Release of mineral-bound water prior to subduction tied to shallow seismogenic slip off Sumatra

Andre Hupers , Marta E. Torres , Satoko Owari , Lisa C. Mcneill (1) , Brandon Dugan , Timothy J. Henstock (1) , Kitty Milliken , Katerina E. Petronotis , Jan Backman , Sylvain Bourlange (2) , Farid Chemale Junior (3) , Chen Wenhuang , Tobias A. Colson , Marina C.G. Frederik , Gilles Guérin , Mari Hamahashi , Brian M. House , Tamara N. Jeppson , Sarah Kachovich , Abby Kenigsberg , Mebae Kuranaga , Steffen Kutterolf , Freya L. Mitchison , Hideki Mukoyoshi , Nisha Nair , Kevin T. Pickering , Hugo Pouderoux (4) , Yehua Sahn , Insun Song , Paola Vannucchi , Peter J. Vroljik , Tao Yang , Xixi Zhao

1 NOC - National Oceanography Centre [Southampton]
2 GeoRessources
3 Instituto de Geociências, Universidade de Brasilia
4 GR - Géosciences Rennes

Plate-boundary fault rupture during the 2004 Sumatra-Andaman subduction earthquake extended closer to the trench than expected, increasing earthquake and tsunami size. International Ocean Discovery Program Expedition 362 sampled incoming sediments offshore northern Sumatra, revealing recent release of fresh water within the deep sediments. Thermal modeling links this freshening to amorphous silica dehydration driven by rapid burial-induced temperature increases in the past 9 million years. Complete dehydration of silicates is expected before plate subduction, contrasting with prevailing models for subduction seismogenesis calling for fluid production during subduction. Shallow slip offshore Sumatra appears driven by diagenetic strengthening of deeply buried fault-forming sediments, contrasting with weakening proposed for the shallow Tohoku-Oki 2011 rupture, but our results are applicable to other thickly sedimented subduction zones including those with limited earthquake records.

Domains: Earth Sciences

Andre Hupers, Marta E. Torres, Satoko Owari, Lisa C. Mcneill, Brandon Dugan, et al.. Release of mineral-bound water prior to subduction tied to shallow seismogenic slip off Sumatra. Science, 2017, 356 (6340), pp.841-844. ⟨10.1126/science.aal3429⟩. ⟨insu-01528723⟩