Geodynamic importance of the strike-slip faults at the eastern part of the Anatolian Scholle: Inferences from the uplift and slip rate of the Malatya Fault (Malatya-Ovacık Fault Zone, eastern Turkey)

Two major fault systems host Mw>7 earthquakes in Central and Northern Sulawesi, Indonesia: the Minahassa subduction interface and the Palu-Koro strike-slip fault. The Celebes Sea oceanic lithosphere subducts beneath the north arm of Sulawesi at the Minahassa subduction zone. At the western termination of the Minahassa subduction zone, it connects to the left-lateral Palu-Koro strike-slip fault zone. This fault strikes onshore at Palu Bay and then crosses Sulawesi. Interseismic GNSS velocities indicate that the Palu-Koro fault zone accommodates about 4 cm/yr of relative motion in the Palu Bay area, with a ~10 km locking depth. This shallowly locked segment of the Palu-Koro fault around the Palu Bay area ruptured during the devastating, tsunami-generating, 2018 Mw7.5 Palu earthquake. This complex event highlights the high seismic hazard for the island of Sulawesi.We have a >20-year record of GNSS velocities on Sulawesi, where the densest cluster of monument sites surrounds the Palu-Koro fault, specifically around Palu Bay, whereas the rest of the island is less densely covered. High quality estimates of interseismic velocities reveal second-order complex patterns of transient deformation in the wake of major earthquakes: the velocities in northern Sulawesi and around the Palu-Koro fault do not follow their interseismic trends after a major subduction earthquake has occurred, for several years after the event. This effect of transient deformation reaches more than 400km away from the epicentre of the major earthquakes. Surprisingly, a deviation from the background slip rate on the Palu-Koro fault is not accompanied by a deviation from the background (micro)seismic activity.We construct a 3D numerical model based on the structural and seismological data in the Sulawesi region. We investigate the post-seismic relaxation pattern from a subduction earthquake and determine whether the slip rate on the Palu-Koro fault changes due to this earthquake through forward model calculations. With a modelling focus on the 1996 Mw7.9 and 2008 Mw7.4 earthquakes that ruptured the Minahassa subduction interface, this study outlines the triggering of transient deformation and continual interaction between the Minahassa subduction interface and the Palu-Koro strike-slip fault.

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Deformation of continental blocks within convergent plates: Anatolia as a case study

10.5194/egusphere-egu2020-18856 ◽

2020 ◽

Author(s):

Cengiz Zabcı ◽

Taylan Sançar ◽

Müge Yazıcı ◽

Anke M. Friedrich ◽

Naki Akçar

Keyword(s):

Fault Zone ◽

Plate Boundary ◽

Slip Rate ◽

Shear Zones ◽

Strike Slip ◽

Central Anatolia ◽

Western Boundary ◽

The West ◽

Secondary Importance ◽

Continental Block

Anatolia is part of the west-central Alpide plate-boundary zone, particularly where the deformation is characterized by the westward extrusion of this continental block between the Arabian-Eurasian collision in the east and the Hellenic Subduction in the west. Although, this motion mostly happens along the boundary structures, i.e., the North Anatolian and East Anatolian shear zones, there are multiple studies documenting the active deformation along NE-striking sinistral and NW-striking dextral strike-slip faults within the central and eastern parts of Anatolia. These secondary faults slice Anatolia into several pieces giving formation of the Malatya-Erzincan, Cappadocian and Central Anatolian slices from east to west, where their boundary geometries are strongly controlled by the weak zones, the Tethyan Suture Zones.We compiled all geological slip-rate and palaeoseismological studies, which point out inhomogeneous magnitude of deformation along different sections of these secondary structures. The Central Anatolian Fault Zone, the westernmost NE-striking sinistral strike-slip structure and the western boundary between the Central Anatolia and Cappadocian slices, has an average horizontal slip-rate of about 1 to 1.5 mm/a for the last few tens of thousands of years. The earthquake recurrence of about 4500 years between two events revealed on the northern sections of the CAFZ also support this rate of deformation. However, the Malatya-Ovac&#305;k Fault Zone has a bimodal behaviour in terms of deformation rate, which is 2.5 times higher along its northern member, the Ovac&#305;k Fault (OF) than the southern one, the Malatya Fault (MF) (2.5 to 1 mm/a), respectively. This velocity difference between two distinct members of the same fault zone can be explained by the relative westward motion of slices where the OF makes the direct contact between the Central Anatolian and Malatya-Erzincan, and the MF delimits Cappadocian and Malatya-Erzincan slices. Although these structures, which are shallow and probably deform only the upper crust, are of having secondary importance, yet they are still capable of producing infrequent but strong earthquakes within this highly deforming convergent setting. This study is supported by T&#220;B&#304;TAK projects no. 114Y227 and 114Y580.

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Present-Day Deformation of the Gyaring Co Fault Zone, Central Qinghai–Tibet Plateau, Determined Using Synthetic Aperture Radar Interferometry

Remote Sensing ◽

10.3390/rs11091118 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1118

Author(s):

Yong Zhang ◽

Chuanjin Liu ◽

Wenting Zhang ◽

Fengyun Jiang

Keyword(s):

Synthetic Aperture Radar ◽

Fault Zone ◽

Crustal Deformation ◽

Tectonic Evolution ◽

Slip Rate ◽

Strike Slip ◽

Synthetic Aperture ◽

Tibet Plateau ◽

Regional Tectonic ◽

Qinghai Tibet Plateau

Because of the constant northward movement of the Indian plate and blockage of the Eurasian continent, the Qinghai–Tibet Plateau has been extruded by north–south compressive stresses since its formation. This has caused the plateau to escape eastward to form a large-scale east–west strike-slip fault and a north–south extensional tectonic system. The Karakorum–Jiali fault, a boundary fault between the Qiangtang and Lhasa terranes, plays an important role in the regional tectonic evolution of the Qinghai–Tibet Plateau. The Gyaring Co fault, in the middle of the Karakoram–Jiali fault zone, is a prominent tectonic component. There have been cases of strong earthquakes of magnitude 7 or greater in this fault, providing a strong earthquake occurrence background. However, current seismic activity is weak. Regional geodetic observation stations are sparsely distributed; thus, the slip rate of the Gyaring Co fault remains unknown. Based on interferometric synthetic aperture radar (InSAR) technology, we acquired current high-spatial resolution crustal deformation characteristics of the Gyaring Co fault zone. The InSAR-derived deformation features were highly consistent with Global Positioning System observational results, and the accuracy of the InSAR deformation fields was within 2 mm/y. According to InSAR results, the Gyaring Co fault controlled the regional crustal deformation pattern, and the difference in far-field deformation on both sides of the fault was 3–5 mm/y (parallel to the fault). The inversion results of the back-slip dislocation model indicated that the slip rate of the Gyaring Co fault was 3–6 mm/y, and the locking depth was ~20 km. A number of v-shaped conjugate strike-slip faults, formed along the Bangong–Nujiang suture zone in the central and southern parts of the -Tibet Plateau, played an important role in regional tectonic evolution. V-shaped conjugate shear fault systems include the Gyaring Co and Doma–Nima faults, and the future seismic risk cannot be ignored.

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RHEOLOGIC EVOLUTION OF A CRUSTAL-SCALE STRIKE-SLIP FAULT ZONE: A CASE STUDY OF THE KELLYLAND FAULT ZONE IN EASTERN MAINE

10.1130/abs/2019ne-328268 ◽

2019 ◽

Author(s):

Walter A. Sullivan ◽

Keyword(s):

Fault Zone ◽

Strike Slip ◽

Strike Slip Fault

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GEOLOGIC AND GEODETIC ANALYSES TO DEFINE THE LOCATION, CREEP, TRIGGERED SLIP, SLIP RATE, AND GEOMETRY WITHIN A VOLUMINOUS HIDDEN SPRING FAULT ZONE, SOUTHERN CALIFORNIA

10.1130/abs/2020am-358849 ◽

2020 ◽

Author(s):

Rebekah A. Riemann ◽

◽

James P. Evans ◽

Susanne Janecke ◽

Andrea Donnellan ◽

...

Keyword(s):

Fault Zone ◽

Southern California ◽

Slip Rate

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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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Late Pleistocene-Holocene tectonic landforms developed along the strike-slip Xianshuihe Fault Zone, Tibetan Plateau, China

Journal of Geodynamics ◽

10.1016/j.jog.2018.05.005 ◽

2018 ◽

Vol 120 ◽

pp. 11-22 ◽

Cited By ~ 1

Author(s):

Bing Yan ◽

Dong Jia ◽

Aiming Lin

Keyword(s):

Tibetan Plateau ◽

Fault Zone ◽

Late Pleistocene ◽

Strike Slip ◽

Xianshuihe Fault Zone

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

Journal of Structural Geology ◽

10.1016/j.jsg.2005.04.007 ◽

2005 ◽

Vol 27 (8) ◽

pp. 1379-1398 ◽

Cited By ~ 160

Author(s):

Guang Zhu ◽

Yongsheng Wang ◽

Guosheng Liu ◽

Manlan Niu ◽

Chenglong Xie ◽

...

Keyword(s):

Fault Zone ◽

Strike Slip ◽

East China ◽

Slip Motion

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

Canadian Journal of Earth Sciences ◽

10.1139/e81-071 ◽

1981 ◽

Vol 18 (4) ◽

pp. 776-788 ◽

Cited By ~ 23

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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