We document the evolution of two 15° strike-slip restraining bends within wet kaolin. Computer-controlled stepper motors displace one half of the split-box apparatus at a constant rate of 0.5 mm/min to induce dextral faulting in a 2.5 cm thick layer of wet kaolin. The basal plate discontinuity has a 15° bend with a 2 cm stepover distance. Prior to any loading we cut a vertical fault surface that follows the basal plate discontinuity into the wet kaolin with an electrified probe and wooden template.
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.
The presented datasets and scripts have been obtained for testing the performance of a trigger algorithm for use in combination with a ringshear tester ‘RST-01.pc’. Glass beads (fused quartz microbeads, 300-400 µm diameter) and thai rice are sheared at varying velocity, stiffness and normal load. The data is provided as preprocessed mat-files ('*.mat') to be opened with Matlab R2015a and later. Several scripts are provided to reproduce the figures found in (Rudolf et al., submitted). A detailed list of files together with the respective software needed to view and execute them is available in 'List_of_Files_Rudolf-et-al-2018.pdf' (also available in MS Excel Format). More information on the datasets and a small documentation of the scripts is given in 'Explanations_Rudolf-et-al-2018.pdf'. The complete data publication, including all descriptions, datasets, and evaluation scripts is available as 'Dataset_Rudolf-et-al-2018.zip'.
The data set includes photos, force measurements, and incremental displacement fields captured in experiment E240 run at the physical modeling laboratory (GEC) at the Université de Cergy-Pontoise. We built the accretionary wedge using a novel sedimentation device [Maillot, 2013] that distributes sand in planar layers and creates homogeneous sandpacks. We include photos of the side of the accretionary wedge in a zipped folder (E240_sideviews). Throughout the experiment, we took a photo every 5 seconds.We include the incremental displacement fields calculated from digital image correlation of sequential photos [Adam et al., 2005; Hoth, 2005] as matlab (.mat) files in a zipped folder (E240_001-062_DIC_MAT), and as .csv files in a zipped folder (E240_001-062_DIC_CSV). The .mat and .csv files are numbered to indicate which sequential photo pairs were used to calculate the displacements. For example, E240_001-062_0001_CSV.csv (and E240_001-062_0001.mat) contain the incremental displacements between photo 001.jpg and 002.jpg. All files are included in a single zip folder (Souloumiac-et-al-2017-supplementary-datasets.zip).The matlab files include the variable arrays x, y, u, v, which are the x and y coordinates (in pixels relative to the upper left corner of the image), and the horizontal (u) and vertical (v) incremental displacement fields (in pixels), respectively. The .csv files contain four columns of data with the x and y coordinates in the first two columns, and the horizontal (u) and vertical (v) displacements in the last two columns. We include force measurements in a text file (E240_force_corrected) with two columns: the first column is the total displacement of the backwall in millimeters at the time that the force measurement was recorded, and the second column is the normal force exerted on the backwall, in Newtons. The force measurements are calculated from measurements of strain gauges mounted on a wall of the sand box (i.e., the backwall) [e.g., Souloumiac et al., 2012].