Data for Laboratory simulation of earthquake-induced damage in lava dome rocks

We performed laboratory time-dependent creep and stress-oscillation earthquake simulations in uniaxial loading in compression and tension on four blocks of porphyritic dacite collected from pyroclastic deposits of Mt. Fugen, of the Unzen-dake volcanic complex in Japan (referred to as ‘Unzen volcano’). Experiments were carried out in the Experimental Volcanology and Geothermal Research Laboratory at the University of Liverpool. Loading experiments were carried out in a 100 kN Instron 8800 uniaxial press at room temperature using both compression tests, and Brazilian disk tests to provide the indirect tensile strength (hereafter referred to as tensile strength/tension tests). Load was recorded by an Instron Dynacell 2527 load cell at 100 Hz, which has an accuracy of ±0.1% of the full load capacity (100 kN). Strain is recorded using an Instron LVDT (Linear Variable Differential Transformer) Deflection Sensor, which has an accuracy of ±0.00001 mm or ±0.05% of the measured displacement, whichever is the largest. For the compression tests, cylindrical specimens with a 20-mm diameter were cored and then cut to a length of 40 mm to form cylinders with a 2:1 length:diameter ratio. The cylinders were axially compressed between two parallel plates in the loading frame during testing. For the Brazilian tests, cylindrical specimens with a 40-mm diameter were cored and then cut to a length of 20 mm to form disks with a 2:1 diameter:length ratio. The disks were diametrically compressed between two parallel plates in the loading frame to induce tensional stresses in the orthogonal direction. The specimen dimensions and loading frame setup follow American Society for Testing and Material (ASTM) standards for unconfined (uniaxial) compression and Brazil tensile strength testing (ASTM Standard D7012 (ASTM, 2014) and ASTM Standard D3967 (ASTM, 2016), respectively). Following preparation, specimens were oven dried at 60°C for 24 hours and then placed into a vacuum chamber for one week prior to mechanical experiments.

File names indicate the specimen name (e.g., UNZ1_6) and the testing conditions. File names beginning with “load_hold” indicates testing was conducted in load hold conditions, and “oscillation” indicates testing was conducted in stress-oscillation conditions. File names ending in “_tension” indicates the given test was a Brazilian disk tension experiment, and “_compression” indicates the test was conducted in uniaxial compression. For example, the filed “load_hold_UNZ1_6_tension.txt” indicates data is from a load hold test in tension (Brazilian disk test) that was conducted on block UNZ1, specimen 6. The following are provided for each experiment: time (in seconds), stress (in megapascal, MPa), and axial strain (for compression, unitless) or equivalent axial strain (for tension, unitless).

These data support a study described in Schaefer et al. (2023), which contains details of each specimen’s dimensions and physical parameters.

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References
American Society for Testing and Materials (ASTM), 2014, Standard Test Methods for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures (ASTM Standard D7012-14e1): ASTM International, West Conshohocken, USA, 9 p. https://doi.org/10.1520/D7012-14E01

American Society for Testing and Materials (ASTM), 2016, Standard Test Method for Splitting Tensile Strength of Intact Rock Core Specimens (ASTM Standard D3967–08): ASTM International, West Conshohocken, USA, 4 p. https://doi.org/ 10.1520/D3967-08

Schaefer, L.N., Kendrick, J.E., Lavallee, Y., Schauroth, J., Lamur, A., Lamb, O.D., Miwa, T., Kennedy, B.M., 2023, Laboratory simulation of earthquake-induced damage in lava dome rocks: Tektonika.