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.
This dataset includes video sequences depicting the evolution in map view and lateral view of 7 analogue experiments studying mantle-scale subduction systems. The experiments are performed under a natural gravity field and are designed to understand the role of convergence obliquity on upper plate deformation and partitioning, with a particular emphasis on the role played by lithospheric inherited structures on the development of sliver tectonics.
All experiments were performed at the Laboratory of Tectonic modelling of the University of Rennes 1 (France). The experimental set-up corresponds to a lithosphere and sub-lithospheric upper mantle system. The lithospheric plates are simulated with PDMS silicone (Polydimethylsiloxane Silicone) with different viscosities and densities, and the upper mantle with glucose syrup. In particular, for the overriding plate, we simulate the presence of a weaker volcanic arc that can eventually be decoupled from the forearc by a pre-existing discontinuity. The materials are placed into a Plexiglas tank, where the impermeable bottom of the tank represents the 660 km discontinuity. The subduction is initiated by manually forcing the slab into the mantle and it then evolves under the combined effects of internal buoyancy forces (slab pull) and external boundary forces. The subducting plate is pushed toward the trench at a constant velocity of 1.5 cm/min while the overriding plate is maintained fixed during the duration of the experiments.
The evolution of the experiments is monitored by DSLR cameras (24 Mpx) taking pictures every 30 seconds at the top and on one side of the experiments. Pictures are then assembled into video-sequences. The scale bar, with black & white rectangles corresponds to 10 cm.
The set of experiments consists of one reference model (MODEL-01) with orthogonal convergence, and six models with oblique convergence (Table 1). Among these models, three do not embed a pre-existing lithospheric discontinuity in the overriding plate (MODEL-02, MODEL-03, and MODEL-04) while the three other (MODEL-05, MODEL-06, and MODEL-07) have such a discontinuity. For the models with oblique convergence, we vary the angle between the convergence direction and the trench from 80° (MODEL-02 and MODEL-05) to 60° (MODEL-03 and MODEL-06) and 50° (MODEL-04 and MODEL-07).
For details on the experimental set-up, and interpretation of the results, please refer to Suárez et al. (submitted to Tectonophysics) to which these data are supplementary material.