Print Email Facebook Twitter Precursory Signals to Injection Induced Fault Reactivation in the Laboratory Using Active Ultrasonic Monitoring Methods Title Precursory Signals to Injection Induced Fault Reactivation in the Laboratory Using Active Ultrasonic Monitoring Methods Author Veltmeijer, A.V. (TU Delft Applied Geophysics and Petrophysics) Naderloo, M. (TU Delft Reservoir Engineering) Pluymakers, Anne (TU Delft Applied Geophysics and Petrophysics) Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics) Date 2024 Abstract Induced earthquakes are still highly unpredictable, and often caused by variations in pore fluid pressure. Monitoring and understanding the mechanisms of fluid-induced fault slip is essential for seismic risk mitigation and seismicity forecasting. Fluid-induced slip experiments were performed on critically stressed faulted sandstone samples, and the evolution of the actively sent ultrasonic waves throughout the experiment was measured. Two different fault types were used: smooth saw-cut fault samples at a 35° angle, and a rough fault created by in situ faulting of the samples. Variations in the seismic slip velocity and friction along the fault plane were identified by the coda of the ultrasonic waves. Additionally, ultrasonic amplitudes show precursory signals to laboratory fault reactivation. Our results show that small and local variations in stress before fault failure can be inferred using coda wave interferometry for time-lapse monitoring, as coda waves are more sensitive to small perturbations in a medium than direct waves. Hence, these signals can be used as precursors to laboratory fault slip and to give insight into reactivation mechanisms. Our results show that time-lapse monitoring of coda waves can be used to monitor local stress changes associated with fault reactivation in this laboratory setting of fluid-induced fault reactivation. This is a critical first step toward a method for continuous monitoring of natural fault zones, contributing to seismic risk mitigation of induced and natural earthquakes. Subject coda wave interferometryfault mechanicsinjection-induced seismicityultrasonic monitoring To reference this document use: http://resolver.tudelft.nl/uuid:40986389-2340-4a5f-b8e9-e74cf5e24ccd DOI https://doi.org/10.1029/2023JB028505 ISSN 2169-9313 Source JGR Solid Earth, 129 (2) Part of collection Institutional Repository Document type journal article Rights © 2024 A.V. Veltmeijer, M. Naderloo, Anne Pluymakers, A. Barnhoorn Files PDF JGR_Solid_Earth_-_2024_-_ ... _Using.pdf 3.01 MB Close viewer /islandora/object/uuid:40986389-2340-4a5f-b8e9-e74cf5e24ccd/datastream/OBJ/view