scholarly journals Surface mapping, structural modelling and kinematics along the sinistral strike-slip fault zone, NE Potwar, Pakistan

2021 ◽  
Author(s):  
Muhammad Nouman ◽  
Gohar Rehman ◽  
Muhammad Yaseen ◽  
Sohail Wahid ◽  
Ibrahim Safi ◽  
...  
Keyword(s):  
Fault Zone ◽  
Cross Sections ◽  
Strike Slip ◽  
Computer Application ◽  
Deformation Pattern ◽  
Surface Mapping ◽  
Geological Map ◽  
Dip Isogons ◽  
Splay Faults ◽  
Bounding Surfaces

AbstractThis research was carried out to understand the nature of strike-slip Jhelum Fault zone and to propose a model for the surface to subsurface deformation pattern. Field data along with satellite images are used to construct the geological map. Moreover, the subsurface model has been proposed using the mechanism of dip-isogons in computer application which connects points of equal inclination or dip on the outer and inner bounding surfaces of a folded layers. The proposed geological map and subsurface model shows that the Jhelum Fault when propagated in the south from Hazara-Kashmir Syntaxis forms a continuous shear zone on surface with some discontinuous exposure of splay faults rather than exposed as continuous discrete break. Likewise, the subsurface cross sections show that deformation along the fault zone is accumulated by splay faults from the main Jhelum Fault, which forms a positive flower structure with steep north-eastward dips, which is characteristics of strike-slip movement along Jhelum Fault Zone. The vertical stratigraphic throw along these faults shows small offsets and little east–west shortening, indicating that the major slip along the fault is strike slip.

New insight into the 24 January 2020, Mw 6.8 Elazığ earthquake (Turkey): An evidence for rupture-parallel pull-apart basin activation along the East Anatolian Fault Zone constrained by Geodetic and Seismological data

2021 ◽  
Vol 64 (4) ◽  
pp. SE439
Author(s):  
T Serkan Irmak ◽  
Mustafa Toker ◽  
Evrim Yavuz ◽  
Erman Şentürk ◽  
Muhammed Ali Güvenaltın
Keyword(s):  
Fault Zone ◽  
Surface Deformation ◽  
Waveform Inversion ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Deformation Pattern ◽  
Pull Apart Basin ◽  
Insight Into ◽  
East Anatolian Fault Zone ◽  
East Anatolian Fault

In this study, we investigated the main features of the causative fault of the 24 January 2020, Mw 6.8 Elazığ earthquake (Turkey) using seismological and geodetic data sets to provide new insight into the East Anatolian Fault Zone (EAFZ). We first constrained the co-seismic surface deformation and the rupture geometry of the causative fault segment using Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1A/B satellites) and teleseismic waveform inversion, respectively. Also, we determined the centroid moment tensor (CMT) solutions of focal mechanisms of the 27 aftershocks using the regional waveform inversion method. Finally, we evaluated the co-seismic slip distribution and the CMT solutions of the causative fault as well as of adjacent segments using the 27 focal solutions of the aftershocks, superimposed on the surface deformation pattern. The CMT solution of the 24 January 2020Elazığ earthquake reveals a pure strike-slip focal mechanism, consistent with the structural pattern and left-lateral motion of the EAFZ. The rupture process of the Elazığ event indicated that the rupture is started at 12 km around the hypocenter, and then propagated bilaterally along the NE-SW but mainly toward the southwest. The rupture slip has initially propagated toward the southwest (first 10 s) and northeast (4 s), and again toward the southwest (9 s). Maximum displacement is calculated as 1.3 m about 20 km southwest of the hypocenter at 6 km depth (centroid depth). The rupture stopped to down-dip around 20 km depth toward the southwest. The distribution of the slip vectors indicates that the rupture continued mostly through a normal oblique movement. Most of the moment release was released SW of the hypocenter and the rupture reached up to around 50 km. The focal mechanisms of analyzed 27 aftershocks show strike-slip, but mostly normal and normal oblique-slip faulting with an orientation of the tensional axes (NNE-SSW), indicating a normal oblique-slip, “transtensional” stress regime, parallel-subparallel to the strike of the EAFZ, consistent with SW-rupture directivity and co- seismic deformation pattern. Finally, based on the co-seismic surface deformation compatible with the distributional pattern of normal focal solutions, normal and normal oblique-slip focals of the aftershocks evidence the rupture-parallel pull-apart basin activation as a segment boundary of the left-lateral strike-slip movement of the EAFZ.

scholarly journals Effects of transpression on the rocks exposed at the Jhelum Fault Zone in the east of Potwar Basin, Pakistan: implications on the subsurface deformation pattern

2021 ◽  
Author(s):  
Ibrahim Safi ◽  
Gohar Rehman ◽  
Muhammad Yaseen ◽  
Sohail Wahid ◽  
Muhammad Nouman ◽  
...  
Keyword(s):  
Fault Zone ◽  
Stress Component ◽  
Satellite Image ◽  
Fault System ◽  
Deformation Pattern ◽  
The North ◽  
Lateral Extent ◽  
Geological Map ◽  
Potwar Basin ◽  
Well Data

AbstractJhelum Fault is the north–south-oriented major structural lineament originating from the Hazara-Kashmir Syntaxis and extending southwards towards the Mangla Lake. Geographic extent, nature and significance of Jhelum Fault are the subjects which have been approached by different researchers in the past. The previous research provides enough evidence for the presence of Jhelum Fault as well as they discourse its surface extent. None of the previous research addresses the subsurface model of this fault; consequently, its surface extent has been ambiguous and variably reported. The current research takes into account both the surface lineament as well as the subsurface behaviour of the deformed strata to draft the most reasonable depiction of this fault. Field data were coupled with satellite image of 1.5 m ground resolution to produce the geological map of the study area at 1:25,000 scale. The subsurface model was created along four traverse lines by considering the lateral extent of the structures and their shifting trends on the geological map. The stratigraphic package was taken from the nearby hydrocarbon exploratory well data (Missakeswal-01 well of OGDCL) as no rocks older than middle to late Miocene were exposed in the area. The consistent through-going map extents of many faults in the study area prove that faults are playing the major role in the tectonic evolution of the Jhelum Fault Zone. In the subsurface model, the same faults show very little stratigraphic throw, which signify the major stress component to be associated more with wrenching than pure compression. Therefore, most faults in the area are of transpressional nature having dominant lateral component with relatively smaller push towards west on steeply east dipping faults. The model also shows the positive flower structure with dominantly west verging fault system with few east verging back thrusts. The subsurface proposed model shows that the Jhelum Fault is extendible southwards to the Mangla Lake in the subsurface; however, it acts like a continuous shear zone on the surface where there all the shearing is accommodated by tight refolded fold axes. The east–west shortening does not exceed 14.5% which shows smaller compression in the study area. The 3D model further clarifies the model by showing the consistency of the fault system along strike.

Strain Partitioning Between the Izmir-Balikesir Transfer Zone and the North Anatolian Fault Zone, NW Turkey

2020 ◽  
Author(s):  
Levent Tosun ◽  
Elif Çakır ◽  
Bora Uzel ◽  
Ökmen Sümer ◽  
Atilla Arda Özacar ◽  
...  
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
North Anatolian Fault ◽  
Western Anatolia ◽  
Deformation Pattern ◽  
Strain Partitioning ◽  
North Anatolian Fault Zone ◽  
The North ◽  
Nw Turkey ◽  
Transfer Zone

<p>The present tectonic framework of the Western Anatolia has been dominated by two major deformations. The first one is the product of the slab-edge processes related to the convergence between Eurasian and African plates along with the Aegean-Cyprean subduction system since the Oligocene, and the second one is the westwards escape of Anatolian Block along the North Anatolian Fault Zone (NAFZ) since the late Miocene. The first one resulted in a widespread extensional deformation in the Western Anatolia and the Aegean region and is associated with slab-detachment and slab-tear processes that gave rise to the development of dynamic topography and various core-complexes (e.g., Cyclades and Menderes). Recent studies have shown that the deferential extensional strain between the core complexes in the region has been accommodated by strike-slip dominated transfer zones, the İzmir-Balıkesir Transfer Zone (İBTZ), which developed (sub)parallel to the extension direction and accommodate differential extension and rotational deformation in the region. The second one gave way to the development of a complex strike-slip deformation pattern and an array of pull-apart basin complexes throughout the northern margin of the Anatolian Block. The NAFZ and İBTZ interact around the Balıkesir-Bursa region resulting in a very peculiar deformation style due to partitioning of strain between these major structures.<br>This study aims at unraveling how the strain partitioning operates between İBTZ and NAFZ and to reveal the kinematic constraints that produced the present tectonic scheme in the region. The geometry and kinematics of the faults are determined by analyzing 2773 fault slip data obtained from 49 sites evenly distributed throughout the study area. The preliminary results show that the İzmir-Balıkesir Transfer Zone localized after Miocene with the decoupling of strike-slip faults, and to the episodic exhumation of the metamorphic core complexes. The focal mechanism solutions of the recent earthquakes support this decoupling and manifest the seismic activity of the İBTZ. This study is supported by a Tübitak Project, Grant Number of 117R011.</p>

The Hospital coal basin (Massif Central, France): relay on the left-lateral strike-slip Argentat fault in relation to the Variscan postorogenic extension

2005 ◽  
Vol 176 (2) ◽  
pp. 151-159
Author(s):  
Jean-Philippe Bellot ◽  
Jean-Yves Roig ◽  
Antonin Genna
Keyword(s):  
Fault Zone ◽  
Cross Sections ◽  
Tectonic Setting ◽  
Regional Scale ◽  
Theoretical Models ◽  
Strike Slip ◽  
Flower Structure ◽  
Coal Basin ◽  
Massif Central ◽  
Lateral Strike Slip

Abstract Structural and microstructural analyses of the Argentat fault, combined with sedimentological and structural analyses of the associated Hospital basin allow us to discuss the tectonic control of coal basins by crustal-scale faults during the late Palaeozoic evolution of the Variscan lithosphere in the French Massif Central. The brittle Argentat fault zone consists of first- and second-order strike-slip faults, with dominant NNW-sinistral faults, NNE-dextral or sinistral faults and secondary ENE-dextral faults. Several experimental and theoretical models explain the observed fault patterns, like en echelon faults, A-type secondary faults, conjugate faults and Riedel shears. Strike-slip faulting is responsible for folding of the metamorphic formations characterized by N-S to NE-SW-trending axis. The regional-scale geometry of brittle faults and associated folds corresponds to a positive flower structure centered on the brittle Argentat fault, combined to a negative flower structure centered on the coal basin. Using tectonic inversion software, we show that these structures result from a left-lateral movement of the brittle Argentat fault in relation to a tectonic regime intermediate between extension and strike-slip, with a horizontal NE-SW to NNE-SSW-trending maximum stretching axis. Detailed map and cross-sections, and sedimentological interpretations of the late Stephanian Hospital basin show the occurrence of intra-basin syn-sedimentary strike-slip faults and progressive overlaying, indicating that sedimentation occurs during left-lateral strike-slip faulting and folding of basement along the Argentat fault. These data are consistent with a model of N-S to NE-SW-trending postorogenic extension proposed to account for the late Carboniferous evolution of the Variscan lithosphere. They also point out the complexity and the variety of structures developed along a regional brittle strike-slip fault zone and the necessity to take into account all the structures and the resulting geometry of the basement in order to better constrain the tectonic setting of intra-continental deposits.

scholarly journals Structural evolution of the Hawasina Window, Oman Mountains

GeoArabia ◽  
2010 ◽  
Vol 15 (3) ◽  
pp. 85-124 ◽  
Author(s):  
László Csontos ◽  
Tamás Pocsai ◽  
Ágoston Sasvári ◽  
Márton Palotai ◽  
Gizella Árgyelán-Bagoly ◽  
...  
Keyword(s):  
Cross Sections ◽  
Structural Evolution ◽  
Structural Features ◽  
Strike Slip ◽  
Arabian Plate ◽  
Oman Mountains ◽  
Tectonic Events ◽  
Northern Edge ◽  
Geological Map ◽  
Tectonic Boundaries

ABSTRACT This paper presents field observations and measurements from the Hawasina Window, Oman Mountains. An updated geological map is based partly on previous publications and four NEtrending cross-sections. Along each cross-section key structural features are described, illustrated and interpreted. Based on these (and other) observations several differences between our interpretation and the former published geological maps and cross sections were noted as follows.(1) Late Cretaceous original (Hamrat Duru; Haybi) nappes that formed during intra-oceanic obduction underwent out-of-sequence thrusting beneath the Semail thrust. The repetitions of the nappe complexes are out-of-sequence because: (a) repetition of original nappe packages; (b) the presence of Haybi-derived lenses along boundaries between two Hamrat Duru nappes; (c) the presence of sheared serpentinite in the same nappe boundaries. The Hamrat Duru and Haybi nappes are repeated three times.(2) The tectonic boundaries of the Hawasina Window are steep, normal- or strike-slip faults, unconformable to, and cutting the original nappe boundaries. A main strike-slip corridor at the southern edge of the Hawasina structure was mapped. The northern edge is a top-north thrust.(3) Ductile-brittle extension created mega-boudins of preserved nappe units and areas where complete nappe units are missing. Extension is present in Sumeini and Hamrat Duru units; therefore it is post-out-of-sequence thrusting.(4) Two main antiforms were recognised inside the Hawasina Window (Jabal Rais and its northward and southward continuations in Hamrat Duru units, and Jabals Mawq - Matid). Several folding phases were recognised and the two antiforms are the result of interference. A main, sub-horizontal axial plane, syn-regional cleavage folding is present in the whole Window. This folding gives top NE or N regional shear.(5) Structural dips of regional cleavage suggest a major NW-striking dome beneath the Hawasina Window. This dome would correspond to the upwarp of the Autochthon, similar to Al Jabal al-Akhdar. In the southern zone of this dome we observed several occurrences of small gypsum diapirs. The best outcrops of these features are in the Wadi ad Dil-Wadi Hawasina area, where the evaporite bodies rise from beneath the Hawasina nappes. We suggest that they originate from the underlying Arabian Platform, or they form the basal detachment of the Sumeini units. Our observations are fit into a proposed deformation scenario resulting from plate-tectonic events occurring at the Arabian Plate margin during Cretaceous – Tertiary time.

scholarly journals Kinematic partitioning in the Southern Andes (39° S–46° S) inferred from lineament analysis and reassessment of exhumation rates

2021 ◽  
Author(s):  
Paul Leon Göllner ◽  
Jan Oliver Eisermann ◽  
Catalina Balbis ◽  
Ivan A. Petrinovic ◽  
Ulrich Riller
Keyword(s):  
Fault Zone ◽  
Vertical Displacement ◽  
Strike Slip ◽  
Structural Studies ◽  
Southern Andes ◽  
Plate Convergence ◽  
Exhumation Rates ◽  
Lineament Analysis ◽  
Dextral Strike Slip ◽  
Data Call

AbstractThe Southern Andes are often viewed as a classic example for kinematic partitioning of oblique plate convergence into components of continental margin-parallel strike-slip and transverse shortening. In this regard, the Liquiñe-Ofqui Fault Zone, one of Earth’s most prominent intra-arc deformation zones, is believed to be the most important crustal discontinuity in the Southern Andes taking up margin-parallel dextral strike-slip. Recent structural studies, however, are at odds with this simple concept of kinematic partitioning, due to the presence of margin-oblique and a number of other margin-parallel intra-arc deformation zones. However, knowledge on the extent of such zones in the Southern Andes is still limited. Here, we document traces of prominent structural discontinuities (lineaments) from the Southern Andes between 39° S and 46° S. In combination with compiled low-temperature thermochronology data and interpolation of respective exhumation rates, we revisit the issue of kinematic partitioning in the Southern Andes. Exhumation rates are maximal in the central parts of the orogen and discontinuity traces, trending predominantly N–S, WNW–ESE and NE–SW, are distributed across the entire width of the orogen. Notably, discontinuities coincide spatially with large gradients in Neogene exhumation rates and separate crustal domains characterized by uniform exhumation. Collectively, these relationships point to significant components of vertical displacement on these discontinuities, in addition to horizontal displacements known from published structural studies. Our results agree with previously documented Neogene shortening in the Southern Andes and indicate orogen-scale transpression with maximal vertical extrusion of rocks in the center of the transpression zone. The lineament and thermochronology data call into question the traditional view of kinematic partitioning in the Southern Andes, in which deformation is focused on the Liquiñe-Ofqui Fault Zone.

40Ar/39Ar dating of strike-slip motion on the Tan–Lu fault zone, East China

2005 ◽  
Vol 27 (8) ◽  
pp. 1379-1398 ◽  
Author(s):  
Guang Zhu ◽  
Yongsheng Wang ◽  
Guosheng Liu ◽  
Manlan Niu ◽  
Chenglong Xie ◽  
...  
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
East China ◽  
Slip Motion

Queen Charlotte fault zone: microearthquakes from a temporary array of land stations and ocean bottom seismographs

1981 ◽  
Vol 18 (4) ◽  
pp. 776-788 ◽  
Author(s):  
R. D. Hyndman ◽  
R. M. Ellis
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
Ocean Bottom ◽  
Small Component ◽  
Queen Charlotte Islands ◽  
The North ◽  
Vertical Fault ◽  
Linear Sections ◽  
Ocean Bottom Seismographs ◽  
Steep Slopes

A temporary array of land and ocean bottom seismograph stations was used to accurately locate microearthquakes on the Queen Charlotte fault zone, which occurs along the continental margin of western Canada. The continental slope has two steep linear sections separated by a 25 km wide irregular terrace at a depth of 2 km. Eleven events were located with magnitudes from 0.5 to 2.0, 10 of them beneath the landward one of the two steep slopes, some 5 km off the coast of the southern Queen Charlotte Islands. No events were located beneath the seaward and deeper steep slope. The depths of seven of these events were constrained by the data to between 9 and 21 km with most near 20 km. The earthquake and other geophysical data are consistent with a near vertical fault zone having mainly strike-slip motion. A model including a small component of underthrusting in addition to strike-slip faulting is suggested to account for the some 15° difference between the relative motion of the North America and Pacific plates from plate tectonic models and the strike of the margin. One event was located about 50 km inland of the main active zone and probably occurred on the Sandspit fault. The rate of seismicity on the Queen Charlotte fault zone during the period of the survey was similar to that predicted by the recurrence relation for the region from the long-term earthquake record.

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