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Found 41 results.

Ring-shear test data of quartz sand SIBELCO S80 used for analogue modelling in the Tectonic Laboratory (TecLab) at Utrecht University

This dataset provides friction data from ring-shear tests on quartz sand SIBELCO S80 used in analogue modelling of tectonic processes as a rock analogue for the earth’s upper crust (e.g., Klinkmüller et al., 2016). According to our analysis the material shows a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak, dynamic and reactivation friction coefficients of quartz sand S80 are µP = 0.75, µD = 0.59, and µR = 0.69, respectively (Table 5). Cohesion of the material ranges between 0-80 Pa. The material shows no rate-dependency (<1% per ten-fold change in shear velocity v). The tested bulk material consists of quartz sand SIBELCO S80 with grain size of ~0.63-355 µm (D50 = 175 µm. Bulk and grain densities are 1300 kg/m³ and 2650 kg/m³, respectively and the hardness is 7 on Moh’s scale. S80 is sold e.g., by the company SIBELCO (sibelco.com).

Ring-shear test data of colored quartz sand used for analogue modelling in the experimental tectonics laboratory at China University of Petroleum (Beijing)

This dataset provides friction data from ring-shear tests colored quartz sand used for analogue modelling in the experimental tectonics laboratory at China University of Petroleum (Beijing). According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak, dynamic and reactivation friction coefficients of corundum sand are µP = 0.75, µD = 0.59, and µR = 0.67, respectively (Table 5). Cohesion of the material ranges between 20-90 Pa. The tested bulk material consists of blue colored quartz sand with grain size of 180-380 µm and is sold under the name "Colored Sand" with the product number A1 by the company Xinran Mineral Products (1688.com). The data presented here are derived by ring shear testing using a SCHULZE RST-01.pc (Schulze, 1994, 2003, 2008) at HelTec, the Laboratory for experimental tectonics at the Helmholtz Center Potsdam – GFZ German Research Centre for Geosciences in Potsdam, Germany. The RST is specially designed to measure friction coefficients µ and cohesions C in loose granular material accurately at low confining pressures (<20 kPa) and shear velocities (<1 mm/sec) similar to sandbox experi-ments. In this tester, a granular bulk material layer is sheared internally at constant normal stress σN and shear velocity v while shear force and lid displacement (corresponding to density and vol-ume change ΔV) are measured continuously. For more details see Klinkmüller et al. (2016).

Digital image correlation data from laboratory subduction megathrust models

This data set includes digital image correlation data from analog earthquakes experiments. The data consists of grids of surface strain and time series of surface displacement (horizontal and vertical) and strain. The data have been derived using a stereo camera setup and processed with LaVision Davis 10 software. Detailed descriptions of the experiments and results regarding the surface pattern of the strain can be found in Kosari et al. (2022), to which this data set is supplementary. We use an analog seismotectonic scale model approach (Rosenau et al., 2019 and 2017) to generate a catalog of analog megathrust earthquakes (Table 1). The presented experimental setup is modified from the 3D setup used in Rosenau et al. (2019) and Kosari et al. ( 2020). The subduction forearc model wedge is set up in a glass-sided box (1000 mm across strike, 800mm along strike, and 300 mm deep) with a dipping, elastic basal conveyor belt and a rigid backwall. An elastoplastic sand-rubber mixture (50 vol.% quartz sandG12: 50 vol.% EPDM rubber) is sieved into the setup representing a 240 km long forearc segment from the trench to the volcanic arc. The shallow part of the wedge includes a basal layer of sticky rice grains characterized by unstable stick-slip sliding representing the seismogenic zone. Stick-slip sliding in rice is governed by a rate-and-state dependent friction law similar to natural rocks. According to Coulomb wedge theory (Dahlen et al., 1984), two types of wedge configurations have been designed: a “compressional” configuration represents an interseismically compressional and coseismically stable wedge (compressional configuration), and a “critical” configuration, which is interseismically stable (close to critically compressional) and may reach a critical extensional state coseismically (critical configuration). In the compressional configuration, a flat-top (surface slope α=0) wedge overlies a single large rectangular in map view stick-slip patch (Width*Length=200*800 mm) over a 15-degree dipping basal thrust. In the critical configuration, the surface angle of the elastoplastic wedge varies from the coastal segment onshore (α=10) to the inner-wedge offshore (α=15) segments over a 5-degree dipping basal thrust. Slow continuous compression of the wedge by moving the basal conveyor belt at a speed velocity of 0.05 mm/s simulates plate convergence and results in the quasi-periodic nucleation of quasi-periodic stick-slip events (analog earthquakes) within the rice layer. The wedge responds elastically to these basal slip events, similar to crustal rebound during natural subduction megathrust earthquakes.

A database of analogue models documenting fault reactivation during multiphase extension.

In this dataset we provide top-view photos and perspective photos (to create topographic data, i.e. Digital Elevation Models, DEMs) documenting analogue model deformation. For more details on modelling setup, experimental series Wang et al. (2021), to which this dataset is supplementary material. For details on analogue materials refer to Del Ventisette et al., 2019, Maestrelli et al. (2020). The analogue modelling experiments were carried out at the TOOLab (Tectonic Modelling Laboratory) of the Institute of Geosciences and Earth Resources of the National Research Council of Italy, Italy, and the Department of Earth Sciences of the University of Florence. The laboratory work that produced these data was supported by the European Plate Observing System (EPOS) and by the Joint Research Unit (JRU) EPOS Italia. Additional analysis, following the original work, was supported by the “Monitoring Earth’s Evolution and Tectonics” (MEET) project

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.

High-speed digital image correlation data from laboratory subduction megathrust models

This data set includes data derived from high-speed surface displacement observations from analog earthquake experiments. The data consists of surface displacement of the experiment upper plate and slab, slip distribution, and grids of Coulomb Failure Stress (CFS). The surface displacement observations have been captured using a highspeed CMOS (Complementary Metal Oxide Semiconductor) camera (Phantom VEO 640L camera, 12 bit) and processed with LaVision Davis 10 software. Description of the experiments and results regarding the surface displacement observation, Slip distribution, and CFS can be found in Kosari et al. (2022), to which this data set is supplementary. We use an analog seismotectonic scale model approach (Rosenau et al., 2019 and 2017) to generate a catalog of analog megathrust earthquakes. The presented experimental setup is modified from the 3D setup used in Rosenau et al. (2019) and Kosari et al. ( 2020 and 2022). The subduction forearc model wedge is set up in a glass-sided box (1000 mm across strike, 800mm along strike, and 300 mm deep) with a dipping, elastic basal conveyor belt, and a rigid backwall. An elastoplastic sand-rubber mixture (50 vol.% quartz sandG12: 50 vol.% EPDM rubber) is sieved into the setup representing a 240 km long forearc segment from the trench to the volcanic arc. The shallow part of the wedge includes a basal layer of sticky rice grains characterized by unstable stick-slip sliding representing the seismogenic zone. The Stick-slip sliding in rice is governed by a rate-and-state dependent friction law similar to natural rocks. A flat-top (surface slope α=0) wedge overlies rectangular stick-slip patch/es over a 15-degree dipping basal thrust. Two different seismic configurations of the shallow part of the wedge base (the megathrust) represent the depth extent of the seismogenic zone in nature. In the first configuration (homogeneous configuration), a single large rectangular stick-slip patch (Width*Length=200*800 mm) is implemented as the main slip patch (MSP). In the second case (heterogeneous configuration), two square-shaped MSPs (200*200mm) have been emplaced, acting as two medium-size seismogenic asperities surrounded by a salt matrix hosting frequent small events. Slow continuous compression of the wedge by moving the basal conveyor belt at a speed velocity of 0.05 mm/s simulates plate convergence and results in the quasi-periodic nucleation of quasi-periodic stick-slip events (analog earthquakes) within the sticky-rice layer. The wedge responds elastically to these basal slip events, similar to crustal rebound during natural subduction megathrust earthquakes.

Digital image correlation data from analogue modelling experiments addressing extension of weakened crust

This data set includes the results of digital image correlation analysis applied to analogue modelling experiments (Table 1) on the effect of weakness during distributed crustal extension performed at the Helmholtz Laboratory for Tectonic Modelling (HelTec) of the GFZ German Research Centre for Geosciences in Potsdam. Ten generic analogue models made of a layer of Quartz sand (G12, Rosenau et al., 2018) including a weak silicone oil “seed” (PDMS G30M, Rudolf et al., 2016) to localize deformation have been extended on top of a basal foam block. A benchmark experiment (basal foam only) and a reference model (layer of sand without seed) are also reported. Detailed descriptions of the experiments can be found in Osagiede et al. (2021) to which this data set is supplement. The models have been monitored by means of digital image correlation (DIC) analysis (Adam et al., 2005). DIC analysis yields quantitative information about model surface deformation in 2D and 3D. The data presented here are visualized as finite strain and displacement maps as well as cumulative strain and displacement profiles.

Digital Volume Correlation (DVC) data from an analogue experiment exploring kinematic coupling of brittle and viscous deformation

This dataset includes volumetric data sets from a Digital Volume Correlation (DVC) analysis for recreating images of a re-analyzed analogue models previously presented in (Zwaan et al., 2018). Using a brittle-viscous two-layer setup, this experiment focused on the evolution of a rift-pass structure. On top of the viscous layer, two viscous seeds are placed with a right-stepping stair-case offset to simulate two propagating rift segments, confining a central rift-pass block (Fig. 1). The selected model was analyzed by means of Digital Volume Correlation (DVC) applied on X-Ray computed tomography (XRCT) volumes. The data set includes DVC data in the form of .mat files for incremental (i.e., 20 min intervals) and cumulative displacement components. In addition, this dataset provides a MATLAB script for 1) recreating volumetric displacement sets of subsequent time steps 2) calculating finite stretches and 3) rigid-body rotations. The used experiment was performed at the Tectonic Modelling Laboratory of the University of Bern (UB). DVC analysis was performed at the Royal Holloway University London (RHUL). The model consists of a two-layer brittle-viscous set up with a total thickness of 8 cm and the set up lies on top of a 5 cm thick foam-plexiglass base with a length and width of 800 mm by 305 mm, respectively. Before model construction, the foam-plexiglass assemblage is placed between longitudinal side walls and expands during the course of the experiment as the mobile sidewalls move apart. The applied divergence velocity is 7.5 mm/h and with has an orthogonal direction with respect to the viscous seeds. This results in a maximum displacement of 30 mm after a total run time of 4h. Detailed descriptions of the experiment, mechanical properties as well as monitoring techniques can be found in Schmid et al. (2024).

Digital image correlation data from analogue subduction megathrust earthquakes addressing the control of geodetic coverage on coseismic slip inversion

This data set includes digital image correlation data from thirteen analogue earthquakes generated by means of an analogue seismotectonic scale model approach. The data consists of grids of 3D static coseismic surface displacements. The data have been derived using a stereo camera setup and processed with LaVision Davis 8 software. Detailed descriptions of the experiments and results regarding the control of geodetic coverage on the slip inversion problem can be found in Kosari et al. (2020) to which this data set is supplementary material. We use an analogue seismotectonic scale model approach (Rosenau et al., 2017) to generate a catalogue of analogue megathrust earthquakes (Table 1). The presented experimental setup is modified from the 3D setup used in Rosenau et al. (2019). To monitor surface deformation of the wedge analogue model a stereoscopic set of two CCD cameras (LaVision Imager pro X 11MPx, 14 bit) monitors images the wedge surface continuously at 2.5 Hz. To derive observational data similar to those from geodetic techniques, i.e. velocities at the location on the surface, we use digital image correlation (DIC, Adam et al., 2005) to derive the 3D incremental surface displacement (or velocity) at high spatial resolution (< 0.1 mm). The time series of incremental surface displacement data was calculated using LaVision Davis 8 software. The result is an evenly spaced grid of vectors per time step, oriented parallel with respect to the principal dimensions of the box.

Ring-shear test data of quartz sand G23 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) for a quartz sand (type “G23”). This material is used in various types of analogue experiments in the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam for simulating brittle rocks in the upper crust (e,g. Kenkmann et al., 2007; Contardo et al., 2011; Reiter et al., 2011;Warsitzka et al., 2013; Santimano,et al., 2015; Warsitzka et al., 2015; Ritter et al., 2016; 2018 a,b). The material has been characterized by means of internal friction coefficients µ and cohesions C. According to our analysis the material shows a Mohr-Coulomb behaviour characterized by a linear failure envelope and peak, dynamic and reactivation friction coefficients of µP = 0.73, µD = 0.57 and µR = 0.65, respectively. Cohesions C are in the order of 10 – 120 Pa. The material shows 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.

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