Expedition scientists 8 countries

Expedition 319: Key Scientific Results

Riser borehole: Measure stress and pressure. Conduct imaging study of plate boundary (W-VSP). Develop protocls for cuttings measurements. Activity, history of megasplay Install monitoring sensors in megasplay fault

Drill Site Locations Megasplay site Riser drill site above locked fault

- Control of borehole pressure - Deeper drilling - New tools & measurements - Stress, pressure - First time in IODP history Riser Drilling:

(Front view) (Rear view) MDT Tool: Successful Stress, Pressure Measurement

Stress directions and Magnitude Combined result from new data and Stage 1 boreholes Indicate changes in stress regime possibly related to locked fault below

Stress directions and Magnitude Narrow region of stress rotation above megasplay fault Provides clues about fault behavior beneath the drill sites

Stress directions and Magnitude Narrow region of stress rotation above megasplay fault Provides clues about fault behavior beneath the drill sites

Geologic History of Kumano Basin Cores and drill cuttings Provide clues about activity and geologic history

Size fractions from washed cuttings Woody fragments Chips of hard sediment

Cuttings Lithologic Components

Washed cuttings, 1-4mm, “silty clay” Unit III Unit IV

Geologic History of Kumano Basin Cores and drill cuttings

Geologic History of Kumano Basin Age of sediment: records rapid filling of the Kumano Basin Provides clues about activity and history of the Megasplay fault

Megasplay Drillsite:

Successful Installation of Retrievable Subseafloor Observatory: Monitoring the Megasplay

Retrievable Observatory “Smartplug”

At the wellhead: 2.5 km below sea level

Primary Results New information on stress conditions above the locked plate boundary fault zone; achieved by riser drilling. New information about history of Mega-splay fault system. First observatory sensors installed by D/V Chikyu, and first observatory in NanTroSEIZE project.

One Science Party, Two “Shifts”