This data set is digital image correlation data, including surface displacement and strain data from laboratory subduction megathrust earthquake cycles. The data consists of grids of surface strain (elastic and permanent), trench-normal surface displacement, vorticity and divergence maps over analog seismic cycles, and time series of surface displacement. 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. (2023), to which this data set is supplementary.
We use three configurations to mimic the along-strike heterogeneous spatiotemporal distribution of frictional locking (Rosenau et al., 2019; Kosari et al., 2022b). A central patch separates two stick-slip zones as an aseismic barrier in all configurations. The frictional properties of the central patch vary as a velocity-strengthening (VS configuration), a velocity-neutral (VN), and a velocity-weakening (VW configuration). The VW zone generates smaller slip events with a higher frequency (i.e., recurrence interval) than the stick-slip zones. Four frictionally different materials have been emplaced on the interface: The sticky-rice as velocity-weakening material (a-b<0) resulting in stick-slip cycles simulating earthquake cycles, fine-grained sugar and rubber-sand mixture as velocity-strengthening (a-b>0) and velocity-neutral (a-b=0) material, and fine-grained salt as velocity-weakening material (a-b<0) (Kosari et al., 2023).
This dataset provides rheometric data of magnetorheological (MR) silicones, i.e., mixtures of Polydimethylsiloxane (PDMS SGM36) and carbonyl iron powder. We characterized the viscous behavior of MR silicones at room temperature (i.e., T = 25 °C) as a function of carbonyl iron powder concentration and magnetic field strength using rotational (controlled shear rate and controlled shear stress) tests (Mezger, 2020). This dataset also provides the displacement and velocity fields of a simple experiment performed to test the use of magnetorheological silicones for experimental tectonics purposes. For a detailed description of sample preparation procedure, experimental setup and monitoring technique, as well as results interpretation, please refer to Brizzi et al. (under review).
Forced folding of a low-permeable, competent sediment layer in response to magmatic sill intrusion, remobilisation of fluidized sand or fluid overpressure in underlying porous reservoir formations can cause the formation of complex fracture networks. The opening modes and geometries of these fractures affect the bulk permeability of the cover layer and, thus, are crucial for understanding fluid flow processes in sedimentary basins. We carried out analog experiments in the laboratory of the Institute of Geosciences, Friedrich Schiller University Jena (project: Mobilization of Unconsolidated Sediments Related to CO2 Storage) to simulate the evolution of fracture networks during forced folding, its differences between a 2D and 3D modelling approach and its variability depending on the rheological stratification of the cover. To produce a fluid overpressure in the layered analog materials, air was injected from the base of the layering and additionally through a point-like needle valve penetrating into the lowermost layer with a stepwise increasing air flux (Q). Pressure sensors recorded the air pressure at the base of the reservoir layer and in the needle valve. The experiments were monitored with a digital SLR camera and analyzed by the digital image correlation software DaVis 10.0 (LaVision GmbH) to calculate displacement and strain patterns in the analog materials. Furthermore, a fracture analysis was performed for which we measured length and dips or strikes, respectively, in the side view of the 2D experiments and in top view in the 3D experiments. Based on these data, opening modes of the fractures were determined and statistical analyses were applied. The outcomes of these analyses are shown in rose diagram and histograms. The data set presented here includes:
1) Original data:
-PhotosOriginal.zip: Photos of the experimental evolution
-FractureData.zip: Measured lengths and dips (from side views of the 2D experiments) or strikes (from top view of the 3D experiments) of individual fracture segments
-PneumaticData.zip: Data of volumetric air flow rate (Q) and air pressure (P) recorded during the experiments
2) Analyzed data:
-DigitalImageCorrelation.zip: Results of digital image correlation including edited photographs as well as data and plots of the displacement vector fields
-SurfaceDisplacement.zip: Edited photos and a Python script for analyzing the vertical displacements of the experimental surface.
-RoseDiagrams.zip: Rose diagrams plotting the dips or strikes, respectively, of the fracture segments
-Histograms.zip: Histogram showing the abundance of fracture segments along the vertical z-axis in the 2D experiments or along the horizontal x and y axes in the 3D experiments
Detailed descriptions of the experiments, method and results can be found in Warsitzka, et al. (2022) to which this data set is supplement.