Dextral strike‐slip and normal faulting during middle Miocene back‐arc extension and westward Anatolia extrusion in Central Greece

The Finsterort and Anton vein system is located in the central zone of the Middle Miocene Štiavnica Stratovolcano between Vyhne and Hodruša-Hámre villages. The vein system contains several partial veins and veinlets and has generally NNE - SSW strike with moderate to steep eastward dip. Kinematics of the veins is characterised by older dextral strike-slip movement replaced by younger normal faulting. The mineralization is associated with the normal faults and the veins contain interesting paragenesis of Au-Ag bearing minerals. Minerals of precious metals are represented by argentotetrahedrite-(Zn) and rozhdestvenskayaite-(Zn), Au-Ag alloys, members of polybasite-pearceite and pyrargyrite-proustite solid solutions, acanthite and uytenbogaardtite. Au-Ag mineralization is accompanied by older paragenesis comprising mainly pyrite, galena, sphalerite and chalcopyrite. Besides quartz, carbonates (calcite, siderite and dolomite) are the main gangue minerals.

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The Germania Land deformation zone and related structures, North-East Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v162.8253 ◽

1994 ◽

Vol 162 ◽

pp. 113-127

Author(s):

J.M Hull ◽

J.A Gilotti

Keyword(s):

Deformation Zone ◽

Strike Slip ◽

Low Grade ◽

High Grade ◽

Normal Faulting ◽

East Greenland ◽

North East ◽

Parallel Movement ◽

Land Deformation ◽

Dextral Strike Slip

The Germania Land deformation zone in North-East Greenland consists of two subparallel, NW-striking strands of mylonites and cataclasites. The quasiplastic mylonites formed under low grade (biotite zone) conditions following high grade Caledonian metamorphism. Displacements on the Germania Land deformation zone and parallel zones at Danmarkshavn were predominantly dextral strike slip. Along with the similar, but sinistral, Storstrømmen shear zone, these zones record a late Caledonian phase of orogen-parallel movement. The Germania Land deformation zone is also the locus of Carboniferous normal faulting and basin development.

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Structural evolution of basement gneisses and Hadrynian cover, Bulldog Creek area, Rocky Mountains, British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/e88-159 ◽

1988 ◽

Vol 25 (10) ◽

pp. 1687-1702 ◽

Cited By ~ 9

Author(s):

Michael R. McDonough ◽

Philip S. Simony

Keyword(s):

British Columbia ◽

Structural Evolution ◽

Rocky Mountain ◽

Strike Slip ◽

Normal Faulting ◽

The West ◽

Kinematic Indicators ◽

Thrust Sheets ◽

Dextral Strike Slip ◽

Southern Rocky Mountain

Two gneiss bodies are contained in thrust sheets on the west edge of the Rocky Mountain Main Ranges near Valemount, British Columbia. The Bulldog Gneiss comprises Aphebian or older paragneiss and amphibolitic gneiss intruded by Aphebian orthogneiss sheets. The Yellowjacket Gneiss is granodioritic orthogneiss of unknown age. Both gneiss bodies are basement highs with thin Hadrynian metasediment cover sequences. The cover sequences are assigned to the lower Miette Group and are correlated with Horsethief Creek Group.Internal shortening of gneiss thrust sheets is expressed by recumbent folding and stacking of thin thrust sheets of gneiss and cover. The Bulldog Gneiss and its cover were carried on the postmetamorphic Purcell Thrust. The Yellowjacket Gneiss and its cover were carried on the pre- to synmetamorphic Bear Foot Thrust. Northeast and northwest displacement is documented on the moderately southwest-dipping Bear Foot Thrust, and a dextral oblique-slip – thrust model is proposed to explain the duality of thrust and dextral strike-slip kinematic indicators in mylonite from the fault. An estimate of shortening in the fore-land suggests that basement thrust sheets were translated more than 200 km to the northeast.Correlation of gneisses and cover with the westerly adjacent Malton Gneiss and its cover precludes major dextral strike-slip motion on the Southern Rocky Mountain Trench (SRMT) during and after thrusting. The SRMT was the locus of post-thrusting and postmetamorphic, Eocene(?), brittle, west-side-down, normal faulting.

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Record of Late Mississippian tectonics in the new Percé Group (Viséan) of eastern Gaspésie, Quebec

Canadian Journal of Earth Sciences ◽

10.1139/e05-024 ◽

2005 ◽

Vol 42 (5) ◽

pp. 815-832 ◽

Cited By ~ 11

Author(s):

Pierre Jutras ◽

Gilbert Prichonnet

Keyword(s):

Slip System ◽

Marine Sediments ◽

Strike Slip ◽

Alluvial Fan ◽

Normal Faulting ◽

Broad Area ◽

Tectonic Events ◽

Upper Paleozoic ◽

Maritimes Basin ◽

Dextral Strike Slip

Viséan clastic units and structures at the northwest margin of the upper Paleozoic Maritimes Basin provide information on tectonic events that are only poorly recorded in more central parts of the basin. These continental units are time equivalent to marine sediments of the Windsor Group of Nova Scotia. They are herein assigned to the new Percé Group, which includes the La Coulée and Bonaventure formations, as well as a new unit, the Cap d'Espoir Formation. The latter unit unconformably underlies the Bonaventure Formation in a small but thick sub-basin of the Ristigouche Basin in eastern Quebec. It is characterized by a succession of sandstone and mudstone rhythmites that contrast with the coarse alluvial fan deposits of the overlying Bonaventure Formation. The Cap d'Espoir Formation was sourced from a broad area of subdued topography occupied by the Viséan La Coulée Formation and underlying units. Erosional remnants of the La Coulée Formation are unconformably overlain by the Bonaventure Formation in marginal parts of the Ristigouche Basin, whereas these units are separated by the Cap d'Espoir Formation in more central areas of the basin. The La Coulée and Cap d'Espoir formations underwent tilting and erosion during a normal faulting event that preceded deposition of the fault-controlled Bonaventure Formation. This series of events is interpreted to represent different steps in the reactivation of a pre-Carboniferous dextral strike-slip system in response to northwestsoutheast compression during the Viséan in Gaspésie.

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Neotectonic development of the Struma (Kraištid) Lineament, southwest Bulgaria and northern Greece

Geological Magazine ◽

10.1017/s0016756800008281 ◽

1992 ◽

Vol 129 (2) ◽

pp. 197-222 ◽

Cited By ~ 36

Author(s):

I. S. Zagorčev

Keyword(s):

Middle Miocene ◽

Balkan Peninsula ◽

Strike Slip ◽

Northern Greece ◽

Compression Phase ◽

Tectonic Zones ◽

Early Neogene ◽

Fault Belt ◽

In The Beginning ◽

Back Arc

AbstractThe Struma (Kraištid) Lineament is a part of a fault belt of regional importance. It strikes NNW-SSE and cuts through different Alpine tectonic zones along the whole Balkan Peninsula. Normal and strike-slip faults occurred in environments of extension and graben formation during collapse after or between collision epochs in the Palaeogene and Early Neogene, and in a back-arc extensional environment during the neotectonic (end of Middle Miocene-Quaternary) stage. The last Alpine compression phase occurred in the beginning of the Miocene, and Early-Middle Miocene planation formed the initial peneplain. New intense faulting marked the beginning of the neotectonic stage (Late Badenian), and the neotectonic development, including sedimentation, proceeded in four regional macrocycles: Badenian-Sarmatian; Maeotian; Pontian-Dacian; and Eopleistocene-Pleistocene. The neotectonic development was marked by formation of the Serbo-Macedonian Swell as well as by rifting (the Vardar and Struma rifts).

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Seismotectonic Analysis of the 2019–2020 Puerto Rico Sequence: The Value of Absolute Earthquake Relocations in Improved Interpretations of Active Tectonics

Seismological Research Letters ◽

10.1785/0220210238 ◽

2021 ◽

Author(s):

Copeland W. Cromwell ◽

Kevin P. Furlong ◽

Eric A. Bergman ◽

Harley M. Benz ◽

Will L. Yeck ◽

...

Keyword(s):

Puerto Rico ◽

Moment Tensor ◽

Active Tectonics ◽

Strike Slip ◽

Fault System ◽

Normal Faulting ◽

Rupture Area ◽

Extensional Faulting ◽

Dextral Strike Slip ◽

East West

Abstract We present a new catalog of calibrated earthquake relocations from the 2019–2020 Puerto Rico earthquake sequence related to the 7 January 2020 Mw 6.4 earthquake that occurred offshore of southwest Puerto Rico at a depth of 15.9 km. Utilizing these relocated earthquakes and associated moment tensor solutions, we can delineate several distinct fault systems that were activated during the sequence and show that the Mw 6.4 mainshock may have resulted from positive changes in Coulomb stress from earlier events. Seismicity and mechanisms define (1) a west–southwest (∼260°) zone of seismicity comprised of largely sinistral strike-slip and oblique-slip earthquakes that mostly occurs later in the sequence and to the west of the mainshock, (2) an area of extensional faulting that includes the mainshock and occurs largely within the mainshock’s rupture area, and (3) an north–northeast (∼30°)-striking zone of seismicity, consisting primarily of dextral strike-slip events that occurs before and following the mainshock and generally above (shallower than) the normal-faulting events. These linear features intersect within the Mw 6.4 mainshock’s fault plane in southwest Puerto Rico. In addition, we show that earthquake relocations for M 4+ normal-faulting events, when traced along their fault planes, daylight along east–west-trending bathymetric features offshore of southwest Puerto Rico. Correlation of these normal-faulting events with bathymetric features suggests an active fault system that may be a contributor to previously uncharacterized seismic hazards in southwest Puerto Rico.

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THE PSACHNA (EVIA ISLAND) EARTHQUAKE SWARM OF JUNE 2003

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.16504 ◽

2004 ◽

Vol 36 (3) ◽

pp. 1379 ◽

Cited By ~ 7

Author(s):

C. Benetatos ◽

A. Kiratzi ◽

K. Kementzetzidou ◽

Z. Roumelioti ◽

G. Karakaisis ◽

...

Keyword(s):

Source Parameters ◽

Earthquake Swarm ◽

Broad Band ◽

Strike Slip ◽

Focal Mechanisms ◽

Horizontal Motion ◽

Double Difference ◽

Normal Faults ◽

Normal Faulting ◽

Central Greece

Evia Island (Greece) lies in a transition zone from strike-slip faulting in the east, due to the strands of the North Anatolian Fault (NAF) that enter to the Aegean Sea, to normal faulting in the west along central Greece. In June 2003 a series of moderate events occurred in central Evia whose source parameters are investigated. These earthquakes caused serious damage to almost 20 residencies mainly in the town of Psachna. The sequence could be identified as an earthquake swarm with earthquake magnitudes in the range of 3 < M < 4.9. We used the Ρ and S arrivals at the stations of the National Seismic Network to relocate the events using the double-difference algorithm. All Ρ and S phase pickings were made by us using the broad band records from the network operated by the Geodynamic Institute of Athens. The relocated epicenters define a pronounced ENE- WSW zone, parallel to the high topography of the area. All depths are shallow from 1 to 8 Km. Regional waveform modeling was applied to determine the focal mechanisms of the larger events and FPFIT for the focal mechanisms of the smaller magnitude events. The majority of the focal mechanisms indicate normal faulting along almost E-W striking planes suggesting that deformation is mainly taken by normal faulting with a minor dextral horizontal motion. Normal faults with a N-S strike have been also observed showing that the E-W extension is present as it is observed in other parts of the Aegean region. Evia Island and its pattern of deformation is very interesting from the seismotectonic point of view. The fact that no large magnitude earthquake has occurred in Evia Island during instrumental times, makes the study of this earthquake swarm important. Previous work (Kiratzi, 2002) has shown that the deformation in northern Evia Island is taken up mainly by strike-slip faulting. Moreover, depending on the orientation of the activated faults in respect to the present state stress field, dextral or sinistral horizontal motion is observed. The Psachna earthquakes showed that an almost N-S extensional field prevails in central Evia Island with a few strikeslip focal mechanisms, suggesting that this part is mostly affected by the normal faulting system of central Greece.

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The use of kink bands to constrain fault displacements: an example from the Bala Lineament, Wales

Geological Magazine ◽

10.1017/s0016756800021798 ◽

1992 ◽

Vol 129 (5) ◽

pp. 625-632 ◽

Cited By ~ 6

Author(s):

W. T. Pratt

Keyword(s):

Fault Zone ◽

Strike Slip ◽

Normal Faulting ◽

Qualitative Information ◽

Close Link ◽

Lower Carboniferous ◽

Early Devonian ◽

Kink Bands ◽

Lower Palaeozoic ◽

Dextral Strike Slip

AbstractThe Bala Lineament is a major NE-SW-striking fault zone that crosses the Lower Palaeozoic Welsh Basin. The southwest segment of it, the Tal-y-llyn Fault, mostly lies within a tract of Ordovician mudstones with few marker bands. Consequently, post-Caledonian (early Devonian) displacements are poorly understood. However, there is a close link between the distribution of kink bands and the fault zone. The kink bands provide information about the contemporary stress conditions and, in combination with slickensided fractures, give qualitative information about the various fault displacements. Matching of major folds across the fault suggests approximately 3–4 km of dextral strike-slip, probably of Lower Carboniferous age. A younger episode of normal faulting, perhaps related to Mesozoic extension, was accompanied by kink bands with more brittle characteristics.

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

International Journal of Earth Sciences ◽

10.1007/s00531-021-02068-y ◽

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.

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Coseismic fault-slip distribution of the 2019 Ridgecrest Mw6.4 and Mw7.1 earthquakes

Scientific Reports ◽

10.1038/s41598-021-93521-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yang Gao ◽

HuRong Duan ◽

YongZhi Zhang ◽

JiaYing Chen ◽

HeTing Jian ◽

...

Keyword(s):

Strike Slip ◽

Fault Slip ◽

Slip Distribution ◽

Synthetic Aperture ◽

Seismic Events ◽

Interferometric Synthetic Aperture Radar ◽

The Past ◽

Dextral Strike Slip Fault ◽

Fault Slip Distribution ◽

Dextral Strike Slip

AbstractThe 2019 Ridgecrest, California seismic sequence, including an Mw6.4 foreshock and Mw7.1 mainshock, represent the largest regional seismic events within the past 20 years. To obtain accurate coseismic fault-slip distribution, we used precise positioning data of small earthquakes from January 2019 to October 2020 to determine the dip parameters of the eight fault geometry, and used the Interferometric Synthetic Aperture Radar (InSAR) data processed by Xu et al. (Seismol Res Lett 91(4):1979–1985, 2020) at UCSD to constrain inversion of the fault-slip distribution of both earthquakes. The results showed that all faults were sinistral strike-slips with minor dip-slip components, exception for dextral strike-slip fault F2. Fault-slip mainly occurred at depths of 0–12 km, with a maximum slip of 3.0 m. The F1 fault contained two slip peaks located at 2 km of fault S4 and 6 km of fault S5 depth, the latter being located directly above the Mw7.1hypocenter. Two slip peaks with maximum slip of 1.5 m located 8 and 20 km from the SW endpoint of the F2 fault were also identified, and the latter corresponds to the Mw6.4 earthquake. We also analyzed the influence of different inversion parameters on the fault slip distribution, and found that the slip momentum smoothing condition was more suitable for the inversion of the earthquakes slip distribution than the stress-drop smoothing condition.

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