scholarly journals Fault zone architecture and its scaling laws: where does the damage zone start and stop?

2019 ◽  
Vol 496 (1) ◽  
pp. 99-124 ◽  
Author(s):  
A. Torabi ◽  
T. S. S. Ellingsen ◽  
M. U. Johannessen ◽  
B. Alaei ◽  
A. Rotevatn ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Damage Zone ◽  
Break Point ◽  
Deformation Bands ◽  
High Deformation ◽  
Zone Width ◽  
Deformation Features ◽  
Fault Zone Architecture ◽  
Siliciclastic Rocks ◽  
Power Law Distributions

AbstractDamage zones of different fault types are investigated in siliciclastics (Utah, USA), carbonates (Majella Mountain, Italy) and metamorphic rocks (western Norway). The study was conducted taking measurements of deformation features such as fractures and deformation bands on multiple 1D scanlines along fault walls. The resulting datasets are used to plot the frequency distribution of deformation features and to constrain the geometrical width of the damage zone for the studied faults. The damage-zone width of a single fault is constrained by identifying the changes in the slope of cumulative plots made on the frequency data. The cumulative plot further shows high deformation frequency by a steep slope (inner damage zone) and less deformation as a gentle slope (outer damage zone). Statistical distributions of displacement and damage-zone width and their relationship are improved, and show two-slope power-law distributions with a break point at c. 100 m displacement. Bleached sandstones in the studied siliciclastic rocks of Utah are associated with a higher frequency of deformation bands and a wider damage zone compared to the unbleached zone of similar lithology. Fault damage zones in the carbonate rocks of Majella are often host to open fractures (karst), demonstrating that they can also be conductive to fluid flow.

Physical and chemical strain-hardening during faulting in poorly lithified sandstone: The role of kinematic stress field and selective cementation

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1183-1200 ◽  
Author(s):  
Mattia Pizzati ◽  
Fabrizio Balsamo ◽  
Fabrizio Storti ◽  
Paola Iacumin
Keyword(s):  
Stress Field ◽  
Strain Hardening ◽  
Fault Zone ◽  
Deformation Band ◽  
Early Stage ◽  
Damage Zone ◽  
Isotope Analysis ◽  
Deformation Bands ◽  
Multidisciplinary Study ◽  
Diagenetic Evolution

Abstract In this work, we report the results of a multidisciplinary study describing the structural architecture and diagenetic evolution of the Rocca di Neto extensional fault zone developed in poorly lithified sandstones of the Crotone Basin, Southern Italy. The studied fault zone has an estimated displacement of ∼90 m and consists of: (1) a low-deformation zone with subsidiary faults and widely spaced deformation bands; (2) an ∼10-m-wide damage zone, characterized by a dense network of conjugate deformation bands; (3) an ∼3-m-wide mixed zone produced by tectonic mixing of sediments with different grain size; (4) an ∼1-m-wide fault core with bedding transposed into foliation and ultra-comminute black gouge layers. Microstructural investigations indicate that particulate flow was the dominant early-stage deformation mechanism, while cataclasis became predominant after porosity loss, shallow burial, and selective calcite cementation. The combination of tectonic compaction and preferential cementation led to a strain-hardening behavior inducing the formation of “inclined conjugate deformation band sets” inside the damage zone, caused by the kinematic stress field associated with fault activity. Conversely, conjugate deformation band sets with a vertical bisector formed outside the damage zone in response to the regional extensional stress field. Stable isotope analysis helped in constraining the diagenetic environment of deformation, which is characterized by mixed marine-meteoric signature for cements hosted inside the damage zone, while it progressively becomes more meteoric moving outside the fault zone. This evidence supports the outward propagation of fault-related deformation structures in the footwall damage zone.

Controls on fault damage zone width, structure, and symmetry in the Bandelier Tuff, New Mexico

2010 ◽  
Vol 32 (6) ◽  
pp. 766-780 ◽  
Author(s):  
Paul R. Riley ◽  
Laurel B. Goodwin ◽  
Claudia J. Lewis
Keyword(s):  
New Mexico ◽  
Damage Zone ◽  
Zone Width ◽  
Bandelier Tuff ◽  
Fault Damage Zone

Revealing microstructural properties of shocked and tectonically deformed zircon from the Vredefort impact structure: Raman spectroscopy combined with SEM microanalyses

2021 ◽  
Author(s):  
Elizaveta Kovaleva ◽  
Dmitry A. Zamyatin
Keyword(s):  
Raman Spectroscopy ◽  
Raman Band ◽  
Impact Structure ◽  
Chemical Mapping ◽  
Deformation Bands ◽  
Electron Backscattered Diffraction ◽  
Granite Sample ◽  
Deformation Features ◽  
Ebsd Technique ◽  
Deformation Patterns

ABSTRACT Finite deformation patterns of accessory phases can indicate the tectonic regime and deformation history of the host rocks and geological units. In this study, tectonically deformed, seismically deformed, and shocked zircon grains from a granite sample from the core of the Vredefort impact structure were analyzed in situ, using a combination of Raman spectroscopy, backscatter electron (BSE) imaging, electron backscattered diffraction (EBSD) mapping, electron probe microanalyses (EPMA), energy-dispersive X-ray spectroscopy (EDS) qualitative chemical mapping, and cathodoluminescence (CL) imaging. We aimed to reveal the effects of marginal grain-size reduction, planar deformation bands (PDBs), and shock microtwins on the crystal structure and microchemistry of zircon. Deformation patterns such as PDBs, microtwins, and subgrains did not show any significant effect on zircon crystallinity/metamictization degree or on the CL signature. However, the ratio of Raman band intensities B1g (1008 cm–1) to Eg (356 cm–1) slightly decreased within domains with low misorientation. The ratio values were affected in shocked grains, particularly in twinned domains with high misorientation. B1g/Eg ratio mapping combined with metamictization degree mapping (full width at half maximum of B1g peak) suggest the presence of shock deformation features in zircon; however, due to the lower spatial resolution of the method, they must be used in combination with the EBSD technique. Additionally, we discovered anatase, quartz, goethite, calcite, and hematite micro-inclusions in the studied zircon grains, with quartz and anatase specifically being associated with strongly deformed domains of shocked zircon crystals.

Digital image correlation shows localized deformation bands in inelastic loading of fibrolamellar bone

2009 ◽  
Vol 24 (2) ◽  
pp. 421-429 ◽  
Author(s):  
Gunthard Benecke ◽  
Michael Kerschnitzki ◽  
Peter Fratzl ◽  
Himadri S. Gupta
Keyword(s):  
Plastic Strain ◽  
Tensile Deformation ◽  
Image Correlation ◽  
Correlation Technique ◽  
Length Scale ◽  
Strain Rates ◽  
Deformation Bands ◽  
Localized Deformation ◽  
High Deformation ◽  
Multiple Regions

Irreversible or plastic deformation in bone is associated with both permanent plastic strain as well as localized microdamage. Whereas mechanisms at the molecular and mesoscopic level have been proposed to explain aspects of irreversible deformation, a quantitative correlation of mechanical yielding, microstructural deformation, and macroscopic plastic strain does not exist. To address this issue, we developed and applied a two-dimensional image correlation technique to the tensile deformation of bovine fibrolamellar bone, to determine the spatial distribution of strain fields at the length scale of 10 μm to 1 mm in bone during irreversible tensile deformation. We find that tensile deformation is relatively homogeneous in the elastic regime and starts at the yield point, showing regions of locally higher strain. Multiple regions of high deformation can exist at the same time over a length scale of 1 to 10 mm. Macroscopic fracture always occurs at one of the locally highly deformed regions, but the selection of which region cannot be predicted. Locally, strain rates can be enhanced by a factor of 3 to 10 over global strain rates in the highly deformed zones and are lower but always positive in all other regions. Light microscopic imaging shows the onset of structural “banding” in the regions of high deformation, which is most likely correlated to microstructural damage at the inter- and intrafibrillar level.

scholarly journals Fault zone architecture of a large plate-bounding strike-slip fault: a case study from the Alpine Fault, New Zealand

2019 ◽  
Author(s):  
Bernhard Schuck ◽  
Anja M. Schleicher ◽  
Christoph Janssen ◽  
Virginia G. Toy ◽  
Georg Dresen
Keyword(s):  
Fault Zone ◽  
Complex Geometry ◽  
Damage Zone ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Unconsolidated Sediments ◽  
Multiple Slip ◽  
Large Plate ◽  
Alpine Fault ◽  
Fault Zone Architecture

Abstract. New Zealand's Alpine Fault is a large, plate-bounding strike-slip fault, that ruptures in large (MW > 8) earthquakes. Its hazard potential is linked to its geometrical properties. We conducted field and laboratory analyses of fault rocks to elucidate their influence on its fault zone architecture. Results reveal that the Alpine Fault zone has a complex geometry, comprising an anastomosing network of multiple slip planes that have accommodated different amounts of displacement. Within it, slip zone width is demonstrably not related to lithological differences of quartzofeldspathic lithologies, which vary slightly along- strike. The young, largely unconsolidated sediments that constitute the footwall in some outcrops have a much more significant influence on fault gouge rheological properties and structure. Additionally, seismic investigations indicate that the exposed complex fault zone architecture extends into the basement. This study reveals the Alpine Fault contains multiple slip zones surrounded by a broader damage zone; properties elsewhere associated with carbonate or phyllosilicate-rich faults.

Fault geometry and architecture, an integrated study

2021 ◽  
Author(s):  
Anita Torabi ◽  
Behzad Alaei ◽  
Audun Libak
Keyword(s):  
Seismic Data ◽  
Co2 Storage ◽  
Damage Zone ◽  
Petroleum Exploration ◽  
Fault Geometry ◽  
Deformation Bands ◽  
Research Areas ◽  
Slip Surfaces ◽  
Damaged Zone ◽  
Fault Damage Zone

<p>Understanding fault geometry and processes of faulting are important research areas for many applications such as petroleum exploration and production; geothermal energy managements; hydrogeology; waste disposal and CO2 storage underground; earthquake seismology and geological hazard studies. Faults can be described as comprising a core and an enveloping damage zone (e.g. Caine et al. 1996).  The fault core accommodates most of the displacement along multiple slip surfaces and may include fault rocks such as fault gouge, cataclasites, breccia, clay smear, fractures, diagenetic features, and lenses of deformed and undeformed rocks trapped between slip surfaces. Whereas, the deformation is less intense in the damage zone and may include fractures and/or deformation bands depending on the initial porosity of the host rock, minor faults, and folds (Torabi et al., 2020). Fault geometric attributes include fault shape, fault displacement, length, damage zone width and fault core thickness (Caine et al., 1996; Torabi and Berg, 2011). Currently, there are uncertainties in defining and understanding of fault 3D geometry. These uncertainties are to some extent related to the accessibility of the fault geometric attributes and the methodological constraints, utilizing biased data. Details of fault damage zone and fault core structures can be mapped at outcrop, however, their descriptions and statistical handling are usually constrained by their accessibility in the field and their definitions by individual researchers.</p><p>Reflection seismic data is used to study faults in the subsurface, although the interpretation of faults could be affected by the seismic resolution and the accuracy of interpretation (Marchal et al., 2003; Lohr et al., 2008; Iacopini et al., 2016; Torabi et al., 2016). Utilizing seismic attributes, we are able to directly images faults from seismic without a need for interpretation. Using this method, we extracted fault geometric attributes directly from fault images in the fault attribute volumes and studied the 3D shape and displacement distribution of faults (Torabi et al., 2019). By integrating spectral decomposition with seismic attribute workflows, we created enhanced fault attribute volumes with a high resolution, allowing us to detect, and map fault damaged zone (fault damage zone plus fault core in outcrop scale) in seismic data (Alaei and Torabi, 2017). Finally, we integrated the data from outcrop and seismic study in the scaling relations between the faults geometric attributes in order to predict the fault geometry in the subsurface.</p><p> </p><p> </p>

Fracture attributes in reservoir-scale carbonate fault damage zones and implications for damage zone width and growth in the deep subsurface

2019 ◽  
Vol 118 ◽  
pp. 181-193 ◽  
Author(s):  
Guanghui Wu ◽  
Lianhua Gao ◽  
Yintao Zhang ◽  
Chaozhong Ning ◽  
En Xie
Keyword(s):  
Damage Zone ◽  
Deep Subsurface ◽  
Zone Width

scholarly journals Effect of Mineral Processes and Deformation on the Petrophysical Properties of Soft Rocks during Active Faulting

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 444
Author(s):  
Anita Torabi ◽  
Juan Jiménez-Millán ◽  
Rosario Jiménez-Espinosa ◽  
Francisco Juan García-Tortosa ◽  
Isabel Abad ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Damage Zone ◽  
Active Faults ◽  
Soft Rock ◽  
Microstructural Characterization ◽  
Rock Properties ◽  
Deformation Bands ◽  
Carbonate Cement ◽  
Granada Basin

We have studied damage zones of two active faults, Baza and Padul faults in Guadix-Baza and Granada basins, respectively, in South Spain. Mineral and microstructural characterization by X-ray diffraction and field emission electron microscopy studies have been combined with structural fieldwork and in situ measurements of rock properties (permeability and Young’s modulus) to find out the relation between deformation behavior, mineral processes, and changes in the soft rock and sediment properties produced by fluid flow during seismic cycles. Our results show that microsealing produced by precipitation of dolomite and aragonite along fractures in the damage zone of Baza Fault reduces the permeability and increases the Young’s modulus. In addition, deformation bands formed in sediments richer in detrital silicates involved cataclasis as deformation mechanism, which hamper permeability of the sediments. In the Granada Basin, the calcarenitic rocks rich in calcite and clays in the damage zone of faults associated to the Padul Fault are characterized by the presence of stylolites without any carbonate cement. On the other hand, marly lithofacies affected by faults are characterized by the presence of disaggregation bands that involve cracking and granular flow, as well as clay smear. The presence of stylolites and deformation bands in these rocks reduces permeability.

Seismic imaging of fault damaged zone and its scaling relation with displacement

2017 ◽  
Vol 5 (4) ◽  
pp. SP83-SP93 ◽  
Author(s):  
Behzad Alaei ◽  
Anita Torabi
Keyword(s):  
Seismic Data ◽  
Process Zone ◽  
Damage Zone ◽  
Frequency Resolution ◽  
Segment Length ◽  
Time Frequency ◽  
Zone Width ◽  
Damaged Zone ◽  
Fault Bend ◽  
Different Depths

We have studied seismically resolved damaged zone of normal faults in siliciclastic rocks of the Norwegian continental shelf. The workflow we have developed reveals structural details of the fault damaged zone and in particular, the subsidiary synthetic faults, horsetail at the main lateral fault tips at different depths and fault bend. These subsidiary or small fault segments form an area that can be clearly followed laterally and vertically. We call this area fault damaged zone. The studied damaged zone on seismic data comprises the fault core and the fault damage zone, as defined in outcrop studies. Spectral decomposition (short-time Fourier transform for time-frequency resolution and continuous wavelet transform) was performed on the data centered around faulted intervals. The magnitude of higher frequencies was used to generate coherence attribute volumes. Coherence attributes were filtered to enhance fault images. This integrated workflow improves fault images on reflection seismic data. Our approach reveals details of damaged zone geometry and morphology, which are comparable with the outcrop studies of similar examples conducted by previous researchers or us. We have extracted the fault geometry data including the segment length, displacement, and damaged zone width at different depths. Our results show that subsidiary faults, fault bends, linkage of fault segments, and branching in the fault tip (horsetail structure or process zone) all affect the width of the damaged zone and the distribution of displacement. We have seen a distinct increase in the fault damaged zone width near the fault bend locations. The fault segment length decreases with depth toward the lower fault tip, which is below the base Cretaceous unconformity. In addition, the displacement increases below the unconformity. In general, there is a positive correlation between fault displacement and the corresponding damaged zone width measured in this study, which is in agreement with previous studies.

Seismic characterization of fault facies models

2017 ◽  
Vol 5 (4) ◽  
pp. SP9-SP26 ◽  
Author(s):  
Charlotte Botter ◽  
Nestor Cardozo ◽  
Dongfang Qu ◽  
Jan Tveranger ◽  
Dmitriy Kolyukhin
Keyword(s):  
Internal Structure ◽  
Fault Zone ◽  
Damage Zone ◽  
Seismic Attributes ◽  
Wave Frequency ◽  
Seismic Facies ◽  
Zone Model ◽  
Deformation Bands ◽  
Reservoir Models ◽  
Seismic Image

Faults play a key role in reservoirs by enhancing or restricting fluid flow. A fault zone can be divided into a fault core that accommodates most of the displacement and a surrounding damage zone. Interpretation of seismic data is a key method for studying subsurface features, but the internal structure and properties of fault zones are often at the limit of seismic resolution. We have investigated the seismic response of a vertical fault zone model in sandstone, populated with fault facies based on deformation band distributions. Deformation bands reduce the porosity of the sandstone, and they condition its elastic properties. We generate synthetic seismic cubes of the fault facies model for several wave frequencies and under realistic conditions of reservoir burial and seismic acquisition. Seismic image quality and fault zone definition are highly dependent on wave frequency. At a low wave frequency (e.g., 10 Hz), the fault zone is broader and no information about its fault facies distribution can be extracted. At higher wave frequencies (e.g., 30 and 60 Hz), seismic attributes, such as tensor and envelope, can be used to characterize the fault volume and its internal structure. Based on these attributes, we can subdivide the fault zone into several seismic facies from the core to the damage zone. Statistical analyses indicate a correlation between the seismic attributes and the fault internal structure, although seismic facies, due to their coarser resolution, cannot be matched to individual fault facies. The seismic facies can be used as input for reservoir models as spatial conditioning parameters for fault facies distributions inside the fault zone. However, relying only on the information provided by seismic analyses might not be enough to create high-resolution fault reservoir models.

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