Benchmarking numerical models of brittle thrust wedges

Buiter, Susanne; Schreurs, Guido; Albertz, Markus; Gerya, Taras; Kaus, Boris; Landry, Walter; Pourhiet, Laëtitia Le; Mishin, Yury; Egholm, David Lundbek; Cooke, Michele L.; Maillot, Bertrand; Thieulot, Cédric; Crook, Tony; May, David A.; Souloumiac, Pauline; Beaumont, Christopher

doi:10.1016/j.jsg.2016.03.003

Cited by 93 publications

(79 citation statements)

References 71 publications

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“…Localization dynamics of faults and shear zones depend on the included weakening mechanisms and the employed numerical resolution [ Buiter et al , , ]. Reducing the element size to 10 km and/or switching off strain softening for model A1 indeed changes the temporal evolution of the rift.…”

Section: Numerical Modelingsupporting

confidence: 84%

Controls of inherited lithospheric heterogeneity on rift linkage: Numerical and analog models of interaction between the Kenyan and Ethiopian rifts across the Turkana depression

2017

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Inherited rheological structures in the lithosphere are expected to have large impact on the architecture of continental rifts. The Turkana depression in the East African Rift connects the Main Ethiopian Rift to the north with the Kenya rift in the south. This region is characterized by a NW‐SE trending band of thinned crust inherited from a Mesozoic rifting event, which is cutting the present‐day N‐S rift trend at high angle. In striking contrast to the narrow rifts in Ethiopia and Kenya, extension in the Turkana region is accommodated in subparallel deformation domains that are laterally distributed over several hundred kilometers. We present both analog experiments and numerical models that reproduce the along‐axis transition from narrow rifting in Ethiopia and Kenya to a distributed deformation within the Turkana depression. Similarly to natural observations, our models show that the Ethiopian and Kenyan rifts bend away from each other within the Turkana region, thus forming a right‐lateral step over and avoiding a direct link to form a continuous N‐S depression. The models reveal five potential types of rift linkage across the preexisting basin: three types where rifts bend away from the inherited structure connecting via a (1) wide or (2) narrow rift or by (3) forming a rotating microplate, (4) a type where rifts bend towards it, and (5) straight rift linkage. The fact that linkage type 1 is realized in the Turkana region provides new insights on the rheological configuration of the Mesozoic rift system at the onset of the recent rift episode.

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Section: Numerical Modelingsupporting

confidence: 84%

Controls of inherited lithospheric heterogeneity on rift linkage: Numerical and analog models of interaction between the Kenyan and Ethiopian rifts across the Turkana depression

2017

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“…Supplementary Materials: The following are available online at www.mdpi.com/2076-3263/7/3/71/s1 [311][312][313][314][315][316][317][318].…”

Section: Discussionmentioning

confidence: 99%

Thick-Skinned and Thin-Skinned Tectonics: A Global Perspective

Pfiffner

2017

Geosciences

119

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This paper gives an overview of the large-scale tectonic styles encountered in orogens worldwide. Thin-skinned and thick-skinned tectonics represent two end member styles recognized in mountain ranges. Both styles are encountered in former passive margins of continental plates. Thick-skinned style including the entire crust and possibly the lithospheric mantle are associated with intracontinental contraction. Delamination of subducting continental crust and horizontal protrusion of upper plate crust into the opening gap occurs in the terminal stage of continent-continent collision. Continental crust thinned prior to contraction is likely to develop relatively thin thrust sheets of crystalline basement. A true thin-skinned type requires a detachment layer of sufficient thickness. Thickness of the décollement layer as well as the mechanical contrast between décollement layer and detached cover control the style of folding and thrusting within the detached cover units. In subduction-related orogens, thin-and thick-skinned deformation may occur several hundreds of kilometers from the plate contact zone. Basin inversion resulting from horizontal contraction may lead to the formation of basement uplifts by the combined reactivation of pre-existing normal faults and initiation of new reverse faults. In most orogens thick-skinned and thin-skinned structures both occur and evolve with a pattern where nappe stacking propagates outward and downward.

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“…Dynamic pressure P is given by the mean stress:

P = - \frac{σ_{k k}}{3}, with k = 1, 2, 3,

where P is positive under compression. Computing the dynamic pressure as a solution of the continuity and momentum equations is especially crucial to obtain correct angles of forming faults that differ from a constant Roscoe angle (Buiter, ; Buiter et al, ; Kaus, ). Because our simulation represents a compressive state of stress, that is, σ 1 > σ 2 and we ignore dilation, that is, ψ =0, the four potential fracture surface orientations predicted by the Arthur angle (equation ) reduce to α 1 = 45° −( φ /4) and α 2 =−45° +( φ /4) (conjugate).…”

Section: Methodsmentioning

confidence: 99%

Seismic and Aseismic Fault Growth Lead to Different Fault Orientations

et al. 2019

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Orientations of natural fault systems are subject to large variations. They often contradict classical Coulomb failure theory as they are misoriented relative to the regional Andersonian stress field. This is ascribed to local effects of structural or stress heterogeneities and reorientations of structures or stresses on the long term. To better understand the relation between fault orientation and regional stresses, we simulate spontaneous fault growth and its effect on the stress field. Our approach incorporates earthquake rupture dynamics, viscoelastoplastic brittle deformation and a rate‐ and state‐dependent friction formulation in a continuum mechanics framework. We investigate how strike‐slip faults orient according to local and far‐field stresses during their growth. We identify two modes of fault growth, seismic and aseismic, distinguished by different fault angles and slip velocities. Seismic fault growth causes a significant elevation of dynamic stresses and friction values ahead of the propagating fault tip. These elevated quantities result in a greater strike angle relative to the maximum principal regional stress than that of a fault segment formed aseismically. When compared to the near‐tip time‐dependent stress field the fault orientations produced by both growth modes follow the classical failure theory. We demonstrate how the two types of fault growth may be distinguished in natural faults by comparing their angles relative to the original regional maximum principal stress. A stress field analysis of the Landers‐Kickapoo fault suggests that an angle greater than ∼25° between two faults indicates seismic fault growth.

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Benchmarking numerical models of brittle thrust wedges

Cited by 93 publications

References 71 publications

Controls of inherited lithospheric heterogeneity on rift linkage: Numerical and analog models of interaction between the Kenyan and Ethiopian rifts across the Turkana depression

Controls of inherited lithospheric heterogeneity on rift linkage: Numerical and analog models of interaction between the Kenyan and Ethiopian rifts across the Turkana depression

Thick-Skinned and Thin-Skinned Tectonics: A Global Perspective

Seismic and Aseismic Fault Growth Lead to Different Fault Orientations

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