Installation of temperature sensors abandoned

　At last the time came to install the temperature sensors for long-term observations inside the borehole and to collect geological samples (core samples).

　Due to bad weather and equipment failure however, they were already past halfway the schedule. At this point neither the target of collecting geological samples, nor that of installing temperature sensors had been achieved.

　One of the co-chief scientists, James J. Mori of Kyoto University tells: “Many of the technical problems were because we were drilling in very deep water of about 6,800 meters, for which CHIKYU has not had previous experience. When some trouble did happen, it took a long time to retrieve and equipment from the ocean floor for another try. The round trip time to 6800 meters was 3 or 4 days. Having to wait during those times was often difficult.”

　On May 10th there was a problem with the electricity supply cable for the underwater camera, which meant that it was no longer possible to continue the work while checking the images from the camera.

　Installing temperature sensors without underwater images is impossible. Temperature sensors are inserted by aiming at a hole drilled before. “It is like suspending a line from the roof of a 20 storey building and entering it in a small hole on the ground,” says Expedition Project Manager Nobuhisa Eguchi of the Center for Deep Earth Exploration(CDEX). It is difficult even when you have images of the seafloor, but without images it really can’t be done. There was no choice but to abandon the completion of one of the two targets within the timeframe of the expedition lasting until May 25.