Integrated Ocean Drilling Program (IODP) Expedition 326 was the first preparatory stage of drilling and coring of the main IODP Hole C0002F to the boundary zone between the Philippine Sea and Eurasian plates in the Nankai accretionary margin, which is one of the main objectives of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) complex drilling project. The objectives for this expedition were purely operational, with the goal being installation of the wellhead assembly and drilling and casing the uppermost 800 m of the planned 7 km deep hole. Accordingly, no science party was on board during the expedition and no scientific results are reported. Scientific objectives for the uppermost 1400 m at this site were previously fulfilled during NanTroSEIZE Stage 1 Expeditions 314 and 315.

This expedition was scheduled to run from 19 July to 8 August 2010. Delays due to various equipment failures and the loss of a casing string caused the expedition to be extended to 20 August. By that time, Hole C0002F had been drilled to 872.5 meters below seafloor and the hole was lined with successfully cemented 20 inch casing. A corrosion cap was set in preparation for a future return to continue drilling. We confirm that Hole C0002F is now ready for deep riser drilling, currently planned for 2011 to 2013.