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These data represent a series of analyses exploring the seismic behaviours of low-cohesion volcanic sediments – in this case the Neapolitan Yellow Tuff - under varying strain rates. The data include deformation logs from triaxial compression experiments, and the accompanying 12-channel acoustic emission recordings at 10 MHz. These are paired with X-Ray Computed Tomography images of one of the cores from both before and after deformation, to examine damage behaviour. These data include: Deformation logs captured from the triaxial press Acoustic emission event data Processed acoustic emission sonograms for selected events Matlab code for processing of sonograms Matlab code for statistical analysis of the acoustic emission data Before and after X-Ray Computed tomography data for a core which underwent 2% strain at a rate of 4x10-6 s-1. These data relate to Rowley et al - Deformation controlled Long-Period seismicity in low cohesion volcanic sediments https://doi.org/10.31223/osf.io/7rkzv
Data (ultrasonic, mechanical) and microstructures of shear failure in Lanhelin granite under upper crustal conditions (NERC Grant NE/M004716/1)
Data has been recorded during triaxial rock deformation experiments where Lanhelin granite samples were subjected to dynamic and half-controlled shear failure. The data consists of mechanical data (load, displacement, confining pressure, strain gauge data), ultrasonic data (AE source locations and arrival times, sensor locations, arrival times of active acoustic surveys), and scanning electron microscope images of the samples after shear failure. Dataset contains all data necessary to evaluate the results presented in the paper entitled: 'Off-fault damage characterisation during and after experimental quasi-static and dynamic rupture in crystal rock from laboratory P-wave tomography and microstructures' by Aben, Brantut, and Mitchell, Journal of Geophysical Research: Solid Earth.
Micromechanics of shear failure in a porous rock: a combined dataset of high-resolution time-resolved 3D x-ray micro-tomography volumes and local 3D strain fields with contemporaneous acoustic emissions and ultrasonic velocity survey waveforms
This dataset shows both the micro-scale mechanisms and acoustic response involved in shear failure of a deforming porous rock. To our knowledge, this is the first such dataset to combine simultaneous acoustic measurements and x-ray tomography imaging. It comprises a time-series of 3D in-situ synchrotron x-ray microtomography (µCT) volumes showing a Clashach sandstone sample (CL10) undergoing triaxial deformation to failure under a constant acoustic emissions (AE) event rate. Use of a constant AE event rate slowed down the failure process after peak stress, enabling shear failure to be captured in unprecedented spatio-temporal detail by the µCT volumes. These volumes are accompanied by the local incremental 3D strain fields and simultaneously acquired waveforms from acoustic emissions and ultrasonic velocity surveys, as well as mechanical bulk stress and strain. These data are fully explained in Cartwright-Taylor et al. Seismic events miss important grain-scale mechanisms governed by kinematics during shear failure of porous rock, in review at Nature Communications. We also include an equivalent time-series of the same data types showing a second Clashach sandstone sample (CL04) undergoing triaxial deformation to failure, this time under a constant strain rate where failure happened abruptly, shortly after peak stress. Both collections were acquired in-situ on the beamline I12-JEEP at the Diamond Light Source, Didcot, UK, in September 2019. Each 3D µCT volume of the sample is contained in a .zip file labelled with the sequential scan number. Each volume comprises reconstructed 16-bit grey-scale data in a sequence of 2D image files (.tif), each numbered according to the depth at which it lies within the sample volume. The file dimensions are pixels, with an edge length of 7.91 µm. Two further .zip files contain the incremental 3D volumetric and deviatoric strain fields, obtained from digital volume correlation between neighbouring µCT volumes. Each strain field consists of a 32-bit 3D image file (.tif) in pixels with an edge length of 316.4 µm, labelled with its scan increment. Also included are (i) .csv files, containing the mechanical stress and strain time-series, the time and mechanical data at which each µCT volume was scanned, and the acoustic emissions event rate data, and (ii) .zip files containing times and waveforms for the acoustic emissions and ultrasonic velocity surveys as .ascii files. The .zip and .xlsx files are labelled with the sample name, the data type (grey-scale, strain-volumetric, strain-deviatoric, seismic, mechanical, mechCT, eventrateAE) and the sequential scan number (grey-scale only) according to the following convention: sample_datatype_scan#. We acknowledge Diamond Light Source for time on beamline I12-JEEP under proposal MG22517. This work is supported by the UK's Natural Environment Research Council (NERC) through the CATFAIL project NE/R001693/1 Catastrophic failure: what controls precursory localisation in rocks?