scholarly journals Geometric and Dynamic Patterns of the Golmud Segment in the Southern Marginal Fault of the Qaidam Basin

2021 ◽  
Vol 9 ◽  
Author(s):  
Hao Luo ◽  
Ji Wang ◽  
Yasen Gou ◽  
Hongmei Yu ◽  
Peng Shu ◽  
...  
Keyword(s):  
High Resolution ◽  
Late Quaternary ◽  
Qaidam Basin ◽  
Structural Evolution ◽  
Strike Slip ◽  
Fault System ◽  
Tibet Plateau ◽  
Deformation Pattern ◽  
Slip Rates ◽  
Lateral Extrusion

The southern marginal fault of the Qaidam Basin (SMQBF) is a block-bounding border fault that has played a key role in the structural evolution of the Kunlun Fault. However, its geometric and dynamic deformation patterns since the Late Pleistocene have not been clearly observed. Field investigations, combined with high-resolution imagery and shallow seismic profiles, show that the SMQBF is a thrust fault with a sinistral strike-slip component composed of several secondary faults. Its Late Quaternary deformation pattern is characterized by piggyback thrust propagation, and the frontal fault may not be exposed to the surface. Due to the flexural slip of the hanging strata of the secondary fault, sub-parallel faults with widths of thousands of meters have formed on high terraces; these are important when assessing the seismic hazard of this area. Based on high-resolution topographic data obtained using an unmanned erial vehicle and optically stimulated luminescence chronology, the slip rates of several secondary faults were obtained. The vertical and strike-slip rates of the SMQBF were determined to be 0.96 ± 0.33 mm/a and 2.66 ± 0.50 mm/a, respectively, which may be the minimum rates for the fault. Considering that the SMQBF is composed of several secondary faults, these rates possibly correspond to minimum deformation only. The evident sinistral strike-slip of the SMQBF indicates that although the sinistral slip of the Kunlun Fault system is concentrated in main fault of this system, the branch faults have a significant influence on the lateral extrusion of the Qinghai-Tibet Plateau.

scholarly journals High-Resolution 3D Seismic Imaging of Fault Interaction and Deformation Offshore San Onofre, California

2021 ◽  
Vol 9 ◽  
Author(s):  
James J. Holmes ◽  
Neal W. Driscoll ◽  
Graham M. Kent
Keyword(s):  
High Resolution ◽  
Strike Slip ◽  
Fault System ◽  
3D Seismic ◽  
Fault Interaction ◽  
Slip Rates ◽  
Slip Step ◽  
Well Data ◽  
Splay Faults ◽  
Step Over

The Inner California Borderland (ICB) records a middle Oligocene transition from subduction to microplate capture along the southern California and Baja coast. The closest nearshore fault system, the Newport-Inglewood/Rose Canyon (NIRC) fault complex is a dextral strike-slip system that extends primarily offshore approximately 120 km from San Diego to Newport Beach, California. Holocene slip rates along the NIRC are 1.5–2.0 mm/year in the south and 0.5 mm/year along its northern extent based on trenching and well data. High-resolution 3D seismic surveys of the NIRC fault system offshore of San Onofre were acquired to define fault interaction across a prominent strike-slip step-over. The step-over deformation results in transpression that structurally controls the width of the continental shelf in this region. Shallow coring on the shelf yields a range of sedimentation rates from 0.27–0.28 mm/year. Additionally, a series of smaller anticlines and synclines record subtle changes in fault trends along with small step-overs and secondary splay faults. Finally, sedimentary units onlapping and dammed by the anticline, place constraints on the onset of deformation of this section of the NIRC fault system. Thickness estimates and radiocarbon dating yield ages of 560,000 to 575,000 years before present for the onset of deformation.

scholarly journals Neogene kinematics of the Giudicarie Belt and eastern Southern Alpine orogenic front (Northern Italy)

2021 ◽  
Author(s):  
Vincent F. Verwater ◽  
Eline Le Breton ◽  
Mark R. Handy ◽  
Vincenzo Picotti ◽  
Azam Jozi Najafabadi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Eastern Alps ◽  
Strike Slip ◽  
Fault System ◽  
Late Oligocene ◽  
Lateral Variation ◽  
Tectonic Structures ◽  
Tauern Window ◽  
Adriatic Plate ◽  
Lateral Extrusion

Abstract. Neogene indentation of the Adriatic plate into Europe led to major modifications of the Alpine orogenic structures and style of deformation in the Eastern Alps. Especially, the offset of the Periadriatic Fault by the Northern Giudicarie Fault marks the initiation of strike-slip faulting and lateral extrusion of the Eastern Alps. Questions remain on the exact role of this fault zone in changes of the Alpine orogen at depth. This necessitates quantitative analysis of the shortening, kinematics and depth of decoupling underneath the Northern Giudicarie Fault and associated fold-and thrust belt in the Southern Alps. Tectonic balancing of a network of seven cross sections through the Giudicarie Belt parallel to the local shortening direction reveals that it comprises two kinematic domains with different amounts and partly overlapping ages of shortening. These two domains are delimitated by the NW-SE oriented strike-slip Trento-Cles – Schio-Vicenza fault system, cross-cutting the Southern Alpine orogenic front in the south and merging with the Northern Giudicarie Fault in the north. The SW kinematic domain (Val Trompia sector) accommodated at least ~18 km of Late Oligocene to Early Miocene shortening. Since the Middle Miocene, the SW kinematic domain experienced a minimum of ~12–22 km shortening, whereas the NE kinematic domain underwent at least ~25–35 km shortening. Together, these domains contributed to an estimated ~53–75 km of sinistral strike-slip motion along the Northern Giudicarie Fault, implying that (most of) the offset of the Periadriatic Fault is due to Late Oligocene to Neogene indentation of the Adriatic plate into the Eastern Alps. Moreover, the faults linking the Giudicarie Belt with the Northern Giudicarie Fault reach ~15–20 km depth, indicating a thick-skinned tectonic style of deformation. These fault detachments may also connect at depth with a lower crustal Adriatic wedge that protruded north of the Periadriatic Fault and was responsible for N-S shortening and eastward escape of deeply exhumed units in the Tauern Window. Finally, the east-west lateral variation of shortening indicates internal deformation and lateral variation in strength of the Adriatic indenter, related to Permian – Mesozoic tectonic structures and paleogeographic domains.

scholarly journals LiDAR and other evidence for the southwest continuation and Late Quaternary reactivation of the Norumbega Fault System and a cross-cutting structure near Biddeford, Maine, USA

2019 ◽  
Vol 55 ◽  
pp. 323-359
Author(s):  
Ronald T. Marple ◽  
James D. Hurd
Keyword(s):  
High Resolution ◽  
New Hampshire ◽  
Late Quaternary ◽  
Light Detection And Ranging ◽  
Fault System ◽  
Light Detection ◽  
Drainage Patterns ◽  
Geomorphic Features ◽  
Wide Zone

High-resolution LiDAR (light detection and ranging) images reveal numerous NE-SW-trending geomorphic lineaments that may represent the southwest continuation of the Norumbega fault system (NFS) along a broad, 30- to 50-km-wide zone of brittle faults that continues at least 100 km across southern Maine and southeastern New Hampshire. These lineaments are characterized by linear depressions and valleys, linear drainage patterns, abrupt bends in rivers, and linear scarps. The Nonesuch River, South Portland, and Mackworth faults of the NFS appear to continue up to 100 km southwest of the Saco River along prominent but discontinuous LiDAR lineaments. Southeast-facing scarps that cross drumlins along some of the lineaments in southern Maine suggest that late Quaternary displacements have occurred along these lineaments. Several NW-SE-trending geomorphic features and geophysical lineaments near Biddeford, Maine, may represent a 30-km-long, NW-SE-trending structure that crosses part of the NFS. Brittle NWSE-trending, pre-Triassic faults in the Kittery Formation at Biddeford Pool, Maine, support this hypothesis.

scholarly journals The Carboneras Fault Zone (southeastern Spain) revisited with Ground Penetrating Radar – Quaternary structural styles from high-resolution images

2001 ◽  
Vol 80 (3-4) ◽  
pp. 129-138 ◽  
Author(s):  
K.R. Reicherter ◽  
S. Reiss
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Ground Penetrating Radar ◽  
Late Quaternary ◽  
Strike Slip ◽  
Tectonic Activity ◽  
Active Set ◽  
Southeastern Spain ◽  
Betic Cordilleras ◽  
Ground Penetrating

AbstractThe Carboneras Fault Zone (CFZ) represents an active set of sinistral strike-slip faults in the Betic Cordilleras of southeastern Spain. It constitutes a major segment of the ‘Trans-Alboran shear zone’ during the Cenozoic, striking NE-SW. The CFZ separates the Cabo de Gata Block (Neogene volcanics) against Neogene basinal sediments and the metamorphic basement of the Alpujarride Complex.Three sites along the CFZ were examined with Ground Penetrating Radar techniques. Radar surveying was complemented by structural studies. Shallow-depth high-resolution imaging of Tyrrhenian beach terraces exhibited both vertical and minor horizontal offsets in the Rambla Morales site in the south. A sinistral strike-slip fault associated with minor thrust faults in a positive flower structure was detected in the middle segment along the La Serrata ridge, sealed by a caliche of late Pleistocene age (> 10 ka). The Playa de Bolmayor section yielded sub-surface evidence for several faults probably related to recent activity of individual fault strands. Our results suggest a distributed tectonic activity of the CFZ during the Late Quaternary.

STRUCTURAL EVOLUTION OF THE CARNARVON TERRACE, WESTERN AUSTRALIA

1995 ◽  
Vol 35 (1) ◽  
pp. 321 ◽  
Author(s):  
P.W. Baillie ◽  
E. Jacobson
Keyword(s):  
High Resolution ◽  
Western Australia ◽  
Long Island ◽  
Structural Evolution ◽  
Early Jurassic ◽  
Seismic Survey ◽  
Fault System ◽  
Late Triassic ◽  
Structural Configuration ◽  
Break Up

The under-explored Carnarvon Terrace is situated offshore of the Cape Range area in the Carnarvon Basin near the boundary of the Gascoyne and Exmouth Sub-basins. The stratigraphy of the area is controlled by only two wells (Pendock-1, Yardie East-1), but several onshore wells aid interpretation of seismic data.Understanding of the structural evolution of the region is facilitated by interpretation of a high-resolution non-exclusive seismic survey acquired by Geco-Prakla in 1993 (GPCTR-93 Survey).Three major tectonic stages are responsible for the structural configuration of the region:Late Palaeozoic extension in the Gascoyne Sub-basin;continental break-up between Australia and Greater India which took place along a major fracture marked by the Flinders-Long Island-Learmonth fault system active in Late Triassic and Early Jurassic times; andthe collision between Australia and Asia that commenced in Miocene times and is continuing to the present day. This event, marked by wrench and compressional structures, and often reactivation of older structures, is one of the most economically important in Australian geological history.From a regional prospectivity viewpoint at least three plays are worthy of further investigation.

Linking dynamic earthquake rupture to tsunami modeling for the Húsavík-Flatey transform fault system in North Iceland

2021 ◽  
Author(s):  
Fabian Kutschera ◽  
Sara Aniko Wirp ◽  
Bo Li ◽  
Alice-Agnes Gabriel ◽  
Benedikt Halldórsson ◽  
...  
Keyword(s):  
Strike Slip ◽  
Strike Slip Fault ◽  
Fault System ◽  
Deformation Pattern ◽  
Tsunami Modeling ◽  
Earthquake Rupture ◽  
Worst Case ◽  
Fault Systems ◽  
Complex Fault ◽  
The Impact

<p>Earthquake generated tsunamis are generally associated with large submarine events on dip-slip faults, in particular on subduction zone megathrusts (Bilek and Lay, 2018). Submerged ruptures across strike-slip fault systems mostly produce minor vertical offset and hence no significant disturbance of the water column. For the 2018 Mw 7.5 Sulawesi earthquake in Indonesia, linked dynamic earthquake rupture and tsunami modeling implies that coseismic, mixed strike-slip and normal faulting induced seafloor displacements were a critical component generating an unexpected and devastating local tsunami in Palu Bay (Ulrich et al., 2019), with important implications for tsunami hazard assessment of submarine strike-slip fault systems in transtensional tectonic settings worldwide. </p><p>We reassess the tsunami potential of the ~100 km Húsavík Flatey Fault (HFF) in North Iceland using physics-based, linked earthquake-tsunami modelling. The HFF consists of multiple fault segments that localise both strike-slip and normal movements, agreeing with a transtensional deformation pattern (Garcia and Dhont, 2005). The HFF hosted several historical earthquakes with M>6. It crosses from off-shore to on-shore in immediate proximity to the town of Húsavík. We analyse simple and complex fault geometries and varying hypocenter locations accounting for newly inferred fault geometries (Einarsson et al., 2019), 3-D subsurface structure (Abril et al., 2020), bathymetry and topography of the area, primary stress orientations and the stress shape ratio constrained by the inversion of earthquake focal mechanisms (Ziegler et al., 2016).</p><p>Dynamic rupture models are simulated with SeisSol (https://github.com/SeisSol/SeisSol), a scientific open-source software for 3D dynamic earthquake rupture simulation (www.seissol.org, Pelties et al., 2014). SeisSol, a flagship code of the ChEESE project (https://cheese-coe.eu), enables us to explore simple and complex fault and subsurface geometries by using unstructured tetrahedral meshes. The dynamically adaptive, parallel software sam(oa)²-flash (https://gitlab.lrz.de/samoa/samoa) is used for tsunami propagation and inundation simulations and solves the hydrostatic shallow water equations (Meister, 2016). We consider the contribution of the horizontal ground deformation of realistic bathymetry to the vertical displacement following Tanioka and Satake, 1996. The tsunami simulations use time-dependent seafloor displacements to initialise bathymetry perturbations. </p><p>We show that up to 2 m of vertical coseismic offset can be generated during dynamic earthquake rupture scenarios across the HFF, which resemble historic magnitudes and are controlled by spontaneous fault interaction in terms of dynamic and static stress transfer and rupture jumping across the complex fault network. Our models reveal rake deviations from pure right-lateral strike-slip motion, indicating the presence of dip-slip components, in combination with large shallow fault slip (~8 m for a hypocenter in the East), which can cause a sizable tsunami affecting North Iceland. Sea surface height (ssh), which is defined as the deviation from the mean sea level, and inundation synthetics give an estimate about the impact of the tsunami along the coastline. We further investigate a physically plausible worst-case scenario of a tsunamigenic HFF event, accounting for tsunami sourcing mechanisms similar to the one causing the Sulawesi Tsunami in 2018.</p>

Regional Tectonics & Structural Framework of Offshore Aceh's Andaman Sub-Basin, Northern Sumatra, Indonesia

2021 ◽  
Author(s):  
S. Clark
Keyword(s):  
High Resolution ◽  
Late Eocene ◽  
Strike Slip ◽  
Hydrocarbon Exploration ◽  
Fault System ◽  
Earth Model ◽  
The West ◽  
Structural Framework ◽  
Geochemical Models ◽  
Regional Tectonics

The three-way collision of the Indo-Australian, Eurasian and Pacific plates have resulted in Southeast Asia being the most tectonically complex region on Earth. This is particularly true for Offshore Aceh’s Andaman Sub-Basin, which has undergone complex late Eocene-Recent evolution. Despite a long history of hydrocarbon exploration and production, data scarcity in the offshore means that the Sub-Basin’s regional tectonics and structural framework have been poorly understood. Pre-1996 2D seismic data were low-fold and low-offset, however the 2019 PGS (NSMC3D) regional 3D survey imaged the entire Cenozoic sequence, enabling the delineation of a high-resolution tectonic framework for the first time. Integration of interpretations drawn from geophysical datasets with a 2019 biostratigraphy study has refined the ages of critical sequence boundaries and advanced the understanding of major structural elements. GEM™, the Geognostics Earth Model, has been used to place these interpretations in a regional tectonic and kinematic context using a series of high resolution plate animations. Andaman Sub-Basin formation initiated in response to the northward motion of India and collision with Eurasia, suturing the West Burma and Sibumasu Terranes through the middle-late Eocene. Continued northward motion of the Indo-Australian Plate resulted in further subduction along the Sunda Trench with associated oblique back-arc extension in present-day onshore and offshore Java and Sumatra. Concurrent rotation of Sundaland, with sinistral strike-slip motion along the Ranong and Khlong Mauri fault zones, resulted in the two rifting phases within the late Eocene (~40Ma) to early Oligocene in the Andaman Sub-Basin. Significant inversion events at 30Ma and 23Ma formed in response to dextral transpression associated with rotational extrusion of Indochina and Sundaland. Rapid subsidence followed the 30Ma inversion, resulting in a switch to post-rift sag and bathyal conditions during which turbidites infilled seabed topography. The onset of dextral strike slip between the West Burma Terrane along the Saigang fault system occurred at ~26Ma, causing transtension in the Andaman Sub-basin that terminated at 23Ma. At approximately 5Ma inversion and toe thrusts developed along the Sub-Basin’s southern margin due to uplift within the Barisan mountains. Refinement of the tectonic model, integrated with updated biostratigraphic and geochemical models, resulted in a revised tectono-stratigraphy for the Andaman Sub-Basin, which provides a predictive depositional model in which paleogeography and structural reactivation can be understood in a regional context.

scholarly journals Spatial variations in late Quaternary slip rates along the Doruneh Fault System (Central Iran)

Tectonics ◽  
2016 ◽  
Vol 35 (2) ◽  
pp. 386-406 ◽  
Author(s):  
Yassaman Farbod ◽  
Esmaeil Shabanian ◽  
Olivier Bellier ◽  
Mohammad Reza Abbassi ◽  
Régis Braucher ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Spatial Variations ◽  
Central Iran ◽  
Fault System ◽  
Slip Rates
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