Future intraplate stress and the longevity of carbon storage

- We model the present and future intraplate stress field of Australia.
- We consider stress field changes due to the evolving plate collision in Timor.
- 10 suggested carbon sequestration sites may experience major changes of in situ stress regimes.
- Areas at risk include the Timor Sea, the Eromanga Basin, the Bass Strait and the Ipswich Basin.

Carbon capture and storage (CCS) is regarded as a promising strategy for mitigating global warming. A 19% CCS contribution to CO2 reduction by 2050, as envisaged by the International Energy Agency, would require the construction of thousands of CCS sites by the 2030s and beyond. CO2 storage may need to last for tens of thousands of years to avoid potential global warming and major Earth system changes, and a critical site selection criterion will be the likelihood of future escape of stored CO2 due to fault reactivation. However, future long-term intraplate stress field changes have not been considered in this context. Here we focus on Australia, where 61 potential CCS sites have been proposed, and model the evolving intraplate stress field due to the future growth of tectonic collisional forces north of Australia. Counter intuitively, the largest changes are predicted for some parts of western, central and southeast Australia, all regions far away from plate boundaries, reflecting the non-linear interaction of plate boundary forces with a geologically heterogeneous continent. We suggest that at least ten suggested CCS sites are located in regions where major changes of in situ stress regimes can be expected in the next 100,000 years, requiring a careful evaluation of potential future fault reactivation and a breach of reservoir seals. Our results highlight the importance of considering future intraplate stress field changes for selecting CCS sites, particularly within continental regions affected by ongoing mountain building processes including Australia, India, South America, Asia and southern Europe.

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