Article | Published:

Increased landslide activity on forested hillslopes following two recent volcanic eruptions in Chile

Abstract

Large explosive eruptions can bury landscapes beneath thick layers of tephra. Rivers subsequently overloaded with excess pyroclastic sediments have some of the highest reported specific sediment yields. Much less is known about how hillslopes respond to tephra loads. Here, we report a pulsed and distinctly delayed increase in landslide activity following the eruptions of the Chaitén (2008) and Puyehue–Cordón Caulle (2011) volcanoes in southern Chile. Remote-sensing data reveal that landslides clustered in densely forested hillslopes mostly two to six years after being covered by tephra. This lagged instability is consistent with a gradual loss of shear strength of decaying tree roots in areas of high tephra loads. Surrounding areas with comparable topography, forest cover, rainfall and lithology maintained landslide rates roughly ten times lower. The landslides eroded the landscape by up to 4.8 mm on average within 30 km of both volcanoes, mobilizing up to 1.6 MtC at rates of about 265 tC km–2 yr–1. We suggest that these yields may reinforce the elevated river loads of sediment and organic carbon in the decade after the eruptions. We recommend that studies of post-eruptive mass fluxes and hazards include lagged landslide responses of tephra-covered forested hillslopes, to avoid substantial underestimates.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Data availability

The data that support the findings of this study are available from the corresponding author upon request. We used the publicly available Landsat and Sentinel-2 satellite imagery (https://earthexplorer.usgs.gov/ and https://sentinel.esa.int/) and Space Shuttle Radar Topgraphy Mission (https://earthexplorer.usgs.gov/) data to map the landslides. Our rainfall analysis draws on Chilean station data (http://www.cr2.cl/datos-de-precipitacion/). The Global Forest Inventory is available at http://earthenginepartners.appspot.com/science-2013-global-forest/download_v1.5.html.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

  1. 1.

    Major, J. J. & Yamakoshi, T. Decadal-scale change of infiltration characteristics of a tephra-mantled hillslope at Mount St Helens, Washington. Hydrol. Proc. 19, 3621–3630 (2005).

  2. 2.

    Pierson, T. C., Major, J. J., Amigo, Á. & Moreno, H. Acute sedimentation response to rainfall following the explosive phase of the 2008–2009 eruption of Chaitén volcano, Chile. Bull. Volcanol. 75, 723 (2013).

  3. 3.

    Korup, O. Earth’s portfolio of extreme sediment transport events. Earth Sci. Rev. 112, 115–125 (2012).

  4. 4.

    National Academies of Sciences, Engineering and Medicine Volcanic Eruptions and Their Repose, Unrest, Precursors, and Timing (National Academies Press, 2017).

  5. 5.

    Veblen, T. T. & Ashton, D. H. Catastrophic influences on the vegetation in the Valdivian Andes, Chile. Vegetatio 36, 149–167 (1978).

  6. 6.

    Grubb, P. J., Bellingham, P. J., Kohyama, T. S., Piper, F. I. & Valido, A. Disturbance regimes, gap-demanding trees and seed mass related to tree height in warm temperate rain forests worldwide. Biol. Rev. 88, 701–744 (2013).

  7. 7.

    Capra, L. et al. Rainfall-triggered lahars at Volcan de Colima, Mexico: surface hydro-repellency as initiation process. Bull. Volcan. Geotherm. Res. 189, 105–117 (2010).

  8. 8.

    Mohr, C. H., Korup, O., Ulloa, H. & Iroumé, A. Pyroclastic eruption boosts organic carbon fluxes into Patagonian fjords. Glob. Biogeochem. Cycles 31, 1626–1638 (2017).

  9. 9.

    Keim, R. F. & Skaugset, A. E. Modelling effects of forest canopies on slope stability. Hydrol. Proc. 17, 1457–1467 (2003).

  10. 10.

    Imaizumi, F., Sidle, R. C. & Kamei, R. Effects of forest harvesting on the occurrence of landslides and debris flows in steep terrain of central Japan. Earth Surf. Proc. Landf. 33, 827–840 (2008).

  11. 11.

    Walsh, R. P. D. et al. Long-term responses of rainforest erosional systems at different spatial scales to selective logging and climate change. Phil. Trans. R. Soc. Lond. B 366, 3340–3353 (2011).

  12. 12.

    Singer, B. S. et al. Eruptive history, geochronology, and magmatic evolution of the Puyehue–Cordón Caulle volcanic complex, Chile. Geol. Soc. Am. Bull. 120, 599–618 (2008).

  13. 13.

    Carn, S. et al. The unexpected awakening of Chaitén volcano, Chile. EOS Trans. 90, 205–212 (2009).

  14. 14.

    Alfano, F. et al. Tephra stratigraphy and eruptive volume of the May, 2008, Chaitén eruption, Chile. Bull. Volcanol. 73, 613–630 (2011).

  15. 15.

    Bertrand, S., Daga, R., Bedert, R. & Fontijn, K. Deposition of the 2011–2012 Cordón Caulle tephra (Chile, 40°S) in lake sediments: implications for tephrochronology and volcanology. J. Geophys. Res. Earth Surf. 119, 2555–2573 (2014).

  16. 16.

    Myers, N., Mittermeier, R. A., Mittermeier, C. G., da Fonseca, G. A. B. & Kent, J. Biodiversity hotspots for conservation priorities. Nature 403, 853–858 (2000).

  17. 17.

    Pollmann, W. & Veblen, T. T. Nothofagus regeneration dynamics in south-central Chile: a test of a general model. Ecol. Monogr. 74, 615–634 (2004).

  18. 18.

    Hansen, M. C. et al. High-resolution global maps of 21st-century forest cover change. Science 342, 850–853 (2013).

  19. 19.

    Urrutia-Jalabert, R., Malhi, Y. & Lara, A. The oldest, slowest rainforests in the world? Massive biomass and slow carbon dynamics of Fitzroya cupressoides temperate forests in southern Chile. PLoS ONE 10, e0137569 (2015).

  20. 20.

    Swanson, F. J., Jones, J. A., Crisafulli, C. M. & Lara, A. Effects of volcanic and hydrologic processes on forest vegetation: Chaitén Volcano, Chile. Andean Geol. 40, 359–391 (2013).

  21. 21.

    Arnalds, O. The influence of volcanic tephra (ash) on ecosystems. Adv. Agron. 121, 331–380 (2013).

  22. 22.

    Swanson, F. J., Jones, J., Crisafulli, C., González, M. E. & Lara, A. Puyehue–Cordón Caulle eruption of 2011: tephra fall and initial forest responses in the Chilean Andes. Bosque 37, 85–96 (2016).

  23. 23.

    Ayris, P. M., & Delmelle, P. The immediate environmental effects of tephra emission. Bull. Volcanol. 74, 1905–1936 (2012).

  24. 24.

    Hotes, S., Poschlod, P., Takahashi, H., Grootjans, A. P. & Adema, E. Effects of tephra deposition on mire vegetation: a field experiment in Hokkaido, Japan. J. Ecol. 92, 624–634 (2004).

  25. 25.

    Martin, R. S. et al. Environmental effects of ashfall in Argentina from the 2008 Chaitén volcanic eruption. J. Volcan. Geotherm. Res. 184, 462–472 (2009).

  26. 26.

    Blackford, J. J., Edwards, K. J., Dugmore, A. J., Cook, G. T. & Buckland, P. C. Icelandic volcanic ash and the mid-Holocene Scots pine (Pinus sylvestris) pollen decline in northern Scotland. Holocene 2, 260–265 (1992).

  27. 27.

    Hinckley, T. M. et al. Impact of tephra deposition on growth in conifers: the year of the eruption. Can. J. Forest Res. 14, 731–739 (1984).

  28. 28.

    De la Fuente, A & Pacheco, N. Biomass, seed production and phenology of Chusquea montana after a massive and synchronous flowering event in Puyehue National Park, Chile. Bosque 38, 601–606 (2017).

  29. 29.

    Major, J. J. et al. Extraordinary sediment delivery and rapid geomorphic response following the 2008–2009 eruption of Chaitén Volcano, Chile. Water Resour. Res. 52, 5075–5094 (2016).

  30. 30.

    Hilton, R. G., Galy, A. & Hovius, N. Riverine particulate organic carbon from an active mountain belt: importance of landslides. Glob. Biogeochem. Cycles 22, GB1017 (2008).

  31. 31.

    Clark, K. E. et al. Storm-triggered landslides in the Peruvian Andes and implications for topography, carbon cycles, and biodiversity. Earth Surf. Dynam. 4, 47–70 (2016).

  32. 32.

    Smith, R. W., Bianchi, T. S., Allison, M., Savage, C. & Galy, V. High rates of organic carbon burial in fjord sediments globally. Nat. Geosci. 8, 450–453 (2015).

  33. 33.

    Sidle, R. C. A conceptual model of changes in root cohesion in response to vegetation management. J. Environ. Qual. 20, 43–52 (1991).

  34. 34.

    Schmidt, K. M. et al. The variability of root cohesion as an influence of shallow landslide susceptibility in the Oregon Coast Range. Can. Geotech. J. 38, 995–1024 (2001).

  35. 35.

    Pierson, T. C. & Major, J. J. Hydrogeomorphic effects of explosive volcanic eruptions on drainage basins. Ann. Rev. Earth Planet. Sci. 42, 469–507 (2014).

  36. 36.

    Larsen, I. J., Montgomery, D. R. & Korup, O. Landslide erosion controlled by hillslope material. Nat. Geosci. 3, 247–251 (2010).

Download references

Acknowledgements

This work was partly funded by the projects CONICYT-BMBF PCCI20130045 and BMBF 01DN13060, courtesy of the German Federal Ministry of Education and Research. We thank A. Iroumé and E. Parra for help with logistics, and appreciate the support of E. Gonzalez and the rangers at Pumalín National Park, as well as the Dirección General Aeronautica Civil for permitting UAV flights. We thank J. J. Major for comments on the manuscript. We ran all computations using the statistical environment R (www.r-project.org).

Author information

O.K. and C.H.M. collected the field data. O.K. and J.S. analysed the data. O.K. designed the study and wrote the manuscript, with input from J.S. and C.H.M.

Competing interests

The authors declare no competing interests.

Correspondence to Oliver Korup.

Supplementary information

  1. Supplementary Information

    Supplementary Figures, Tables and Discussion

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark
Fig. 1: Satellite images of the Chaitén and Puyehue volcanoes, along with post-eruptive forest losses.
Fig. 2: Time series of forest loss and landslide disturbance following the recent eruptions of the Chaitén and Puyehue volcanoes.
Fig. 3: Histograms of absolute and relative areas of post-eruptive forest losses and landslide disturbance with increasing distance from the craters of the Chaitén and Puyehue volcanoes.
Fig. 4: Cumulative distributions of estimated time lags between landslide occurrence and forest loss following the eruptions of the Chaitén and Puyehue volcanoes.
Fig. 5: Post-eruptive landslides in disturbed temperate rainforests around Chaitén Volcano.
Fig. 6: Prediction of landslide volume from footprint area.