Beyond Tides - Determination of Core Properties from Superconducting Gravimeter Observations

Abstract

The analysis of many long records of superconducting gravimeter observations at stations with a wide geographical distribution has led to the detection of the three translational modes of oscillation of Earth's solid inner core, both in European observa tions (Smylie et al., 1993), and in observations outside Europe (Courtier et al., 2000). Due to Earth's rotation, the modes are split with periods found at 3.5822 f 0.0012, 3.7656 f 0.0015, and 4.0150 f 0.0010 hours. In this paper, we show how these observa tions can be used to determine the viscosity in the F-layer just outside the inner core and to confirm the inner core density of Earth model Cal8 of Bolt and Uhrhammer (Bullen and Bolt, 1985, Appendix).