RV Kairei Retrieves Deepest Borehole Observatory Sensors

The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) research vessel Kairei has successfully retrieved the sensors from the deepest borehole observatory ever installed from the extreme ocean depths of nearly 7000 meters on 26th April, 2013.

The R/V Kairei carried out the complex sequence of operations in the Japan Trench using the remotely operated vehicle KAIKO 7000-II to locate, detach and reel-in the array of 55 temperature sensing loggers from a borehole that straddles the plate boundary where the fault slipped ~50 m during the magnitude-9 2011 Tohoku-oki earthquake. The Scientific Drilling Vessel Chikyu installed the observatory in a dedicated borehole that penetrated 855 meters below the seafloor in a water depth of 6897.5 meters during the Japan Trench Fast Drilling Project (JFAST) for the Integrated Ocean Drilling Program (IODP) Expedition 343/343T; April-July 2012.

The recovered sensors provide data that will be used to determine the frictional heat generated by fault slip during the Tohoku-oki earthquake. Scientists will infer the forces on the fault during the earthquake from these measurements of dissipated energy. The new data are critical to understanding the causes of the large, shallow displacements during earthquakes that can generate devastating tsunamis. The JFAST observatory provides the first temperature measurements at a subduction plate boundary fault immediately after an earthquake. Further research results are expected to follow careful analysis.

Schedule of the Research vessel Kairei

9th May: Arrive at Shiogama or Sendai Port for loading materials and embarkation/disembarkation of crews

10th May: Depart Shiogama or Seandai Port

23rd May: Arrive at JAMSTEC, off load materials

The above schedule is subject to change depending on operational requirements and weather.

[mappress]

Press Release, April 30, 2013