophysics Data System (ADS)

Utili, S.

2015-09-01

These Conference Proceedings contain the full papers in electronic format of the International Symposium on 'Geohazards and Geomechanics', held at University of Warwick, UK, on September 10-11, 2015. The Symposium brings together the complementary expertise of world leading groups carrying out research on the engineering assessment, prevention and mitigation of geohazards. A total of 58 papers, including 8 keynote lectures cover phenomena such as landslide initiation and propagation, debris flow, rockfalls, soil liquefaction, ground improvement, hazard zonation, risk mapping, floods and gas and leachates. The techniques reported in the papers to investigate geohazards involve numerical modeling (finite element method, discrete element method, material point method, meshless methods and particle methods), experimentation (laboratory experiments, centrifuge tests and field monitoring) and analytical simplified techniques. All the contributions in this volume have been peered reviewed according to rigorous international standards. However the authors take full responsibility for the content of their papers. Agreements are in place for the edition of a special issue dedicated to the Symposium in three international journals: Engineering Geology, Computational Particle Mechanics and International Journal of Geohazards and Environment. Authors of selected papers will be invited to submit an extended version of their work to these Journals that will independently assess the papers. The Symposium is supported by the Technical Committee 'Geo-mechanics from Micro to Macro' (TC105) of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE), 'Slope Stability in Engineering Practice' (TC208), 'Forensic Geotechnical Engineering' (TC302), the British Geotechnical Association and the EU FP7 IRSES project 'Geohazards and Geomechanics'. Also the organizers would like to thank all authors and their supporting institutions for their contributions. For any further enquiries or information on the conference proceedings please contact the organizer, Dr Stefano Utili, University of Warwick, s.utili@warwick.ac.uk.

Gypsum scarps and asymmetric fluvial valleys in evaporitic terrains. The role of river migration, landslides, karstification and lithology (Ebro River, NE Spain)

NASA Astrophysics Data System (ADS)

Guerrero, J.; Gutiérrez, F.

2017-11-01

Most of the Spanish fluvial systems excavated in Tertiary evaporitic gypsum formations show asymmetric valleys characterized by a stepped sequence of fluvial terraces on one valley flank and kilometric-long and > 100-m high prominent river scarp on the opposite side of the valley. Scarp undermining by the continuous preferential lateral migration of the river channel toward the valley margin leads to vertical to overhanging unstable slopes affected by a large number of slope failures that become the main geological hazard for villages located at the toe of the scarps. Detailed mapping of the gypsum scarps along the Ebro and Huerva Rivers gypsum scarps demonstrates that landslides and lateral spreading processes are predominant when claystones crop out at the base of the scarp, while rockfalls and topples become the dominant movement in those reaches where the rock mass is mainly constituted by evaporites. The dissolution of gypsum nodules, seasonal swelling and shrinking, and dispersion processes contribute to a decrease in the mechanical strength of claystones. The existence of dissolution-enlarged joints, sinkholes, and severely damaged buildings at the toe of the scarp from karstic subsidence demonstrates that the interstratal karstification of evaporites becomes a triggering factor in the instability of the rock mass. The genesis of asymmetric valleys and river gypsum scarps in the study area seem to be caused by the random migration of the river channel in the absence of lateral tilting related to tectonics or dissolution-induced subsidence. Once the scarp is developed, its preservation depends on the physicochemical properties of the substratum, the ratio between bedrock erosion and river incision rates, and climatic conditions that favour runoff erosion versus dissolution.

A conceptual framework for economic optimization of single hazard surveillance in livestock production chains.

PubMed

Guo, Xuezhen; Claassen, G D H; Oude Lansink, A G J M; Saatkamp, H W

2014-06-01

Economic analysis of hazard surveillance in livestock production chains is essential for surveillance organizations (such as food safety authorities) when making scientifically based decisions on optimization of resource allocation. To enable this, quantitative decision support tools are required at two levels of analysis: (1) single-hazard surveillance system and (2) surveillance portfolio. This paper addresses the first level by presenting a conceptual approach for the economic analysis of single-hazard surveillance systems. The concept includes objective and subjective aspects of single-hazard surveillance system analysis: (1) a simulation part to derive an efficient set of surveillance setups based on the technical surveillance performance parameters (TSPPs) and the corresponding surveillance costs, i.e., objective analysis, and (2) a multi-criteria decision making model to evaluate the impacts of the hazard surveillance, i.e., subjective analysis. The conceptual approach was checked for (1) conceptual validity and (2) data validity. Issues regarding the practical use of the approach, particularly the data requirement, were discussed. We concluded that the conceptual approach is scientifically credible for economic analysis of single-hazard surveillance systems and that the practicability of the approach depends on data availability. Copyright © 2014 Elsevier B.V. All rights reserved.

78 FR 11611 - Current Good Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-19

... Manufacturing Practice and Hazard Analysis and Risk- Based Preventive Controls for Human Food; Extension of... Analysis and Risk-Based Preventive Controls for Human Food.'' FOR FURTHER INFORMATION CONTACT: Domini Bean... Practice and Hazard Analysis and Risk-Based Preventive Controls for Human Food'' with a 120-day comment...

Response of a subcritically growing macrocrack in the mining environment to induced stress changes

NASA Astrophysics Data System (ADS)

Becker, Dirk; Cailleau, Beatrice; Kaiser, Diethelm; Dahm, Torsten

2013-04-01

Microcrack activity observed in underground mines may indicate regions prone to future rock burst and rockfall events and may help mitigating risks in the mining environment. We use observed microcrack activity as recorded in a catalog of acoustic emission (AE) events in combination with calculated stress gradients and transients to test physical seismicity models and their forecast potential in mines. The study deals with the response of the rock mass in an abandoned rock salt mine to stress changes induced by backfilling of an old cavity. The high spatial-temporal resolution of our dataset allows the study of slowly growing fractures and the development of microcrack activity in the fracture damage zone of a growing macrockrack. The physical insights we obtain are important to understand the development of possible sudden rockfall events, but may also be useful to better understand the nucleation of earthquakes. A pre-existing fracture of about 15 m length within the hanging wall about 15-20 m above the backfilled cavity was identified by careful analysis of the pre-filling AE activity. This fracture was found to be very responsive to small changes in the traction like terms of the stress field transferred instantaneously after backfilling started. This behaviour was indicated by a slowly spreading front of AE activity migrating at a rate of up to about 1 m/month. The recorded AE events likely occur in the fracture damage zone during its outward growth. Their temporal event rate evolution correlates very well with the forecast of stress-based seismicity models suggesting that concepts like the Coulomb failure model are also applicable on the micro scale. This observation is supported by the response of the microcracking activity of the damage zone to the initiation of a second macrocrack occurring in close proximity. The initiation of this new macrocrack temporally corresponds with a clear break-down of the high positive correlation between AE activity on and the calculated stresses. This suggests a reorganization of the acting stress field and a stress transfer on the scale of 10s meters partly inhibiting further growth of the damage zone. This observation gives insights into the role of a sudden fracture formation or earthquake rupture on subcritical growth of neighboring fractures or fault patches.

UAV-based Natural Hazard Management in High-Alpine Terrain - Case Studies from Austria

NASA Astrophysics Data System (ADS)

Sotier, Bernadette; Adams, Marc; Lechner, Veronika

2015-04-01

Unmanned Aerial Vehicles (UAV) have become a standard tool for geodata collection, as they allow conducting on-demand mapping missions in a flexible, cost-effective manner at an unprecedented level of detail. Easy-to-use, high-performance image matching software make it possible to process the collected aerial images to orthophotos and 3D-terrain models. Such up-to-date geodata have proven to be an important asset in natural hazard management: Processes like debris flows, avalanches, landslides, fluvial erosion and rock-fall can be detected and quantified; damages can be documented and evaluated. In the Alps, these processes mostly originate in remote areas, which are difficult and hazardous to access, thus presenting a challenging task for RPAS data collection. In particular, the problems include finding suitable landing and piloting-places, dealing with bad or no GPS-signals and the installation of ground control points (GCP) for georeferencing. At the BFW, RPAS have been used since 2012 to aid natural hazard management of various processes, of which three case studies are presented below. The first case study deals with the results from an attempt to employ UAV-based multi-spectral remote sensing to monitor the state of natural hazard protection forests. Images in the visible and near-infrared (NIR) band were collected using modified low-cost cameras, combined with different optical filters. Several UAV-flights were performed in the 72 ha large study site in 2014, which lies in the Wattental, Tyrol (Austria) between 1700 and 2050 m a.s.l., where the main tree species are stone pine and mountain pine. The matched aerial images were analysed using different UAV-specific vitality indices, evaluating both single- and dual-camera UAV-missions. To calculate the mass balance of a debris flow in the Tyrolean Halltal (Austria), an RPAS flight was conducted in autumn 2012. The extreme alpine environment was challenging for both the mission and the evaluation of the aerial images: In the upper part of the steep channel there was no GPS-signal available, because of the high surrounding rock faces, the landing area consisted of coarse gravel. Therefore, only a manual flight with a high risk of damage was possible. With the calculated RPAS-based digital surface model, created from the 600 aerial images, a chronologically resolved back-calculation of the last big debris-flow event could be performed. In a third case study, aerial images from RPAS were used for a similar investigation in Virgen, Eastern Tyrol (Austria). A debris flow in the Firschnitzbach catchment caused severe damages to the village of Virgen in August 2012. An RPAS-flight was performed, in order to refine the estimated displaced debris mass for assessment purposes. The upper catchment of the Firschnitzbach is situated above the timberline and covers an area of 6.5 ha at a height difference of 1000 m. Therefore, three separate flights were necessary to achieve a sufficient image overlap. The central part of the Firschnitzbach consists of a steep and partly dense forested canyon / gorge, so there was no flight possible for this section up to now. The evaluation of the surface model from the images showed, that only half of the estimated debris mass came from the upper part of the catchment.

Modeling and Hazard Analysis Using STPA

NASA Astrophysics Data System (ADS)

Ishimatsu, Takuto; Leveson, Nancy; Thomas, John; Katahira, Masa; Miyamoto, Yuko; Nakao, Haruka

2010-09-01

A joint research project between MIT and JAXA/JAMSS is investigating the application of a new hazard analysis to the system and software in the HTV. Traditional hazard analysis focuses on component failures but software does not fail in this way. Software most often contributes to accidents by commanding the spacecraft into an unsafe state(e.g., turning off the descent engines prematurely) or by not issuing required commands. That makes the standard hazard analysis techniques of limited usefulness on software-intensive systems, which describes most spacecraft built today. STPA is a new hazard analysis technique based on systems theory rather than reliability theory. It treats safety as a control problem rather than a failure problem. The goal of STPA, which is to create a set of scenarios that can lead to a hazard, is the same as FTA but STPA includes a broader set of potential scenarios including those in which no failures occur but the problems arise due to unsafe and unintended interactions among the system components. STPA also provides more guidance to the analysts that traditional fault tree analysis. Functional control diagrams are used to guide the analysis. In addition, JAXA uses a model-based system engineering development environment(created originally by Leveson and called SpecTRM) which also assists in the hazard analysis. One of the advantages of STPA is that it can be applied early in the system engineering and development process in a safety-driven design process where hazard analysis drives the design decisions rather than waiting until reviews identify problems that are then costly or difficult to fix. It can also be applied in an after-the-fact analysis and hazard assessment, which is what we did in this case study. This paper describes the experimental application of STPA to the JAXA HTV in order to determine the feasibility and usefulness of the new hazard analysis technique. Because the HTV was originally developed using fault tree analysis and following the NASA standards for safety-critical systems, the results of our experimental application of STPA can be compared with these more traditional safety engineering approaches in terms of the problems identified and the resources required to use it.

Observations of obsidian lava flow emplacement at Puyehue-Cordón Caulle, Chile

NASA Astrophysics Data System (ADS)

Tuffen, H.; Castro, J. M.; Schipper, C. I.; James, M. R.

2012-04-01

The dynamics of obsidian lava flow emplacement remain poorly understood as active obsidian lavas are seldom seen. In contrast with well-documented basaltic lavas, we lack observational data on obsidian flow advance and temporal evolution. The ongoing silicic eruption at Puyehue-Cordón Caulle volcanic complex (PCCVC), southern Chile provides an unprecedented opportunity to witness and study obsidian lava on the move. The eruption, which started explosively on June 4th 2011, has since June 20 generated an active obsidian flow field that remains active at the time of writing (January 2012), with an area of ~6 km2, and estimated volume of ~0.18 km3. We report on observations, imaging and sampling of the north-western lava flow field on January 4th and 10th 2012, when vent activity was characterised by near-continuous ash venting and Vulcanian explosions (Schipper et al, this session) and was simultaneously feeding the advancing obsidian flow (Castro et al, this session). On January 4th the north-western lava flow front was characterised by two dominant facies: predominant rubbly lava approximately 30-40 m thick and mantled by unstable talus aprons, and smoother, thinner lobes of more continuous lava ~50 m in length that extended roughly perpendicular to the overall flow direction, forming lobes that protrude from the flow margin, and lacked talus aprons. The latter lava facies closely resembled squeeze-up structures in basaltic lava flows[1] and appeared to originate from and overlie the talus apron of the rubbly lava. Its upper surface consisted of smooth, gently folded lava domains cut by crevasse-like tension gashes. During ~2 hours of observation the squeeze-up lava lobe was the most frequent location of small-volume rockfalls, which occurred at ~1-10 minute intervals from the flow front and indicated a locus of lava advance. On January 10th the squeeze-up lava lobes had evolved significantly, with disruption and breakage of smooth continuous lava surfaces to form blocky lava domains. Gravitational collapse of lobe toes had created an incipient talus apron that had markedly advanced. In contrast, the rubbly lava had undergone only modest evolution, reflecting continued rockfall and subtle advance of its well-developed talus apron. Visualisation of the lava morphology and evolution was assisted by 3D models of the lava flow front, produced by an automated photo-reconstruction technique (SfM-MVS, a combination of structure from motion and multi-view stereo algorithms), and >1000 digital images taken at the scene. Additionally samples were collected from the rubbly lava and squeeze-up lava lobe facies. Sample textures, geochemistry and volatile concentrations will provide further insight into the evolving physical and chemical state of the lava. Our observations indicate that endogenous growth plays a major role in obsidian lava flow advance, with effective thermal insulation of lava that emerges from squeeze-ups close to the flow margin. This has important implications for the longevity, mobility and hazard potential of obsidian flows and indicates striking similarities with the dynamics of basaltic lava flow emplacement. [1]Applegarth L.J. et al. 2010 Bull. Volcanol. 72, 641-656.

Risk analysis based on hazards interactions

NASA Astrophysics Data System (ADS)

Rossi, Lauro; Rudari, Roberto; Trasforini, Eva; De Angeli, Silvia; Becker, Joost

2017-04-01

Despite an increasing need for open, transparent, and credible multi-hazard risk assessment methods, models, and tools, the availability of comprehensive risk information needed to inform disaster risk reduction is limited, and the level of interaction across hazards is not systematically analysed. Risk assessment methodologies for different hazards often produce risk metrics that are not comparable. Hazard interactions (consecutive occurrence two or more different events) are generally neglected, resulting in strongly underestimated risk assessment in the most exposed areas. This study presents cases of interaction between different hazards, showing how subsidence can affect coastal and river flood risk (Jakarta and Bandung, Indonesia) or how flood risk is modified after a seismic event (Italy). The analysis of well documented real study cases, based on a combination between Earth Observation and in-situ data, would serve as basis the formalisation of a multi-hazard methodology, identifying gaps and research frontiers. Multi-hazard risk analysis is performed through the RASOR platform (Rapid Analysis and Spatialisation Of Risk). A scenario-driven query system allow users to simulate future scenarios based on existing and assumed conditions, to compare with historical scenarios, and to model multi-hazard risk both before and during an event (www.rasor.eu).

Anomalous winter-snow-amplified earthquake-induced disaster of the 2015 Langtang avalanche in Nepal

NASA Astrophysics Data System (ADS)

Fujita, Koji; Inoue, Hiroshi; Izumi, Takeki; Yamaguchi, Satoru; Sadakane, Ayako; Sunako, Sojiro; Nishimura, Kouichi; Immerzeel, Walter W.; Shea, Joseph M.; Kayastha, Rijan B.; Sawagaki, Takanobu; Breashears, David F.; Yagi, Hiroshi; Sakai, Akiko

2017-05-01

Coseismic avalanches and rockfalls, as well as their simultaneous air blast and muddy flow, which were induced by the 2015 Gorkha earthquake in Nepal, destroyed the village of Langtang. In order to reveal volume and structure of the deposit covering the village, as well as sequence of the multiple events, we conducted an intensive in situ observation in October 2015. Multitemporal digital elevation models created from photographs taken by helicopter and unmanned aerial vehicles reveal that the deposit volumes of the primary and succeeding events were 6.81 ± 1.54 × 106 and 0.84 ± 0.92 × 106 m3, respectively. Visual investigations of the deposit and witness statements of villagers suggest that the primary event was an avalanche composed mostly of snow, while the collapsed glacier ice could not be dominant source for the total mass. Succeeding events were multiple rockfalls which may have been triggered by aftershocks. From the initial deposit volume and the area of the upper catchment, we estimate an average snow depth of 1.82 ± 0.46 m in the source area. This is consistent with anomalously large snow depths (1.28-1.52 m) observed at a neighboring glacier (4800-5100 m a.s.l.), which accumulated over the course of four major snowfall events between October 2014 and the earthquake on 25 April 2015. Considering long-term observational data, probability density functions, and elevation gradients of precipitation, we conclude that this anomalous winter snow was an extreme event with a return interval of at least 100 years. The anomalous winter snowfall may have amplified the disastrous effects induced by the 2015 Gorkha earthquake in Nepal.

Headwater sediment dynamics in a debris flow catchment constrained by high-resolution topographic surveys

NASA Astrophysics Data System (ADS)

Loye, Alexandre; Jaboyedoff, Michel; Theule, Joshua Isaac; Liébault, Frédéric

2016-06-01

Debris flows have been recognized to be linked to the amounts of material temporarily stored in torrent channels. Hence, sediment supply and storage changes from low-order channels of the Manival catchment, a small tributary valley with an active torrent system located exclusively in sedimentary rocks of the Chartreuse Massif (French Alps), were surveyed periodically for 16 months using terrestrial laser scanning (TLS) to study the coupling between sediment dynamics and torrent responses in terms of debris flow events, which occurred twice during the monitoring period. Sediment transfer in the main torrent was monitored with cross-section surveys. Sediment budgets were generated seasonally using sequential TLS data differencing and morphological extrapolations. Debris production depends strongly on rockfall occurring during the winter-early spring season, following a power law distribution for volumes of rockfall events above 0.1 m3, while hillslope sediment reworking dominates debris recharge in spring and autumn, which shows effective hillslope-channel coupling. The occurrence of both debris flow events that occurred during the monitoring was linked to recharge from previous debris pulses coming from the hillside and from bedload transfer. Headwater debris sources display an ambiguous behaviour in sediment transfer: low geomorphic activity occurred in the production zone, despite rainstorms inducing debris flows in the torrent; still, a general reactivation of sediment transport in headwater channels was observed in autumn without new debris supply, suggesting that the stored debris was not exhausted. The seasonal cycle of sediment yield seems to depend not only on debris supply and runoff (flow capacity) but also on geomorphic conditions that destabilize remnant debris stocks. This study shows that monitoring the changes within a torrent's in-channel storage and its debris supply can improve knowledge on recharge thresholds leading to debris flow.

Analysing the spatial patterns of erosion scars using point process theory at the coastal chalk cliff of Mesnil-Val, (Normandy, Northern France)

NASA Astrophysics Data System (ADS)

Rohmer, J.; Dewez, D.

2014-09-01

Over the last decade, many cliff erosion studies have focused on frequency-size statistics using inventories of sea cliff retreat sizes. By comparison, only a few paid attention to quantifying the spatial and temporal organisation of erosion scars over a cliff face. Yet, this spatial organisation carries essential information about the external processes and the environmental conditions that promote or initiate sea-cliff instabilities. In this article, we use summary statistics of spatial point process theory as a tool to examine the spatial and temporal pattern of a rockfall inventory recorded with repeated terrestrial laser scanning surveys at the chalk coastal cliff site of Mesnil-Val (Normandy, France). Results show that: (1) the spatial density of erosion scars is specifically conditioned alongshore by the distance to an engineered concrete groin, with an exponential-like decreasing trend, and vertically focused both at wave breaker height and on strong lithological contrasts; (2) small erosion scars (10-3-10-2 m3) aggregate in clusters within a radius of 5 to 10 m, which suggests some sort of attraction or focused causative process, and disperse above this critical distance; (3) on the contrary, larger erosion scars (10-2-101 m3) tend to disperse above a radius of 1 to 5 m, possibly due to the spreading of successive failures across the cliff face; (4) large scars significantly occur albeit moderately, where previous large rockfalls have occurred during preceeding winter; (5) this temporal trend is not apparent for small events. In conclusion, this study shows, with a worked example, how spatial point process summary statistics are a tool to test and quantify the significance of geomorphological observation organisation.

Analysing the spatial patterns of erosion scars using point process theory at the coastal chalk cliff of Mesnil-Val, Normandy, northern France

NASA Astrophysics Data System (ADS)

Rohmer, J.; Dewez, T.

2015-02-01

Over the last decade, many cliff erosion studies have focused on frequency-size statistics using inventories of sea cliff retreat sizes. By comparison, only a few paid attention to quantifying the spatial and temporal organisation of erosion scars over a cliff face. Yet, this spatial organisation carries essential information about the external processes and the environmental conditions that promote or initiate sea-cliff instabilities. In this article, we use summary statistics of spatial point process theory as a tool to examine the spatial and temporal pattern of a rockfall inventory recorded with repeated terrestrial laser scanning surveys at the chalk coastal cliff site of Mesnil-Val (Normandy, France). Results show that: (1) the spatial density of erosion scars is specifically conditioned alongshore by the distance to an engineered concrete groyne, with an exponential-like decreasing trend, and vertically focused both at wave breaker height and on strong lithological contrasts; (2) small erosion scars (10-3 to 10-2 m3) aggregate in clusters within a radius of 5 to 10 m, which suggests some sort of attraction or focused causative process, and disperse above this critical distance; (3) on the contrary, larger erosion scars (10-2 to 101 m3) tend to disperse above a radius of 1 to 5 m, possibly due to the spreading of successive failures across the cliff face; (4) large scars significantly occur albeit moderately, where previous large rockfalls have occurred during preceding winter; (5) this temporal trend is not apparent for small events. In conclusion, this study shows, with a worked example, how spatial point process summary statistics are a tool to test and quantify the significance of geomorphological observation organisation.

Hazardous Materials Routing Study Phase II: Analysis of Hazardous Materials Truck Routes in Proximity to the Dallas Central Business District

DOT National Transportation Integrated Search

1985-10-01

This report summarizes the findings from the second phase of a two-part analysis of hazardous materials truck routes in the Dallas-Fort Worth area. Phase II of this study analyzes the risk of transporting hazardous materials on freeways and arterial ...

21 CFR 123.6 - Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2013 CFR

2013-04-01

... identified food safety hazards, including as appropriate: (i) Critical control points designed to control... control points designed to control food safety hazards introduced outside the processing plant environment... Control Point (HACCP) plan. 123.6 Section 123.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...

21 CFR 123.6 - Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2011 CFR

2011-04-01

... identified food safety hazards, including as appropriate: (i) Critical control points designed to control... control points designed to control food safety hazards introduced outside the processing plant environment... Control Point (HACCP) plan. 123.6 Section 123.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...

21 CFR 123.6 - Hazard analysis and Hazard Analysis Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2014 CFR

2014-04-01

... identified food safety hazards, including as appropriate: (i) Critical control points designed to control... control points designed to control food safety hazards introduced outside the processing plant environment... Control Point (HACCP) plan. 123.6 Section 123.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...

Using Qualitative Hazard Analysis to Guide Quantitative Safety Analysis

NASA Technical Reports Server (NTRS)

Shortle, J. F.; Allocco, M.

2005-01-01

Quantitative methods can be beneficial in many types of safety investigations. However, there are many difficulties in using quantitative m ethods. Far example, there may be little relevant data available. This paper proposes a framework for using quantitative hazard analysis to prioritize hazard scenarios most suitable for quantitative mziysis. The framework first categorizes hazard scenarios by severity and likelihood. We then propose another metric "modeling difficulty" that desc ribes the complexity in modeling a given hazard scenario quantitatively. The combined metrics of severity, likelihood, and modeling difficu lty help to prioritize hazard scenarios for which quantitative analys is should be applied. We have applied this methodology to proposed concepts of operations for reduced wake separation for airplane operatio ns at closely spaced parallel runways.

Impacts of the November 2014 extreme rainfall event in Ticino, Switzerland

NASA Astrophysics Data System (ADS)

Voumard, Jérémie; Matasci, Battista; Derron, Marc-Henri; Jaboyedoff, Michel

2015-04-01

The 2-17th November, a meteorological block in the south of the Alps produced record rain precipitations in the North of Italy and in the canton of Ticino, Switzerland. During those fifteen days, the rain quantity was three to five times higher than the November average monthly rain. The Lugano meteorological station recorded a new precipitation record with 538 mm during this period. During this event, the rainfall triggered many landslides and floods. Four people died in two different events 11 km apart. In the first case, a two-storey house, located in a large wooded area 10 km West of Lugano, was destroyed by a 1'000 m3 landslide composed of mud, trees and rock masses which flew over 150 meters on November 5th 2014. The two occupants, a mother and her three years old daughter, were killed. The second event occurred in an urban area of the Lugano agglomeration where a wall, weakened by the heavy rainfalls, located 50 m away and above a three-storey apartment building broke, releasing 500 m3 to 1'000 m3 of muddy material. Besides two fatalities, one man was seriously injured, three persons were slightly injured and one person kept uninjured. Concerning the transportation network, more than twenty roads and railways were blocked by landslides, floods and rockfalls. Some of them were closed over one month. The two secondary roads to Arogno and Rovio villages were blocked by landslides. The only asphalted access to those villages was a 45 km deviation of more than one hour travel time through Italy. Two hamlets a couple of kilometers away were isolated by a landslide. The only access was by boat from the lake. Two main roads and one railway along the Lake Maggiore and the Tresa River taken by Italian cross-border commuters who work in Switzerland were cut by floods and landslides generating economic and societal inconveniences. The two main lakes of the canton of Ticino -lakes Maggiore and Lugano- reached their maximum flood level. In Locarno, the 3rd biggest city of the canton of Ticino with over 15'500 citizen, the shores along the Lake Maggiore were flooded until 300 meters inside the land. Dozens of basements and ground floor of buildings were flooded. Hillslopes were strongly affected by landslides, while floods occurred in valley bottoms. The aim of this study is to document the natural events and their consequences in terms of transportation networks and societal inconveniences caused by this rainfall event. Damages and consequences of the events were documented during a field visit, obtained from the media and the official reports as well as by the aid of a drone in two areas. We suspected that many impacted houses were located in areas where landslides could be expected. A first assessment based on geomorphological landscape analysis with an Airborne Lidar DEM show that some of these infrastructures seem to be built on alluvial / debris cones, suspected ancient landslides or steep slopes susceptible to be affected by (shallow) landslides, debris flows or rockfalls during extreme meteorological events. This raises the delicate question of urbanization in steep mountain slopes even if since a several tens of years nothing happened. More detailed studies about those hypotheses are necessary to understand the relationship between suspected old slope movements and the shallow landslides occurred during the November 2014 extreme rainfall event. The transportation network in the canton of Ticino is vulnerable to extreme natural events because of a high number of artificially cut and fill slopes along the lanes. In some cases, a possibility to investigate could be to reduce the number of roads leading to a same place in order to concentrate enough financial, logistic and maintenance strengths on only one access well protected against natural hazards.

Accident analysis and control options in support of the sludge water system safety analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

HEY, B.E.

A hazards analysis was initiated for the SWS in July 2001 (SNF-8626, K Basin Sludge and Water System Preliminary Hazard Analysis) and updated in December 2001 (SNF-10020 Rev. 0, Hazard Evaluation for KE Sludge and Water System - Project A16) based on conceptual design information for the Sludge Retrieval System (SRS) and 60% design information for the cask and container. SNF-10020 was again revised in September 2002 to incorporate new hazards identified from final design information and from a What-if/Checklist evaluation of operational steps. The process hazards, controls, and qualitative consequence and frequency estimates taken from these efforts have beenmore » incorporated into Revision 5 of HNF-3960, K Basins Hazards Analysis. The hazards identification process documented in the above referenced reports utilized standard industrial safety techniques (AIChE 1992, Guidelines for Hazard Evaluation Procedures) to systematically guide several interdisciplinary teams through the system using a pre-established set of process parameters (e.g., flow, temperature, pressure) and guide words (e.g., high, low, more, less). The teams generally included representation from the U.S. Department of Energy (DOE), K Basins Nuclear Safety, T Plant Nuclear Safety, K Basin Industrial Safety, fire protection, project engineering, operations, and facility engineering.« less

Supplemental Hazard Analysis and Risk Assessment - Hydrotreater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowry, Peter P.; Wagner, Katie A.

A supplemental hazard analysis was conducted and quantitative risk assessment performed in response to an independent review comment received by the Pacific Northwest National Laboratory (PNNL) from the U.S. Department of Energy Pacific Northwest Field Office (PNSO) against the Hydrotreater/Distillation Column Hazard Analysis Report issued in April 2013. The supplemental analysis used the hazardous conditions documented by the previous April 2013 report as a basis. The conditions were screened and grouped for the purpose of identifying whether additional prudent, practical hazard controls could be identified, using a quantitative risk evaluation to assess the adequacy of the controls and establish amore » lower level of concern for the likelihood of potential serious accidents. Calculations were performed to support conclusions where necessary.« less

Tracking Hazard Analysis Data in a Jungle of Changing Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Robin S.; Young, Jonathan

2006-05-16

Tracking hazard analysis data during the 'life cycle' of a project can be an extremely complicated task. However, a few simple rules, used consistently, can give you the edge that will save countless headaches and provide the information that will help integrate the hazard analysis and design activities even if performed in parallel.

75 FR 8239 - School Food Safety Program Based on Hazard Analysis and Critical Control Point Principles (HACCP...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... 0584-AD65 School Food Safety Program Based on Hazard Analysis and Critical Control Point Principles... Safety Program Based on Hazard Analysis and Critical Control Point Principles (HACCP) was published on... of Management and Budget (OMB) cleared the associated information collection requirements (ICR) on...

Hazard Analysis for the Mark III Space Suit Assembly (SSA) Used in One-g Operations

NASA Technical Reports Server (NTRS)

Mitchell, Kate; Ross, Amy; Blanco, Raul; Wood, Art

2012-01-01

This Hazard Analysis document encompasses the Mark III Space Suit Assembly (SSA) and associated ancillary equipment. It has been prepared using JSC17773, "Preparing Hazard Analyses for JSC Ground Operation", as a guide. The purpose of this document is to present the potential hazards involved in ground (23 % maximum O2, One-g) operations of the Mark III and associated ancillary support equipment system. The hazards listed in this document are specific to suit operations only; each supporting facility (Bldg. 9, etc.) is responsible for test specific Hazard Analyses. A "hazard" is defined as any condition that has the potential for harming personnel or equipment. This analysis was performed to document the safety aspects associated with manned use of the Mark III for pressurized and unpressurized ambient, ground-based, One-g human testing. The hazards identified herein represent generic hazards inherent to all standard JSC test venues for nominal ground test configurations. Non-standard test venues or test specific configurations may warrant consideration of additional hazards analysis prior to test. The cognizant suit engineer is responsible for the safety of the astronaut/test subject, space suit, and suit support personnel. The test requester, for the test supported by the suit test engineer and suited subject, is responsible for overall safety and any necessary Test Readiness Reviews (TRR).

Vulnerabilities, Influences and Interaction Paths: Failure Data for Integrated System Risk Analysis

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Fleming, Land

2006-01-01

We describe graph-based analysis methods for identifying and analyzing cross-subsystem interaction risks from subsystem connectivity information. By discovering external and remote influences that would be otherwise unexpected, these methods can support better communication among subsystem designers at points of potential conflict and to support design of more dependable and diagnosable systems. These methods identify hazard causes that can impact vulnerable functions or entities if propagated across interaction paths from the hazard source to the vulnerable target. The analysis can also assess combined impacts of And-Or trees of disabling influences. The analysis can use ratings of hazards and vulnerabilities to calculate cumulative measures of the severity and importance. Identification of cross-subsystem hazard-vulnerability pairs and propagation paths across subsystems will increase coverage of hazard and risk analysis and can indicate risk control and protection strategies.

Large-scale field testing on flexible shallow landslide barriers

NASA Astrophysics Data System (ADS)

Bugnion, Louis; Volkwein, Axel; Wendeler, Corinna; Roth, Andrea

2010-05-01

Open shallow landslides occur regularly in a wide range of natural terrains. Generally, they are difficult to predict and result in damages to properties and disruption of transportation systems. In order to improve the knowledge about the physical process itself and to develop new protection measures, large-scale field experiments were conducted in Veltheim, Switzerland. Material was released down a 30° inclined test slope into a flexible barrier. The flow as well as the impact into the barrier was monitored using various measurement techniques. Laser devices recording flow heights, a special force plate measuring normal and shear basal forces as well as load cells for impact pressures were installed along the test slope. In addition, load cells were built in the support and retaining cables of the barrier to provide data for detailed back-calculation of load distribution during impact. For the last test series an additional guiding wall in flow direction on both sides of the barrier was installed to achieve higher impact pressures in the middle of the barrier. With these guiding walls the flow is not able to spread out before hitting the barrier. A special constructed release mechanism simulating the sudden failure of the slope was designed such that about 50 m3 of mixed earth and gravel saturated with water can be released in an instant. Analysis of cable forces combined with impact pressures and velocity measurements during a test series allow us now to develop a load model for the barrier design. First numerical simulations with the software tool FARO, originally developed for rockfall barriers and afterwards calibrated for debris flow impacts, lead already to structural improvements on barrier design. Decisive for the barrier design is the first dynamic impact pressure depending on the flow velocity and afterwards the hydrostatic pressure of the complete retained material behind the barrier. Therefore volume estimation of open shallow landslides by assessing the thickness of the failure layer and the width of the possible failure are essential for the required barrier design parameter height and width. First results of the calculated drag coefficients of dynamic impact pressure measurements showed that the dynamic coefficient cw is much lower than 1.0 which is contradictory to most of existing dimensioning property protection guidelines. It appears to us that special adaptation to the system like smaller mesh sizes and special ground-barrier interface compared to normal rock-fall barriers and channelised debris flow barriers are necessary to improve the retention behavior of shallow landslide barriers. Detailed analysis of the friction coefficient in relationship with pore water pressure measurements gives interesting insights into the dynamic of fluid-solid mixed flows. Impact pressures dependencies on flow features are analyzed and discussed with respect to existing models and guidelines for shallow landslides.

Integrated Safety Analysis Tiers

NASA Technical Reports Server (NTRS)

Shackelford, Carla; McNairy, Lisa; Wetherholt, Jon

2009-01-01

Commercial partnerships and organizational constraints, combined with complex systems, may lead to division of hazard analysis across organizations. This division could cause important hazards to be overlooked, causes to be missed, controls for a hazard to be incomplete, or verifications to be inefficient. Each organization s team must understand at least one level beyond the interface sufficiently enough to comprehend integrated hazards. This paper will discuss various ways to properly divide analysis among organizations. The Ares I launch vehicle integrated safety analyses effort will be utilized to illustrate an approach that addresses the key issues and concerns arising from multiple analysis responsibilities.

Seismic hazard assessment: Issues and alternatives

USGS Publications Warehouse

Wang, Z.

2011-01-01

Seismic hazard and risk are two very important concepts in engineering design and other policy considerations. Although seismic hazard and risk have often been used inter-changeably, they are fundamentally different. Furthermore, seismic risk is more important in engineering design and other policy considerations. Seismic hazard assessment is an effort by earth scientists to quantify seismic hazard and its associated uncertainty in time and space and to provide seismic hazard estimates for seismic risk assessment and other applications. Although seismic hazard assessment is more a scientific issue, it deserves special attention because of its significant implication to society. Two approaches, probabilistic seismic hazard analysis (PSHA) and deterministic seismic hazard analysis (DSHA), are commonly used for seismic hazard assessment. Although PSHA has been pro-claimed as the best approach for seismic hazard assessment, it is scientifically flawed (i.e., the physics and mathematics that PSHA is based on are not valid). Use of PSHA could lead to either unsafe or overly conservative engineering design or public policy, each of which has dire consequences to society. On the other hand, DSHA is a viable approach for seismic hazard assessment even though it has been labeled as unreliable. The biggest drawback of DSHA is that the temporal characteristics (i.e., earthquake frequency of occurrence and the associated uncertainty) are often neglected. An alternative, seismic hazard analysis (SHA), utilizes earthquake science and statistics directly and provides a seismic hazard estimate that can be readily used for seismic risk assessment and other applications. ?? 2010 Springer Basel AG.

The eastern front of the Sierra Nevada; prone to earthquakes and volcanic eruption

USGS Publications Warehouse

Rinehart, C.D.; Smith, W.C.

1981-01-01

On Sunday morning, May 25, 1980, the weather at Mammoth Lakes, Calif., was sunny and brisk. Suddenly, just before 9:33 a.m, the world became a jarring, lurching, unstable place. Along the front of the Sierra Nevada, the muffled thunder of rockfalls and avalanches prolonged the confusion of sound and motion and added the spectacle of large, rising dust clouds. Three geysers, one 30 ft high, suddenly roared into the air at Hot Creek, although none survived more than a few hours. Some new boiling pools appeared, while many existing hot springs and pools became hotter and more active. 

The Klamath Falls, Oregon, earthquakes on September 20, 1993

USGS Publications Warehouse

Brantley, S.R.

1993-01-01

The mainshocks caused light moderate damage at Klamath Falls, a town of about 18,000 residents located only about 20 km east of the epicentral area. Damage included toppled chimneys, cracked masonry, and fallen parapets. Power outages occurred after the strongest shocks. In addition, strong shaking broke water mains, and landslides temporarily blocked highways. the earthquakes also caused two fatalities. A rockfall crushed an automobile, killing a motorist, and an elderly lady had a heart attack. the low population density in the epicentral area- less than five people per sq km- kept the toatl dollar loss to about 7.5 million dollars. 

A Bimodal Hybrid Model for Time-Dependent Probabilistic Seismic Hazard Analysis

NASA Astrophysics Data System (ADS)

Yaghmaei-Sabegh, Saman; Shoaeifar, Nasser; Shoaeifar, Parva

2018-03-01

The evaluation of evidence provided by geological studies and historical catalogs indicates that in some seismic regions and faults, multiple large earthquakes occur in cluster. Then, the occurrences of large earthquakes confront with quiescence and only the small-to-moderate earthquakes take place. Clustering of large earthquakes is the most distinguishable departure from the assumption of constant hazard of random occurrence of earthquakes in conventional seismic hazard analysis. In the present study, a time-dependent recurrence model is proposed to consider a series of large earthquakes that occurs in clusters. The model is flexible enough to better reflect the quasi-periodic behavior of large earthquakes with long-term clustering, which can be used in time-dependent probabilistic seismic hazard analysis with engineering purposes. In this model, the time-dependent hazard results are estimated by a hazard function which comprises three parts. A decreasing hazard of last large earthquake cluster and an increasing hazard of the next large earthquake cluster, along with a constant hazard of random occurrence of small-to-moderate earthquakes. In the final part of the paper, the time-dependent seismic hazard of the New Madrid Seismic Zone at different time intervals has been calculated for illustrative purpose.

Probabilistic analysis of tsunami hazards

USGS Publications Warehouse

Geist, E.L.; Parsons, T.

2006-01-01

Determining the likelihood of a disaster is a key component of any comprehensive hazard assessment. This is particularly true for tsunamis, even though most tsunami hazard assessments have in the past relied on scenario or deterministic type models. We discuss probabilistic tsunami hazard analysis (PTHA) from the standpoint of integrating computational methods with empirical analysis of past tsunami runup. PTHA is derived from probabilistic seismic hazard analysis (PSHA), with the main difference being that PTHA must account for far-field sources. The computational methods rely on numerical tsunami propagation models rather than empirical attenuation relationships as in PSHA in determining ground motions. Because a number of source parameters affect local tsunami runup height, PTHA can become complex and computationally intensive. Empirical analysis can function in one of two ways, depending on the length and completeness of the tsunami catalog. For site-specific studies where there is sufficient tsunami runup data available, hazard curves can primarily be derived from empirical analysis, with computational methods used to highlight deficiencies in the tsunami catalog. For region-wide analyses and sites where there are little to no tsunami data, a computationally based method such as Monte Carlo simulation is the primary method to establish tsunami hazards. Two case studies that describe how computational and empirical methods can be integrated are presented for Acapulco, Mexico (site-specific) and the U.S. Pacific Northwest coastline (region-wide analysis).

Analysis of On-board Hazard Detection and Avoidance for Safe Lunar Landing

NASA Technical Reports Server (NTRS)

Johnson, Andrew E.; Huertas, Andres; Werner, Robert A.; Montgomery, James F.

2008-01-01

Landing hazard detection and avoidance technology is being pursued within NASA to improve landing safety and increase access to sites of interest on the lunar surface. The performance of a hazard detection and avoidance system depends on properties of the terrain, sensor performance, algorithm design, vehicle characteristics and the overall all guidance navigation and control architecture. This paper analyzes the size of the region that must be imaged, sensor performance parameters and the impact of trajectory angle on hazard detection performance. The analysis shows that vehicle hazard tolerance is the driving parameter for hazard detection system design.

Guide for Hydrogen Hazards Analysis on Components and Systems

NASA Technical Reports Server (NTRS)

Beeson, Harold; Woods, Stephen

2003-01-01

The physical and combustion properties of hydrogen give rise to hazards that must be considered when designing and operating a hydrogen system. One of the major concerns in the use of hydrogen is that of fire or detonation because of hydrogen's wide flammability range, low ignition energy, and flame speed. Other concerns include the contact and interaction of hydrogen with materials, such as the hydrogen embrittlement of materials and the formation of hydrogen hydrides. The low temperature of liquid and slush hydrogen bring other concerns related to material compatibility and pressure control; this is especially important when dissimilar, adjoining materials are involved. The potential hazards arising from these properties and design features necessitate a proper hydrogen hazards analysis before introducing a material, component, or system into hydrogen service. The objective of this guide is to describe the NASA Johnson Space Center White Sands Test Facility hydrogen hazards analysis method that should be performed before hydrogen is used in components and/or systems. The method is consistent with standard practices for analyzing hazards. It is recommended that this analysis be made before implementing a hydrogen component qualification procedure. A hydrogen hazards analysis is a useful tool for hydrogen-system designers, system and safety engineers, and facility managers. A hydrogen hazards analysis can identify problem areas before hydrogen is introduced into a system-preventing damage to hardware, delay or loss of mission or objective, and possible injury or loss of life.

An evaluation of treatment strategies for head and neck cancer in an African American population.

PubMed

Ignacio, D N; Griffin, J J; Daniel, M G; Serlemitsos-Day, M T; Lombardo, F A; Alleyne, T A

2013-07-01

This study evaluated treatment strategies for head and neck cancers in a predominantly African American population. Data were collected utilizing medical records and the tumour registry at the Howard University Hospital. Kaplan-Meier method was used for survival analysis and Cox proportional hazards regression analysis predicted the hazard of death. Analysis revealed that the main treatment strategy was radiation combined with platinum for all stages except stage I. Cetuximab was employed in only 1% of cases. Kaplan-Meier analysis revealed stage II patients had poorer outcome than stage IV while Cox proportional hazard regression analysis (p = 0.4662) showed that stage I had a significantly lower hazard of death than stage IV (HR = 0.314; p = 0.0272). Contributory factors included tobacco and alcohol but body mass index (BMI) was inversely related to hazard of death. There was no difference in survival using any treatment modality for African Americans.

A situational analysis of priority disaster hazards in Uganda: findings from a hazard and vulnerability analysis.

PubMed

Mayega, R W; Wafula, M R; Musenero, M; Omale, A; Kiguli, J; Orach, G C; Kabagambe, G; Bazeyo, W

2013-06-01

Most countries in sub-Saharan Africa have not conducted a disaster risk analysis. Hazards and vulnerability analyses provide vital information that can be used for development of risk reduction and disaster response plans. The purpose of this study was to rank disaster hazards for Uganda, as a basis for identifying the priority hazards to guide disaster management planning. The study as conducted in Uganda, as part of a multi-country assessment. A hazard, vulnerability and capacity analysis was conducted in a focus group discussion of 7 experts representing key stakeholder agencies in disaster management in Uganda. A simple ranking method was used to rank the probability of occurance of 11 top hazards, their potential impact and the level vulnerability of people and infrastructure. In-terms of likelihood of occurance and potential impact, the top ranked disaster hazards in Uganda are: 1) Epidemics of infectious diseases, 2) Drought/famine, 3) Conflict and environmental degradation in that order. In terms of vulnerability, the top priority hazards to which people and infrastructure were vulnerable were: 1) Conflicts, 2) Epidemics, 3) Drought/famine and, 4) Environmental degradation in that order. Poverty, gender, lack of information, and lack of resilience measures were some of the factors promoting vulnerability to disasters. As Uganda develops a disaster risk reduction and response plan, it ought to prioritize epidemics of infectious diseases, drought/famine, conflics and environmental degradation as the priority disaster hazards.

Preliminary hazards analysis -- vitrification process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coordes, D.; Ruggieri, M.; Russell, J.

1994-06-01

This paper presents a Preliminary Hazards Analysis (PHA) for mixed waste vitrification by joule heating. The purpose of performing a PHA is to establish an initial hazard categorization for a DOE nuclear facility and to identify those processes and structures which may have an impact on or be important to safety. The PHA is typically performed during and provides input to project conceptual design. The PHA is then followed by a Preliminary Safety Analysis Report (PSAR) performed during Title 1 and 2 design. The PSAR then leads to performance of the Final Safety Analysis Report performed during the facility`s constructionmore » and testing. It should be completed before routine operation of the facility commences. This PHA addresses the first four chapters of the safety analysis process, in accordance with the requirements of DOE Safety Guidelines in SG 830.110. The hazards associated with vitrification processes are evaluated using standard safety analysis methods which include: identification of credible potential hazardous energy sources; identification of preventative features of the facility or system; identification of mitigative features; and analyses of credible hazards. Maximal facility inventories of radioactive and hazardous materials are postulated to evaluate worst case accident consequences. These inventories were based on DOE-STD-1027-92 guidance and the surrogate waste streams defined by Mayberry, et al. Radiological assessments indicate that a facility, depending on the radioactive material inventory, may be an exempt, Category 3, or Category 2 facility. The calculated impacts would result in no significant impact to offsite personnel or the environment. Hazardous materials assessment indicates that a Mixed Waste Vitrification facility will be a Low Hazard facility having minimal impacts to offsite personnel and the environment.« less

A high-resolution modelling approach on spatial wildfire distribution in the Tyrolean Alps

NASA Astrophysics Data System (ADS)

Malowerschnig, Bodo; Sass, Oliver

2013-04-01

Global warming will cause increasing danger of wildfires in Austria, which can have long-lasting consequences on woodland ecosystems. The protective effect of forest can be severely diminished, leading to natural hazards like avalanches and rockfall. However, data on wildfire frequency and distribution have been sparse and incomplete for Austria. Long-lasting postfire degradation under adverse preconditions (steep slopes, limestone) was a common phenomenon in parts of the Tyrolean Alps several decades ago and should become relevant again under a changing fire frequency. The FIRIA project compiles historical wildfire data, information on fuel loads, fire weather indices (FWI) and vegetation recovery patterns. The governing climatic, topographic and socio-economic factors of forest fire distribution were assessed to trigger a distribution model of currently fire-prone areas in Tyrol. By collecting data from different sources like old newspapers archives and fire-fighter databases, we were able to build up a fire database of wildfire occurrences containing more than 1400 forest fires since the 15th century in Tyrol. For the period from 1993 to 2011, the database is widely complete and covers 482 fires. Using a non-parametrical statistical method it was possible to select the best suited fire weather index (FWI) for the prediction. The testing of 19 FWI's shows that it is necessary to use two discriminative indices to differentiate between summer and winter season. Together with compiled topographic, socio-economic, infrastructure and forest maps, the dataset was the base for a multifactorial analysis, performed by comparing the maximum entropy approach (Maxent) with an ensemble classifier (Random Forests). Both approaches have their background in the spatial habitat distribution and are easy to adapt to the requirements of a wildfire ignition model. The aim of this modelling approach was to determine areas which are particularly prone to wildfire. Due to the pronounced relief curvature we based our model on 100 x 100 m cells to identify individual slopes and their topography. The first provisional result is a map of fire probability under current climate conditions (fire hot-spots). Our modelling approach indicates the fire weather index as the main driver, which is followed closely by socioeconomic (population density) and infrastructure factors (roads density, aerial railways, building density). The leverage of the forest community or its management is rather low; the same applies to topographic influences like aspect or sea level. The derived fire hot-spots are either placed close to the valley ground or around touristic infrastructure, with an overall preference for inner alpine areas and south-facing slopes. In the next step, the impact of climate change on the distribution and frequency of fires will be assessed by calculating a climate change model adapted to the 1x1km INCA dataset and based on different regional climate change models. Finally, a selection of fire-hot-spots from the previous modelling steps will be used for enhanced 3D-modelling approaches of natural hazards after wildfire-driven deforestation.

Analysis and design of randomised clinical trials involving competing risks endpoints.

PubMed

Tai, Bee-Choo; Wee, Joseph; Machin, David

2011-05-19

In randomised clinical trials involving time-to-event outcomes, the failures concerned may be events of an entirely different nature and as such define a classical competing risks framework. In designing and analysing clinical trials involving such endpoints, it is important to account for the competing events, and evaluate how each contributes to the overall failure. An appropriate choice of statistical model is important for adequate determination of sample size. We describe how competing events may be summarised in such trials using cumulative incidence functions and Gray's test. The statistical modelling of competing events using proportional cause-specific and subdistribution hazard functions, and the corresponding procedures for sample size estimation are outlined. These are illustrated using data from a randomised clinical trial (SQNP01) of patients with advanced (non-metastatic) nasopharyngeal cancer. In this trial, treatment has no effect on the competing event of loco-regional recurrence. Thus the effects of treatment on the hazard of distant metastasis were similar via both the cause-specific (unadjusted csHR = 0.43, 95% CI 0.25 - 0.72) and subdistribution (unadjusted subHR 0.43; 95% CI 0.25 - 0.76) hazard analyses, in favour of concurrent chemo-radiotherapy followed by adjuvant chemotherapy. Adjusting for nodal status and tumour size did not alter the results. The results of the logrank test (p = 0.002) comparing the cause-specific hazards and the Gray's test (p = 0.003) comparing the cumulative incidences also led to the same conclusion. However, the subdistribution hazard analysis requires many more subjects than the cause-specific hazard analysis to detect the same magnitude of effect. The cause-specific hazard analysis is appropriate for analysing competing risks outcomes when treatment has no effect on the cause-specific hazard of the competing event. It requires fewer subjects than the subdistribution hazard analysis for a similar effect size. However, if the main and competing events are influenced in opposing directions by an intervention, a subdistribution hazard analysis may be warranted.

14 CFR 417.223 - Flight hazard area analysis.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Flight hazard area analysis. 417.223 Section 417.223 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... to control the risk to the public from debris impact hazards. The risk management requirements of...

14 CFR 417.223 - Flight hazard area analysis.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Flight hazard area analysis. 417.223 Section 417.223 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... to control the risk to the public from debris impact hazards. The risk management requirements of...

14 CFR 417.223 - Flight hazard area analysis.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Flight hazard area analysis. 417.223 Section 417.223 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... to control the risk to the public from debris impact hazards. The risk management requirements of...

14 CFR 417.223 - Flight hazard area analysis.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Flight hazard area analysis. 417.223 Section 417.223 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... to control the risk to the public from debris impact hazards. The risk management requirements of...

Hazard Analysis of Commercial Space Transportation: Volume 1: Operations. Volume 2: Hazards. Volume 3: Risk Analysis

DOT National Transportation Integrated Search

1988-05-01

The report is devoted to the review and discussion of generic hazards associated with the ground, launch, orbital and re-entry phases of space operations. Since the DOT Office of Commercial Space Transportation (OCST) has been charged with protecting...

9 CFR 417.4 - Validation, Verification, Reassessment.

Code of Federal Regulations, 2012 CFR

2012-01-01

... not have a HACCP plan because a hazard analysis has revealed no food safety hazards that are.... 417.4 Section 417.4 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... ACT HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.4 Validation, Verification...

9 CFR 417.4 - Validation, Verification, Reassessment.

Code of Federal Regulations, 2010 CFR

2010-01-01

... not have a HACCP plan because a hazard analysis has revealed no food safety hazards that are.... 417.4 Section 417.4 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... ACT HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.4 Validation, Verification...

9 CFR 417.4 - Validation, Verification, Reassessment.

Code of Federal Regulations, 2011 CFR

2011-01-01

... not have a HACCP plan because a hazard analysis has revealed no food safety hazards that are.... 417.4 Section 417.4 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... ACT HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.4 Validation, Verification...

14 CFR 417.223 - Flight hazard area analysis.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Flight hazard area analysis. 417.223 Section 417.223 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... to control the risk to the public from debris impact hazards. The risk management requirements of...

Applying Qualitative Hazard Analysis to Support Quantitative Safety Analysis for Proposed Reduced Wake Separation Conops

NASA Technical Reports Server (NTRS)

Shortle, John F.; Allocco, Michael

2005-01-01

This paper describes a scenario-driven hazard analysis process to identify, eliminate, and control safety-related risks. Within this process, we develop selective criteria to determine the applicability of applying engineering modeling to hypothesized hazard scenarios. This provides a basis for evaluating and prioritizing the scenarios as candidates for further quantitative analysis. We have applied this methodology to proposed concepts of operations for reduced wake separation for closely spaced parallel runways. For arrivals, the process identified 43 core hazard scenarios. Of these, we classified 12 as appropriate for further quantitative modeling, 24 that should be mitigated through controls, recommendations, and / or procedures (that is, scenarios not appropriate for quantitative modeling), and 7 that have the lowest priority for further analysis.

A fluvial and pluvial probabilistic flood hazard analysis for Can Tho city, Vietnam

NASA Astrophysics Data System (ADS)

Apel, Heiko; Martinez, Oriol; Thi Chinh, Do; Viet Dung, Nguyen

2014-05-01

Can Tho city is the largest city and the economic heart of the Mekong Delta, Vietnam. Due to its economic importance and envisaged development goals the city grew rapidly in population size and extend over the last two decades. Large parts of the city are located in flood prone areas, and also the central parts of the city recently experienced an increasing number of flood events, both of fluvial and pluvial nature. As the economic power and asset values are constantly increasing, this poses a considerable risk for the city. The the aim of this study is to perform a flood hazard analysis considering both fluvial and pluvial floods and to derive probabilistic flood hazard maps. This requires in a first step an understanding of the typical flood mechanisms. Fluvial floods are triggered by a coincidence of high water levels during the annual flood period in the Mekong Delta with high tidal levels, which cause in combination short term inundations in Can Tho. Pluvial floods are triggered by typical tropical convective rain storms during the monsoon season. These two flood pathways are essentially independent in its sources and can thus be treated in the hazard analysis accordingly. For the fluvial hazard analysis we propose a bivariate frequency analysis of the Mekong flood characteristics, the annual maximum flood discharge Q and the annual flood volume V at the upper boundary of the Mekong Delta, the gauging station Kratie. This defines probabilities of exceedance of different Q-V pairs, which are transferred into synthetic flood hydrographs. The synthetic hydrographs are routed through a quasi-2D hydrodynamic model of the entire Mekong Delta in order to provide boundary conditions for a detailed hazard mapping of Can Tho. This downscaling step is necessary, because the huge complexity of the river and channel network does not allow for a proper definition of boundary conditions for Can Tho city by gauge data alone. In addition the available gauge data around Can Tho are too short for a meaningful frequency analysis. The detailed hazard mapping is performed by a 2D hydrodynamic model for Can Tho city. As the scenarios are derived in a Monte-Carlo framework, the final flood hazard maps are probabilistic, i.e. show the median flood hazard along with uncertainty estimates for each defined level of probabilities of exceedance. For the pluvial flood hazard a frequency analysis of the hourly rain gauge data of Can Tho is performed implementing a peak-over-threshold procedure. Based on this frequency analysis synthetic rains storms are generated in a Monte-Carlo framework for the same probabilities of exceedance as in the fluvial flood hazard analysis. Probabilistic flood hazard maps were then generated with the same 2D hydrodynamic model for the city. In a last step the fluvial and pluvial scenarios are combined assuming independence of the events. These scenarios were also transferred into hazard maps by the 2D hydrodynamic model finally yielding combined fluvial-pluvial probabilistic flood hazard maps for Can Tho. The derived set of maps may be used for an improved city planning or a flood risk analysis.

Large Rock-Slope Failures Impacting on Lakes - Event Reconstruction and Interaction Analysis in Two Alpine Regions Using Sedimentology and Geophysics

NASA Astrophysics Data System (ADS)

Knapp, S.; Anselmetti, F.; Gilli, A.; Krautblatter, M.; Hajdas, I.

2016-12-01

Massive rock-slope failures are responsible for more than 60% of all catastrophic landslides disasters. Lateglacial and Holocene rock-slope failures often occur as multistage failures, but we have only limited datasets to reconstruct detailed stages and still aim at improving our knowledge of mobility processes. In this context, studying lakes will become more and more important for two main reasons. On the one hand, the lake background sedimentation acts as a natural chronometer, which enables the stratigraphic positioning of events and helps to reconstruct the event history. This way we will be able to improve our knowledge on multistage massive rock-slope failures. On the other hand, climate warming forces us to face an increase of lakes forming due to glacial melting, leading to new hazardous landscape settings. We will be confronted with complex reaction chains and feedback loops related to rock-slope instability, stress adaptation, multistage rock-slope failures, lake tsunamis, entrainment of water and fines, and finally lubrication. As a result, in future we will have to deal more and more with failed rock material impacting on lakes with much longer runout-paths than expected, and which we have not been able to reconstruct in our models so far. Here we want to present the key findings of two of our studies on lake sediments related to large rock-slope failures: We used reflection seismic profiles and sediment cores for the reconstruction of the rockfall history in the landslide-dammed Lake Oeschinen in the Bernese Oberland, Switzerland, where we detected and dated ten events and correlated them to (pre)historical data. As a second project, we have been working on the mobility processes of the uppermost sediments deposited during the late event stadium of the Eibsee rock avalanche at Mount Zugspitze in the Bavarian Alps, Germany. In the reflection seismic profiles we detected sedimentary structures that show high levels of fluidization and thus would hint at the presence of a paleolake. We could also reconstruct the post-evental paleotopography and aim at retrieving long sediment cores at suitable locations for seismic-to-core-correlation. Here we show how lake studies can help to decipher the multistage character of rock-slope failures and to improve the understanding of the processes related to runout dynamics.

75 FR 14361 - Notification, Documentation, and Recordkeeping Requirements for Inspected Establishments

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-25

... establishment's process control plans, that is, its Hazard Analysis and Critical Control Point plans. DATES... control plans, i.e., its Hazard Analysis and Critical Control Point (HACCP) plans; and (3) make the recall... systematic prevention of biological, chemical, and physical hazards. HACCP plans are establishment-developed...

21 CFR 120.7 - Hazard analysis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Hazard analysis. 120.7 Section 120.7 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... determine whether there are food hazards that are reasonably likely to occur for each type of juice...

Forensic and homeland security applications of modern portable Raman spectroscopy.

PubMed

Izake, Emad L

2010-10-10

Modern detection and identification of chemical and biological hazards within the forensic and homeland security contexts may well require conducting the analysis in field while adapting a non-contact approach to the hazard. Technological achievements on both surface and resonance enhancement Raman scattering re-developed Raman spectroscopy to become the most adaptable spectroscopy technique for stand-off and non-contact analysis of hazards. On the other hand, spatially offset Raman spectroscopy proved to be very valuable for non-invasive chemical analysis of hazards concealed within non-transparent containers and packaging. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

A Case Study of Measuring Process Risk for Early Insights into Software Safety

NASA Technical Reports Server (NTRS)

Layman, Lucas; Basili, Victor; Zelkowitz, Marvin V.; Fisher, Karen L.

2011-01-01

In this case study, we examine software safety risk in three flight hardware systems in NASA's Constellation spaceflight program. We applied our Technical and Process Risk Measurement (TPRM) methodology to the Constellation hazard analysis process to quantify the technical and process risks involving software safety in the early design phase of these projects. We analyzed 154 hazard reports and collected metrics to measure the prevalence of software in hazards and the specificity of descriptions of software causes of hazardous conditions. We found that 49-70% of 154 hazardous conditions could be caused by software or software was involved in the prevention of the hazardous condition. We also found that 12-17% of the 2013 hazard causes involved software, and that 23-29% of all causes had a software control. The application of the TPRM methodology identified process risks in the application of the hazard analysis process itself that may lead to software safety risk.

Hazards and occupational risk in hard coal mines - a critical analysis of legal requirements

NASA Astrophysics Data System (ADS)

Krause, Marcin

2017-11-01

This publication concerns the problems of occupational safety and health in hard coal mines, the basic elements of which are the mining hazards and the occupational risk. The work includes a comparative analysis of selected provisions of general and industry-specific law regarding the analysis of hazards and occupational risk assessment. Based on a critical analysis of legal requirements, basic assumptions regarding the practical guidelines for occupational risk assessment in underground coal mines have been proposed.

Hazard function theory for nonstationary natural hazards

NASA Astrophysics Data System (ADS)

Read, L.; Vogel, R. M.

2015-12-01

Studies from the natural hazards literature indicate that many natural processes, including wind speeds, landslides, wildfires, precipitation, streamflow and earthquakes, show evidence of nonstationary behavior such as trends in magnitudes through time. Traditional probabilistic analysis of natural hazards based on partial duration series (PDS) generally assumes stationarity in the magnitudes and arrivals of events, i.e. that the probability of exceedance is constant through time. Given evidence of trends and the consequent expected growth in devastating impacts from natural hazards across the world, new methods are needed to characterize their probabilistic behavior. The field of hazard function analysis (HFA) is ideally suited to this problem because its primary goal is to describe changes in the exceedance probability of an event over time. HFA is widely used in medicine, manufacturing, actuarial statistics, reliability engineering, economics, and elsewhere. HFA provides a rich theory to relate the natural hazard event series (x) with its failure time series (t), enabling computation of corresponding average return periods and reliabilities associated with nonstationary event series. This work investigates the suitability of HFA to characterize nonstationary natural hazards whose PDS magnitudes are assumed to follow the widely applied Poisson-GP model. We derive a 2-parameter Generalized Pareto hazard model and demonstrate how metrics such as reliability and average return period are impacted by nonstationarity and discuss the implications for planning and design. Our theoretical analysis linking hazard event series x, with corresponding failure time series t, should have application to a wide class of natural hazards.

Multi-hazard Assessment and Scenario Toolbox (MhAST): A Framework for Analyzing Compounding Effects of Multiple Hazards

NASA Astrophysics Data System (ADS)

Sadegh, M.; Moftakhari, H.; AghaKouchak, A.

2017-12-01

Many natural hazards are driven by multiple forcing variables, and concurrence/consecutive extreme events significantly increases risk of infrastructure/system failure. It is a common practice to use univariate analysis based upon a perceived ruling driver to estimate design quantiles and/or return periods of extreme events. A multivariate analysis, however, permits modeling simultaneous occurrence of multiple forcing variables. In this presentation, we introduce the Multi-hazard Assessment and Scenario Toolbox (MhAST) that comprehensively analyzes marginal and joint probability distributions of natural hazards. MhAST also offers a wide range of scenarios of return period and design levels and their likelihoods. Contribution of this study is four-fold: 1. comprehensive analysis of marginal and joint probability of multiple drivers through 17 continuous distributions and 26 copulas, 2. multiple scenario analysis of concurrent extremes based upon the most likely joint occurrence, one ruling variable, and weighted random sampling of joint occurrences with similar exceedance probabilities, 3. weighted average scenario analysis based on a expected event, and 4. uncertainty analysis of the most likely joint occurrence scenario using a Bayesian framework.

21 CFR 120.8 - Hazard Analysis and Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2010 CFR

2010-04-01

...: (i) Critical control points designed to control food hazards that are reasonably likely to occur and could be introduced inside the processing plant environment; and (ii) Critical control points designed... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Hazard Analysis and Critical Control Point (HACCP...

21 CFR 120.8 - Hazard Analysis and Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2012 CFR

2012-04-01

...: (i) Critical control points designed to control food hazards that are reasonably likely to occur and could be introduced inside the processing plant environment; and (ii) Critical control points designed... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Hazard Analysis and Critical Control Point (HACCP...

21 CFR 120.8 - Hazard Analysis and Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2013 CFR

2013-04-01

...: (i) Critical control points designed to control food hazards that are reasonably likely to occur and could be introduced inside the processing plant environment; and (ii) Critical control points designed... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Hazard Analysis and Critical Control Point (HACCP...

21 CFR 120.8 - Hazard Analysis and Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2014 CFR

2014-04-01

...: (i) Critical control points designed to control food hazards that are reasonably likely to occur and could be introduced inside the processing plant environment; and (ii) Critical control points designed... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Hazard Analysis and Critical Control Point (HACCP...

21 CFR 120.8 - Hazard Analysis and Critical Control Point (HACCP) plan.

Code of Federal Regulations, 2011 CFR

2011-04-01

...: (i) Critical control points designed to control food hazards that are reasonably likely to occur and could be introduced inside the processing plant environment; and (ii) Critical control points designed... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Hazard Analysis and Critical Control Point (HACCP...

Hues in a Crater Slope

NASA Image and Video Library

2017-01-02

Impact craters expose the subsurface materials on steep slopes. However, these slopes often experience rockfalls and debris avalanches that keep the surface clean of dust, revealing a variety of hues, like in this enhanced-color image, representing different rock types. The bright reddish material at the top of the crater rim is from a coating of the Martian dust. The long streamers of material are from downslope movements. Also revealed in this slope are a variety of bedrock textures, with a mix of layered and jumbled deposits. This sample is typical of the Martian highlands, with lava flows and water-lain materials depositing layers, then broken up and jumbled by many impact events. http://photojournal.jpl.nasa.gov/catalog/PIA14454

Influence of tectonic disturbances on the parameters of excavation support with rock anchor

NASA Astrophysics Data System (ADS)

Dyomin, V. F.; Yavorsky, V. V.; Demina, T. V.; Baidikova, N. V.; Protsenko, A. V.

2017-10-01

The mechanism of deformation, movement and rockfalls in structurally disturbed nonuniform rock mass using analytical modeling operation for assessment of the strain-stress state (SSS) of the rock mass around mining has been investigated. The SSS research of the rock masses by means of the ANSYS program of the excavation in the “Saransk” mine of coal mining JSC “ArselorMittal Temirtau” in the Karaganda coal basin has been conducted. The parameters of the exploitation of the anchor support on the mines for fixing the rock bolts in the workings to ensure the safety of mining operations in the areas of geological disturbances have been determined.

Microbiological quality of food in relation to hazard analysis systems and food hygiene training in UK catering and retail premises.

PubMed

Little, C L; Lock, D; Barnes, J; Mitchell, R T

2003-09-01

A meta-analysis of eight UK food studies was carried out to determine the microbiological quality of food and its relationship with the presence in food businesses of hazard analysis systems and food hygiene training. Of the 19,022 premises visited to collect food samples in these studies between 1997 and 2002, two thirds (66%) were catering premises and one third (34%) were retail premises. Comparison with PHLS Microbiological Guidelines revealed that significantly more ready-to-eat food samples from catering premises (20%; 2,511/12,703) were of unsatisfactory or unacceptable microbiological quality compared to samples from retail premises (12%; 1,039/8,462) (p < 0.00001). Three quarters (76%) of retail premises had hazard analysis systems in place compared with 59% of catering premises (p < 0.00001). In 87% of retail premises the manager had received some form of food hygiene training compared with 80% of catering premises (p < 0.00001). From premises where the manager had received no food hygiene training a greater proportion of samples were of unsatisfactory and unacceptable microbiological quality (20% retail, 27% catering) compared with premises where the manager had received food hygiene training (11% retail, 19% catering) (p < 0.00001). Where the manager of the premises had received food hygiene training, documented hazard analysis systems were more likely to be in place (p < 0.00001). Higher proportions of samples of unsatisfactory and unacceptable microbiological quality (17% retail, 22% catering) were from premises where there was no hazard analysis system in place compared to premises that had a documented hazard analysis system in place (10% retail, 18% catering) (p < 0.00001). Our meta-analysis suggests that the lower microbiological quality of ready-to-eat foods from catering premises compared with those collected from retail premises may reflect differences in management food hygiene training and the presence of a hazard analysis system. The importance of adequate training for food handlers and their managers as a pre-requisite for effective hazard analysis and critical control point (HACCP) based controls is therefore emphasised.

Glaciation of alpine valleys: The glacier - debris-covered glacier - rock glacier continuum

NASA Astrophysics Data System (ADS)

Anderson, Robert S.; Anderson, Leif S.; Armstrong, William H.; Rossi, Matthew W.; Crump, Sarah E.

2018-06-01

Alpine ice varies from pure ice glaciers to partially debris-covered glaciers to rock glaciers, as defined by the degree of debris cover. In many low- to mid-latitude mountain ranges, the few bare ice glaciers that do exist in the present climate are small and are found where snow is focused by avalanches and where direct exposure to radiation is minimized. Instead, valley heads are more likely to be populated by rock glaciers, which can number in the hundreds. These rock-cloaked glaciers represent some of the most identifiable components of the cryosphere today in low- to mid-latitude settings, and the over-steepened snouts pose an often overlooked hazard to travel in alpine terrain. Geomorphically, rock glaciers serve as conveyor belts atop which rock is pulled away from the base of cliffs. In this work, we show how rock glaciers can be treated as an end-member case that is captured in numerical models of glaciers that include ice dynamics, debris dynamics, and the feedbacks between them. Specifically, we focus on the transition from debris-covered glaciers, where the modern equilibrium line altitude (ELA) intersects the topography, to rock glaciers, where the modern ELA lies above the topography. On debris-covered glaciers (i.e., glaciers with a partial rock mantle), rock delivered to the glacier from its headwall, or from sidewall debris swept into the glacier at tributary junctions, travels englacially to emerge below the ELA. There it accumulates on the surface and damps the rate of melt of underlying ice. This allows the termini of debris-covered glaciers to extend beyond debris-free counterparts, thereby decreasing the ratio of accumulation area to total area of the glacier (AAR). In contrast, rock glaciers (i.e., glaciers with a full rock mantle) occur where and when the environmental ELA rises above the topography. They require avalanches and rockfall from steep headwalls. The occurrence of rock glaciers reflects this dependence on avalanche sources because they are most common on lee sides of ridges and peaks where wind-blown snow enhances the strength of the avalanche source. To maintain positive mass balance, the avalanche cone developed in the winter must be sufficiently thick not to melt entirely in the summer, thus providing an ice accumulation area for the rock glacier. In the absence of rockfall, this would support a short cirque glacier. The presence of debris, however, facilitates the development of rock glaciers with lengths of hundreds of meters, thicknesses of tens of meters, and speeds of meters per year that are well described by numerical models. Numerical models are used to explore the alpine glacier response to its climate history. In warming climates, a debris-covered glacier can transform into a much shorter rock glacier, leaving in its wake a thinning ice-cored moraine. Rock glaciers will persist in landscapes well beyond debris-free counterparts because they have much longer response times to climate change. The headwaters of alpine basins with steep headwalls will therefore oscillate between glacier and rock glacier occupation over glacial-interglacial cycles, maintaining a means by which rock from the headwall can be conveyed away. This enhances the asymmetry of alpine ridgelines, with downwind valleys biting deeply into the range crests, as originally noted by G.K. Gilbert.

Grand Junction projects office mixed-waste treatment program, VAC*TRAX mobile treatment unit process hazards analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bloom, R.R.

1996-04-01

The objective of this report is to demonstrate that a thorough assessment of the risks associated with the operation of the Rust Geotech patented VAC*TRAX mobile treatment unit (MTU) has been performed and documented. The MTU was developed to treat mixed wastes at the US Department of Energy (DOE) Albuquerque Operations Office sites. The MTU uses an indirectly heated, batch vacuum dryer to thermally desorb organic compounds from mixed wastes. This process hazards analysis evaluated 102 potential hazards. The three significant hazards identified involved the inclusion of oxygen in a process that also included an ignition source and fuel. Changesmore » to the design of the MTU were made concurrent with the hazard identification and analysis; all hazards with initial risk rankings of 1 or 2 were reduced to acceptable risk rankings of 3 or 4. The overall risk to any population group from operation of the MTU was determined to be very low; the MTU is classified as a Radiological Facility with low hazards.« less

Technical Guidance for Hazardous Analysis, Emergency Planning for Extremely Hazardous Substances

EPA Pesticide Factsheets

This current guide supplements NRT-1 by providing technical assistance to LEPCs to assess the lethal hazards related to potential airborne releases of extremely hazardous substances (EHSs) as designated under Section 302 of Title Ill of SARA.

Rasmussen's legacy: A paradigm change in engineering for safety.

PubMed

Leveson, Nancy G

2017-03-01

This paper describes three applications of Rasmussen's idea to systems engineering practice. The first is the application of the abstraction hierarchy to engineering specifications, particularly requirements specification. The second is the use of Rasmussen's ideas in safety modeling and analysis to create a new, more powerful type of accident causation model that extends traditional models to better handle human-operated, software-intensive, sociotechnical systems. Because this new model has a formal, mathematical foundation built on systems theory (as was Rasmussen's original model), new modeling and analysis tools become possible. The third application is to engineering hazard analysis. Engineers have traditionally either omitted human from consideration in system hazard analysis or have treated them rather superficially, for example, that they behave randomly. Applying Rasmussen's model of human error to a powerful new hazard analysis technique allows human behavior to be included in engineering hazard analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Space Propulsion Hazards Analysis Manual (SPHAM). Volume 2. Appendices

DTIC Science & Technology

1988-10-01

lb. RESTRICTIVE MARKINGS UNCLASSIFIED 2a. SECURITY CLASSIFICATION AUTHORITY 3 . DISTRIBUTION/AVAILABILITY OF REPORT Approved for public release...Volume I Chapter 2 - Requirementb and the Hazards Analysis Process .... Volume I Chapter 3 - Accident Scenarios...list of the hazardous materials that are discussed; 3 ) description of the failure scenarios; 4) type of post-accident environment that is discussed

Annotated bibliography, seismicity of and near the island of Hawaii and seismic hazard analysis of the East Rift of Kilauea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, F.W.

1994-03-28

This bibliography is divided into the following four sections: Seismicity of Hawaii and Kilauea Volcano; Occurrence, locations and accelerations from large historical Hawaiian earthquakes; Seismic hazards of Hawaii; and Methods of seismic hazard analysis. It contains 62 references, most of which are accompanied by short abstracts.

An alternative approach to probabilistic seismic hazard analysis in the Aegean region using Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Weatherill, Graeme; Burton, Paul W.

2010-09-01

The Aegean is the most seismically active and tectonically complex region in Europe. Damaging earthquakes have occurred here throughout recorded history, often resulting in considerable loss of life. The Monte Carlo method of probabilistic seismic hazard analysis (PSHA) is used to determine the level of ground motion likely to be exceeded in a given time period. Multiple random simulations of seismicity are generated to calculate, directly, the ground motion for a given site. Within the seismic hazard analysis we explore the impact of different seismic source models, incorporating both uniform zones and distributed seismicity. A new, simplified, seismic source model, derived from seismotectonic interpretation, is presented for the Aegean region. This is combined into the epistemic uncertainty analysis alongside existing source models for the region, and models derived by a K-means cluster analysis approach. Seismic source models derived using the K-means approach offer a degree of objectivity and reproducibility into the otherwise subjective approach of delineating seismic sources using expert judgment. Similar review and analysis is undertaken for the selection of peak ground acceleration (PGA) attenuation models, incorporating into the epistemic analysis Greek-specific models, European models and a Next Generation Attenuation model. Hazard maps for PGA on a "rock" site with a 10% probability of being exceeded in 50 years are produced and different source and attenuation models are compared. These indicate that Greek-specific attenuation models, with their smaller aleatory variability terms, produce lower PGA hazard, whilst recent European models and Next Generation Attenuation (NGA) model produce similar results. The Monte Carlo method is extended further to assimilate epistemic uncertainty into the hazard calculation, thus integrating across several appropriate source and PGA attenuation models. Site condition and fault-type are also integrated into the hazard mapping calculations. These hazard maps are in general agreement with previous maps for the Aegean, recognising the highest hazard in the Ionian Islands, Gulf of Corinth and Hellenic Arc. Peak Ground Accelerations for some sites in these regions reach as high as 500-600 cm s -2 using European/NGA attenuation models, and 400-500 cm s -2 using Greek attenuation models.

Hazard function theory for nonstationary natural hazards

NASA Astrophysics Data System (ADS)

Read, L. K.; Vogel, R. M.

2015-11-01

Impact from natural hazards is a shared global problem that causes tremendous loss of life and property, economic cost, and damage to the environment. Increasingly, many natural processes show evidence of nonstationary behavior including wind speeds, landslides, wildfires, precipitation, streamflow, sea levels, and earthquakes. Traditional probabilistic analysis of natural hazards based on peaks over threshold (POT) generally assumes stationarity in the magnitudes and arrivals of events, i.e. that the probability of exceedance of some critical event is constant through time. Given increasing evidence of trends in natural hazards, new methods are needed to characterize their probabilistic behavior. The well-developed field of hazard function analysis (HFA) is ideally suited to this problem because its primary goal is to describe changes in the exceedance probability of an event over time. HFA is widely used in medicine, manufacturing, actuarial statistics, reliability engineering, economics, and elsewhere. HFA provides a rich theory to relate the natural hazard event series (X) with its failure time series (T), enabling computation of corresponding average return periods, risk and reliabilities associated with nonstationary event series. This work investigates the suitability of HFA to characterize nonstationary natural hazards whose POT magnitudes are assumed to follow the widely applied Generalized Pareto (GP) model. We derive the hazard function for this case and demonstrate how metrics such as reliability and average return period are impacted by nonstationarity and discuss the implications for planning and design. Our theoretical analysis linking hazard event series X, with corresponding failure time series T, should have application to a wide class of natural hazards with rich opportunities for future extensions.

Hazard function theory for nonstationary natural hazards

NASA Astrophysics Data System (ADS)

Read, Laura K.; Vogel, Richard M.

2016-04-01

Impact from natural hazards is a shared global problem that causes tremendous loss of life and property, economic cost, and damage to the environment. Increasingly, many natural processes show evidence of nonstationary behavior including wind speeds, landslides, wildfires, precipitation, streamflow, sea levels, and earthquakes. Traditional probabilistic analysis of natural hazards based on peaks over threshold (POT) generally assumes stationarity in the magnitudes and arrivals of events, i.e., that the probability of exceedance of some critical event is constant through time. Given increasing evidence of trends in natural hazards, new methods are needed to characterize their probabilistic behavior. The well-developed field of hazard function analysis (HFA) is ideally suited to this problem because its primary goal is to describe changes in the exceedance probability of an event over time. HFA is widely used in medicine, manufacturing, actuarial statistics, reliability engineering, economics, and elsewhere. HFA provides a rich theory to relate the natural hazard event series (X) with its failure time series (T), enabling computation of corresponding average return periods, risk, and reliabilities associated with nonstationary event series. This work investigates the suitability of HFA to characterize nonstationary natural hazards whose POT magnitudes are assumed to follow the widely applied generalized Pareto model. We derive the hazard function for this case and demonstrate how metrics such as reliability and average return period are impacted by nonstationarity and discuss the implications for planning and design. Our theoretical analysis linking hazard random variable X with corresponding failure time series T should have application to a wide class of natural hazards with opportunities for future extensions.

Statistical analysis of the uncertainty related to flood hazard appraisal

NASA Astrophysics Data System (ADS)

Notaro, Vincenza; Freni, Gabriele

2015-12-01

The estimation of flood hazard frequency statistics for an urban catchment is of great interest in practice. It provides the evaluation of potential flood risk and related damage and supports decision making for flood risk management. Flood risk is usually defined as function of the probability, that a system deficiency can cause flooding (hazard), and the expected damage, due to the flooding magnitude (damage), taking into account both the exposure and the vulnerability of the goods at risk. The expected flood damage can be evaluated by an a priori estimation of potential damage caused by flooding or by interpolating real damage data. With regard to flood hazard appraisal several procedures propose to identify some hazard indicator (HI) such as flood depth or the combination of flood depth and velocity and to assess the flood hazard corresponding to the analyzed area comparing the HI variables with user-defined threshold values or curves (penalty curves or matrixes). However, flooding data are usually unavailable or piecemeal allowing for carrying out a reliable flood hazard analysis, therefore hazard analysis is often performed by means of mathematical simulations aimed at evaluating water levels and flow velocities over catchment surface. As results a great part of the uncertainties intrinsic to flood risk appraisal can be related to the hazard evaluation due to the uncertainty inherent to modeling results and to the subjectivity of the user defined hazard thresholds applied to link flood depth to a hazard level. In the present work, a statistical methodology was proposed for evaluating and reducing the uncertainties connected with hazard level estimation. The methodology has been applied to a real urban watershed as case study.

Applicability of the Common Safety Method for Risk Evaluation and Assessment (CSM-RA) to the Space Domain

NASA Astrophysics Data System (ADS)

Moreira, Francisco; Silva, Nuno

2016-08-01

Safety systems require accident avoidance. This is covered by application standards, processes, techniques and tools that support the identification, analysis, elimination or reduction to an acceptable level of system risks and hazards. Ideally, a safety system should be free of hazards. However, both industry and academia have been struggling to ensure appropriate risk and hazard analysis, especially in what concerns completeness of the hazards, formalization, and timely analysis in order to influence the specifications and the implementation. Such analysis is also important when considering a change to an existing system. The Common Safety Method for Risk Evaluation and Assessment (CSM- RA) is a mandatory procedure whenever any significant change is proposed to the railway system in a European Member State. This paper provides insights on the fundamentals of CSM-RA based and complemented with Hazard Analysis. When and how to apply them, and the relation and similarities of these processes with industry standards and the system life cycles is highlighted. Finally, the paper shows how CSM-RA can be the basis of a change management process, guiding the identification and management of the hazards helping ensuring the similar safety level as the initial system. This paper will show how the CSM-RA principles can be used in other domains particularly for space system evolution.

Monte Carlo simulation for slip rate sensitivity analysis in Cimandiri fault area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratama, Cecep, E-mail: great.pratama@gmail.com; Meilano, Irwan; Nugraha, Andri Dian

Slip rate is used to estimate earthquake recurrence relationship which is the most influence for hazard level. We examine slip rate contribution of Peak Ground Acceleration (PGA), in probabilistic seismic hazard maps (10% probability of exceedance in 50 years or 500 years return period). Hazard curve of PGA have been investigated for Sukabumi using a PSHA (Probabilistic Seismic Hazard Analysis). We observe that the most influence in the hazard estimate is crustal fault. Monte Carlo approach has been developed to assess the sensitivity. Then, Monte Carlo simulations properties have been assessed. Uncertainty and coefficient of variation from slip rate formore » Cimandiri Fault area has been calculated. We observe that seismic hazard estimates is sensitive to fault slip rate with seismic hazard uncertainty result about 0.25 g. For specific site, we found seismic hazard estimate for Sukabumi is between 0.4904 – 0.8465 g with uncertainty between 0.0847 – 0.2389 g and COV between 17.7% – 29.8%.« less

Hydrogen Hazards Assessment Protocol (HHAP): Approach and Methodology

NASA Technical Reports Server (NTRS)

Woods, Stephen

2009-01-01

This viewgraph presentation reviews the approach and methodology to develop a assessment protocol for hydrogen hazards. Included in the presentation are the reasons to perform hazards assessment, the types of hazard assessments that exist, an analysis of hydrogen hazards, specific information about the Hydrogen Hazards Assessment Protocol (HHAP). The assessment is specifically tailored for hydrogen behavior. The end product of the assesment is a compilation of hazard, mitigations and associated factors to facilitate decision making and achieve the best practice.

Analysis of a school building damaged by the 2015 Ranau earthquake Malaysia

NASA Astrophysics Data System (ADS)

Takano, Shugo; Saito, Taiki

2017-10-01

On June 5th, 2015 a severe earthquake with a moment Magnitude of 6.0 occurred in Ranau, Malaysia. Depth of the epicenter is 10 km. Due to the earthquake, many facilities were damaged and 18 people were killed due to rockfalls [1]. Because the British Standard (BS) is adopted as a regulation for built buildings in Malaysia, the seismic force is not considered in the structural design. Therefore, the seismic resistance of Malaysian buildings is unclear. To secure the human life and building safety, it is important to grasp seismic resistance of the building. The objective of this study is to evaluate the seismic resistance of the existing buildings in Malaysia built by the British Standard. A school building that was damaged at the Ranau earthquake is selected as the target building. The building is a four story building and the ground floor is designed to be a parking space for the staff. The structural types are infill masonries where main frame is configured by reinforced concrete columns and beams and brick is installed inside the frame as walls. Analysis is performed using the STERA_3D software that is the software to analyze the seismic performance of buildings developed by one of the authors. Firstly, the natural period of the building is calculated and compared with the result of micro-tremor measurement. Secondly, the nonlinear push-over analysis was conducted to evaluate the horizontal load bearing capacity of the building. Thirdly, the earthquake response analysis was conducted using the time history acceleration data measured at the Ranau earthquake by the seismograph installed at Kota Kinabalu. By comparing the results of earthquake response analysis and the actual damage of the building, the reason that caused damage to the building is clarified.

Application of a Cloud Model-Set Pair Analysis in Hazard Assessment for Biomass Gasification Stations.

PubMed

Yan, Fang; Xu, Kaili

2017-01-01

Because a biomass gasification station includes various hazard factors, hazard assessment is needed and significant. In this article, the cloud model (CM) is employed to improve set pair analysis (SPA), and a novel hazard assessment method for a biomass gasification station is proposed based on the cloud model-set pair analysis (CM-SPA). In this method, cloud weight is proposed to be the weight of index. In contrast to the index weight of other methods, cloud weight is shown by cloud descriptors; hence, the randomness and fuzziness of cloud weight will make it effective to reflect the linguistic variables of experts. Then, the cloud connection degree (CCD) is proposed to replace the connection degree (CD); the calculation algorithm of CCD is also worked out. By utilizing the CCD, the hazard assessment results are shown by some normal clouds, and the normal clouds are reflected by cloud descriptors; meanwhile, the hazard grade is confirmed by analyzing the cloud descriptors. After that, two biomass gasification stations undergo hazard assessment via CM-SPA and AHP based SPA, respectively. The comparison of assessment results illustrates that the CM-SPA is suitable and effective for the hazard assessment of a biomass gasification station and that CM-SPA will make the assessment results more reasonable and scientific.

Application of a Cloud Model-Set Pair Analysis in Hazard Assessment for Biomass Gasification Stations

PubMed Central

Yan, Fang; Xu, Kaili

2017-01-01

Because a biomass gasification station includes various hazard factors, hazard assessment is needed and significant. In this article, the cloud model (CM) is employed to improve set pair analysis (SPA), and a novel hazard assessment method for a biomass gasification station is proposed based on the cloud model-set pair analysis (CM-SPA). In this method, cloud weight is proposed to be the weight of index. In contrast to the index weight of other methods, cloud weight is shown by cloud descriptors; hence, the randomness and fuzziness of cloud weight will make it effective to reflect the linguistic variables of experts. Then, the cloud connection degree (CCD) is proposed to replace the connection degree (CD); the calculation algorithm of CCD is also worked out. By utilizing the CCD, the hazard assessment results are shown by some normal clouds, and the normal clouds are reflected by cloud descriptors; meanwhile, the hazard grade is confirmed by analyzing the cloud descriptors. After that, two biomass gasification stations undergo hazard assessment via CM-SPA and AHP based SPA, respectively. The comparison of assessment results illustrates that the CM-SPA is suitable and effective for the hazard assessment of a biomass gasification station and that CM-SPA will make the assessment results more reasonable and scientific. PMID:28076440

Agent-based simulation for human-induced hazard analysis.

PubMed

Bulleit, William M; Drewek, Matthew W

2011-02-01

Terrorism could be treated as a hazard for design purposes. For instance, the terrorist hazard could be analyzed in a manner similar to the way that seismic hazard is handled. No matter how terrorism is dealt with in the design of systems, the need for predictions of the frequency and magnitude of the hazard will be required. And, if the human-induced hazard is to be designed for in a manner analogous to natural hazards, then the predictions should be probabilistic in nature. The model described in this article is a prototype model that used agent-based modeling (ABM) to analyze terrorist attacks. The basic approach in this article of using ABM to model human-induced hazards has been preliminarily validated in the sense that the attack magnitudes seem to be power-law distributed and attacks occur mostly in regions where high levels of wealth pass through, such as transit routes and markets. The model developed in this study indicates that ABM is a viable approach to modeling socioeconomic-based infrastructure systems for engineering design to deal with human-induced hazards. © 2010 Society for Risk Analysis.

Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

DOEpatents

Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

2016-06-14

A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

New approaches to wipe sampling methods for antineoplastic and other hazardous drugs in healthcare settings.

PubMed

Connor, Thomas H; Smith, Jerome P

2016-09-01

At the present time, the method of choice to determine surface contamination of the workplace with antineoplastic and other hazardous drugs is surface wipe sampling and subsequent sample analysis with a variety of analytical techniques. The purpose of this article is to review current methodology for determining the level of surface contamination with hazardous drugs in healthcare settings and to discuss recent advances in this area. In addition it will provide some guidance for conducting surface wipe sampling and sample analysis for these drugs in healthcare settings. Published studies on the use of wipe sampling to measure hazardous drugs on surfaces in healthcare settings drugs were reviewed. These studies include the use of well-documented chromatographic techniques for sample analysis in addition to newly evolving technology that provides rapid analysis of specific antineoplastic. Methodology for the analysis of surface wipe samples for hazardous drugs are reviewed, including the purposes, technical factors, sampling strategy, materials required, and limitations. The use of lateral flow immunoassay (LFIA) and fluorescence covalent microbead immunosorbent assay (FCMIA) for surface wipe sample evaluation is also discussed. Current recommendations are that all healthc a re settings where antineoplastic and other hazardous drugs are handled include surface wipe sampling as part of a comprehensive hazardous drug-safe handling program. Surface wipe sampling may be used as a method to characterize potential occupational dermal exposure risk and to evaluate the effectiveness of implemented controls and the overall safety program. New technology, although currently limited in scope, may make wipe sampling for hazardous drugs more routine, less costly, and provide a shorter response time than classical analytical techniques now in use.

40 CFR 68.67 - Process hazard analysis.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) CHEMICAL ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.67 Process hazard analysis. (a... instrumentation with alarms, and detection hardware such as hydrocarbon sensors.); (4) Consequences of failure of...

40 CFR 68.67 - Process hazard analysis.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) CHEMICAL ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.67 Process hazard analysis. (a... instrumentation with alarms, and detection hardware such as hydrocarbon sensors.); (4) Consequences of failure of...

Probabilistic wind/tornado/missile analyses for hazard and fragility evaluations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Y.J.; Reich, M.

Detailed analysis procedures and examples are presented for the probabilistic evaluation of hazard and fragility against high wind, tornado, and tornado-generated missiles. In the tornado hazard analysis, existing risk models are modified to incorporate various uncertainties including modeling errors. A significant feature of this paper is the detailed description of the Monte-Carlo simulation analyses of tornado-generated missiles. A simulation procedure, which includes the wind field modeling, missile injection, solution of flight equations, and missile impact analysis, is described with application examples.

Critical asset and portfolio risk analysis: an all-hazards framework.

PubMed

Ayyub, Bilal M; McGill, William L; Kaminskiy, Mark

2007-08-01

This article develops a quantitative all-hazards framework for critical asset and portfolio risk analysis (CAPRA) that considers both natural and human-caused hazards. Following a discussion on the nature of security threats, the need for actionable risk assessments, and the distinction between asset and portfolio-level analysis, a general formula for all-hazards risk analysis is obtained that resembles the traditional model based on the notional product of consequence, vulnerability, and threat, though with clear meanings assigned to each parameter. Furthermore, a simple portfolio consequence model is presented that yields first-order estimates of interdependency effects following a successful attack on an asset. Moreover, depending on the needs of the decisions being made and available analytical resources, values for the parameters in this model can be obtained at a high level or through detailed systems analysis. Several illustrative examples of the CAPRA methodology are provided.

An Independent Evaluation of the FMEA/CIL Hazard Analysis Alternative Study

NASA Technical Reports Server (NTRS)

Ray, Paul S.

1996-01-01

The present instruments of safety and reliability risk control for a majority of the National Aeronautics and Space Administration (NASA) programs/projects consist of Failure Mode and Effects Analysis (FMEA), Hazard Analysis (HA), Critical Items List (CIL), and Hazard Report (HR). This extensive analytical approach was introduced in the early 1970's and was implemented for the Space Shuttle Program by NHB 5300.4 (1D-2. Since the Challenger accident in 1986, the process has been expanded considerably and resulted in introduction of similar and/or duplicated activities in the safety/reliability risk analysis. A study initiated in 1995, to search for an alternative to the current FMEA/CIL Hazard Analysis methodology generated a proposed method on April 30, 1996. The objective of this Summer Faculty Study was to participate in and conduct an independent evaluation of the proposed alternative to simplify the present safety and reliability risk control procedure.

Application of systems and control theory-based hazard analysis to radiation oncology.

PubMed

Pawlicki, Todd; Samost, Aubrey; Brown, Derek W; Manger, Ryan P; Kim, Gwe-Ya; Leveson, Nancy G

2016-03-01

Both humans and software are notoriously challenging to account for in traditional hazard analysis models. The purpose of this work is to investigate and demonstrate the application of a new, extended accident causality model, called systems theoretic accident model and processes (STAMP), to radiation oncology. Specifically, a hazard analysis technique based on STAMP, system-theoretic process analysis (STPA), is used to perform a hazard analysis. The STPA procedure starts with the definition of high-level accidents for radiation oncology at the medical center and the hazards leading to those accidents. From there, the hierarchical safety control structure of the radiation oncology clinic is modeled, i.e., the controls that are used to prevent accidents and provide effective treatment. Using STPA, unsafe control actions (behaviors) are identified that can lead to the hazards as well as causal scenarios that can lead to the identified unsafe control. This information can be used to eliminate or mitigate potential hazards. The STPA procedure is demonstrated on a new online adaptive cranial radiosurgery procedure that omits the CT simulation step and uses CBCT for localization, planning, and surface imaging system during treatment. The STPA procedure generated a comprehensive set of causal scenarios that are traced back to system hazards and accidents. Ten control loops were created for the new SRS procedure, which covered the areas of hospital and department management, treatment design and delivery, and vendor service. Eighty three unsafe control actions were identified as well as 472 causal scenarios that could lead to those unsafe control actions. STPA provides a method for understanding the role of management decisions and hospital operations on system safety and generating process design requirements to prevent hazards and accidents. The interaction of people, hardware, and software is highlighted. The method of STPA produces results that can be used to improve safety and prevent accidents and warrants further investigation.

A Subject Reference: Benefit-Cost Analysis of Toxic Substances, Hazardous Materials and Solid Waste Control (1977)

EPA Pesticide Factsheets

Discussion of methodological issues for conducting benefit-cost analysis and provides guidance for selecting and applying the most appropriate and useful mechanisms in benefit-cost analysis of toxic substances, hazardous materials, and solid waste control

40 CFR 148.5 - Waste analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Waste analysis. 148.5 Section 148.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) HAZARDOUS WASTE INJECTION RESTRICTIONS General § 148.5 Waste analysis. Generators of hazardous wastes that are...

40 CFR 148.5 - Waste analysis.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Waste analysis. 148.5 Section 148.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) HAZARDOUS WASTE INJECTION RESTRICTIONS General § 148.5 Waste analysis. Generators of hazardous wastes that are...

14 CFR 417.409 - System hazard controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... hazard as identified by the ground safety analysis and satisfy the requirements of this section. A launch... electrical power and signal circuits that interface with hazardous subsystems. (e) Propulsion systems. A...

14 CFR 417.409 - System hazard controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... hazard as identified by the ground safety analysis and satisfy the requirements of this section. A launch... electrical power and signal circuits that interface with hazardous subsystems. (e) Propulsion systems. A...

14 CFR 417.409 - System hazard controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... hazard as identified by the ground safety analysis and satisfy the requirements of this section. A launch... electrical power and signal circuits that interface with hazardous subsystems. (e) Propulsion systems. A...

14 CFR 417.409 - System hazard controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... hazard as identified by the ground safety analysis and satisfy the requirements of this section. A launch... electrical power and signal circuits that interface with hazardous subsystems. (e) Propulsion systems. A...

Population and business exposure to twenty scenario earthquakes in the State of Washington

USGS Publications Warehouse

Wood, Nathan; Ratliff, Jamie

2011-01-01

This report documents the results of an initial analysis of population and business exposure to scenario earthquakes in Washington. This analysis was conducted to support the U.S. Geological Survey (USGS) Pacific Northwest Multi-Hazards Demonstration Project (MHDP) and an ongoing collaboration between the State of Washington Emergency Management Division (WEMD) and the USGS on earthquake hazards and vulnerability topics. This report was developed to help WEMD meet internal planning needs. A subsequent report will provide analysis to the community level. The objective of this project was to use scenario ground-motion hazard maps to estimate population and business exposure to twenty Washington earthquakes. In consultation with the USGS Earthquake Hazards Program and the Washington Division of Geology and Natural Resources, the twenty scenario earthquakes were selected by WEMD (fig. 1). Hazard maps were then produced by the USGS and placed in the USGS ShakeMap archive.

Hazard assessment of landslide and debris flow in the Rjeina river valley, Croatia

NASA Astrophysics Data System (ADS)

Wang, Chunxiang; Watanabe, Naoki; Marui, Hideaki

2013-04-01

The Rječina River extends approximately 18.7km long and flows into the Adriatic Sea at the center of Rijeka City, Croatia. Landslide, debris flow and rockfall are main geohazards in the middle part of the Rječina river basin. The zone between the Valići reservoir dam and the Pasac Bridge is particularly the most unstable and hazardous area in the river basin. The Grohovo landslide in the middle part of the river basin is located on the valley's slope facing southwest and situated at just downstream of the Valići dam. This landslide is the largest active landslide along the Adriatic Sea coast in Croatia. Assuming that serious heavy rainfall or earthquake occurs, it is most likely to occur two types of geohazard event. One scenario is that the debris deposited on the Grohovo landslide will move down to the channel of the Rječina River and dam up the river course. Another scenario is that the slope deposits on the landslide will be mixed with water and subsequently turn into a debris flow reaching to Rijeka City. We simulate both two cases of the formation of landslide-dam and the occurrence of debris-flow by two integrated models using GIS to represent the dynamic process across 3D terrains. In the case of the formation of landslide-dam, it is assumed that slope deposits will move downhill after failing along a shear zone. GIS-based revised Hovland's 3D limit equilibrium model is used to simulate the movement and stoppage of the slope deposits to form landslide-dam. The 3D factor of safety will be calculated step by step during the sliding process simulation. Stoppage is defined by the factor of safety much greater than one and the velocity equal to zero. The simulation result shows that the height of the landslide-dam will be nine meters. In case of debris flow, the mixture of slope deposits and water will be differentiated from landslide by fluid-like deformation of the mobilized material. GIS-based depth-averaged 2D numerical model is used to predict the runout distance and inundated area of the debris flow. The simulation result displays the propagation and deposition of the debris flow across the complex topography and shows that the debris flow takes about 16 minutes to travel about 6 km along the Rječina River and consequently reaches to Rijeka City.

75 FR 35366 - Pipeline Safety: Applying Safety Regulation to All Rural Onshore Hazardous Liquid Low-Stress Lines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-22

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Part... Onshore Hazardous Liquid Low-Stress Lines AGENCY: Pipeline and Hazardous Materials Safety Administration... pipelines to perform a complete ``could affect'' analysis to determine which rural low-stress pipeline...

76 FR 25576 - Pipeline Safety: Applying Safety Regulations to All Rural Onshore Hazardous Liquid Low-Stress Lines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-05

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Part... to All Rural Onshore Hazardous Liquid Low-Stress Lines AGENCY: Pipeline and Hazardous Materials... burdensome to require operators of these pipelines to perform a complete ``could affect'' analysis to...

A Gis Model Application Supporting The Analysis of The Seismic Hazard For The Urban Area of Catania (italy)

NASA Astrophysics Data System (ADS)

Grasso, S.; Maugeri, M.

After the Summit held in Washington on August 20-22 2001 to plan the first World Conference on the mitigation of Natural Hazards, a Group for the analysis of Natural Hazards within the Mediterranean area has been formed. The Group has so far determined the following hazards: (1) Seismic hazard (hazard for historical buildings included); (2) Hazard linked to the quantity and quality of water; (3) Landslide hazard; (4) Volcanic hazard. The analysis of such hazards implies the creation and the management of data banks, which can only be used if the data are properly geo-settled to allow a crossed use of them. The obtained results must be therefore represented on geo-settled maps. The present study is part of a research programme, namely "Detailed Scenarios and Actions for Seismic Prevention of Damage in the Urban Area of Catania", financed by the National Department for the Civil Protection and the National Research Council-National Group for the Defence Against Earthquakes (CNR-GNDT). Nowadays the south-eastern area of Sicily, called the "Iblea" seismic area of Sicily, is considered as one of the most intense seismic zones in Italy, based on the past and current seismic history and on the typology of civil buildings. Safety against earthquake hazards has two as pects: structural safety against potentially destructive dynamic forces and site safety related to geotechnical phenomena such as amplification, land sliding and soil liquefaction. So the correct evaluation of seismic hazard is highly affected by risk factors due to geological nature and geotechnical properties of soils. The effect of local geotechnical conditions on damages suffered by buildings under seismic conditions has been widely recognized, as it is demonstrated by the Manual for Zonation on Seismic Geotechnical Hazards edited by the International Society for Soil Mechanics and Geotechnical Engineering (TC4, 1999). The evaluation of local amplification effects may be carried out by means of either rigorous complex methods of analysis or qualitative procedures. A semi quantitative procedure based on the definition of the geotechnical hazard index has been applied for the zonation of the seismic geotechnical hazard of the city of Catania. In particular this procedure has been applied to define the influence of geotechnical properties of soil in a central area of the city of Catania, where some historical buildings of great importance are sited. It was also performed an investigation based on the inspection of more than one hundred historical ecclesiastical buildings of great importance, located in the city. Then, in order to identify the amplification effects due to the site conditions, a geotechnical survey form was prepared, to allow a semi quantitative evaluation of the seismic geotechnical hazard for all these historical buildings. In addition, to evaluate the foundation soil time -history response, a 1-D dynamic soil model was employed for all these buildings, considering the non linearity of soil behaviour. Using a GIS, a map of the seismic geotechnical hazard, of the liquefaction hazard and a preliminary map of the seismic hazard for the city of Catania have been obtained. From the analysis of obtained results it may be noticed that high hazard zones are mainly clayey sites

Hazard function theory for nonstationary natural hazards

DOE PAGES

Read, Laura K.; Vogel, Richard M.

2016-04-11

Impact from natural hazards is a shared global problem that causes tremendous loss of life and property, economic cost, and damage to the environment. Increasingly, many natural processes show evidence of nonstationary behavior including wind speeds, landslides, wildfires, precipitation, streamflow, sea levels, and earthquakes. Traditional probabilistic analysis of natural hazards based on peaks over threshold (POT) generally assumes stationarity in the magnitudes and arrivals of events, i.e., that the probability of exceedance of some critical event is constant through time. Given increasing evidence of trends in natural hazards, new methods are needed to characterize their probabilistic behavior. The well-developed field ofmore » hazard function analysis (HFA) is ideally suited to this problem because its primary goal is to describe changes in the exceedance probability of an event over time. HFA is widely used in medicine, manufacturing, actuarial statistics, reliability engineering, economics, and elsewhere. HFA provides a rich theory to relate the natural hazard event series ( X) with its failure time series ( T), enabling computation of corresponding average return periods, risk, and reliabilities associated with nonstationary event series. This work investigates the suitability of HFA to characterize nonstationary natural hazards whose POT magnitudes are assumed to follow the widely applied generalized Pareto model. We derive the hazard function for this case and demonstrate how metrics such as reliability and average return period are impacted by nonstationarity and discuss the implications for planning and design. As a result, our theoretical analysis linking hazard random variable  X with corresponding failure time series  T should have application to a wide class of natural hazards with opportunities for future extensions.« less

Hazard function theory for nonstationary natural hazards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Read, Laura K.; Vogel, Richard M.

Impact from natural hazards is a shared global problem that causes tremendous loss of life and property, economic cost, and damage to the environment. Increasingly, many natural processes show evidence of nonstationary behavior including wind speeds, landslides, wildfires, precipitation, streamflow, sea levels, and earthquakes. Traditional probabilistic analysis of natural hazards based on peaks over threshold (POT) generally assumes stationarity in the magnitudes and arrivals of events, i.e., that the probability of exceedance of some critical event is constant through time. Given increasing evidence of trends in natural hazards, new methods are needed to characterize their probabilistic behavior. The well-developed field ofmore » hazard function analysis (HFA) is ideally suited to this problem because its primary goal is to describe changes in the exceedance probability of an event over time. HFA is widely used in medicine, manufacturing, actuarial statistics, reliability engineering, economics, and elsewhere. HFA provides a rich theory to relate the natural hazard event series ( X) with its failure time series ( T), enabling computation of corresponding average return periods, risk, and reliabilities associated with nonstationary event series. This work investigates the suitability of HFA to characterize nonstationary natural hazards whose POT magnitudes are assumed to follow the widely applied generalized Pareto model. We derive the hazard function for this case and demonstrate how metrics such as reliability and average return period are impacted by nonstationarity and discuss the implications for planning and design. As a result, our theoretical analysis linking hazard random variable  X with corresponding failure time series  T should have application to a wide class of natural hazards with opportunities for future extensions.« less

Assessing the need for an update of a probabilistic seismic hazard analysis using a SSHAC Level 1 study and the Seismic Hazard Periodic Reevaluation Methodology

DOE PAGES

Payne, Suzette J.; Coppersmith, Kevin J.; Coppersmith, Ryan; ...

2017-08-23

A key decision for nuclear facilities is evaluating the need for an update of an existing seismic hazard analysis in light of new data and information that has become available since the time that the analysis was completed. We introduce the newly developed risk-informed Seismic Hazard Periodic Review Methodology (referred to as the SHPRM) and present how a Senior Seismic Hazard Analysis Committee (SSHAC) Level 1 probabilistic seismic hazard analysis (PSHA) was performed in an implementation of this new methodology. The SHPRM offers a defensible and documented approach that considers both the changes in seismic hazard and engineering-based risk informationmore » of an existing nuclear facility to assess the need for an update of an existing PSHA. The SHPRM has seven evaluation criteria that are employed at specific analysis, decision, and comparison points which are applied to seismic design categories established for nuclear facilities in United States. The SHPRM is implemented using a SSHAC Level 1 study performed for the Idaho National Laboratory, USA. The implementation focuses on the first six of the seven evaluation criteria of the SHPRM which are all provided from the SSHAC Level 1 PSHA. Finally, to illustrate outcomes of the SHPRM that do not lead to the need for an update and those that do, the example implementations of the SHPRM are performed for nuclear facilities that have target performance goals expressed as the mean annual frequency of unacceptable performance at 1x10 -4, 4x10 -5 and 1x10 -5.« less

Assessing the need for an update of a probabilistic seismic hazard analysis using a SSHAC Level 1 study and the Seismic Hazard Periodic Reevaluation Methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payne, Suzette J.; Coppersmith, Kevin J.; Coppersmith, Ryan

A key decision for nuclear facilities is evaluating the need for an update of an existing seismic hazard analysis in light of new data and information that has become available since the time that the analysis was completed. We introduce the newly developed risk-informed Seismic Hazard Periodic Review Methodology (referred to as the SHPRM) and present how a Senior Seismic Hazard Analysis Committee (SSHAC) Level 1 probabilistic seismic hazard analysis (PSHA) was performed in an implementation of this new methodology. The SHPRM offers a defensible and documented approach that considers both the changes in seismic hazard and engineering-based risk informationmore » of an existing nuclear facility to assess the need for an update of an existing PSHA. The SHPRM has seven evaluation criteria that are employed at specific analysis, decision, and comparison points which are applied to seismic design categories established for nuclear facilities in United States. The SHPRM is implemented using a SSHAC Level 1 study performed for the Idaho National Laboratory, USA. The implementation focuses on the first six of the seven evaluation criteria of the SHPRM which are all provided from the SSHAC Level 1 PSHA. Finally, to illustrate outcomes of the SHPRM that do not lead to the need for an update and those that do, the example implementations of the SHPRM are performed for nuclear facilities that have target performance goals expressed as the mean annual frequency of unacceptable performance at 1x10 -4, 4x10 -5 and 1x10 -5.« less

Comprehensive Seismological Monitoring of Geomorphic Processes in Taiwan

NASA Astrophysics Data System (ADS)

Chao, W. A.; Chen, C. H.

2016-12-01

Geomorphic processes such as hillslope mass wasting and river sediment transport are important for studying landscape dynamics. Mass movements induced from geomorphic events can generate seismic waves and be recorded by seismometers. Recent studies demonstrate that seismic monitoring techniques not only fully map the spatiotemporal patterns of geomorphic activity but also allow for exploration of the dynamic links between hillslope failures and channel processes, which may not be resolved by conventional techniques (e.g., optical remote sensing). We have recently developed a real-time landquake monitoring system (RLMS, here we use the term `landquake' to represent all hillslope failures such as rockfall, rock avalanche and landslide), which has been continuously monitoring landquake activities in Taiwan since June 2015 based on broadband seismic records, yielding source information (e.g., location, occurrence time, magnitude and mechanism) for large-sized events (http://140.112.57.117/main.html). Several seismic arrays have also been deployed over the past few years around the catchments and along the river channels in Taiwan for monitoring erosion processes at catchment scale, improving the spatiotemporal resolution in exploring the interaction between geomorphic events and specific meteorological conditions. Based on a forward model accounting for the impulsive impacts of saltating particles, we can further invert for the sediment load flux, a critical parameter in landscape evolution studies, by fitting the seismic observations only. To test the validity of the seismologically determined sediment load flux, we conduct a series of controlled dam breaking experiments that are advantageous in well constraining the spatiotemporal variations of the sediment transport. Incorporating the seismological constrains on geomorphic processes with the effects of tectonic and/or climate perturbations can provide valuable and quantitative information for more fully understanding and modeling of the dynamics of erosional mountain landscapes. Comprehensive seismic monitoring also yields important information for the evaluation, assessment and emergency response of hazardous geomorphic events.

Characterization of blocks impacts from acoustic emissions: insights from laboratory experiments

NASA Astrophysics Data System (ADS)

Farin, Maxime; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud; Shapiro, Nikolaï

2014-05-01

Rockfalls, debris flows and rock avalanches represent a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and glass and over rock blocks. The elastic energy emitted by a single bouncing bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. We obtained simple scaling laws relating the impactor characteristics (size, height of fall, material,...) to the elastic energy and spectral content. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, accelerometers (1 Hz to 56 kHz) were used to record the signals in a wide frequency range. The experiments were also monitored optically using fast cameras. Eventually, we looked at what types of features in the signal are affected by individual impacts, rolling of beads or by the large scale geometry of the avalanche.

Characterization of blocks impacts from elastic waves: insights from laboratory experiments

NASA Astrophysics Data System (ADS)

Farin, M.; Mangeney, A.; Toussaint, R.; De Rosny, J.; Shapiro, N.

2013-12-01

Rockfalls, debris flows and rock avalanches constitute a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and rock blocks. The elastic energy emitted by a single bouncing steel bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, two types of acoustic sensors were used to record the signals in a wide frequency range: accelerometers (1 Hz to 56 kHz) and piezoelectric sensors (100 kHz to 1 MHz). The experiments were also monitored optically using fast cameras. We developed a technique to use quantitatively both types of sensors to evaluate the elastic energy emitted by the sources. Eventually, we looked at what types of features in the signal are affected by individual shocks or by the large scale geometry of the avalanche.

Kulanaokuaiki Tephra (ca, A.D. 400-1000): Newly recognized evidence for highly explosive eruptions at Kilauea Volcano, Hawai'i

USGS Publications Warehouse

Fiske, R.S.; Rose, T.R.; Swanson, D.A.; Champion, D.E.; McGeehin, J.P.

2009-01-01

K??lauea may be one of the world's most intensively monitored volcanoes, but its eruptive history over the past several thousand years remains rather poorly known. Our study has revealed the vestiges of thin basaltic tephra deposits, overlooked by previous workers, that originally blanketed wide, near-summit areas and extended more than 17 km to the south coast of Hawai'i. These deposits, correlative with parts of tephra units at the summit and at sites farther north and northwest, show that K??lauea, commonly regarded as a gentle volcano, was the site of energetic pyroclastic eruptions and indicate the volcano is significantly more hazardous than previously realized. Seventeen new calibrated accelerator mass spectrometry (AMS) radiocarbon ages suggest these deposits, here named the Kulanaokuaiki Tephra, were emplaced ca. A.D. 400-1000, a time of no previously known pyroclastic activity at the volcano. Tephra correlations are based chiefly on a marker unit that contains unusually high values of TiO2 and K2O and on paleomagnetic signatures of associated lava flows, which show that the Kulanaokuaiki deposits are the time-stratigraphic equivalent of the upper part of a newly exhumed section of the Uw??kahuna Ash in the volcano's northwest caldera wall. This section, thought to have been permanently buried by rockfalls in 1983, is thicker and more complete than the previously accepted type Uw??kahuna at the base of the caldera wall. Collectively, these findings justify the elevation of the Uw??kahuna Ash to formation status; the newly recognized Kulanaokuaiki Tephra to the south, the chief focus of this study, is defined as a member of the Uw??kahuna Ash. The Kulanaokuaiki Tephra is the product of energetic pyroclastic falls; no surge- or pyroclastic-flow deposits were identified with certainty, despite recent interpretations that Uw??kahuna surges extended 10-20 km from K??lauea's summit. ?? 2009 Geological Society of America.

Detecting Slow Deformation Signals Preceding Dynamic Failure: A New Strategy For The Mitigation Of Natural Hazards (SAFER)

NASA Astrophysics Data System (ADS)

Vinciguerra, S.; Colombero, C.; Comina, C.; Umili, G.

2015-12-01

Rock slope monitoring is a major aim in territorial risk assessment and mitigation. The use of "site specific" microseismic monitoring systems can allow to detect pre-failure signals in unstable sectors within the rock mass and to predict the possible acceleration to the failure. To this aim multi-scale geophysical methods can provide a unique tool for an high-resolution imaging of the internal structure of the rock mass and constraints on the physical state of the medium. We present here a cross-hole seismic tomography survey coupled with laboratory ultrasonic velocity measurements and determination of physical properties on rock samples to characterize the damaged and potentially unstable granitic cliff of Madonna del Sasso (NW, Italy). Results allowed to achieve two main advances, in terms of obtaining: i) a lithological interpretation of the velocity field obtained at the site, ii) a systematic correlation of the measured velocities with physical properties (density and porosity) and macroscopic features of the granite (weathering and anisotropy) of the cliff. A microseismic monitoring system developed by the University of Turin/Compagnia San Paolo, consisting of a network of 4 triaxial geophones (4.5 Hz) connected to a 12-channel data logger, has been deployed on the unstable granitic cliff. More than 2000 events with different waveforms, duration and frequency content were recorded between November 2013 and July 2014. By inspecting the acquired events we identified the key parameters for a reliable distinction among the nature of each signal, i.e. the signal shape (in terms of amplitude, duration, kurtosis) and the frequency content (maximum frequency content and frequency distribution). Four main classes of recorded signals can be recognised: microseismic events, regional earthquakes, electrical noises and calibration signals, and unclassified events (probably grouping rockfalls, quarry blasts, other anthropic and natural sources of seismic noise).

Rapid Detection of Small Movements with GNSS Doppler Observables

NASA Astrophysics Data System (ADS)

Hohensinn, Roland; Geiger, Alain

2017-04-01

High-alpine terrain reacts very sensitively to varying environmental conditions. As an example, increasing temperatures cause thawing of permafrost areas. This, in turn causes an increasing threat by natural hazards like debris flow (e.g. rock glaciers) or rockfalls. The Institute of Geodesy and Photogrammetry is contributing to alpine mass-movement monitoring systems in different project areas in the Swiss Alps. A main focus lies on providing geodetic mass-movement information derived from GNSS static solutions on a daily and a sub-daily basis, obtained with low-cost and autonomous GNSS stations. Another focus is set on rapidly providing reliable geodetic information in real-time i.e. for an integration in early warning systems. One way to achieve this is the estimation of accurate station velocities from observations of range rates, which can be obtained as Doppler observables from time derivatives of carrier phase measurements. The key for this method lies in a precise modeling of prominent effects contributing to the observed range rates, which are satellite velocity, atmospheric delay rates and relativistic effects. A suitable observation model is then devised, which accounts for these predictions. The observation model, combined with a simple kinematic movement model forms the basis for the parameter estimation. Based on the estimated station velocities, movements are then detected using a statistical test. To improve the reliablity of the estimated parameters, another spotlight is set on an on-line quality control procedure. We will present the basic algorithms as well as results from first tests which were carried out with a low-cost GPS L1 phase receiver. With a u-blox module and a sampling rate of 5 Hz, accuracies on the mm/s level can be obtained and velocities down to 1 cm/s can be detected. Reliable and accurate station velocities and movement information can be provided within seconds.

Transportation systems safety hazard analysis tool (SafetyHAT) user guide (version 1.0)

DOT National Transportation Integrated Search

2014-03-24

This is a user guide for the transportation system Safety Hazard Analysis Tool (SafetyHAT) Version 1.0. SafetyHAT is a software tool that facilitates System Theoretic Process Analysis (STPA.) This user guide provides instructions on how to download, ...

Research on the spatial analysis method of seismic hazard for island

NASA Astrophysics Data System (ADS)

Jia, Jing; Jiang, Jitong; Zheng, Qiuhong; Gao, Huiying

2017-05-01

Seismic hazard analysis(SHA) is a key component of earthquake disaster prevention field for island engineering, whose result could provide parameters for seismic design microscopically and also is the requisite work for the island conservation planning’s earthquake and comprehensive disaster prevention planning macroscopically, in the exploitation and construction process of both inhabited and uninhabited islands. The existing seismic hazard analysis methods are compared in their application, and their application and limitation for island is analysed. Then a specialized spatial analysis method of seismic hazard for island (SAMSHI) is given to support the further related work of earthquake disaster prevention planning, based on spatial analysis tools in GIS and fuzzy comprehensive evaluation model. The basic spatial database of SAMSHI includes faults data, historical earthquake record data, geological data and Bouguer gravity anomalies data, which are the data sources for the 11 indices of the fuzzy comprehensive evaluation model, and these indices are calculated by the spatial analysis model constructed in ArcGIS’s Model Builder platform.

Combined fluvial and pluvial urban flood hazard analysis: method development and application to Can Tho City, Mekong Delta, Vietnam

NASA Astrophysics Data System (ADS)

Apel, H.; Trepat, O. M.; Hung, N. N.; Chinh, D. T.; Merz, B.; Dung, N. V.

2015-08-01

Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas, and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either fluvial or pluvial flood hazard, studies of combined fluvial and pluvial flood hazard are hardly available. Thus this study aims at the analysis of fluvial and pluvial flood hazard individually, but also at developing a method for the analysis of combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as example. In this tropical environment the annual monsoon triggered floods of the Mekong River can coincide with heavy local convective precipitation events causing both fluvial and pluvial flooding at the same time. Fluvial flood hazard was estimated with a copula based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. Pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data, and a stochastic rain storm generator. Inundation was simulated by a 2-dimensional hydrodynamic model implemented on a Graphical Processor Unit (GPU) for time-efficient flood propagation modelling. All hazards - fluvial, pluvial and combined - were accompanied by an uncertainty estimation considering the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by percentile maps. The results are critically discussed and ways for their usage in flood risk management are outlined.

Hazard Management Dealt by Safety Professionals in Colleges: The Impact of Individual Factors.

PubMed

Wu, Tsung-Chih; Chen, Chi-Hsiang; Yi, Nai-Wen; Lu, Pei-Chen; Yu, Shan-Chi; Wang, Chien-Peng

2016-12-03

Identifying, evaluating, and controlling workplace hazards are important functions of safety professionals (SPs). The purpose of this study was to investigate the content and frequency of hazard management dealt by safety professionals in colleges. The authors also explored the effects of organizational factors/individual factors on SPs' perception of frequency of hazard management. The researchers conducted survey research to achieve the objective of this study. The researchers mailed questionnaires to 200 SPs in colleges after simple random sampling, then received a total of 144 valid responses (response rate = 72%). Exploratory factor analysis indicated that the hazard management scale (HMS) extracted five factors, including physical hazards, biological hazards, social and psychological hazards, ergonomic hazards, and chemical hazards. Moreover, the top 10 hazards that the survey results identified that safety professionals were most likely to deal with (in order of most to least frequent) were: organic solvents, illumination, other chemicals, machinery and equipment, fire and explosion, electricity, noise, specific chemicals, human error, and lifting/carrying. Finally, the results of one-way multivariate analysis of variance (MANOVA) indicated there were four individual factors that impacted the perceived frequency of hazard management which were of statistical and practical significance: job tenure in the college of employment, type of certification, gender, and overall job tenure. SPs within colleges and industries can now discuss plans revolving around these five areas instead of having to deal with all of the separate hazards.

Hazard Management Dealt by Safety Professionals in Colleges: The Impact of Individual Factors

PubMed Central

Wu, Tsung-Chih; Chen, Chi-Hsiang; Yi, Nai-Wen; Lu, Pei-Chen; Yu, Shan-Chi; Wang, Chien-Peng

2016-01-01

Identifying, evaluating, and controlling workplace hazards are important functions of safety professionals (SPs). The purpose of this study was to investigate the content and frequency of hazard management dealt by safety professionals in colleges. The authors also explored the effects of organizational factors/individual factors on SPs’ perception of frequency of hazard management. The researchers conducted survey research to achieve the objective of this study. The researchers mailed questionnaires to 200 SPs in colleges after simple random sampling, then received a total of 144 valid responses (response rate = 72%). Exploratory factor analysis indicated that the hazard management scale (HMS) extracted five factors, including physical hazards, biological hazards, social and psychological hazards, ergonomic hazards, and chemical hazards. Moreover, the top 10 hazards that the survey results identified that safety professionals were most likely to deal with (in order of most to least frequent) were: organic solvents, illumination, other chemicals, machinery and equipment, fire and explosion, electricity, noise, specific chemicals, human error, and lifting/carrying. Finally, the results of one-way multivariate analysis of variance (MANOVA) indicated there were four individual factors that impacted the perceived frequency of hazard management which were of statistical and practical significance: job tenure in the college of employment, type of certification, gender, and overall job tenure. SPs within colleges and industries can now discuss plans revolving around these five areas instead of having to deal with all of the separate hazards. PMID:27918474

Probabilistic and Scenario Seismic and Liquefaction Hazard Analysis of the Mississippi Embayment Incorporating Nonlinear Site Effects

NASA Astrophysics Data System (ADS)

Cramer, C. H.; Dhar, M. S.

2017-12-01

The influence of deep sediment deposits of the Mississippi Embayment (ME) on the propagation of seismic waves is poorly understood and remains a major source of uncertainty for site response analysis. Many researchers have studied the effects of these deposits on seismic hazard of the area using available information at the time. In this study, we have used updated and newly available resources for seismic and liquefaction hazard analyses of the ME. We have developed an improved 3D geological model. Additionally, we used surface geological maps from Cupples and Van Arsdale (2013) to prepare liquefaction hazard maps. Both equivalent linear and nonlinear site response codes were used to develop site amplification distributions for use in generating hazard maps. The site amplification distributions are created using the Monte Carlo approach of Cramer et al. (2004, 2006) on a 0.1-degree grid. The 2014 National Seismic Hazard model and attenuation relations (Petersen et al., 2014) are used to prepare seismic hazard maps. Then liquefaction hazard maps are generated using liquefaction probability curves from Holzer (2011) and Cramer et al. (2015). Equivalent linear response (w/ increased precision, restricted nonlinear behavior with depth) shows similar hazard for the ME compared to nonlinear analysis (w/o pore pressure) results. At short periods nonlinear deamplification dominates the hazard, but at long periods resonance amplification dominates. The liquefaction hazard tends to be high in Holocene and late Pleistocene lowland sediments, even with lowered ground water levels, and low in Pleistocene loess of the uplands. Considering pore pressure effects in nonlinear site response analysis at a test site on the lowlands shows amplification of ground motion at short periods. PGA estimates from ME liquefaction and MMI observations are in the 0.25 to 0.4 g range. Our estimated M7.5 PGA hazard within 10 km of the fault can exceed this. Ground motion observations from liquefaction sites in New Zealand and Japan support PGAs below 0.4 g, except at sites within 20 km exhibiting pore-pressure induced acceleration spikes due to cyclic mobility where PGA ranges from 0.5 to 1.5 g. This study is being extended to more detailed seismic and liquefaction hazard studies in five western Tennessee counties under a five year grant from HUD.

9 CFR 417.4 - Validation, Verification, Reassessment.

Code of Federal Regulations, 2013 CFR

2013-01-01

... analysis. Any establishment that does not have a HACCP plan because a hazard analysis has revealed no food.... 417.4 Section 417.4 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... ACT HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.4 Validation, Verification...

9 CFR 417.4 - Validation, Verification, Reassessment.

Code of Federal Regulations, 2014 CFR

2014-01-01

... analysis. Any establishment that does not have a HACCP plan because a hazard analysis has revealed no food.... 417.4 Section 417.4 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... ACT HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.4 Validation, Verification...

Step 1: Human System Integration Pilot-Technology Interface Requirements for Weather Management

NASA Technical Reports Server (NTRS)

2005-01-01

This document involves definition of technology interface requirements for Hazardous Weather Avoidance. Technology concepts in use by the Access 5 Weather Management Work Package were considered. Beginning with the Human System Integration (HIS) high-level functional requirement for Hazardous Weather Avoidance, and Hazardous Weather Avoidance technology elements, HSI requirements for the interface to the pilot were identified. Results of the analysis describe (1) the information required by the pilot to have knowledge of hazardous weather, and (2) the control capability needed by the pilot to obtain hazardous weather information. Fundamentally, these requirements provide the candidate Hazardous Weather Avoidance technology concepts with the necessary human-related elements to make them compatible with human capabilities and limitations. The results of the analysis describe how Hazardous Weather Avoidance operations and functions should interface with the pilot to provide the necessary Weather Management functionality to the UA-pilot system. Requirements and guidelines for Hazardous Weather Avoidance are partitioned into four categories: (1) Planning En Route (2) Encountering Hazardous Weather En Route, (3) Planning to Destination, and (4) Diversion Planning Alternate Airport. Each requirement is stated and is supported with a rationale and associated reference(s).

C-Band Airport Surface Communications System Engineering-Initial High-Level Safety Risk Assessment and Mitigation

NASA Technical Reports Server (NTRS)

Zelkin, Natalie; Henriksen, Stephen

2011-01-01

This document is being provided as part of ITT's NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract: "New ATM Requirements--Future Communications, C-Band and L-Band Communications Standard Development." ITT has completed a safety hazard analysis providing a preliminary safety assessment for the proposed C-band (5091- to 5150-MHz) airport surface communication system. The assessment was performed following the guidelines outlined in the Federal Aviation Administration Safety Risk Management Guidance for System Acquisitions document. The safety analysis did not identify any hazards with an unacceptable risk, though a number of hazards with a medium risk were documented. This effort represents an initial high-level safety hazard analysis and notes the triggers for risk reassessment. A detailed safety hazards analysis is recommended as a follow-on activity to assess particular components of the C-band communication system after the profile is finalized and system rollout timing is determined. A security risk assessment has been performed by NASA as a parallel activity. While safety analysis is concerned with a prevention of accidental errors and failures, the security threat analysis focuses on deliberate attacks. Both processes identify the events that affect operation of the system; and from a safety perspective the security threats may present safety risks.

L-Band Digital Aeronautical Communications System Engineering - Initial Safety and Security Risk Assessment and Mitigation

NASA Technical Reports Server (NTRS)

Zelkin, Natalie; Henriksen, Stephen

2011-01-01

This document is being provided as part of ITT's NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: "New ATM Requirements--Future Communications, C-Band and L-Band Communications Standard Development." ITT has completed a safety hazard analysis providing a preliminary safety assessment for the proposed L-band (960 to 1164 MHz) terrestrial en route communications system. The assessment was performed following the guidelines outlined in the Federal Aviation Administration Safety Risk Management Guidance for System Acquisitions document. The safety analysis did not identify any hazards with an unacceptable risk, though a number of hazards with a medium risk were documented. This effort represents a preliminary safety hazard analysis and notes the triggers for risk reassessment. A detailed safety hazards analysis is recommended as a follow-on activity to assess particular components of the L-band communication system after the technology is chosen and system rollout timing is determined. The security risk analysis resulted in identifying main security threats to the proposed system as well as noting additional threats recommended for a future security analysis conducted at a later stage in the system development process. The document discusses various security controls, including those suggested in the COCR Version 2.0.

Two-dimensional fuzzy fault tree analysis for chlorine release from a chlor-alkali industry using expert elicitation.

PubMed

Renjith, V R; Madhu, G; Nayagam, V Lakshmana Gomathi; Bhasi, A B

2010-11-15

The hazards associated with major accident hazard (MAH) industries are fire, explosion and toxic gas releases. Of these, toxic gas release is the worst as it has the potential to cause extensive fatalities. Qualitative and quantitative hazard analyses are essential for the identification and quantification of these hazards related to chemical industries. Fault tree analysis (FTA) is an established technique in hazard identification. This technique has the advantage of being both qualitative and quantitative, if the probabilities and frequencies of the basic events are known. This paper outlines the estimation of the probability of release of chlorine from storage and filling facility of chlor-alkali industry using FTA. An attempt has also been made to arrive at the probability of chlorine release using expert elicitation and proven fuzzy logic technique for Indian conditions. Sensitivity analysis has been done to evaluate the percentage contribution of each basic event that could lead to chlorine release. Two-dimensional fuzzy fault tree analysis (TDFFTA) has been proposed for balancing the hesitation factor involved in expert elicitation. Copyright © 2010 Elsevier B.V. All rights reserved.

Site specific probabilistic seismic hazard analysis at Dubai Creek on the west coast of UAE

NASA Astrophysics Data System (ADS)

Shama, Ayman A.

2011-03-01

A probabilistic seismic hazard analysis (PSHA) was conducted to establish the hazard spectra for a site located at Dubai Creek on the west coast of the United Arab Emirates (UAE). The PSHA considered all the seismogenic sources that affect the site, including plate boundaries such as the Makran subduction zone, the Zagros fold-thrust region and the transition fault system between them; and local crustal faults in UAE. PSHA indicated that local faults dominate the hazard. The peak ground acceleration (PGA) for the 475-year return period spectrum is 0.17 g and 0.33 g for the 2,475-year return period spectrum. The hazard spectra are then employed to establish rock ground motions using the spectral matching technique.

Simulation-Based Probabilistic Tsunami Hazard Analysis: Empirical and Robust Hazard Predictions

NASA Astrophysics Data System (ADS)

De Risi, Raffaele; Goda, Katsuichiro

2017-08-01

Probabilistic tsunami hazard analysis (PTHA) is the prerequisite for rigorous risk assessment and thus for decision-making regarding risk mitigation strategies. This paper proposes a new simulation-based methodology for tsunami hazard assessment for a specific site of an engineering project along the coast, or, more broadly, for a wider tsunami-prone region. The methodology incorporates numerous uncertain parameters that are related to geophysical processes by adopting new scaling relationships for tsunamigenic seismic regions. Through the proposed methodology it is possible to obtain either a tsunami hazard curve for a single location, that is the representation of a tsunami intensity measure (such as inundation depth) versus its mean annual rate of occurrence, or tsunami hazard maps, representing the expected tsunami intensity measures within a geographical area, for a specific probability of occurrence in a given time window. In addition to the conventional tsunami hazard curve that is based on an empirical statistical representation of the simulation-based PTHA results, this study presents a robust tsunami hazard curve, which is based on a Bayesian fitting methodology. The robust approach allows a significant reduction of the number of simulations and, therefore, a reduction of the computational effort. Both methods produce a central estimate of the hazard as well as a confidence interval, facilitating the rigorous quantification of the hazard uncertainties.

A seismic hazard uncertainty analysis for the New Madrid seismic zone

USGS Publications Warehouse

Cramer, C.H.

2001-01-01

A review of the scientific issues relevant to characterizing earthquake sources in the New Madrid seismic zone has led to the development of a logic tree of possible alternative parameters. A variability analysis, using Monte Carlo sampling of this consensus logic tree, is presented and discussed. The analysis shows that for 2%-exceedence-in-50-year hazard, the best-estimate seismic hazard map is similar to previously published seismic hazard maps for the area. For peak ground acceleration (PGA) and spectral acceleration at 0.2 and 1.0 s (0.2 and 1.0 s Sa), the coefficient of variation (COV) representing the knowledge-based uncertainty in seismic hazard can exceed 0.6 over the New Madrid seismic zone and diminishes to about 0.1 away from areas of seismic activity. Sensitivity analyses show that the largest contributor to PGA, 0.2 and 1.0 s Sa seismic hazard variability is the uncertainty in the location of future 1811-1812 New Madrid sized earthquakes. This is followed by the variability due to the choice of ground motion attenuation relation, the magnitude for the 1811-1812 New Madrid earthquakes, and the recurrence interval for M>6.5 events. Seismic hazard is not very sensitive to the variability in seismogenic width and length. Published by Elsevier Science B.V.

Nitrate Waste Treatment Sampling and Analysis Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vigil-Holterman, Luciana R.; Martinez, Patrick Thomas; Garcia, Terrence Kerwin

2017-07-05

This plan is designed to outline the collection and analysis of nitrate salt-bearing waste samples required by the New Mexico Environment Department- Hazardous Waste Bureau in the Los Alamos National Laboratory (LANL) Hazardous Waste Facility Permit (Permit).

The Hazard Analysis and Critical Control Points (HACCP) generic model for the production of Thai fermented pork sausage (Nham).

PubMed

Paukatong, K V; Kunawasen, S

2001-01-01

Nham is a traditional Thai fermented pork sausage. The major ingredients of Nham are ground pork meat and shredded pork rind. Nham has been reported to be contaminated with Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes. Therefore, it is a potential cause of foodborne diseases for consumers. A Hazard Analysis and Critical Control Points (HACCP) generic model has been developed for the Nham process. Nham processing plants were observed and a generic flow diagram of Nham processes was constructed. Hazard analysis was then conducted. Other than microbial hazards, the pathogens previously found in Nham, sodium nitrite and metal were identified as chemical and physical hazards in this product, respectively. Four steps in the Nham process have been identified as critical control points. These steps are the weighing of the nitrite compound, stuffing, fermentation, and labeling. The chemical hazard of nitrite must be controlled during the weighing step. The critical limit of nitrite levels in the Nham mixture has been set at 100-200 ppm. This level is high enough to control Clostridium botulinum but does not cause chemical hazards to the consumer. The physical hazard from metal clips could be prevented by visual inspection of every Nham product during stuffing. The microbiological hazard in Nham could be reduced in the fermentation process. The critical limit of the pH of Nham was set at lower than 4.6. Since this product is not cooked during processing, finally, educating the consumer, by providing information on the label such as "safe if cooked before consumption", could be an alternative way to prevent the microbiological hazards of this product.

Assessment of pre-crisis and syn-crisis seismic hazard at Campi Flegrei and Mt. Vesuvius volcanoes, Campania, southern Italy

NASA Astrophysics Data System (ADS)

Convertito, Vincenzo; Zollo, Aldo

2011-08-01

In this study, we address the issue of short-term to medium-term probabilistic seismic hazard analysis for two volcanic areas, Campi Flegrei caldera and Mt. Vesuvius in the Campania region of southern Italy. Two different phases of the volcanic activity are considered. The first, which we term the pre-crisis phase, concerns the present quiescent state of the volcanoes that is characterized by low-to-moderate seismicity. The second phase, syn-crisis, concerns the unrest phase that can potentially lead to eruption. For the Campi Flegrei case study, we analyzed the pattern of seismicity during the 1982-1984 ground uplift episode (bradyseism). For Mt. Vesuvius, two different time-evolutionary models for seismicity were adopted, corresponding to different ways in which the volcano might erupt. We performed a site-specific analysis, linked with the hazard map, to investigate the effects of input parameters, in terms of source geometry, mean activity rate, periods of data collection, and return periods, for the syn-crisis phase. The analysis in the present study of the pre-crisis phase allowed a comparison of the results of probabilistic seismic hazard analysis for the two study areas with those provided in the Italian national hazard map. For the Mt. Vesuvius area in particular, the results show that the hazard can be greater than that reported in the national hazard map when information at a local scale is used. For the syn-crisis phase, the main result is that the data recorded during the early months of the unrest phase are substantially representative of the seismic hazard during the whole duration of the crisis.

Uncertainty in natural hazards, modeling and decision support: An introduction to this volume [Chapter 1

Treesearch

Karin Riley; Matthew Thompson; Peter Webley; Kevin D. Hyde

2017-01-01

Modeling has been used to characterize and map natural hazards and hazard susceptibility for decades. Uncertainties are pervasive in natural hazards analysis, including a limited ability to predict where and when extreme events will occur, with what consequences, and driven by what contributing factors. Modeling efforts are challenged by the intrinsic...

Software System Architecture Modeling Methodology for Naval Gun Weapon Systems

DTIC Science & Technology

2010-12-01

Weapon System HAR Hazard Action Report HERO Hazards of Electromagnetic Radiation to Ordnance IOC Initial Operational Capability... radiation to ordnance ; and combinations therein. Equipment, systems, or procedures and processes whose malfunction would hazard the safe manufacturing...NDI Non-Development Item OPEVAL Operational Evaluation ORDALTS Ordnance Alterations O&SHA Operating and Support Hazard Analysis PDA

Design and application analysis of prediction system of geo-hazards based on GIS in the Three Gorges Reservoir

NASA Astrophysics Data System (ADS)

Li, Deying; Yin, Kunlong; Gao, Huaxi; Liu, Changchun

2009-10-01

Although the project of the Three Gorges Dam across the Yangtze River in China can utilize this huge potential source of hydroelectric power, and eliminate the loss of life and damage by flood, it also causes environmental problems due to the big rise and fluctuation of the water, such as geo-hazards. In order to prevent and predict geo-hazards, the establishment of prediction system of geo-hazards is very necessary. In order to implement functions of hazard prediction of regional and urban geo-hazard, single geo-hazard prediction, prediction of landslide surge and risk evaluation, logical layers of the system consist of data capturing layer, data manipulation and processing layer, analysis and application layer, and information publication layer. Due to the existence of multi-source spatial data, the research on the multi-source transformation and fusion data should be carried on in the paper. Its applicability of the system was testified on the spatial prediction of landslide hazard through spatial analysis of GIS in which information value method have been applied aims to identify susceptible areas that are possible to future landslide, on the basis of historical record of past landslide, terrain parameter, geology, rainfall and anthropogenic activity. Detailed discussion was carried out on spatial distribution characteristics of landslide hazard in the new town of Badong. These results can be used for risk evaluation. The system can be implemented as an early-warning and emergency management tool by the relevant authorities of the Three Gorges Reservoir in the future.

Use of Remotely Piloted Aircraft System (RPAS) in the analysis of historical landslide occurred in 1885 in the Rječina River Valley, Croatia

NASA Astrophysics Data System (ADS)

Dugonjić Jovančević, Sanja; Peranić, Josip; Ružić, Igor; Arbanas, Željko; Kalajžić, Duje; Benac, Čedomir

2016-04-01

Numerous instability phenomena have been recorded in the Rječina River Valley, near the City of Rijeka, in the past 250 years. Large landslides triggered by rainfall and floods, were registered on both sides of the Valley. Landslide inventory in the Valley was established based on recorded historical events and LiDAR imagery. The Rječina River is a typical karstic river 18.7km long, originating from the Gorski Kotar Mountains. The central part of the Valley, belongs to the dominant morphostructural unit that strikes in the northwest-southeast direction along the Rječina River. Karstified limestone rock mass is visible on the top of the slopes, while the flysch rock mass is present on the lower slopes and at the bottom of the Valley. Different types of movements can be distinguished in the area, such as the sliding of slope deposits over the flysch bedrock, rockfalls from limestone cliffs, sliding of huge rocky blocks, and active landslide on the north-eastern slope. The paper presents investigation of the dormant landslide located on the south-western slope of the Valley, which was recorded in 1870 in numerous historical descriptions. Due to intense and long-term rainfall, the landslide was reactivated in 1885, destroying and damaging houses in the eastern part of the Grohovo Village. To predict possible reactivation of the dormant landslide on the south-western side of the Valley, 2D stability back analyses were performed on the basis of landslide features, in order to approximate the position of sliding surface and landslide dimensions. The landslide topography is very steep, and the slope is covered by unstable debris material, so therefore hard to perform any terrestrial geodetic survey. Consumer-grade DJI Phantom 2 Remotely Piloted Aircraft System (RPAS) was used to provide the data about the present slope topography. The landslide 3D point cloud was derived from approximately 200 photographs taken with RPAS, using structure-from-motion (SfM) photogrammetry. Images were processed using the online Autodesk service "ReCap". Ground control points (GCP) collected with Total Station are identified on photorealistic point cloud and used for geo-referencing. Cloud Compare software was used for the point cloud processing. This study compared georeferenced landslide point cloud delivered from images with data acquired from laser scanning. RAPS and SfM application produced high accuracy landslide 3D point cloud, characterized by safe and quick data acquisition. Based on the adopted rock mass strength parameters, obtained from the back analysis, a stability analysis of the present slope situation was performed, and the present stability of the landslide body is determined. The unfavourable conditions and possible triggering factors such as saturation of the slope, caused by heavy rain and earthquake, were included in the analyses what enabled estimation of future landslide hazard and risk.

Historical analysis of US pipeline accidents triggered by natural hazards

NASA Astrophysics Data System (ADS)

Girgin, Serkan; Krausmann, Elisabeth

2015-04-01

Natural hazards, such as earthquakes, floods, landslides, or lightning, can initiate accidents in oil and gas pipelines with potentially major consequences on the population or the environment due to toxic releases, fires and explosions. Accidents of this type are also referred to as Natech events. Many major accidents highlight the risk associated with natural-hazard impact on pipelines transporting dangerous substances. For instance, in the USA in 1994, flooding of the San Jacinto River caused the rupture of 8 and the undermining of 29 pipelines by the floodwaters. About 5.5 million litres of petroleum and related products were spilled into the river and ignited. As a results, 547 people were injured and significant environmental damage occurred. Post-incident analysis is a valuable tool for better understanding the causes, dynamics and impacts of pipeline Natech accidents in support of future accident prevention and mitigation. Therefore, data on onshore hazardous-liquid pipeline accidents collected by the US Pipeline and Hazardous Materials Safety Administration (PHMSA) was analysed. For this purpose, a database-driven incident data analysis system was developed to aid the rapid review and categorization of PHMSA incident reports. Using an automated data-mining process followed by a peer review of the incident records and supported by natural hazard databases and external information sources, the pipeline Natechs were identified. As a by-product of the data-collection process, the database now includes over 800,000 incidents from all causes in industrial and transportation activities, which are automatically classified in the same way as the PHMSA record. This presentation describes the data collection and reviewing steps conducted during the study, provides information on the developed database and data analysis tools, and reports the findings of a statistical analysis of the identified hazardous liquid pipeline incidents in terms of accident dynamics and consequences.

Risk analysis of hematopoietic stem cell transplant process: failure mode, effect, and criticality analysis and hazard analysis critical control point methods integration based on guidelines to good manufacturing practice for medicinal product ANNEX 20 (February 2008).

PubMed

Gianassi, S; Bisin, S; Bindi, B; Spitaleri, I; Bambi, F

2010-01-01

The collection and handling of hematopoietic stem cells (HSCs) must meet high quality requirements. An integrated Quality Risk Management can help to identify and contain potential risks related to HSC production. Risk analysis techniques allow one to "weigh" identified hazards, considering the seriousness of their effects, frequency, and detectability, seeking to prevent the most harmful hazards. The Hazard Analysis Critical Point, recognized as the most appropriate technique to identify risks associated with physical, chemical, and biological hazards for cellular products, consists of classifying finished product specifications and limits of acceptability, identifying all off-specifications, defining activities that can cause them, and finally establishing both a monitoring system for each Critical Control Point and corrective actions for deviations. The severity of possible effects on patients, as well as the occurrence and detectability of critical parameters, are measured on quantitative scales (Risk Priority Number [RPN]). Risk analysis was performed with this technique on manipulation process of HPC performed at our blood center. The data analysis showed that hazards with higher values of RPN with greater impact on the process are loss of dose and tracking; technical skills of operators and manual transcription of data were the most critical parameters. Problems related to operator skills are handled by defining targeted training programs, while other critical parameters can be mitigated with the use of continuous control systems. The blood center management software was completed by a labeling system with forms designed to be in compliance with standards in force and by starting implementation of a cryopreservation management module. Copyright 2010 Elsevier Inc. All rights reserved.

ANALYSIS OF GEOTHERMAL WASTES FOR HAZARDOUS COMPONENTS

EPA Science Inventory

Regulations governing the disposal of hazardous wastes led to an assessment for geothermal solid wastes for potentially hazardous properties. Samples were collected from three active geothermal sites in the western United States: The Geysers, Imperial Valley, and northwestern Nev...

Probabilistic Approaches for Multi-Hazard Risk Assessment of Structures and Systems

NASA Astrophysics Data System (ADS)

Kwag, Shinyoung

Performance assessment of structures, systems, and components for multi-hazard scenarios has received significant attention in recent years. However, the concept of multi-hazard analysis is quite broad in nature and the focus of existing literature varies across a wide range of problems. In some cases, such studies focus on hazards that either occur simultaneously or are closely correlated with each other. For example, seismically induced flooding or seismically induced fires. In other cases, multi-hazard studies relate to hazards that are not dependent or correlated but have strong likelihood of occurrence at different times during the lifetime of a structure. The current approaches for risk assessment need enhancement to account for multi-hazard risks. It must be able to account for uncertainty propagation in a systems-level analysis, consider correlation among events or failure modes, and allow integration of newly available information from continually evolving simulation models, experimental observations, and field measurements. This dissertation presents a detailed study that proposes enhancements by incorporating Bayesian networks and Bayesian updating within a performance-based probabilistic framework. The performance-based framework allows propagation of risk as well as uncertainties in the risk estimates within a systems analysis. Unlike conventional risk assessment techniques such as a fault-tree analysis, a Bayesian network can account for statistical dependencies and correlations among events/hazards. The proposed approach is extended to develop a risk-informed framework for quantitative validation and verification of high fidelity system-level simulation tools. Validation of such simulations can be quite formidable within the context of a multi-hazard risk assessment in nuclear power plants. The efficiency of this approach lies in identification of critical events, components, and systems that contribute to the overall risk. Validation of any event or component on the critical path is relatively more important in a risk-informed environment. Significance of multi-hazard risk is also illustrated for uncorrelated hazards of earthquakes and high winds which may result in competing design objectives. It is also illustrated that the number of computationally intensive nonlinear simulations needed in performance-based risk assessment for external hazards can be significantly reduced by using the power of Bayesian updating in conjunction with the concept of equivalent limit-state.

Manned space flight nuclear system safety. Volume 3: Reactor system preliminary nuclear safety analysis. Part 2: Accident Model Document (AMD)

NASA Technical Reports Server (NTRS)

1972-01-01

The Accident Model Document is one of three documents of the Preliminary Safety Analysis Report (PSAR) - Reactor System as applied to a Space Base Program. Potential terrestrial nuclear hazards involving the zirconium hydride reactor-Brayton power module are identified for all phases of the Space Base program. The accidents/events that give rise to the hazards are defined and abort sequence trees are developed to determine the sequence of events leading to the hazard and the associated probabilities of occurence. Source terms are calculated to determine the magnitude of the hazards. The above data is used in the mission accident analysis to determine the most probable and significant accidents/events in each mission phase. The only significant hazards during the prelaunch and launch ascent phases of the mission are those which arise form criticality accidents. Fission product inventories during this time period were found to be very low due to very limited low power acceptance testing.

A Guidance Manual: Waste Analysis at Facilities that Generate, Treat, Store, and Dispose of Hazardous Wastes

EPA Pesticide Factsheets

Discusses how a person can perform waste analyses and develop waste analysis plans (WAPs) in accordance with the federal hazardous waste regulations of the Resource Conservation and Recovery Act (RCRA)

Space Station Furnace Facility. Volume 2: Requirements Definition and Conceptual Design Study. Appendix 3: Environment Analysis. Volume 2; Appendix 3

NASA Technical Reports Server (NTRS)

1992-01-01

A Preliminary Safety Analysis (PSA) is being accomplished as part of the Space Station Furnace Facility (SSFF) contract. This analysis is intended to support SSFF activities by analyzing concepts and designs as they mature to develop essential safety requirements for inclusion in the appropriate specifications, and designs, as early as possible. In addition, the analysis identifies significant safety concerns that may warrant specific trade studies or design definition, etc. The analysis activity to date concentrated on hazard and hazard cause identification and requirements development with the goal of developing a baseline set of detailed requirements to support trade study, specifications development, and preliminary design activities. The analysis activity will continue as the design and concepts mature. Section 2 defines what was analyzed, but it is likely that the SSFF definitions will undergo further changes. The safety analysis activity will reflect these changes as they occur. The analysis provides the foundation for later safety activities. The hazards identified will in most cases have Preliminary Design Review (PDR) applicability. The requirements and recommendations developed for each hazard will be tracked to ensure proper and early resolution of safety concerns.

21 CFR 120.11 - Verification and validation.

Code of Federal Regulations, 2013 CFR

2013-04-01

... analysis. Whenever a juice processor has no HACCP plan because a hazard analysis has revealed no food... analysis whenever there are any changes in the process that could reasonably affect whether a food hazard... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Verification and validation. 120.11 Section 120.11...

21 CFR 120.11 - Verification and validation.

Code of Federal Regulations, 2012 CFR

2012-04-01

... analysis. Whenever a juice processor has no HACCP plan because a hazard analysis has revealed no food... analysis whenever there are any changes in the process that could reasonably affect whether a food hazard... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Verification and validation. 120.11 Section 120.11...

21 CFR 120.11 - Verification and validation.

Code of Federal Regulations, 2011 CFR

2011-04-01

... analysis. Whenever a juice processor has no HACCP plan because a hazard analysis has revealed no food... analysis whenever there are any changes in the process that could reasonably affect whether a food hazard... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Verification and validation. 120.11 Section 120.11...

21 CFR 120.11 - Verification and validation.

Code of Federal Regulations, 2014 CFR

2014-04-01

... analysis. Whenever a juice processor has no HACCP plan because a hazard analysis has revealed no food... analysis whenever there are any changes in the process that could reasonably affect whether a food hazard... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Verification and validation. 120.11 Section 120.11...

21 CFR 120.11 - Verification and validation.

Code of Federal Regulations, 2010 CFR

2010-04-01

... analysis. Whenever a juice processor has no HACCP plan because a hazard analysis has revealed no food... analysis whenever there are any changes in the process that could reasonably affect whether a food hazard... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Verification and validation. 120.11 Section 120.11...

Application of the FTA and ETA Method for Gas Hazard Identification for the Performance of Safety Systems in the Industrial Department

NASA Astrophysics Data System (ADS)

Ignac-Nowicka, Jolanta

2018-03-01

The paper analyzes the conditions of safe use of industrial gas systems and factors influencing gas hazards. Typical gas installation and its basic features have been characterized. The results of gas threat analysis in an industrial enterprise using FTA error tree method and ETA event tree method are presented. Compares selected methods of identifying hazards gas industry with respect to the scope of their use. The paper presents an analysis of two exemplary hazards: an industrial gas catastrophe (FTA) and an explosive gas explosion (ETA). In both cases, technical risks and human errors (human factor) were taken into account. The cause-effect relationships of hazards and their causes are presented in the form of diagrams in the drawings.

Guide for Oxygen Hazards Analyses on Components and Systems

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Dees, Jesse; Poe, Robert F.

1996-01-01

Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite at lower temperatures in an oxygen-enriched environment than in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Many metals burn violently in an oxygen-enriched environment when ignited. Lubricants, tapes, gaskets, fuels, and solvents can increase the possibility of ignition in oxygen systems. However, these hazards do not preclude the use of oxygen. Oxygen may be safely used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. These ignition and combustion hazards necessitate a proper oxygen hazards analysis before introducing a material or component into oxygen service. The objective of this test plan is to describe the White Sands Test Facility oxygen hazards analysis to be performed on components and systems before oxygen is introduced and is recommended before implementing the oxygen component qualification procedure. The plan describes the NASA Johnson Space Center White Sands Test Facility method consistent with the ASTM documents for analyzing the hazards of components and systems exposed to an oxygen-enriched environment. The oxygen hazards analysis is a useful tool for oxygen-system designers, system engineers, and facility managers. Problem areas can be pinpointed before oxygen is introduced into the system, preventing damage to hardware and possible injury or loss of life.

Causal Mediation Analysis for the Cox Proportional Hazards Model with a Smooth Baseline Hazard Estimator.

PubMed

Wang, Wei; Albert, Jeffrey M

2017-08-01

An important problem within the social, behavioral, and health sciences is how to partition an exposure effect (e.g. treatment or risk factor) among specific pathway effects and to quantify the importance of each pathway. Mediation analysis based on the potential outcomes framework is an important tool to address this problem and we consider the estimation of mediation effects for the proportional hazards model in this paper. We give precise definitions of the total effect, natural indirect effect, and natural direct effect in terms of the survival probability, hazard function, and restricted mean survival time within the standard two-stage mediation framework. To estimate the mediation effects on different scales, we propose a mediation formula approach in which simple parametric models (fractional polynomials or restricted cubic splines) are utilized to approximate the baseline log cumulative hazard function. Simulation study results demonstrate low bias of the mediation effect estimators and close-to-nominal coverage probability of the confidence intervals for a wide range of complex hazard shapes. We apply this method to the Jackson Heart Study data and conduct sensitivity analysis to assess the impact on the mediation effects inference when the no unmeasured mediator-outcome confounding assumption is violated.