Characterisation of the Tohoku subduction fault zone using downhole logging measurements and physical properties data taken on recovered core.

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The 2011 Tohoku Earthquake (Mw 9.0) off the coast of Japan produced huge slip (~50 metres). The large displacement on this portion of the subduction zone was unexpected by earthquake scientists and produced a devastating tsunami that took over 23,000 lives and caused massive damage along the northeast coast of Honshu. The primary science objective of Integrated Ocean Drilling Program (IODP) Expedition 343 is to understand the physical mechanisms of large slip earthquakes, which at present, is poorly understood. It is a subject of great societal relevance regarding the evaluation of severe shaking and large tsunamis from future earthquakes originating at subduction zones.Between 1 April and 24 May 2012 the Expedition will be offshore Japan drilling, coring, logging and deploying borehole observatories from the R/V Chikyu. This project will use a combination of physical properties data collected in situ downhole and measurements on recovered core to: help precisely locate the fault zone, characterise the formations encountered, and investigate the regional stress regime. Hence, it will directly contribute to the major objectives set out by this expedition.