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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.

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 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.

Supplement to “Synchronization of great subduction megathrust earthquakes: Insights from scale model analysis”

This data set provides data from subduction zone earthquake experiments and analysis described in Rosenau et al. (2019). In the experiments analogue seismotectonic scale models of subduction zones characterized by two seismogenic asperities are used to study the interaction of asperities over multiple seismic cycles by means of static (Coulomb failure) stress transfer. Various asperity geometries (lateral/along-strike of the subduction zone distance and vertical/across-strike of the subduction zone offset) are tested on their effect on recurrence pattern of simulated great (M8+) earthquakes.The results demonstrate the role of stress coupling in the synchronization of asperities leading to multi-asperity M9+ events in nature. The data set contains time series of experimental surface velocities from which analogue earthquakes are detected and classified into synchronized events and solo events. The latter are subcategorized into main events and aftershocks and into normal and thrust events. An analogue earthquake catalogue lists all categorized events of the 12 experiments used for statistical analysis. Moreover, results from elastic dislocation modelling aimed ate quantifying the stress coupling between the asperities for the various geometries are summarized. Basic statistics of classified events (e.g. percentage of categorized events, coefficient of variation in size and recurrence time etc.) are documented. Matlab scripts are provided to visualize the data as in the paper.

Properties of rock analogue materials used for Foamquake: a novel seismotectonic analog model mimicking the megathrust seismic cycle at RomaTre University (Italy)

This dataset provides friction and elasticity data from ring shear and axial tests, respectively, on rock analogue materials used at the University Roma Tre (Rome, IT) in “Foamquake”, a novel seismotectonic analog model mimicking the megathrust seismic cycle (Mastella et al., under review). Two granular materials (quartz sand and Jasmine rice) have been characterized by means of internal friction coefficients µ and cohesions C. An elastic material (foam rubber) have been characterized by means of Young’s modulus E and Poisson’s ratio v. According to our analysis the granular materials show Mohr-Coulomb behaviour characterized by linear failure envelopes in the shear stress vs. normal load Mohr space. Peak, dynamic and reactivation friction coefficients of the quartz sand are µP = 0.69, µD = 0.56 and µR = 0.64, respectively. Cohesion ranges between 50 and 100 Pa. Rate-dependency of friction in quartz sand seems insignificant. Peak, dynamic and reactivation friction coefficients of the Jasmine rice are µP = 0.70, µD = 0.59 and µR = 0.61, respectively. Cohesion ranges between 30 and 50 Pa. Rate-weakening of Jasmine rice is c. 6% per tenfold change in shear velocity v. The Young’s modulus of the foam rubber has been constrained to 30 kPa, its Poisson’s ratio is v=0.1.

Supplementary material to "Machine Learning can predict the timing and size of analog earthquakes"

This data set includes the results of digital image correlation of one experiment on subduction megathrust earthquakes with interacting asperities performed at the Laboratory of Experimental Tectonics (LET) Univ. Roma Tre in the framework of AspSync, the Marie Curie project (grant agreement 658034) lead by F. Corbi in 2016-2017. Detailed descriptions of the experiments and monitoring techniques can be found in Corbi et al. (2017 and 2019) to which this data set is supplementary material.We here provide Digital Image Correlation (DIC) data relative to a 7 min long interval during which the experiment 
produces 40 seismic cycles with average duration of about 10.5 s (see Figure S1 in Corbi et al., 2019). The DIC analysis yields quantitative about the velocity field characterizing two consecutive frames, measured in this case at the model surface. For a detailed description of the experimental procedure, set-up and materials used, please refer to the article of Corbi et al. (2017) paragraph 2. This data set has been used for: a) studying the correlation between apparent slip-deficit maps and earthquake slip pattern (see Corbi et al., 2019; paragraph 4); and b) as input for the Machine Learning investigation (see Corbi et al., 2019; paragraph 5).Further technical information about the methods, data products and matlab scripts is proviced in the data description file. The list of files explains the file and folder structure of the data set.

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.

Experimental data of analogue models of subduction investigating the interplays between mantle flow and slab pull

This dataset includes images depicting the evolution in map view and lateral view of 7 analogue experiments of subduction to better understand the interplays between slab pull and mantle flow at subduction zones. The experiments are performed under a natural gravity field and are designed to understand the influence of plate width and magnitude and direction of mantle flow on slab geometry, trench kinematics and shape, and superficial mantle deformation around the subduction zone. All experiments were performed at the Laboratory of Experimental Tectonics at the Università Roma Tre (Italy). The laboratory models consist of one viscous layer of silicone putty representing the subducting lithosphere resting on top of a tank filled with glucose syrup, representing the convective mantle. We impose a horizontal flow in the convective mantle by pushing at a constant velocity a piston in the glucose syrup below an intermediate horizontal plate representing the upper mantle-lower mantle discontinuity. The pictures show the time evolution of each experiment from the top (« top » folder) and lateral position (« lateral » folder) and were taken synchronously every 30 seconds, and downsampled to 5 minutes in this dataset. The entire set of pictures are available from the authors upon request. Model F14 is the reference model, without imposed mantle flow and with a slab width of 2000. Models F15 and F16 are models with 660 km and 4000 km, respectively. They allow us analyzing the effect of slab width in the absence of a background flow. Models F17 and F20 are models with slab width of 2000 km and a background flow coming from above the slab at velocities of 0.9 and 1.8 mm/min in the lab (corresponding to 0.9 and 2 cm/yr once scaled to nature), respectively. Models F24 and F26 are models with slab width of 2000 km and a background flow coming from below the slab at velocities of 0.9 and 1.8 mm/min in the lab (corresponding to 1.2 and 2.7 cm/yr once scaled to nature), respectively. For details on the experimental set-up, monitoring techniques and interpretation of the results, please refer to Guillaume et al. (2021) to which these data are supplementary material.

Supplementary material to "Rough subducting seafloor reduces interseismic coupling and mega-earthquake occurrence: insights from analogue models"

This dataset contains digital image correlation (DIC) data of eight seismotectonic analogue experiments that were performed at the Laboratory of Experimental Tectonics (LET), Univ. Rome Tre, to investigate the effect of subduction interface roughness on the seismogenic behaviour of the megathrust. The study has been done in the framework of the Marie Sklodowska-Curie grant agreement 642029 – ITN CREEP. Together with DIC data we also provide analogue earthquake characteristics and Matlab scripts for visualization.Here we provide Digital Image Correlation data for eight experiments that last about 20 minutes (i.e., including tens of seismic cycles), of which four experiments include a smooth subduction interface and four a rough subduction interface. The DIC analysis provides a velocity field between two consecutive frames, measured at the surface of the model. Details about the nature and geometry of this interface, as well as the experimental procedure, model set-up and materials can be found in van Rijsingen et al. (2019), paragraph 2 and supporting information.A more detailed description of the data that we provide, the methods and the matlab scripts used for visualisation can be found in the data description file. An overview of the dataset can be found in the list of files.

A database of analogue models and geophysical data investigating caldera resurgence; DynamiCal project

In this dataset we provide data for 6 experimental models of caldera collapse and subsequent resurgence monitored through geophysical sensors (a force or “impact sensor”, Piezotronics PCB 104 200B02 and a Triaxial piezoelectric accelerometer, Model 356B18). The analogue modelling experiments were carried out at the TOOLab (Tectonic Modelling Laboratory), which is a joint laboratory between the Istituto di Geoscienze e Georisorse of the Consiglio Nazionale delle Ricerche, Italy and the Department of Earth Sciences of the University of Florence. The laboratory work that produced these data was partly supported by the European Plate Observing System (EPOS), by the Joint Research Unit (JRU) EPOS Italia and by the “Monitoring Earth's Evolution and Tectonics” (MEET) project (NextGenerationEU). Specifically, this work was performed in the frame of the DynamiCal project, funded by the 2° TNA-NOA call of the ILGE-MEET project.

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