Evidence of Characteristic Earthquakes on Thrust Faults From Paleo‐Rupture Behavior Along the Longmenshan Fault System

Tectonics ◽  
2019 ◽  
Vol 38 (7) ◽  
pp. 2401-2410 ◽  
Author(s):  
Yongkang Ran ◽  
Xiwei Xu ◽  
Hu Wang ◽  
Wenshan Chen ◽  
Lichun Chen ◽  
...  
Keyword(s):  
Fault System ◽  
Thrust Faults ◽  
Longmenshan Fault System ◽  
Longmenshan Fault ◽  
Characteristic Earthquakes ◽  
Rupture Behavior

Bayesian probabilities of earthquake occurrences in Longmenshan fault system (China)

2014 ◽  
Vol 19 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Ying Wang ◽  
Keyin Zhang ◽  
Qigang Gan ◽  
Wen Zhou ◽  
Liang Xiong ◽  
...  
Keyword(s):  
Fault System ◽  
Longmenshan Fault System ◽  
Longmenshan Fault

Fault System Evolution and Its Influences on Buried-hills Formation in Tanhai Area of Jiyang Depression, Bohai Bay Basin, China

2020 ◽  
Author(s):  
Meng Zhang ◽  
Zhiping Wu ◽  
Shiyong Yan
Keyword(s):  
Stress Field ◽  
Cross Sections ◽  
Large Scale ◽  
Structural Evolution ◽  
Fault System ◽  
Mountain Range ◽  
Bohai Bay ◽  
Thrust Faults ◽  
Bohai Bay Basin ◽  
Jiyang Depression

<p>Buried-hills, paleotopographic highs covered by younger sediments, become the focused area of exploration in China in pace with the reduction of hydrocarbon resources in the shallow strata. A number of buried-hill fields have been discovered in Tanhai area located in the northeast of Jiyang Depression within Bohai Bay Basin, which provides an excellent case study for better understanding the structural evolution and formation mechanism of buried-hills. High-quality 3-D seismic data calibrated by well data makes it possible to research deeply buried erosional remnants. In this study, 3-D visualization of key interfaces, seismic cross-sections, fault polygons maps and thickness isopach maps are shown to manifest structural characteristics of buried-hills. Balanced cross-sections and fault growth rates are exhibited to demonstrate the forming process of buried-hills. The initiation and development of buried-hills are under the control of fault system. According to strike variance, main faults are grouped into NW-, NNE- and near E-trending faults. NW-trending main faults directly dominate the whole mountain range, while NNE- and near E-trending main faults have an effect on dissecting mountain range and controlling the single hill. In addition, secondary faults with different nature complicate internal structure of buried-hills. During Late Triassic, NW-trending thrust faults formed in response to regional compressional stress field, preliminarily building the fundamental NW-trending structural framework. Until Late Jurassic-Early Cretaceous, rolling-back subduction of Pacific Plate and sinistral movement of Tan-Lu Fault Zone (TLFZ) integrally converted NW-trending thrust faults into normal faults. The footwall of NW-trending faults quickly rose and became a large-scale NW-trending mountain range. The intense movement of TLFZ simultaneously induced a series of secondary NNE-trending strike-slip faults, among which large-scale ones divided the mountain range into northern, middle and southern section. After entry into Cenozoic, especially Middle Eocene, the change of subduction direction of Pacific Plate induced the transition of regional stress field. Near E-trending basin-controlling faults developed and dissected previous tectonic framework. The middle section of mountain range was further separated into three different single hill. Subsequently, the mountain range was gradually submerged and buried by overlying sediments, due to regional thermal subsidence. Through multiphase structural evolution, the present-day geometry of buried-hills is eventually taken shape.</p>

scholarly journals Tectonostratigraphy and major structures of the Georgian Greater Caucasus: Implications for structural architecture, along-strike continuity, and orogen evolution

Geosphere ◽  
2022 ◽  
Author(s):  
Charles C. Trexler ◽  
Eric Cowgill ◽  
Nathan A. Niemi ◽  
Dylan A. Vasey ◽  
Tea Godoladze
Keyword(s):  
Fault System ◽  
Thrust Faults ◽  
Geologic Mapping ◽  
Greater Caucasus ◽  
The Core ◽  
The North ◽  
Thrust Sheets ◽  
Southern Half ◽  
Caucasus Mountains ◽  
Structural Architecture

Although the Greater Caucasus Mountains have played a central role in absorbing late Cenozoic convergence between the Arabian and Eurasian plates, the orogenic architecture and the ways in which it accommodates modern shortening remain debated. Here, we addressed this problem using geologic mapping along two transects across the southern half of the western Greater Caucasus to reveal a suite of regionally coherent stratigraphic packages that are juxtaposed across a series of thrust faults, which we call the North Georgia fault system. From south to north within this system, stratigraphically repeated ~5–10-km-thick thrust sheets show systematically increasing bedding dip angles (<30° in the south to subvertical in the core of the range). Likewise, exhumation depth increases toward the core of the range, based on low-temperature thermochronologic data and metamorphic grade of exposed rocks. In contrast, active shortening in the modern system is accommodated, at least in part, by thrust faults along the southern margin of the orogen. Facilitated by the North Georgia fault system, the western Greater Caucasus Mountains broadly behave as an in-sequence, southward-propagating imbricate thrust fan, with older faults within the range progressively abandoned and new structures forming to accommodate shortening as the thrust propagates southward. We suggest that the single-fault-centric “Main Caucasus thrust” paradigm is no longer appropriate, as it is a system of faults, the North Georgia fault system, that dominates the architecture of the western Greater Caucasus Mountains.

scholarly journals Structural modeling and evolution of the piedmont zone in north margin of Qaidam Basin, northeastern Tibetan Plateau

2020 ◽  
Vol 38 (6) ◽  
pp. 2649-2666
Author(s):  
Li Zongxing ◽  
Wang Dahua ◽  
Wang Xianchao ◽  
Xiao Yongjun ◽  
Peng Bo
Keyword(s):  
Qaidam Basin ◽  
Distribution Patterns ◽  
Structural Modeling ◽  
Strike Slip ◽  
Structural Deformation ◽  
Fault System ◽  
Thrust Faults ◽  
Study Results ◽  
Thrust System ◽  
Basin Margin

The analysis and interpretation of the Dachaidan area, Qaidam Basin, is difficult, owing to the co-location of two groups of thrust faults (N–E faults and N–W faults) there and the area’s complicated structural deformation history. To address this problem, field geological investigation, seismic study, well logging, and drilling data were used to identify the key fault systems and their distribution patterns through the area. By integrating surface and subsurface structural features and seismic and non-seismic data, we carried out studies using structural modeling and analysis of the Dachaidan area. Study results identified two systems of thrust faults (N–W faults and W–E faults). We found that these faults could be categorized into three systems: a basin-margin thrust system, an intro-basin thrust system, and an intro-basin compression and strike-slip fault system. These systems showed different features in different areas and zones. We also constructed interpretation models of different deformation mechanisms in the basin and on basin margins. Three tectonic systems (compression, extension, and strike-slip) were identified, which were further divided into eight structural domains. We also established structure coexistence and distribution patterns. The overall structural character of the area was summarized as the northern and southern parts belonging to different zones, with the western and eastern parts belonging to different systems. By analyzing the SW–NE tectonic evolution sections, we defined the back-propagation structural evolution sequences of thrust nappes (on the basin margin or in the basin) and back-thrust structures (in the basin) as well as their influence on the residual Mesozoic strata.

Stratigraphy, palynology, and provenance of the Colorado Creek basin, Alaska, USA: Oligocene transpressional tectonics along the central Denali fault system

2004 ◽  
Vol 41 (4) ◽  
pp. 457-480 ◽  
Author(s):  
Jeffrey M Trop ◽  
Kenneth D Ridgway ◽  
Arthur R Sweet
Keyword(s):  
Compositional Data ◽  
Middle Eocene ◽  
Volcanic Eruptions ◽  
Fault System ◽  
Thrust Faults ◽  
South Side ◽  
Denali Fault ◽  
The North ◽  
Early Oligocene ◽  
Middle Unit

New sedimentologic, biostratigraphic, and compositional data from a 415-m-thick section of siliciclastic and volcanic strata document Oligocene synthrusting sedimentation south of the McKinley segment of the Denali fault system. Strata of the Colorado Creek basin are presently exposed on the south side of the central Alaska Range in the footwalls of north-dipping thrust faults. New measured sections define a three-part stratigraphy. Lowermost strata consist of a ~30-m-thick unit of marine sandstone and mudstone that contain Late Cretaceous dinoflagellate taxa. The middle unit consists of ~330 m of conglomerate, sandstone, and mudstone interpreted as braided stream and floodplain deposits. This middle unit contains early Oligocene pollen and spore assemblages. The upper unit is 55 m thick and contains lava flows, tuff, and pumice interpreted as the product of subaerial volcanic eruptions. Direct age data are lacking from the upper unit. Compositional data from the middle unit indicate that detritus was derived from sedimentary and igneous source terranes exposed on both the north and south side of the McKinley fault. Matching source lithologies north of the McKinley fault with conglomerate clast types in the Colorado Creek basin implies 30–33 km of maximum post-early Oligocene dextral displacement along the fault. We interpret the Oligocene strata of the Colorado Creek basin as a product of transpressional deformation that produced north-dipping thrust faults associated with strike-slip displacement on the central Denali fault. Our data from the Colorado Creek basin, in combination with previous studies, document a major episode of middle Eocene – late Oligocene synorogenic sedimentation along the Denali fault from British Columbia to southwestern Alaska.

scholarly journals Drainage Development in the Dunhuang Basin, NE Tibet, Controlled by Multi-Segment Fault Growth

2021 ◽  
Vol 9 ◽  
Author(s):  
Gan Chen ◽  
Wenjun Zheng ◽  
Jingjun Yang ◽  
Lei Duan ◽  
Shumin Liang ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Field Investigation ◽  
Fault System ◽  
Asymmetry Factor ◽  
Mountain Range ◽  
Thrust Faults ◽  
Altyn Tagh ◽  
High Resolution Satellite Images ◽  
Fault Growth ◽  
Drainage Development

The Dongbatu Shan (DBTS, also known as the Nanjie Shan), which interrupts the northern Tibetan foreland in the Dunhuang basin, is an active anticline. It has accommodated the northwestern growth of the eastern Altyn Tagh fault system (ATF). Although several thrust faults have been identified around the DBTS, their evolution history and influence on regional landscape have received little attention during the late-Quaternary. In this study, several geomorphic methods are used to investigate the interaction between drainage development and tectonic movement around DBTS. Based on high-resolution satellite images, field investigation, and cosmogenic nuclide 10Be dating method, the fluvial landform sequences around DBTS were constructed. Using quantitative geomorphology methods including landscape relief profile, asymmetry factor (AF), and transverse topographic symmetry factor (T), we hypothesize that drainage deflection is controlled by multi-segment fault growth. Combining the results of the above-mentioned methods, we propose that Yulin He, flowing across the DBTS, had gone through several abandonments since the late mid-Pleistocene due to the lateral propagation of DBTS. Affected by the discharge of channel and multi-segment fault growth, our research confirms that the direction of river abandonment may have decoupled with the mountain range propagation trend. Based on the chronology dating, the DBTS has gone through two severe uplifts since ∼208 ka and the shortening rate across the central DBTS is constrained to be ∼1.47 mm/yr since ∼83 ka. Given the fact that thrust faults are widely developed around DBTS, we propose that the flower-like structure formed by the northward growth of the eastern ATF could better explain the development of the secondary subparallel faults.

SEM study of quartz grains from recent sediments: Western Iraq

1990 ◽  
Vol 48 (4) ◽  
pp. 860-861
Author(s):  
F. Al-Kufaishi
Keyword(s):  
Factor Loading ◽  
Fault System ◽  
Clay Material ◽  
Crustal Material ◽  
Factor Analyses ◽  
Five Factors ◽  
Sem Study ◽  
Recent Sediments ◽  
Quartz Grains ◽  
Positive Factor

Two localities (Al-Marij and Laik) were selected to investigate the type of Quartz Grains from crustal material formed by evaporation of waters discharged by springs in Hit area, western Iraq, Previous studies on the crustal material (1,2) showed that the water discharged by these springs are associated with Abu-Jir fault system which run parallel to the Euphrates river,Factor analyses of the crustal and soil materials (50 samples analysed for 16 variables)(2) showed five factors; the first factor includes SiO2, Al2O3 and TiO2 with positive factor loading, and CaO, L.O.I. with negative loading and hence lead to the conclusion that the distribution of these variables is a reflection of transported clay material.This study concentrates on the use of SEM to investigate the contribution of Quartz grains found in the crustal material on two selected sites.

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