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Sumatra - IODP map

Sediments tell a tsunami story.

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. More...


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Planetary Ices Group



The Planetary Ices Group carries out world leading research into the structure, dynamics and astrobiological potential of icy planetary bodies, with a particular focus on determining the properties of their constituent icy ‘minerals’. Planetary bodies are essentially crystalline aggregates: the structure and evolution of all such bodies are thus fundamentally due to the microscopic behaviour of the component crystals – equilibrium structures, elasticity, and transport properties for example. In determining the magnitudes of these properties for different ices and for the highly hydrated phases thought to exist in the interiors of outer solar-system moons we employ a coordinated multidisciplinary approach involving a combination of experimental and computational techniques.