Magnetization distribution of hydrothermal deposits from three component magnetometer survey using ROV in the Lau Basin, the southwestern Pacific

Abstract

Deep sea three component magnetic surveys, using ROV (Remotely Operated Vehicle), were conducted at Apr., 2011 and Jan., 2012 in TA25 and TA26 seamounts, the Lau Basin, the southwestern Pacific. At 2011, the survey area was only the western slope of the caldera of TA25 using IBRV(Ice Breaker Research Vessel) ARAON of KIOST (Korea Institute of Ocean Science & Technology) and ROV of Oceaneering Co. And, at Jan. 2012, the magnetic survey was conducted in the western (site A) and eastern (site B) slopes of the caldera of TA25 and the summit area of TA26 using German R/V SONNE and ROV of ROPOS Co. The 2011 and 2012 three component magnetic survey lines were the 13 N-S lines and the 29 N-S lines (TA25-East : 12 lines, TA25-West : 11 lines, TA26 : 6 lines) with about 100 m spacing, respectively. Also, we conducted the 8 figure circle rotation survey of ROV for magnetic calibration at 2011 and 2012. For the magnetic survey, the magnetometer sensor was attached with the line frame of ROV and the data logger and motion sensor in ROV. The three component magnetometer measure the X (North), Y (East) and Z (Vertical) vector components of a magnetic field. A motion sensor (Octans) provided us the data of pitch, roll, yaw for the correction of the magnetic data to the motion of ROV. In the survey, ROV followed the tracks of the plan at 50 m above seafloor. The data of the magnetometer and motion sensors and the USBL(Ultra Short B slope of the caldera of TA25 using IBRV(Ice Breaker Research Vessel) ARAON of KIOST (Korea Institute of Ocean Science & Technology) and ROV of Oceaneering Co. And, at Jan. 2012, the magnetic survey was conducted in the western (site A) and eastern (site B) slopes of the caldera of TA25 and the summit area of TA26 using German R/V SONNE and ROV of ROPOS Co. The 2011 and 2012 three component magnetic survey lines were the 13 N-S lines and the 29 N-S lines (TA25-East : 12 lines, TA25-West : 11 lines, TA26 : 6 lines) with about 100 m spacing, respectively. Also, we conducted the 8 figure circle rotation survey of ROV for magnetic calibration at 2011 and 2012. For the magnetic survey, the magnetometer sensor was attached with the line frame of ROV and the data logger and motion sensor in ROV. The three component magnetometer measure the X (North), Y (East) and Z (Vertical) vector components of a magnetic field. A motion sensor (Octans) provided us the data of pitch, roll, yaw for the correction of the magnetic data to the motion of ROV. In the survey, ROV followed the tracks of the plan at 50 m above seafloor. The data of the magnetometer and motion sensors and the USBL(Ultra Short B