2 graphs from the paper.
Seismicity migration and rates during load‑following EGS operation. (a) Time–distance plot of events relative to the injector, colored by elapsed time, and with downhole pressure in blue. A best‑fit diffusion front (red) with uncertainty bounds (dashed black) indicates pressure‑controlled triggering (D = 0.43 m2s-1). Cycles I–III retain some production, whereas IV–V stop it entirely so that pressure builds. Unrestricted production periods after injection are shaded green. (b) Magnitudes vs. time show predominantly small events (–1 to –0.5) and a single magnitude 0.45 outlier, with symbol color/size scaling by magnitude; bursts align with pressure peaks but not with systematic magnitude escalation. The figure shows that operational strategy can modulate both seismic rate and spatial evolution. Credit: Chamarczuk et al. [2025], Figure 6(a, b)
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth

Previous studies of the microearthquakes (MEQs) produced from Enhanced Geothermal Systems (EGSs) have focused on the initial phase of high‑pressure “stimulation.” Chamarczuk et al. [2025] track what happens during normal operation, the phase in which plants will spend most of their lives.

Using a distributed acoustic sensing (DAS) cable in a monitoring well and on‑site processing, the authors built a two‑month MEQ catalog through stimulation, crossflow testing, and five load‑following cycles. During those cycles, seismicity rose and fell with subsurface fluid pressure, then settled toward an equilibrium between injections. Event locations formed a cloud whose growth matched a simple diffusion model, which points to pressure migration as the main earthquake triggering mechanism.

These observations suggest that operators have the ability to control seismicity through careful management of injection rates and fluid pressure. They also demonstrate that affordable, real‑time monitoring is feasible for future commercial projects.

Citation: Chamarczuk, M., Ajo-Franklin, J., Nayak, A., Norbeck, J., Latimer, T., Titov, A., & Dadi, S. (2025). Insights into seismicity associated with flexibly operating enhanced geothermal system from real-time distributed acoustic sensing. Journal of Geophysical Research: Solid Earth, 130, e2025JB031634. https://doi.org/10.1029/2025JB031634

—David Dempsey, Associate Editor, JGR: Solid Earth

Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.