Three-component magnetic logging in the Louisville seamounts

2010年12月至2011年2月，国际海洋钻探计划将对太平洋海底火山链路易斯维尔海山进行考察。在我们的项目中，我们将分析在探险队的四个钻孔中进行的钻孔磁性测量。其目的是确定穿透熔岩的反射磁化，由此可以估计岩石形成时的地理位置。这提供了关于路易斯维尔热点可能运动的重要信息，路易斯维尔热点是探险的主要目标之一。测量将使用哥廷根钻孔磁力计进行，这是世界上唯一配备光纤陀螺仪的磁力计。陀螺仪允许精确的工具定向，从而确定磁场的所有三个分量。三分量数据使我们能够确定的方向，特别是衰减的reflectance磁化，这构成了一个重要的信息，以重建路易斯维尔热点运动。要达到足够的精度，需要广泛的标定、数值模拟以及校正方法和反演程序的改进。

From December 2010 to February 2011, an expedition of the international ocean drilling program (IODP) will be carried out to the Louisville seamounts, a submarine volcanic chain in the Pacific Ocean. In our project, we will analyse borehole magnetic measurements taken in the four boreholes of the expedition. The aim is to determine the remanent magnetization of the penetrated lavas, from which the geographic location at the time of the rock formation can be estimated. This provides important information on the possible motion of the Louisville hotspot, one of the main goals of the expedition. The measurements will be taken with the Göttingen borehole magnetometer, the only magnetometer worldwide equipped with fiber optic gyros. The gyros allow an accurate tool orientation and thus the determination of all three components of the magnetic field. The three-component data enable us to determine the direction, in particular the declination of the remanent magnetization, which constitutes an essential piece of information to reconstruct the Louisville hotspot motion. The achievement of a sufficient accuracy requires extensive calibration, numercial simulation and the improvement of correction methods and inversion routines.