A New Method For Precise Determination of the Position and Strike of Magnetic Boundaries Using Vector Data of the Geomagnetic Anomaly Field

Abstract

SUMMARY We present a new method which provides precise determination of the position and strike of magnetic boundaries using vector data of the geomagnetic anomaly field. Assuming a 2-D magnetic structure, the intensity of spatial differential vectors (ISDV) exhibits a peak at the boundary of magnetic structures. the strike of the magnetic boundary is obtained using the fact that the magnetic field is zero in the direction parallel to the boundary. We have also applied this method to 3-D magnetic structures. Our method requires only the relative changes of the three components, which are more accurately measured than their actual magnitudes. We have applied this method to data from the southern Juan de Fuca Ridge obtained on the R/V ‘Hakuho-maru’ expedition in 1988 (KH-88-3). the results are summarized in magnetic boundary strike diagrams (MBSD); these are maps that show the position, strike and character of the magnetic boundaries. MBSD provides valuable information for understanding the magnetic structure of oceanic crust, such as magnetic lineations, pseudo-faults, fracture zones and the central anomaly magnetic high (CAMH). Therefore, relatively few vector magnetic profiles provide information similar to extensive total intensity geomagnetic surveys.