Circular scanlines and circular windows: new tools for characterizing the geometry of fracture traces

Mauldon, Matthew; Dunne, William M.; Rohrbaugh, M.B.

doi:10.1016/s0191-8141(00)00094-8

Cited by 258 publications

(198 citation statements)

References 24 publications

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“…Discontinuity window mapping was undertaken according to the procedure suggested by Sturzenegger et al (2011): three circular windows with a radius equal to 20 m were selected for each point cloud (pre-and post-failure). Mauldon et al (2001) noted that the use of circular windows can eliminate the sampling bias along mapped surfaces. The windows were located on exposures with different orientation, to reduce the orientation bias occurring in the third dimension.…”

Section: Terrestrial Laser Scanner Surveymentioning

confidence: 99%

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

et al. 2015

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Landslides of the lateral spreading type, involving brittle geological units overlying ductile terrains, are a common occurrence in the sandstone and limestone plateaux of the northern Apennines of Italy. The edges of these plateaux are often the location of rapid landslide phenomena, such as rock slides, rock falls and topples. In this paper we present a back-analysis of a recent landslide (February 2014), involving the north-eastern sector of the San Leo rock slab (northern Apennines, Emilia-Romagna Region) which is a representative example of this type of phenomena. The aquifer hosted in the fractured slab, due to its relatively higher secondary permeability in comparison to the lower clayey units leads to the development of perennial and ephemeral springs at the contact between the two units. The related piping erosion phenomena, together with slope processes in the clayshales have led to the progressive undermining of the slab, eventually predisposing large-scale landslides. Stability analyses were conducted coupling Terrestrial Laser Scanning (TLS) and Distinct Element Methods (DEMs). TLS point clouds were analyzed to determine the pre-and post-failure geometry, the extension of the detachment area and the joint network characteristics. The block dimensions in the landslide deposit were mapped and used to infer the spacing of the discontinuities for insertion into the numerical model. Threedimensional distinct element simulations were conducted, with and without undermining of the rock slab. The analyses allowed an assessment of the role of the undermining, together with the presence of an almost vertical joint set, striking sub-parallel to the cliff orientation, on the development of the slope instability processes. Based on the TLS and on the numerical simulation results, an interpretation of the landslide mechanism is proposed.

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Section: Terrestrial Laser Scanner Surveymentioning

confidence: 99%

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

et al. 2015

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“…All visible fractures intersecting the circle were counted, with no differentiation 246 made between epidote-mineralized and unmineralised, annealed fractures. As fractures intersecting 247 the circle were counted rather than fractures terminating within the circle, the measure obtained is 248 for fracture intensity rather than fracture density (Mauldon et al, 2001). On the west bank 249 background fracture intensity is 10 fractures/m and on the east bank 16.5 fractures/m Fracture 250 intensity decreases outwards from the fault core, from a maximum of 58 fracture/m reaching 251 background levels between 40m and 60m from the fault wall (Fig.…”

mentioning

confidence: 99%

Brittle structures focused on subtle crustal heterogeneities: implications for flow in fractured rocks

Soden

Shipton

Lunn

et al. 2014

JGS

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This version is available at https://strathprints.strath.ac.uk/50617/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. Host rock mechanical heterogeneities influence the spatial distribution of deformation structures 13 and hence, predictions of fault architecture and fluid flow. A critical factor, commonly overlooked, 14 is how rock mechanical properties can vary over time, and how this will alter deformation processes 15 and resultant structures. We present field data from an area in the Borborema Province, NE Brazil, 16 that demonstrate how temporal changes in deformation conditions, and consequently processes, 17 exerts a primary control on the spatial distribution and geometric attributes of evolving deformation 18 structures. Further, each temporal deformation phase imparted different hydraulic architecture. The 19 earliest flowing structures localized upon subtle ductile heterogeneities. Following fault formation, 20 both fault core and damage zone were flow conduits. In later stages of faulting pseudotachylyte 21 welding created a low-permeability fault core and annealed high-permeability fractures within the 22 fault damage zone. Modern flow occurs along a zone of later open shear fractures, defined by the 23 mechanical strength contrast between the host rock and annealed fault. This second hydraulically-24 conductive zone extends 100s of meters from the edge of the annealed fault damage zone, creating a 25 flow zone far wider than would be predicted using traditional fault scaling relationships. Our results 26 demonstrate the importance of understanding successive deformation events for predicting the 27 temporal and spatial evolution of hydraulically active fractures. 28 29 2 30 Introduction 31Geometrical attributes of faults and fractures (length, orientation and spatial distribution) are of 32 primary importance in predicting fluid flow through fracture networks. For any particular fracture 33 system these attribu...

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“…In these cases, they can be estimated by counting them on rectangular (Pahl, 1981) or circular windows (Mauldon et al, 2001). Other methods using two or more photographs of an outcrop allow the estimation of orientation, fracturing density and trace length (Thomas et al, 1987;Crosta, 1997).…”

Section: Methods For Sampling the Geometrical Characteristics Of The mentioning

confidence: 99%

Assessing fracture occurrence using "weighted fracturing density": a step towards estimating rock instability hazard

Jaboyedoff

Baillifard

Philippossian

et al. 2004

Nat. Hazards Earth Syst. Sci.

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Abstract. Based on the assumption that major class of rock instabilities are created by discontinuities, a method is proposed to estimate the fracture density by means of a digital elevation model (DEM). By using the mean orientation, the mean spacing and the mean trace length of discontinuity sets potentially involved in slope instabilities and a DEM, it is possible to calculate the mean number of discontinuities of a given set per cell of the DEM. This would allow for an estimation of the probability of the presence of at least one discontinuity in a given area or simply in a topographic cell of the DEM. This analysis highlights sites potentially affected by rockslides within a region. Depending on the available data, the mean number can be calculated either by area, or along a line parallel to the mean apparent spacing. The effective use of the probability of occurrence is dependent on the size of the discontinuities because short and closely spaced discontinuities will have a 100% probability of occurrence in each favorable location. The a posteriori prediction of a recent rockslide is discussed as an example.

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Circular scanlines and circular windows: new tools for characterizing the geometry of fracture traces

Cited by 258 publications

References 24 publications

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

Brittle structures focused on subtle crustal heterogeneities: implications for flow in fractured rocks

Assessing fracture occurrence using "weighted fracturing density": a step towards estimating rock instability hazard

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Circular scanlines and circular windows: new tools for characterizing the geometry of fracture traces

Cited by 258 publications

References 24 publications

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

Brittle structures focused on subtle crustal heterogeneities: implications for flow in fractured rocks

Assessing fracture occurrence using &quot;weighted fracturing density&quot;: a step towards estimating rock instability hazard

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Assessing fracture occurrence using "weighted fracturing density": a step towards estimating rock instability hazard