A reservoir induced earthquake swarm in the Central Highlands of Sri Lanka

A previously undetected reservoir-induced earthquake swarm was identified beneath the Victoria Reservoir in Sri Lanka's Central Highlands, marking the first recorded instance of induced seismicity in the country. The swarm consisted of five small (M W < 3) felt earthquakes and 23 microseismic events, occurring between August and December 2020. A newly developed single-station earthquake location method, combined with seismic waveform template-matching, revealed a seismogenic zone at depths of 1.5 to 3 km beneath the reservoir's western flank. Poroelastic theory predicted peak stresses of ~15 kPa on E-W striking faults, providing a causal link between reservoir-induced stresses and the seismic activity. This study not only establishes a significant finding for Sri Lanka but also introduces efficient computational workflows for monitoring induced seismicity in resource-limited settings.

Herath, P., Attanayake, J., & Gahalaut, K. (2022). A reservoir induced earthquake swarm in the Central Highlands of Sri Lanka. Scientific Reports, 12(1). https://doi.org/10.1038/s41598-022-22791-z