Wang, Lei and Kwiatek, Grzegorz and Renard, François and Guérin-Marthe, Simon and Rybacki, Erik and Bohnhoff, Marco and Naumann, Michael and Dresen, Georg (2024) Fault roughness controls injection-induced seismicity. Proceedings of the National Academy of Sciences, 121 (3). DOI: https://doi.org/10.1073/pnas.2310039121
Full text not available from this repository.Abstract
Surface roughness ubiquitously prevails in natural faults across various length scales. Despite extensive studies highlighting the important role of fault geometry in the dynamics of tectonic earthquakes, whether and how fault roughness affects fluid-induced seismicity remains elusive. Here, we investigate the effects of fault geometry and stress heterogeneity on fluid-induced fault slip and associated seismicity characteristics using laboratory experiments and numerical modeling. We perform fluid injection experiments on quartz-rich sandstone samples containing either a smooth or a rough fault. We find that geometrical roughness slows down injection-induced fault slip and reduces macroscopic slip velocities and fault slip-weakening rates. Stress heterogeneity and roughness control hypocenter distribution, frequency–magnitude characteristics, and source mechanisms of injection-induced acoustic emissions (AEs) (analogous to natural seismicity). In contrast to smooth faults where injection-induced AEs are uniformly distributed, slip on rough faults produces spatially localized AEs with pronounced non-double-couple source mechanisms. We demonstrate that these clustered AEs occur around highly stressed asperities where induced local slip rates are higher, accompanied by lower Gutenberg–Richter b-values. Our findings suggest that real-time monitoring of induced microseismicity during fluid injection may allow identifying progressive localization of seismic activity and improve forecasting of runaway events.
| Item Type: | Article |
|---|---|
| Subjects: | Inducing technology > Laboratory experiment Region > Germany |
| Project: | Geo-INQUIRE > AE LAB-EXPERIMENT: Laboratory experiment |