loading page

Monitoring and Forecasting Injection Induced Fault Reactivation and Seismicity in the Laboratory using Active UltrasonicMethods
  • +1
  • Aukje Veltmeijer,
  • Milad Naderloo,
  • Anne Pluymakers,
  • Auke Barnhoorn
Aukje Veltmeijer
Delft University of Technology

Corresponding Author:[email protected]

Author Profile
Milad Naderloo
Delft University of Technology
Author Profile
Anne Pluymakers
Delft University of Technology
Author Profile
Auke Barnhoorn
Delft University of Technology
Author Profile

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 35º 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 towards a method for continuous monitoring of natural fault zones, contributing to seismic risk mitigation of induced and natural earthquakes.
11 Dec 2023Submitted to ESS Open Archive
11 Dec 2023Published in ESS Open Archive