These data are supplementary to the GJI research article of Blanke et al. 2020, in which static stress drop estimates of laboratory acoustic emission (AE) waveform records were analyzed. Stick-slip experiments were conducted on two triaxial loaded Westerly Granite samples of different roughness: 1) a smooth saw-cut fault (sample S12) and 2) a rough fault (sample W5). Both experiments resulted in six stick-slip failures of which five were analyzed for each fault. A variant of the spectral ratio technique was applied to find the best fitting source parameters.
Laboratory Experiments:
Acoustic emission waveform data of two triaxial stick-slip experiments was recorded at room temperature on cylindrical oven-dried Westerly Granite samples of 105-107 mm height and 40-50 mm diameter. The experiments were conducted on a smooth saw-cut (sample S12) and a rough fault (sample W5). Both experiments were performed in a servo-controlled MTS loading frame equipped with a pressure vessel. The acoustic emission activity was monitored by 16 piezoceramic transducers with a resonance frequency of about 2 MHz. A transient recording system (DAX-Box, Prökel, Germany) recorded full waveform data in triggered mode at a sampling frequency of 10 MHz and an amplitude resolution of 16 bits. The rough fault W5 was first prepared with Teflon-filled saw-cut notches at 30° inclination to the vertical axis and then fractured at 75 MPa. Then, each sample, S12 and W5, was subjected to constant confining pressure of 133 MPa and 150 MPa and then loaded in axial compression using a strain rate of 3*10-4 mm/s and 3*10-6 mm/s, respectively.
Data description:
The tables 2020-008_Blanke-et-al_S1_S12.txt and 2020-008_Blanke-et-al_S2_W5.txt contain AE locations and occurrence, and source parameter estimates of the smooth fault S12 and the rough fault W5, respectively. Both column headers show coordinates of AE locations (X, Y, Z [mm]), temporal occurrence (t [sec]), seismic moment (M0 [Nm]), corner frequency (f0 [Hz]), source radius (r [mm]), static stress drop (stress drop [MPa]), and moment magnitude (MW). M0 and f0 were estimated from the amplitude spectra, using the spectral ratio technique. The source radii were calculated for S-waves using the dynamic circular source model of Madariaga (1976). Static stress drops were estimated following Eshelby (1957). Both tables are used and displayed in Blanke et al. (2020).
This dataset presented herein originates from the JAGUARS (The Japanese German Underground Acoustic Emission Research in South Africa) project, which took place from 2007 to 2009 in Mponeng Gold Mine, South Africa. Project partners included Ritsumeikan University, Earthquake Research Institute University of Tokyo and Tohuku University in Japan, the German Research Center for Geosciences Potsdam and Gesellschaft für Materialprüfung und Geophysik GMuG mbH in Germany, as well as the Council for Scientific and Industrial Research in Johannesburg, Seismogen CC in Cartonville, Anglo Gold Ashanti Ltd and the Institute of Mining Seismology in the Republic of South Africa. This publication forms part of the Geo-INQUIRE initiative (HORIZON-INFRA-2021-SERV-01 call, project number 101058518).
It is cross-referenced on the EPISODES Platform (https://episodesplatform.eu/?lang=en#episode:JAGUARS (not yet existing)), which is managed by the EPOS TCS AH (European Plate Observing System Thematic Core Service Anthropogenic Hazards). Within the EPISODES Platform, the datasets are consolidated into an “episode” titled “JAGUARS: Mining induced picoseismicity associated with gold mining”. The EPISODES Platform offers open access to the integrated research infrastructures of the EPOS TCS AH, enabling users to download data and utilize a range of basic online visualization tools to graphically represent and process the datasets directly within their personal workspace.