Data for Characterization of Acoustic Emissions from Analogue Rocks using Sparse Regression-DMDc

<p>Acoustic emissions (AE) are known to be generate in rock from the loss of moisture. The main sources of the AE during drying arise from induced-cracking caused by differential mineral shrinkage, especially in clay-bearing rock, and from the movement and reconfiguration of fluid interfaces. Experiments were performed to measure AE during the drying of analogue rock samples (with and without clay) to determine if there are differences in AE signals when one or both AE source-types are present.  Dynamic Mode Decomposition with control (DMDc), an unsupervised sparse regression model, was used to characterize the AE signals recorded during  drying of porous analogue rock samples. Effective and accurate reconstruction of acoustic signals emitted from samples that only experience moisture loss without cracking where possible using the DMDc method. However, the method struggles to reconstruct signals from samples with intricate crack networks because if contemporaneous signals generated by both fluid interface movement and induced cracking, and because the resulting waves propagate through drying-induced cracks that can lead to multiple internal reflections and attenuation.</p>

<p>Here, the AE data are supplied for users to reproduce the analysis in the original paper or to try other methods that may classify or identify signatures of different AE mechanisms.  The data consist of raw acoustic emission waveforms collected during the monitoring of moisture loss in synthetic rock samples, i) mortar, ii) distributed clay and iii) localized clay, under ambient laboratory conditions that have propagated through fractured and unfractured porous media in saturated and unsaturated conditions. </p>

<p><em>Mortar:</em>  This data set contains the raw unprocessed signals recorded during moisture loss monitoring of clay-free porous media. This folder contains an information text file (README_MORTAR) with details regarding the number of signals, sampling interval (dt), number of points per signal (npts), and column information in AE waveform “.csv” files.  The directory names refer to the specific sample for which AE was recorded. </p>

<p><em>Distributed:</em>  This data set contains the raw unprocessed signals recorded during moisture loss monitoring of clay-rich porous media. This folder contains an information text file (README_DISTRIBUTED) with details regarding the number of signals, sampling interval (dt), number of points per signal (npts), and column information in AE waveform “.csv” files.  The directory name refers to the specific sample for which AE was recorded and include:</p>

<p><em>Localized:</em>  This data set contains the raw unprocessed signals recorded during moisture loss monitoring of the rock analogue containing a localized body of clay. This folder contains an information text file (README_LOCALIZED) with details regarding the number of signals, sampling interval (dt), number of points per signal (npts), and column information in AE waveform “.csv” files.  The directory name refers to the specific sample for which AE was recorded. </p>

<p><em>Localized Filtered: </em> This data set contains the filtered signals that have an activity level above an amplitude threshold of 0.15, that were recorded during moisture loss monitoring of the rock analogue containing a localized body of clay. This folder contains an information text file (README_LOCALIZED_FILTERED) with details regarding the number of signals, sampling interval (dt), number of points per signal (npts), and column information in AE waveform “.csv” files.  The directory name refer to the specific sample for which AE was recorded, and the process applied to the data it contains. </p>

<p><em>Data To Recreate Paper Figures:</em>  This folder contains the data needed to recreate Figures 7, 8, and 9 found in the manuscript (without having to run the DMDc method on the experimental data). Within this folder i) Accuracies (variance explained), ii) Experimental Data Waveforms Trimmed, iii) FFT Frequencies in kHz, iv) Reconstructed waveforms, and v) Time axis folders can be found. The data in Folder iii) is used to plot the FFT frequencies vs. sample type (Figure 7.a.), and Folder ii) and v) are used to plot the experimental waveforms (Figure 7.b).  Data from folder i) are used in Figure 8.a. to plot the variance against sample type. Folder ii) and v), and iv) are used to plot the experimental data with the reconstructed data superimposed in red (Figure 8.b).  Data from Folders i) and iii) are used to plot Figure 9.a., and data from Folders ii) and v) are used to plot the AE waveforms as seen in Figure 9.b. </p>