scholarly journals Revealing Geometry and Fault Interaction on a Complex Structural System Based on 3D P-Cable Data: The San Mateo and San Onofre Trends, Offshore Southern California

2021 ◽  
Vol 9 ◽  
Author(s):  
James J. Holmes ◽  
Hector Perea ◽  
Neal W. Driscoll ◽  
Graham M. Kent
Keyword(s):  
Southern California ◽  
Lateral Displacement ◽  
Coastal Region ◽  
Fault System ◽  
Small Scale ◽  
Tectonic Deformation ◽  
Fault Interaction ◽  
Fault Systems ◽  
The North ◽  
Blind Thrust

Deformation observed along the San Mateo (SMT) and San Onofre trends (SOT) in southern California has been explained by two opposing structural models, which have very different hazard implications for the coastal region. One model predicts that the deformation is transpressional in a predominantly right lateral fault system with left lateral step-overs. Conversely in the alternative model, the deformation is predicted to be compressional associated with a regional blind thrust that reactivated detachment faults along the continental margin. State-of-the-art 3D P-Cable seismic data were acquired to characterize the geometry and linkage of faults in the SMT and SOT. The new observations provide evidence that deformation along the slope is more consistent with step-over geometry than a regional blind thrust model. For example, regions in the SOT exhibit small scale compressional structures that deflect canyons along jogs in the fault segments across the slope. The deformation observed in the SMT along northwesterly trending faults has a mounded, bulbous character in the swath bathymetry data with steep slopes ( ∼ 25°) separating the toe of the slope and the basin floor. The faulting and folding in the SMT are very localized and occur where the faults trend more northwesterly (average trend ∼ 285°) with the deformation dying away both towards the north and east. In comparison, the SOT faults trend more northerly (average trend ∼ 345°). The boundary between these fault systems is abrupt and characterized by shorter faults that appear to be recording right lateral displacement and possibly accommodating the deformation between the two larger fault systems. Onlapping undeformed turbidite layers reveal that the deformation associated with both major fault systems may be inactive and radiocarbon dating suggests deformation ceased in the middle to late Pleistocene (between 184 and 368 kyr). In summary, our preferred conceptual model for tectonic deformation along the SMT and SOT is best explained by left lateral step-overs along the predominantly right lateral strike-slip fault systems.

scholarly journals Diffuse Tectonic Deformation in the Drum Mountains Fault Zone, Utah, USA: Testing the Utility of Legacy Aerial Photograph-Derived Topography

2021 ◽  
Vol 8 ◽  
Author(s):  
Timothy A. Stahl ◽  
Nathan A. Niemi ◽  
Jaime E. Delano ◽  
Franklin D. Wolfe ◽  
Michael P. Bunds ◽  
...  
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Aerial Photograph ◽  
Basin And Range ◽  
Aerial Photographs ◽  
Fault System ◽  
Tectonic Deformation ◽  
Surface Model ◽  
Basin And Range Province ◽  
Fault Systems

The Basin and Range province in the western United States hosts numerous low-slip-rate normal faults with diffuse and subtle surface expressions. Legacy aerial photographs, widely available across the region, can be used to generate high-resolution digital elevation models of these previously uncharacterized fault systems. Here, we test the limits and utility of aerial photograph-derived elevation products on the Drum Mountains fault zone—a virtually unstudied and enigmatic fault system in the eastern Basin and Range province of central Utah. We evaluate a new 2-m digital surface model produced from aerial photographs against other remotely sensed and field survey data and assess the various factors that contribute to noise, artifacts, and distortions. Despite some challenges, the new elevation model captures the complex array of cross-cutting fault scarps well. We demonstrate that the fault zone has variable net east- or west-down sense of displacement across a c. 8-km-wide zone of antithetic and synthetic traces. Optically stimulated luminescence ages and scarp profiles are used to constrain net extension rates across two transects and reveal that the Drum Mountains fault zone has average extension rates of c. 0.1–0.4 mm yr−1 over the last c. 35 ka. These rates are both faster than previously estimated and faster than most other faults in the region, and could be an order of magnitude higher if steep faults at the surface sole into a detachment at depth. Several models have been proposed for local and regional faulting at depth, but our data show that the offsets, rates, and geometries of faulting can be generated by the reactivation of pre-existing, cross-cutting faults in a structurally complex zone between other fault systems. This study highlights how legacy aerial-photograph-derived elevation products, in lieu of other high-resolution topographic datasets, can be used to study active faults, especially in remote regions where diffuse deformation would otherwise remain undetected.

scholarly journals Quaternary Geometry, Kinematics and Paleoearthquake History at the Intersection of the Strike-Slip North Island Fault System and Taupo Rift, New Zealand

2021 ◽  
Author(s):  
◽  
Vasiliki Mouslopoulou
Keyword(s):  
New Zealand ◽  
Late Quaternary ◽  
Strike Slip ◽  
Fault System ◽  
Alternative Mechanism ◽  
Normal Faulting ◽  
Fault Systems ◽  
The North ◽  
Australian Plate ◽  
C 30

<p>The North Island of New Zealand sits astride the Hikurangi margin along which the oceanic Pacific Plate is being obliquely subducted beneath the continental Australian Plate. The North Island Fault System1 (NIFS), in the North Island of New Zealand, is the principal active strike-slip fault system in the overriding Australian Plate accommodating up to 30% of the margin parallel plate motion. This study focuses on the northern termination of the NIFS, near its intersection with the active Taupo Rift, and comprises three complementary components of research: 1) the investigation of the late Quaternary (c. 30 kyr) geometries and kinematics of the northern NIFS as derived from displaced geomorphic landforms and outcrop geology, 2) examination of the spatial and temporal distribution of  paleoearthquakes in the NIFS over the last 18 kyr, as derived by fault-trenching and displaced landforms, and consideration of how these distributions may have produced the documented late Quaternary (c. 30 kyr) kinematics of the northern NIFS, and 3) Investigation of the temporal stability of the late Quaternary (c. 30 kyr) geometries and kinematics throughout the Quaternary (1-2 Ma), derived from gravity, seismic-reflection, drillhole, topographic and outcrop data. The late Quaternary (c. 30 kyr) kinematics of the northern NIFS transition northward along strike, from strike-slip to oblique-normal faulting, adjacent to the rift. With increasing proximity to the Taupo Rift the slip vector pitch on each of the faults in the NIFS steepens gradually by up to 60 degrees, while the mean fault-dip decreases from 90 degrees to 60 degrees W. Adjustments in the kinematics of the NIFS reflect the gradual accommodation of the NW-SE extension that is distributed outside the main physiographic boundary of the Taupo Rift. Sub-parallelism of slip vectors in the NIFS with the line of intersection between the two synchronous fault systems reduces potential space problems and facilitates the development of a kinematically coherent fault intersection, which allows the strike-slip component of slip to be transferred into the rift. Transfer of displacement from the NIFS into the rift accounts for a significant amount of the northeastward increase of extension along the rift. Steepening of the pitch of slip vectors towards the northern termination of the NIFS allows the kinematics and geometry of faulting to change efficiently, from strike-lip to normal faulting, providing an alternative mechanism to vertical axis rotations for terminating large strike-lip faults. Analyses of kinematic constraints from worldwide examples of synchronous strike-lip and normal faults that intersect to form two or three plate configurations, within either oceanic or continental crust, suggest that displacement is often transferred between the two fault systems in a similar manner to that documented at the NIFS - Taupo Rift fault intersection. The late Quaternary (c. 30 kyr) change in the kinematics of the NIFS along strike, from dominantly strike-slip to oblique-normal faulting, arises due to a combination of rupture arrest during individual earthquakes and variations in the orientation of the coseismic slip vectors. At least 80 % of all surface rupturing earthquakes appear to have terminated within the kinematic transition zone from strike-slip to oblique-normal slip. Fault segmentation reduces the magnitudes of large surface rupturing earthquakes in the northern NIFS from 7.4-7.6 to c. 7.0. Interdependence of throw rates between the NIFS and Taupo Rift suggests that the intersection of the two fault systems has functioned coherently for much of the last 0.6-1.5 Myr. Oblique-normal slip faults in the NIFS and the Edgecumbe Fault in the rift accommodated higher throw rates since 300 kyr than during the last 0.6-1.5 Myr. Acceleration of these throw rates may have occurred in response to eastward migration of rifting, increasing both the rates of faulting and the pitch of slip vectors. The late Quaternary (e.g. 30 kyr) kinematics, and perhaps also the stability, of the intersection zone has been geologically short lived and applied for the last c. 300 kyr.</p>

scholarly journals Brittle tectonic and morphological alteration of Almyros basin

2001 ◽  
Vol 34 (1) ◽  
pp. 371
Author(s):  
Δ. ΓΑΛΑΝΑΚΗΣ
Keyword(s):  
Drainage System ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Fault System ◽  
Morphological Alteration ◽  
Southern Boundary ◽  
Fault Systems ◽  
The North ◽  
River Terraces ◽  
Morphotectonic Evolution

Two crossed fault systems with NW-SE and E-W directions affect on the central and southern part of the Almyros basin. The uplift movement in the western part of the basin, with importance vertical displacement (up to 200m) of the lignite layers and the formation river terraces are related with the activity of the first fault NWSE direction. The second fault with E-W direction, located along Xerias river, affect on drainage system with hydrographie network from the south to the north development. In the southern part of the basin and on the Orthrys mountain a fault system with E-W trending affects on alpine basement and neogene deposits. This fault system forms the southern boundary of the Almyros basin. The recent brittle tectonic during Neogene-Quaternary is connected with the evolution and the configuration of the Almyros basin as well as volcanic activity of the area. The morphological differentiations of Almyros basin, the drainage system and the recent landforms with morphogenic activity are controlled by the recent brittle tectonics. The normal fault systems in the studied area caused by the extensional stress field (σ3), trending N-S to NNW-SSE, which controls the geodynamic regime since Lower Pleistocene. This geodynamic regime has defined the recent morphological and morphotectonic evolution of the studied area.

Complex spatiotemporal patterns of intracontinental earthquakes: a different game

2020 ◽  
Author(s):  
Mian Liu ◽  
Yuxuan Chen ◽  
Seth Stein ◽  
Gang Luo ◽  
Hui Wang
Keyword(s):  
Local Stress ◽  
Cyclic Stress ◽  
Spatiotemporal Patterns ◽  
Fault System ◽  
Eastern United States ◽  
Complex Dynamic ◽  
Fault Interaction ◽  
Fault Systems ◽  
Tectonic Loading ◽  
Earthquake Models

&lt;p&gt;Intracontinental earthquakes show complex spatiotemporal patterns. In North China, no large (M&gt;7) earthquakes ruptured the same fault segments in the past 2000 years; instead they roamed among widespread fault systems. In Australia, morphogenic evidence indicates clusters of earthquakes separated by tens of thousands of years of dormancy. In central and eastern United States, paleoseismic studies suggest that large Holocene earthquakes occurred in places that are seismically inactive today. Such seismicity does not fit existing earthquake models that assume steady tectonic loading and cyclic stress release on fault planes. Intracontinental fault systems are widespread and collectively accommodate slow tectonic loading. A major fault rupture both transfers stress to the neighboring faults and perturbs loading conditions on distant faults. Thus, the loading rate on each individual fault can be variable. Slow tectonic loading means that local stress variations from fault interaction or nontectonic processes, or changes of fault strength, could trigger an earthquake. Furthermore, large intracontinental earthquakes usually rupture multiple fault segments or faults, which vary for each event. For these earthquakes, commonly used concepts such as recurrence intervals and characteristic earthquakes, all based on earthquake models assuming cyclic elastic rebound, are inadequate or inapplicable. On the other hand, the general patterns of intracontinental earthquakes can be described by the theory of complex dynamic systems, in which all faults interact with each other. The rupture of individual fault or fault segment cannot be predetermined, but the system behavior can be studied based on the records of previous events. We found that large intracontinental earthquakes, either on a fault system or in a region, are usually clustered and separated by long but variable periods of quiescence. The lengths of the quiescence periods inversely correlate with tectonic loading rates, and the characteristics of earthquake clusters depend on fault geometry and crustal rheology, through fault interaction and viscoelastic relaxation. Spatially, large intracontinental earthquakes are not limited to faults that are active recently, although weak regions tend to have more earthquakes. Intracontinental earthquakes require a different approach, one that focuses on stress interactions between faults in a complex dynamic system rather than stress accumulation and release on individual faults.&lt;/p&gt;

scholarly journals Mapping of Tertiary basalts on the northern Blosseville Kyst, East Greenland

1979 ◽  
Vol 95 ◽  
pp. 85-86
Author(s):  
W.S Watt ◽  
M Watt
Keyword(s):  
Coastal Region ◽  
Fault System ◽  
Detailed Knowledge ◽  
Stratigraphic Sequence ◽  
East Greenland ◽  
North West ◽  
The North ◽  
Field Team

During the 1978 season work carried out by a helicopter-supported field team was concentrated in the region around Kap Dalton and Stenos Gletscher. The work formed a continuation of that carried out in 1975 in the coastal region between Kap Dalton and Steward Ø. The main objectives were to link the stratigraphic sequence of the coastal region to that established for the Scoresby Sund area to the north and north-west. For this it was essential to gain a detailed knowledge of the inland behaviour of the coastal fault system.

Palaeoenvironmental analysis of a Miocene basin in the high Taurus Mountains (southern Turkey) and its palaeogeographical and structural significance

2002 ◽  
Vol 139 (4) ◽  
pp. 473-487 ◽  
Author(s):  
F. OCAKOĞLU
Keyword(s):  
Depositional Environments ◽  
Coarse Grained ◽  
Fault System ◽  
Small Scale ◽  
The South ◽  
Taurus Mountains ◽  
The North ◽  
South Central ◽  
Southern Turkey ◽  
Basin Fill

Determination of the relationships between the southern, marine-dominated Miocene basins of south central Turkey and their continental hinterland in southern Turkey has traditionally been frustrated by the apparent absence of basin remnants within the Taurus Mountains. The Dikme basin, which seems to be an enclave of basin remnants within the Aladağ Mountains (Eastern Taurides), consists mainly of coarse-grained continental sediments of various facies. These mostly early–middle Miocene sediments were studied to determine the depositional environments and the factors controlling the basin formation and basin fill architecture, to attempt to close the information gap between the Adana Basin to the south and central Anatolian Miocene further to the north. A generally southwest-flowing axial fluvial system and interfingering coarse-grained marginal alluvial clastics derived from northwest and southeast were identified. The marginal facies to the northwest is bounded by a N 55° E-running structural lineament, that starts from the Ecemiş Fault Zone and in digital elevation models extends toward the north of the study area. Along this lineament, Miocene sediments onlap steep fault-line escarpments. Certain Miocene levels are tectonically disrupted, and an intraformational unconformity and boulder conglomerates are also well-developed in the Miocene sequence. The southeast boundary is similarly defined by a NE-trending fault that periodically elevated the adjacent Tufanbeyli autochthon, producing coarse clastics from this area. This boundary fault also induced fining-upwards vertical patterns and synsedimentary deformation in the marginal facies. Additionally, the central part of the basin exhibits a distinct fault-defined morphology characterized by small-scale (tens of metres to 150 m high) valley-and-sill topography. A thin marine interval was also encountered in the southernmost part of the basin, indicating that the clastic system originating around this area debouched into a Miocene sea situated further to the south. The proposed palaeogeography and basin fill model suggests that the Dikme basin and similar Miocene remnants, all controlled mainly by a northeast-running extensional or transtensional fault system, may have been parts of the terrestrial hinterland that supplied sediment to rapidly subsiding marine areas further south, such as the Adana Basin.

scholarly journals Preferential deposition and preservation of structurally-controlled synrift reservoirs: Northeast Red Sea and Gulf of Suez

GeoArabia ◽  
2005 ◽  
Vol 10 (1) ◽  
pp. 97-124 ◽  
Author(s):  
R.Polis Stephen ◽  
T.Angelich Michael ◽  
R.Beeman Charles ◽  
B.Maze William ◽  
J.Reynolds David ◽  
...  
Keyword(s):  
Shear Zone ◽  
Red Sea ◽  
Significant Risk ◽  
Coastal Region ◽  
Block Size ◽  
Alluvial Fan ◽  
Fault System ◽  
Gulf Of Suez ◽  
The North ◽  
Border Fault

ABSTRACT An integrated GIS-based play evaluation, which incorporates restorations of the North Red Sea and Gulf of Suez, has helped to identify potentially prospective areas in the Northeast Red Sea associated with point-sourced synrift sandstone reservoirs. The three largest synrift Gulf of Suez fields (Belayim Land, Belayim Marine, and Morgan) are located along major fault-transfer zones that optimized the conditions for the deposition and preservation of thick point-sourced sands adjacent to extensive hydrocarbon source kitchens. Belayim Land and Morgan fields contain stacked submarine fan, delta, and alluvial fan systems that developed during the deposition of the Miocene Rudeis, Kareem, and Belayim-South Gharib formations, respectively. This continuous, point-sourced sedimentation is indicative of stable drainage and by inference, a stable eastern border fault system. We attribute this stable border fault system to a stress heterogeneity related to the pre-existing Najd Shear Zone, and polarity reversals in upper-plate transport direction. Tectonic restorations indicate that the North Red Sea, like the Gulf of Suez, should have reservoir facies deposited in similar structural positions, but preservation is a significant risk due to additional crustal extension. Although crestal block erosion remains a great concern for reservoir preservation, seismic mapping indicates that block size along the coastal region and inboard areas are similar to the Gulf of Suez. This suggests that most of the strain may have been accommodated along the warmer axial portion of the rift where weaker crustal rheology exists. Landsat mapping of the Northeast Red Sea border fault system has found a high degree of variability in structural styles. The southern Yanbu-Jeddah and Umm Luj-Al Wajh sub-basins are bound by listric, down-to the west-southwest border faults, separated by suture-controlled accommodation zones. To the north, the Midyan-Ifal sub-basin is located along the Miocene flexural margin, and is structurally more complex. Northwesterly-trending (Najd Shear Zone) planar faults are overprinted by a strong northeasterly (Aqaba) trend, such that transpressional and transtensional features exist. Although structurally complex, the offshore northern flexural margin has been determined to have the best potential for localized, second-generation, thick, synrift sediments similar to that of the Gulf of Suez.

scholarly journals Quaternary Geometry, Kinematics and Paleoearthquake History at the Intersection of the Strike-Slip North Island Fault System and Taupo Rift, New Zealand

2021 ◽  
Author(s):  
◽  
Vasiliki Mouslopoulou
Keyword(s):  
New Zealand ◽  
Late Quaternary ◽  
Strike Slip ◽  
Fault System ◽  
Alternative Mechanism ◽  
Normal Faulting ◽  
Fault Systems ◽  
The North ◽  
Australian Plate ◽  
C 30

<p>The North Island of New Zealand sits astride the Hikurangi margin along which the oceanic Pacific Plate is being obliquely subducted beneath the continental Australian Plate. The North Island Fault System1 (NIFS), in the North Island of New Zealand, is the principal active strike-slip fault system in the overriding Australian Plate accommodating up to 30% of the margin parallel plate motion. This study focuses on the northern termination of the NIFS, near its intersection with the active Taupo Rift, and comprises three complementary components of research: 1) the investigation of the late Quaternary (c. 30 kyr) geometries and kinematics of the northern NIFS as derived from displaced geomorphic landforms and outcrop geology, 2) examination of the spatial and temporal distribution of  paleoearthquakes in the NIFS over the last 18 kyr, as derived by fault-trenching and displaced landforms, and consideration of how these distributions may have produced the documented late Quaternary (c. 30 kyr) kinematics of the northern NIFS, and 3) Investigation of the temporal stability of the late Quaternary (c. 30 kyr) geometries and kinematics throughout the Quaternary (1-2 Ma), derived from gravity, seismic-reflection, drillhole, topographic and outcrop data. The late Quaternary (c. 30 kyr) kinematics of the northern NIFS transition northward along strike, from strike-slip to oblique-normal faulting, adjacent to the rift. With increasing proximity to the Taupo Rift the slip vector pitch on each of the faults in the NIFS steepens gradually by up to 60 degrees, while the mean fault-dip decreases from 90 degrees to 60 degrees W. Adjustments in the kinematics of the NIFS reflect the gradual accommodation of the NW-SE extension that is distributed outside the main physiographic boundary of the Taupo Rift. Sub-parallelism of slip vectors in the NIFS with the line of intersection between the two synchronous fault systems reduces potential space problems and facilitates the development of a kinematically coherent fault intersection, which allows the strike-slip component of slip to be transferred into the rift. Transfer of displacement from the NIFS into the rift accounts for a significant amount of the northeastward increase of extension along the rift. Steepening of the pitch of slip vectors towards the northern termination of the NIFS allows the kinematics and geometry of faulting to change efficiently, from strike-lip to normal faulting, providing an alternative mechanism to vertical axis rotations for terminating large strike-lip faults. Analyses of kinematic constraints from worldwide examples of synchronous strike-lip and normal faults that intersect to form two or three plate configurations, within either oceanic or continental crust, suggest that displacement is often transferred between the two fault systems in a similar manner to that documented at the NIFS - Taupo Rift fault intersection. The late Quaternary (c. 30 kyr) change in the kinematics of the NIFS along strike, from dominantly strike-slip to oblique-normal faulting, arises due to a combination of rupture arrest during individual earthquakes and variations in the orientation of the coseismic slip vectors. At least 80 % of all surface rupturing earthquakes appear to have terminated within the kinematic transition zone from strike-slip to oblique-normal slip. Fault segmentation reduces the magnitudes of large surface rupturing earthquakes in the northern NIFS from 7.4-7.6 to c. 7.0. Interdependence of throw rates between the NIFS and Taupo Rift suggests that the intersection of the two fault systems has functioned coherently for much of the last 0.6-1.5 Myr. Oblique-normal slip faults in the NIFS and the Edgecumbe Fault in the rift accommodated higher throw rates since 300 kyr than during the last 0.6-1.5 Myr. Acceleration of these throw rates may have occurred in response to eastward migration of rifting, increasing both the rates of faulting and the pitch of slip vectors. The late Quaternary (e.g. 30 kyr) kinematics, and perhaps also the stability, of the intersection zone has been geologically short lived and applied for the last c. 300 kyr.</p>

Present-day interseismic deformation characteristics of the Beng Co-Dongqiao conjugate fault system in central Tibet: implications from InSAR observations

2020 ◽  
Vol 221 (1) ◽  
pp. 492-503 ◽  
Author(s):  
Li Yongsheng ◽  
Tian Yunfeng ◽  
Yu Chen ◽  
Su Zhe ◽  
Jiang Wenliang ◽  
...  
Keyword(s):  
Strike Slip ◽  
Strike Slip Fault ◽  
Fault System ◽  
Tectonic Deformation ◽  
The Tibetan Plateau ◽  
Conjugate System ◽  
Fault Systems ◽  
Spatial Coverage ◽  
Central Tibet ◽  
Conjugate Fault

SUMMARY Numerous V-shaped conjugate strike-slip fault systems distributed between the Lhasa block and the Qiangtang block serve as some of the main structures accommodating the eastward motion of the Tibetan Plateau. The Beng Co-Dongqiao conjugate fault system is a representative section, and determining its tectonic environment is a fundamental issue for understanding the dynamic mechanism of the V-shaped conjugate strike-slip fault systems throughout central Tibet. In this paper, we investigate the deformation rates of the Beng Co-Dongqiao conjugate faults using 3 yr of SAR data from both ascending and descending tracks of Sentinel-1 satellites. Only interferograms with a long temporal baseline were used to increase the proportion of the deformation signals. The external atmospheric delay product and the InSAR stacking strategy were employed to reduce various errors in the large-spatial-coverage Sentinel-1 data. The InSAR results revealed that the fault-parallel deformation velocities along the eastern and western segments of the Beng Co fault are 5 ± 1 mm/yr and 2.5 ± 1 mm/yr, respectively. The second invariant of the horizontal strain rates shows that the accumulated strain is centered on the eastern segment of the Beng Co Fault and Gulu rift. The velocity and strain rate fields show that the Anduo-Peng Co faults may be paired with the Beng Co fault to form a new conjugate system and the tectonic transformation between the Beng Co fault and Gulu rift. These results can better explain the tectonic deformation environment of the Beng Co-Dongqiao conjugate fault system and provide insights on the crustal dynamics throughout the entire plateau interior.

Fault interaction and strain partitioning in southeastern Tibetan Plateau: from kinematics to geodynamics

2020 ◽  
Author(s):  
Li Yin
Keyword(s):  
Tibetan Plateau ◽  
Fault Slip ◽  
Fault System ◽  
Strain Partitioning ◽  
Fault Interaction ◽  
Slip Rates ◽  
Southeastern Tibetan Plateau ◽  
Fault Systems ◽  
Fault Strength ◽  
Fault Slip Rates

&lt;p&gt;In southeastern Tibetan Plateau, the Xianshuihe-Xiaojiang fault system (XXFS) and its neighboring fault systems collectively accommodates the material extrusion of the Tibetan Plateau. However we do not mechanically understand how these faults interact with each other and how the fault interaction impacts strain partitioning, fault slip rates, and seismicity in this region. We develop and use a three-dimensional viscoelastoplastic finite element model to simulate regional deformation, fault slip rates, and fault interaction in the fault system of southeastern Tibetan Plateau. We investigate the effects of inception and activity of faults, fault strength, lithospheric rheology, and topography on partitioning of strain and fault slip rates. Model results show that fault strength, lithospheric rheology, and topography all significantly influence the strain partitioning and slip rates on faults. The initiation of the Daliangshan fault results mainly from the non-smooth fault geometry of the main trace of the XXFS. Our model results support the hypothesis of codependent slip rate between fault systems. For the present fault configuration, our model predicts localized strain in the Daliangshan faults, Yingjing-Mabian faults, and Lianfeng-Zhaotong faults, where numerous earthquakes occurred in recent years.&lt;/p&gt;

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