海上における地磁気三成分異常の研究

抄録

Vector data of the geomagnetic field provide more detailed information than total intensity geomagnetic data for understanding the magnetic structure of oceanic crust. In the last few years, the invention and development of the Shipboard Three Component Magnetometer (STCM) has successfully provided geomagnetic field vector data in many areas in the oceans. There are two main advantages in using vector geomagnetic anomaly field data: (1) total intensity anomaly amplitudes are often much reduced depending on the orientation of the ambient geomagnetic field and magnetic lineation while these have no effect on vector anomalies, and (2) vector geomagnetic anomaly field data provide the positions, strikes and characters of magnetic boundaries, allowing changes in these boundaries to be identified along individual ship tracks. These advantages permit tectonic interpretations to be well constrained, even in areas of sparse ship track data coverage. Furthermore, intensity variations in the vector geomagnetic anomaly field along spreading axes may be used to investigate spreading axis thermal anomalies.