Temporal evolution and decline of seismicity associated with cyclic operations at the Serajeh underground gas storage, Iran
Abstract
Underground gas storage (UGS) operations can perturb reservoir conditions and modulate local seismicity, but the temporal evolution of this response under cyclic injection–withdrawal remains poorly constrained. We investigate seismicity around the Serajeh UGS in central Iran by combining 29,781 deep-learning-based single-station earthquake detections, multi-station relocation, centroid moment tensor inversion, and operational records. The relocated hypocentres form a compact cluster near the Serajeh structure, primarily at depths of 3–8 km, overlapping with and extending below the 2.4–3.0 km storage interval. Independent comparison with relocated earthquakes confirms that S–P time at the nearby GHVR station provides a useful first-order proxy for local source distance. Cross-correlation between monthly gas injection and seismicity shows a distinct maximum at an offset of approximately 8 months. This feature is reproduced by the phase-randomized ReshuffleCorr analysis, while additional structure-preserving tests indicate that its global statistical strength and exact timing depend on the treatment of temporal variability. An objective change-point analysis identifies a marked decrease in seismicity centred on April 2015, nearly four years after storage operations began, and the decrease remains evident using a conservative magnitude threshold. Seismicity subsequently remains lower despite continued cyclic operations. The selected focal mechanisms show predominantly strike-slip to oblique source kinematics across pre-operational, operational, and post-operational periods. We interpret these observations as evidence for an evolving temporal and spatial association between storage operations and a pre-existing fault–reservoir system. These results highlight the value of integrating high-resolution seismic monitoring with independently constrained locations and operational records for seismic-hazard assessment at UGS sites.
Related
- The 2016 Mw 7.0 Kumamoto Earthquake Sequence, Japan revisited: Insights from Spatio-Temporal Analysis of Seismicity Parameters
- Time-dependent behavior and damage evolution of brittle rock around deep underground excavations subjected to dynamic disturbance
- Development of a Combined Detection and Relocation Workflow (TM2DD) to Characterize Escalating Hydraulic Fracturing Induced Seismicity in the Karnes Trough Fault Zone of the Eagle Ford Shale Play, Texas
- Escalating soil CO ₂ degassing correlates with ground uplift and seismicity during the ongoing unrest of Campi Flegrei (2005–2025)
- Construction of a Global Atmospheric Refractivity Model for Optical Wavelengths Based on Temporal Evolution Characteristics
BibTeX
@article{songhori2026temporal,
title = {{Temporal evolution and decline of seismicity associated with cyclic operations at the Serajeh underground gas storage, Iran}},
author = {Ali Songhori and Habib Rahimi and Mohammadreza Jamalreyhani and Fenglin Niu and Badrodin Karampour and Mostafa Ebrahimi Moghaddam and Reza Zeynaddini-Meymand and Abdolreza Ghods},
journal = {Scientific Reports},
year = {2026},
month = oct,
doi = {10.1038/s41598-026-74195-y},
url = {https://www.nature.com/articles/s41598-026-74195-y},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Temporal evolution and decline of seismicity associated with cyclic operations at the Serajeh underground gas storage, Iran
AU - Ali Songhori
AU - Habib Rahimi
AU - Mohammadreza Jamalreyhani
AU - Fenglin Niu
AU - Badrodin Karampour
AU - Mostafa Ebrahimi Moghaddam
AU - Reza Zeynaddini-Meymand
AU - Abdolreza Ghods
PY - 2026
DA - 2026/10/02
JO - Scientific Reports
DO - 10.1038/s41598-026-74195-y
UR - https://www.nature.com/articles/s41598-026-74195-y
AB - Underground gas storage (UGS) operations can perturb reservoir conditions and modulate local seismicity, but the temporal evolution of this response under cyclic injection–withdrawal remains poorly constrained. We investigate seismicity around the Serajeh UGS in central Iran by combining 29,781 deep-learning-based single-station earthquake detections, multi-station relocation, centroid moment tensor inversion, and operational records. The relocated hypocentres form a compact cluster near the Serajeh structure, primarily at depths of 3–8 km, overlapping with and extending below the 2.4–3.0 km storage interval. Independent comparison with relocated earthquakes confirms that S–P time at the nearby GHVR station provides a useful first-order proxy for local source distance. Cross-correlation between monthly gas injection and seismicity shows a distinct maximum at an offset of approximately 8 months. This feature is reproduced by the phase-randomized ReshuffleCorr analysis, while additional structure-preserving tests indicate that its global statistical strength and exact timing depend on the treatment of temporal variability. An objective change-point analysis identifies a marked decrease in seismicity centred on April 2015, nearly four years after storage operations began, and the decrease remains evident using a conservative magnitude threshold. Seismicity subsequently remains lower despite continued cyclic operations. The selected focal mechanisms show predominantly strike-slip to oblique source kinematics across pre-operational, operational, and post-operational periods. We interpret these observations as evidence for an evolving temporal and spatial association between storage operations and a pre-existing fault–reservoir system. These results highlight the value of integrating high-resolution seismic monitoring with independently constrained locations and operational records for seismic-hazard assessment at UGS sites.
SN - 2045-2322
ER -