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Investigating reservoir-triggered seismicity in the Koyna-Warna region through nodal ambient noise tomography.

Ranjan P, Kumar P, Mandal B, Karuppannan P.

SCIENTIFIC REPORTS

https://doi.org/10.1038/s41598-025-12099-z 

The Koyna–Warna region in southern India exhibits dual Reservoir-Triggered Seismicity (RTS). Using ambient noise surface wave tomography with dense geophone data, the authors mapped shear wave velocity (Vs) and radial anisotropy (ξ) to 5 km depth. Shallow Vs and ξ align with basement depth. Large earthquakes correlate with negative ξ and Vs anomalies, suggesting shear strength influences RTS. A significant Vs anomaly southwest indicates deep water migration, revealing interconnected migration pathways and aiding understanding of RTS evolution near reservoirs.

Isotropic shear wave velocity anomalies in two cross-sections intersecting koyna, warna, and morana reservoirs, and a spatial map showing the outline of cross sections.

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