Late Quaternary slip rates for faults of the central Walker Lane (Nevada, USA): Spatiotemporal strain release in a strike-slip fault system

Abstract The Walker Lane is a broad shear zone that accommodates a significant portion of North American–Pacific plate relative transform motion through a complex of fault systems and block rotations. Analysis of digital elevation models, constructed from both lidar data and structure-from-motion modeling of unmanned aerial vehicle photography, in conjunction with 10Be and 36Cl cosmogenic and optically stimulated luminescence dating define new Late Pleistocene to Holocene minimum strike-slip rates for the Benton Springs (1.5 ± 0.2 mm/yr), Petrified Springs (0.7 ± 0.1 mm/yr), Gumdrop Hills (0.9 +0.3/−0.2 mm/yr), and Indian Head (0.8 ± 0.1 mm/yr) faults of the central Walker Lane (Nevada, USA). Regional mapping of the fault traces within Quaternary deposits further show that the Indian Head and southern Benton Springs faults have had multiple Holocene ruptures, with inferred coseismic displacements of ∼3 m, while absence of displaced Holocene deposits along the Agai Pah, Gumdrop Hills, northern Benton Springs, and Petrified Springs faults suggest they have not. Combining these observations and comparing them with geodetic estimates of deformation across the central Walker Lane, indicates that at least one-third of the ∼8 mm/yr geodetic deformation budget has been focused across strike-slip faults, accommodated by only two of the five faults discussed here, during the Holocene, and possibly half from all the strike-slip faults during the Late Pleistocene. These results indicate secular variations of slip distribution and irregular recurrence intervals amongst the system of strike-slip faults. This makes the geodetic assessment of fault slip rates and return times of earthquakes on closely spaced strike-slip fault systems challenging. Moreover, it highlights the importance of understanding temporal variations of slip distribution within fault systems when comparing geologic and geodetic rates. Finally, the study provides examples of the importance and value in using observations of soil development in assessing the veracity of surface exposure ages determined with terrestrial cosmogenic nuclide analysis.

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

10.5194/egusphere-egu21-15891 ◽

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

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.&#160;We reassess the tsunami potential of the ~100 km H&#250;sav&#237;k 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 Hu&#769;savi&#769;k. 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).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)&#178;-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.&#160;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.

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Concealed Quaternary strike-slip fault resolved with airborne lidar and seismic reflection: The Grizzly Valley fault system, northern Walker Lane, California

Journal of Geophysical Research Solid Earth ◽

10.1002/jgrb.50238 ◽

2013 ◽

Vol 118 (7) ◽

pp. 3753-3766 ◽

Cited By ~ 12

Author(s):

Ryan D. Gold ◽

William J. Stephenson ◽

Jack K. Odum ◽

Richard W. Briggs ◽

Anthony J. Crone ◽

...

Keyword(s):

Seismic Reflection ◽

Strike Slip ◽

Strike Slip Fault ◽

Airborne Lidar ◽

Fault System ◽

Walker Lane

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Quaternary slip rates on the White Mountains fault zone, eastern California: Implications for comparing geologic to geodetic slip rates across the Walker Lane

Geological Society of America Bulletin ◽

10.1130/b35332.1 ◽

2020 ◽

Vol 133 (1-2) ◽

pp. 307-324

Author(s):

Zachery M. Lifton ◽

Jeffrey Lee ◽

Kurt L. Frankel ◽

Andrew V. Newman ◽

Jeffrey M. Schroeder

Keyword(s):

Fault Zone ◽

Late Pleistocene ◽

Slip Rate ◽

North American Plate ◽

Fault System ◽

White Mountains ◽

Slip Rates ◽

Walker Lane ◽

Lateral Displacements ◽

Exposure Ages

Abstract The White Mountains fault zone in eastern California is a major fault system that accommodates right-lateral shear across the southern Walker Lane. We combined field geomorphic mapping and interpretation of high-resolution airborne light detection and ranging (LiDAR) digital elevation models with 10Be cosmogenic nuclide exposure ages to calculate new late Pleistocene and Holocene right-lateral slip rates on the White Mountains fault zone. Alluvial fans were found to have ages of 46.6 + 11.0/–10.0 ka and 7.3 + 4.2/–4.5 ka, with right-lateral displacements of 65 ± 13 m and 14 ± 5 m, respectively, yielding a minimum average slip rate of 1.4 ± 0.3 mm/yr. These new slip rates help to resolve the kinematics of fault slip across this part of the complex Pacific–North American plate boundary. Our results suggest that late Pleistocene slip rates on the White Mountains fault zone were significantly faster than previously reported. These results also help to reconcile a portion of the observed discrepancy between modern geodetic strain rates and known late Pleistocene slip rates in the southern Walker Lane. The total middle to late Pleistocene slip rate from the southern Walker Lane near 37.5°N was 7.9 + 1.3/–0.6 mm/yr, ∼75% of the observed modern geodetic rate.

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

Geophysical Journal International ◽

10.1093/gji/ggaa014 ◽

2020 ◽

Vol 221 (1) ◽

pp. 492-503 ◽

Cited By ~ 1

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.

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Flower structures in sandstones of the Paleozoic Inkisi Group (Brazzaville, Republic of Congo): evidence for two major strike-slip fault systems and geodynamic implications

South African Journal of Geology ◽

10.25131/sajg.123.0038 ◽

2020 ◽

Vol 123 (4) ◽

pp. 531-550

Author(s):

H.M.D-V. Nkodia ◽

T. Miyouna ◽

D. Delvaux ◽

F. Boudzoumou

Keyword(s):

Strike Slip ◽

Strike Slip Fault ◽

Fault System ◽

Republic Of Congo ◽

Fault Systems ◽

Major Fault ◽

Major Strike ◽

Flower Structures ◽

Dextral Strike Slip ◽

East West

Abstract Few studies have reported field descriptions of flower structures associated with strike-slip faults. This study describes and illustrates flower structures near Brazzaville (Republic of Congo) and explains their implication for the tectonic history of the Paleozoic Inkisi Group. Field observations show that the Inkisi Group is affected by two major strike-slip fault systems. The oldest system is dominated by north-northwest–south-southeast striking sinistral strike-slip faults and minor east–west striking dextral strike-slip faults. The youngest system consists of dominant northeast–southwest striking dextral strike-slip faults and minor northwest–southeast striking sinistral strike-slip faults. Flower structures within these major strike slip faults show four types of arrangements that likely depend on fault growth, propagation and damage zones: (i) flower structures associated with wall damage zones; (ii) flower structures associated with linking damage zones; (iii) flower structures associated with tip damage zones; and (iv) “hourglass” flower structures. Paleostress analysis reveals that both major fault systems originated from two differently oriented pure strike-slip regime stress stages. The first stage, which engendered the first major fault system, developed under northwest–southeast compression (i.e, σ1 = 322°). This phase probably coincided with north–south collision in the southern part of Gondwana in the Permo-Triassic and the Late Cretaceous compression times. The second stress stage, creating the second major fault system, developed under east–west (i.e, σ1 = 078°) compression. This phase is correlated with compression from the east–west opening of the Atlantic Ocean in the Miocene times.

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Dextral strike-slip faulting in the Cariboo Mountains, British Columbia: a natural example of wrench tectonics in relation to Cordilleran tectonics

Canadian Journal of Earth Sciences ◽

10.1139/e02-017 ◽

2002 ◽

Vol 39 (6) ◽

pp. 953-970 ◽

Cited By ~ 6

Author(s):

L F Reid ◽

P S Simony ◽

G M Ross

Keyword(s):

British Columbia ◽

Rocky Mountain ◽

Strike Slip ◽

Strike Slip Fault ◽

Fault System ◽

Fault Systems ◽

Dextral Strike Slip Fault ◽

Deformation Event ◽

Step Over ◽

Dextral Strike Slip

The Cariboo Mountains, British Columbia, contain an intracontinental dextral strike-slip fault system that crosscuts the regional fold structures. This fault system accounts for a minimum of 120 km and a maximum of 200 km of dextral strike-slip displacement. This probably accommodates some of the motion associated with the southern termination of the Northern Rocky Mountain Trench Fault and is part of a step-over zone between the Northern Rocky Mountain Trench Fault and the Fraser River Straight Creek fault systems. The Isaac Lake Synclinorium is a kilometre-scale Jurassic fold structure that is bounded by the dextral oblique Isaac Lake and Winder strike-slip faults. These faults are part of the regional strike-slip fault system that is found throughout the Cariboo Mountains. Deformation associated with the strike-slip faults is complex and is partitioned into motion along the faults and into the formation of kilometre-scale folds that are found in areas between the faults. The angular relationship between the strike-slip faults and folds conforms to models developed for dextral strike-slip fault systems with drag on high-friction faults. We interpreted these structures to have formed during a continuous deformation event. Timing constraints indicate that faulting started by the Late Cretaceous and may have had a long and protracted history into the Tertiary.

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