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Results of analogue tectonic models of rifting and tectonic lineament reactivation along the Main Ethiopian Rift

This data set includes results from a total of 13 analogue tectonic models aimed at simulating the activation of tectonic lineaments associated with the Main Ethiopian Rift in eastern Africa. We use a model set-up based on previous work by Zwaan et al. (2021, 2022). This set-up involves a velocity discontinuity (VD, i.e., the edge of a mobile base plate) to induce extension in the overlying brittle- and viscous model materials representing the upper and lower crust, respectively. Additional structural weaknesses (seeds) at the base of the brittle layer serve to represent activated tectonic weaknesses in nature. Model parameters (different VD and seed orientation, and different seed diameters) are summarized in Table 1. The model results presented in this data publication are obtained through Digital Image Correlation (DIC) and Structure-from-Motion (SfM) analyses. A more detailed description of model set-up, model results, and their interpretation can be found in Zwaan et al. (2025)

Ring-shear test data of wheat flour used for analogue experiments in the laboratory of the Institute of Geophysics of the Czech Academy of Science, Prague

This dataset provides friction data from ring-shear tests (RST) for wheat flour used as a fine-grained, cohesive analogue material for simulating brittle upper crustal rocks in the analogue labor-atory of the Institute of Geophysics of the Czech Academy of Science (IGCAS). It is characterized by means of internal friction coefficients µ and cohesion C. According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak friction coefficients µP of the tested material is ~0.72, dynamic friction coeffi-cients µD is ~0.67 and reactivation friction coefficients µR is ~0.70. Cohesions of the material range between 27 and 50 Pa. The material shows a minor rate-weakening of ~1.5% per ten-fold change in shear velocity v and a stick-slip behaviour at low shear velocities.

Experimental data of analogue models addressing the influence of crustal strength, tectonic inheritance and stretching/ shortening rates on crustal deformation and basin reactivation

This dataset includes video sequences and strain analysis of 12 analogue models studying crustal-scale deformation and basin reactivation, performed at the Laboratory of Tectonic modelling of the University of Rennes 1. These models show how parameters such as crustal strength, tectonic inheritance and boundary conditions (ishortening/ stretching) control both the distribution of crustal strain and the possibility for pre-existing structures to be reactivated. This dataset includes top-view movies of the 12 models, including strain analysis based on displacement vectors obtained from digital image correlation. Detailed descriptions of models can be found in Guillaume et al. (2022, special issue of Solid Earth on Analogue modelling of basin inversion) to which this dataset is supplementary.

Material properties of analogue velocity-weakening material used for seismotectonic analogue modeling of strike-slip seismic cycle: the case of twice-broken rice

This dataset provides friction data from ring-shear tests (RST) on twice broken rice used in the GEC Laboratory in CY Cergy Paris University in stick-slip experiments. They were obtained by Sarah Visage as part of her doctoral training (funded by the ANR DISRUPT programme) during an invitation at the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam. Like any granular material, the twice broken rice is characterized by several internal friction coefficients μ and cohesions C, classicaly qualified as dynamic, static, and reactivation coefficients. In adition, since the rice exhibits a stick slip behaviour, the various shear - velocity or shear-displacement curves exhibit high frequency oscillations and we therefore define maximum, minimum, and mean values corresponding respectively to the curve peaks, curve troughs and smoothed curve.

Ring-shear test data of foam glass beads used for analogue experiments in the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam and the Institute of Geosciences, Friedrich Schiller University Jena

This dataset provides friction data from ring-shear tests (RST) for two types of foam glass beads and a mixture of foam glass beads with quartz sand (“G12”; Rosenau et al., 2019). These materials have been used in analogue experiments in Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam and in the Analogue laboratory of the Institute of Geosciences of the Friedrich Schiller University of Jena (FSU Jena). The materials have been characterized by means of internal friction coefficients µ and cohesion C. According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak friction coefficients µP of all tested materials range between 0.70 and 0.75, dynamic friction coefficients µD between 0.52 and 0.55 and reactivation friction coefficients µR between 0.60 and 0.62. Peak cohesions CP of all materials are negative indicating that they are cohesionless. All materials show a minor rate-weakening of ~1% per ten-fold change in shear velocity v.Further information about materical characteristics, measurement procedures, sample preparation, the RST (Ring-shear test) and VST (Velocity stepping test) procedure, as well as the analysed method is proviced in the data description file. The list of files explains the file and folder structure of the data set.

Ring-shear test data of quartz sand – silicate cenospheres mixtures used for analogue experiments at the Institute of Geophysics of the Czech Academy of Science, Prague

This dataset provides friction data from ring-shear tests (RST) for mixtures of quartz sand and sili-cate cenospheres, which are used for analog experiments in the laboratory of the Institute of Geo-physics of the Czech Academy of Science (IG CAS) (Warsitzka et al., 2021). The mixtures have been characterized by means of internal friction coefficients µ and cohesion C as a remote service by the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam. According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak friction coefficients µP of the tested materials range between 0.55 and 0.75, dynamic friction coefficients µD between 0.47 and 0.60 and reactivation friction coefficients µR be-tween 0.52 and 0.65. Cohesions of the materials vary between 20 and 120 Pa. The materials show a minor rate-weakening of <1.2% per ten-fold change in shear velocity v.

PIV and topographic analysis data from analogue experiments involving 3D structural inheritance and multiphase rifting

This data set includes videos depicting the surface evolution (time-lapse photographs and Particle Image Velocimetry or PIV analysis) of 38 analogue models, in five model series (A-E), simulating rift tectonics. In these experiments we examined the influence of differently oriented mantle and crustal weaknesses on rift system development during multiphase rifting (i.e. rifting involving changing divergence directions or -rates) using brittle-viscous set-ups. All experiments were performed at the Tectonic Modelling Laboratory of the University of Bern (UB). The brittle and viscous layers, representing the upper an lower crust, were 3 cm and 1 cm thick, respectively, whereas a mantle weakness was simulated using the edge of a moving basal plate (a velocity discontinuity or VD). Crustal weaknesses were simulated using “seeds” (ridges of viscous material at the base of the brittle layers that locally weaken these brittle layers). The divergence rate for the Model A reference models was 20 mm/h so that the model duration of 2:30 h yielded a total divergence of 5 cm (so that e = 17%, given an initial model width of ca. 30 cm). Multiphase rifting model series B and C involved both a slow (10 mm/h) and fast (100 mm/h) rifting phase of 2.5 cm divergence each, for a total of 5 cm of divergence over a 2:45 h period. Multiphase rifting models series D and E had the same divergence rates (20 mm/h) as the Series A reference models, but involved both an orthogonal (α = 0˚) and oblique rifting (α = 30˚) phase of 2.5 cm divergence each, for a total of 5 cm of divergence over a 2:30 h period. In our models the divergence obliquity angle α was defined as the angle between the normal to the central model axis and the direction of divergence. The orientation and arrangements of the simulated mantle and crustal weaknesses is defined by angle θ (defined as the direction of the weakness with respect to the model axis. An overview of model parameters is provided in Table 1, and detailed descriptions of the model set-up and results, as well as the monitoring techniques can be found in Zwaan et al. (2021).

Effect of sieving height on density and friction of brittle analogue material: Ring-shear test data of quarz sand used for analogue experiments in the Tectonic Modelling Lab of the University of Bern

This dataset provides friction data from ring-shear tests (RST) for a quartz sand (“A”). This material is used in various types of analogue experiments in Tectonic Modelling Lab of the University of Bern as an analogue for brittle layers in the crust or lithosphere. The material has been characterized by means of internal friction coefficients μ and cohesions C. Three sub-datasets represent a systematic increase of the sieving height from 10 cm to 20 cm to 30 cm into a shear cell of type No. 1, following the same protocol. This dataset shows that packing density of quartz sand is dependent on the chosen sieving height. However, the effect of the sieving height on internal friction coefficients μ as well as cohesion C is minor and thus negligible in sandbox experiments. According to our analysis the material shows for a sieving height of 10 cm a Mohr-Coulomb behaviour characterized by a linear failure envelope and peak, dynamic and reactivation friction coefficients of μP = 0.70, μD = 0.60 and μR = 0.65, respectively. Cohesions C are in the order of 40 – 80 Pa.

Effect of sieving height on density and friction of brittle analogue material: Ring-shear test data of corundum sand used for analogue experiments in the Tectonic Modelling Lab of the University of Bern (CH)

This dataset provides friction data from ring-shear tests (RST) for a corundum sand (“NKF120”). This material is used in various types of analogue experiments in Tectonic Modelling Lab of the University of Bern as an analogue for brittle layers in the crust or lithosphere. The material has been characterized by means of internal friction coefficients μ and cohesions C. Three sub-datasets represent a systematic increase of the sieving height from 10 cm to 20 cm to 30 cm into a shear cell of type No. 1, following the same protocol. This dataset shows that packing density of corundum sand is dependent on the chosen sieving height. However, the effect of the sieving height on internal friction coefficients μ as well as cohesion C is minor and thus negligible in sandbox experiments. According to our analysis the material shows for a sieving height of 10 cm a Mohr-Coulomb behaviour characterized by a linear failure envelope and peak, dynamic and reactivation friction coefficients of μP = 0.75, μD = 0.64 and μR = 0.68, respectively. Cohesions C are in the order of 70 – 105 Pa.

Ring shear test data of glass beads 40-70 µm used for analogue experiments in the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam

This dataset provides friction data from ring-shear tests (RST) on glass beads used in the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam as an analogue for “weak” brittle layers in the crust or lithosphere (Ritter et al., 2016; Santimano et al., 2015; Contardo et al., 2011; Reiter et al., 2011; Hoth et al., 2007, 2006; Kenkmann et al., 2007; Deng et al., 2018) or in stick-slip experiments (Rudolf et al., 2019). The glass beads with a diameter of 40-70 µm have been characterized by means of internal friction coefficients µ and cohesions C as a remote service by the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam. According to our analysis the material shows a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak, dynamic and reactivation friction coefficients of the glass beads are µP = 0.46, µD = 0.40 and µR = 0.44, respectively. Cohesion ranges between 33 and 42 Pa. A rate-weakening of ~3 % per ten-fold change in shear velocity v is evident.

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