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Digital Image Correlation data from experiments of releasing bend evolution within different strength wet kaolin

The data set includes the Digital Image Correlation (DIC) results for four experiments of releasing bends along dextral strike-slip faults that were performed at the University of Massachusetts at Amherst (USA). Gabriel et al. (in prep.) used the DIC data sets to investigate how releasing bend fault systems evolve within different strength wet kaolin. Information on the experimental set up and methods can be found in the main text and supplement to Gabriel et al. (in prep.). The data here include the incremental displacement time series, strain animation and surface elevation data at the end of the two experiments with different clay strength, which are presented within Gabriel et al. (in prep). We also include in this data repository incremental displacement time series and strain animations from two experiments that repeat the conditions of the experiments featured in Gabriel et al. (2025).

Digital image correlation data from analogue modelling experiments addressing magma emplacement along simple shear and transtensional fault zones

This data set includes the results of digital image correlation analysis applied to nine experiments (Table 1) on magma-tectonic interaction performed at the Helmholtz Laboratory for Tectonic Modelling (HelTec) of the GFZ German Research Centre for Geosciences in Potsdam in the framework of EPOS transnational access activities in 2017. The models use silicone oil (PDMS G30M, Rudolf et al., 2016) and Quartz sand (G12, Rosenau et al., 2018) to simulate pre-, syn- and post-tectonic intrusion of granitic magma into upper crustal shear zones of simple shear and transtensional (15° obliquity) kinematics. Three reference experiments (simple shear, transtension, intrusion) are also reported. Detailed descriptions of the experiments can be found in Michail et al. (submitted) to which this data set is supplement. The models have been monitored by means of digital image correlation (DIC) analysis including Particle Image Velocimetry (PIV; Adam et al., 2005) and Structure from Motion photogrammetry (SfM; Donnadieu et al., 2003; Westoby et al., 2012). DIC analysis yields quantitative model surface deformation information by means of 3D surface topography and displacements from which surface strain has been calculated. The data presented here are visualized as surface deformation maps and movies, as well as digital elevation and intrusion models. The results of a shape analysis of the model plutons is provided, too.

Digital Image Correlation of strike slip experiments in wet kaolin at different strain rates and boundary conditions

The data set includes the digital image correlation of 16 dextral strike-slip experiments performed at the University of Massachusetts at Amherst (USA). The DIC data sets were used for a machine learning project to build a CNN that can predict off-fault deformation from active fault trace maps. The experimental set up and methods are described with the main text and supplement to Chaipornkaew et al (in prep). To map active fault geometry and calculate the off-fault deformation we use the Digital Image Correlation (DIC) technique of Particle Image Velocimetry (PIV) to produce incremental horizontal displacement maps. Strain maps of the entire region of interest can be calculated from the displacements maps to determine the fault maps and estimate off-fault strain throughout the Region of Interest (ROI). We subdivide each ROI into five subdomains, windows, for training the CNN. This allows a larger dataset from the experimental results. The data posted here include the incremental displacement time series and animations of strain for the entire ROI.

Experimental data on scaled analogue experiments modelling GPS velocity field variations and kinematic partitioning in the Southern Andes (34°S to 42°S)

The southern Andes are regarded as a typical subduction orogen formed by oblique plate convergence. Despite decades of studies, there is considerable uncertainty as to how deformation is kinematically partitioned in the upper plate. Using scaled analogue experiments modelling, we test the concept of dextral transpression for this orogen. We advocate that the GPS velocity field portrays interseismic deformation related to deformation of strong crust north, and weak crust south, of 37°S. Contrary to the popular hypotheses that the Liquiñe-Ofqui Fault Zone, a prominent intra-arc deformation zone, takes up most of the plate boundary-parallel dextral strike-slip, we find that dextral transpression affects the entire model orogen through tectonic segmentation of crust. Moreover, prominent, regularly spaced sinistral oblique-slip thrust faults, interpreted as antithetic Riedel shears, developed spontaneously in all of our experiments and call into question the general believe that their NW-striking natural equivalents formed from pre-Andean discontinuities. Our experiments prompt us to reconsider the apparently well-established geodynamic concept that strain and margin-parallel displacement is localized on a few margin-parallel faults in the southern Andes.

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.

Digital Image Correlation data from oblique convergence experiments with wet kaolin

Experiments of oblique convergence at angles of 5, 10, 15, 20, 25 and 30 degrees from the margin within wet kaolin. One suite of experiments, denoted as ‘precut’, has a vertical surface precut within the clay with an electrified wire. The precut surface lies directly above the basal oblique dislocation. The other suite of experiments is ‘uncut’. Regardless of whether the experiments have a precut surface, slip partitioned fault systems, develop and persist in the experiments. Such systems have two simultaneously active faults with similar strike but different slip sense. Slip partitioning also develops regardless of whether the system first grows a reverse fault or strike slip fault in the experiment. The sequence and nature of strike-slip and reverse fault development depends on present of existing cut and convergence angle.This data set includes time series of incremental displacement maps for eleven experiments performed at the University of Massachusetts Amherst in January 2017 and March 2018 as well as animations of strain and uplift. The dataset includes the 30˚ convergence experiment with precut vertical surface but the 30˚ uncut experiment has not yet been performed. The time series data are organized into 11 netCDF files. The name of each file states the obliquity of convergence and whether the vertical surface was precut or not.Each netCDF file contains the following• ux = the incremental displacement field within the ROI (Region Of Interest) parallel to the margin (x-direction). The third dimension in the array corresponds to increment of deformation through the experiment. Units are mm.• uy = the incremental displacement field within the ROI perpendicular to the margin (y-direction). The third dimension in the array corresponds to increment of deformation through the experiment. Units are mm.• x = position parallel to the margin. Units are mm.• y = position perpendicular to the margin. Units are mm.The incremental displacements are calculated from DIC of photographs taken every 30 seconds using PIVlab (Thielicke, 2019). The net stepper motor speed is ~0.5 mm/min.The animations show strain evolution of all eleven experiments and uplift evolution of the 10 degree precut experiment. The strain evolution experiments overlay colormaps of incremental strain between successive photos on photographs of the experiment. Color saturation indicates the strain rate and hue indicates the slip vector. The uplift maps were made from stereovision analysis from pairs of photos. In most experiments, decorrelation of portions of the map prevented us from producing high quality uplift evolution animations from the start to the end of the experiment. Only the 10 degree convergence with precut vertical surface experiment had full coherence of uplift signal throughout the experiment and that animation.

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