Mw 8.1 North of Macquarie Island
updated 5 May 2022

On 23 December 2004 a great earthquake occurred North of Macquarie Island at a depth of 33 km. The seismic event occurred at 14:59:11 UTC and had an estimated moment magnitude (Mw) 8.1 according to the USGS. The EMSC later estimated a moment magnitude 7.8.

On 19 December critical planetary geometry occurred when Mercury aligned with the Sun and Neptune converging with a high lunar peak (index 18). On the 23rd, as part of the next lunar peak (index 12), the Moon aligned with Mars, which tends to precede larger earthquakes, especially in combination with critical planetary geometry. At the time of the earthquake, Mercury was just 1° away from its alignment with the Sun and Uranus, which may have had more effect on the great earthquake three days later.


Mercury-Sun-Neptune       2004-12-19, 16:43:04  314°44'13"
Mercury-Sun-Uranus        2004-12-23, 20:55:24  336°00'46"

Moon-Earth-Jupiter        2004-12-20,  3:12:25  195°55'20"
Moon-Earth-Mars           2004-12-23, 13:30:06  238°29'55"
SSGI chart
SSGI COMMON graph of critical planetary (PG) and lunar (LG) geometry

SSGI chart
SSGI SUM graph of critical planetary (PG) geometry