Carbon export from mountain forests enhanced by earthquake-triggered landslides over millennia

Frith, N.; Hilton, R.G.; Howarth, J.D.; Gröcke, D.R.; Fitzsimons, S.J.; Croissant, T.; Wang, J.; McClymont, E.L.; Dahl, J.; Densmore, A.L.

Abstract

Rapid ground accelerations during earthquakes can trigger landslides that disturb mountain forests and harvest carbon from soils and vegetation. Although infrequent over human timescales, these co-seismic landslides can set the rates of geomorphic processes over centuries to millennia. However, the long-term impacts of earthquakes and landslides on carbon export from the biosphere remain poorly constrained. Here, we examine the sedimentary fill of Lake Paringa, New Zealand, which is fed by a river draining steep mountains proximal to the Alpine Fault. Carbon isotopes reveal enhanced accumulation rates of biospheric carbon after four large earthquakes over the past ~1,100 years, probably reflecting delivery of soil-derived carbon eroded by deep-seated landslides. Cumulatively these pulses of earthquake-mobilized carbon represent 23 ± 5% of the record length, but account for 43 ± 5% of the biospheric carbon in the core. Landslide simulations suggest that 14 ± 5 million tonnes of carbon (MtC) could be eroded in each earthquake. Our findings support a link between active tectonics and the surface carbon cycle and suggest that large earthquakes can significantly contribute to carbon export from mountain forests over millennia.

Citation

Frith, N., Hilton, R., Howarth, J., Gröcke, D., Fitzsimons, S., Croissant, T., Wang, J., McClymont, E., Dahl, J., & Densmore, A. (2018). Carbon export from mountain forests enhanced by earthquake-triggered landslides over millennia. Nature Geoscience, 11(10), 772-776. https://doi.org/10.1038/s41561-018-0216-3

• Journal Article Type: Article
• Acceptance Date: Jul 26, 2018
• Online Publication Date: Aug 27, 2018
• Publication Date: Oct 1, 2018
• Deposit Date: Aug 10, 2018
• Publicly Available Date: Feb 27, 2019
• Journal: Nature Geoscience
• Print ISSN: 1752-0894
• Electronic ISSN: 1752-0908
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 10
• Pages: 772-776
• DOI: https://doi.org/10.1038/s41561-018-0216-3
• Public URL: https://durham-repository.worktribe.com/output/1323715