Map of the study region and 2 graphs from the study.
(a) Map view of the Gonghe Basin. The upper left inset shows the location of the Gonghe Basin in the broader Tibetan Plateau (red square). Cyan circles show epicenters of earthquakes during January 2009–July 2021 collected from the National Earthquake Data Center (NEDC). Beachballs represent focal mechanisms that mark M≥ 5 aftershocks of the 26 April 1990 Ms 7.0 event (compiled from Diao et al., 2025). All historic large events show reverse faulting mechanism, consistent with the collision between the Indian and Eurasia plate that produced the Tibetan Plateau. The black square shows the EGS site, where the lower right map inset shows the nodal‐array distribution (cyan triangles, numbered s01 to s20), and the lower left inset shows the well trajectories (located between stations s03 and s01). (b) The red (S-wave) and blue (P-wave) dashed lines show the velocity model used for this study, the grey dashed line shows the density variations with depth, and the background shows the temperature distribution with depth. (c) The projected trajectories along depth of the three treatment wells in (a), and the strata are marked as: Quaternary (Q) sandstone, Neogene (N1, N2) mudstone, and Triassic (T3) granite ( Zhang, Yan, et al., 2018). Credit: Feng et al. [2026], Figure 1
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth

Enhanced Geothermal Systems (EGS) can expand low-carbon energy production, but fluid injection may trigger earthquakes whose locations and mechanisms are difficult to predict. Feng et al. [2026] investigate induced seismicity at China’s first EGS site in the Gonghe Basin using a comprehensive observational dataset. Machine learning processing of data from 20 surface seismic stations produced a high-resolution earthquake catalog with well-constrained locations and focal mechanisms. Stress inversion and modeling, constrained by borehole stress measurements, reveal mechanically weak faults with low friction coefficients, indicating that low-to-moderate fluid overpressure can trigger seismic slip. Site-scale analysis shows that seismicity reflects shear reactivation of pre-existing natural faults, rather than the creation of new tensile fractures. Further integration with borehole image logs reveals a fine-scale relationship between the main seismogenic zones and stress heterogeneity, expressed as rotations of the principal stress axes that likely reflect localized lithological contrasts and fault-damage zones.

Together, these integrated analyses show that geothermal-induced seismicity is controlled by inherited fault architecture at the site scale and localized stress heterogeneity at the borehole scale. By linking seismic observations to borehole stress and image-log evidence, the study provides a more physically constrained framework for seismic-hazard assessment and stimulation design in enhanced geothermal reservoirs.

Citation: Feng, P., Wang, R., Zhang, H., Zhang, C., Schultz, R., & Yang, L. (2026). Pre-existing structures and stress variations jointly control the induced seismicity in enhanced geothermal system of Gonghe Basin, China. Journal of Geophysical Research: Solid Earth, 131, e2025JB033158. https://doi.org/10.1029/2025JB033158  

—Xiaowei Chen, Associate Editor, JGR: Solid Earth

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