Above 850 mbsf, the position of several reversals are evident following alternating-field demagnetization. These should be useful in establishing a few magnetostratigraphic tie points in the Pliocene Miocene section at this site. The magnetization of the RCB cores from Hole 1150B is fairly stable, and polarity is dominantly normal below 850 mbsf. The declinations from the Hole 1150B cores have proved useful for reconstructing structural orientations of the numerous microfaults and fractures observed in the core. Normal offset is observed on most of the fault planes, suggesting an east-west extensional stress field is responsible for the deformation observed in this interval.
Data quality is good throughout the logged intervals.
The whole logged section can be divided into six units using the resistivity log in conjunction with other logs. These units are consistent with core descriptions and core measurements. Site 1151 is located 48 km south of Site 1150, in the deep-sea terrace of the Japan Trench, a similar geological setting as at Site 1150. The main objective at this site was to establish another borehole geophysical observatory to monitor active processes in a plate subduction zone with strain, tilt, and seismic sensors. A key difference is that this area is above an aseismic portion of the seismogenic zone.