HR: 16:00h
AN: U42B-01    [PDF]
TI: Is the Recent Decrease in the Geomagnetic Dipole a Precursor of a Reversal?
AU: * Fuller, M
EM: mfuller@soest. hawaii.edu
AF: HIGP-SOEST, U. Hawaii, 1618 East-West Rd.,, Honolulu, HI 96822 United States
AB: Given the remarkable decrease observed in the strength of the geomagnetic dipole, two end members scenarios that may develop are (1) the dipole recovers and secular variation continues and (2) the field reverses within several thousand years. An argument for former is that the dipole has fluctuated in strength repeatedly throughout geological time without reversing. To justify advocating the latter scenario, one needs to show that the present behavior is particularly like the behavior of the geomagnetic field in the early stages of a reversal. However, to establish the transition field during reversals has proved very difficult. Efforts have concentrated on the simpler, but still difficult task of determining the VGP distributions during reversals. These distributions will be reviewed and new analyses presented that confirm earlier suggestions of preferred VGP paths during reversals. Models of the transition field will also be presented. From these, it appears that a region in the southern hemisphere plays an important role in reversals. It has frequently been noted that this is an area that is generating reversed magnetic field at present. Such behavior in the present field might be regarded as indicative of the onset of a reversal, or of an excursion.
DE: 1513 Geomagnetic excursions
DE: 1535 Reversals (process, timescale, magnetostratigraphy)
SC: U
MN: 2003 Fall Meeting