In the afternoon of Wednesday 25 March 1998, a very large magnitude 8.1 earthquake struck a remote area of the Southern Ocean.

[3] Nearby to the Balleny Islands is the Macquarie triple junction, where the Antarctic, Australian, and Pacific Plates meet.

This junction lays nearby to the Australia-Pacific pole of rotation, and so stresses are imparted into the interiors of the plates themselves rather than only at the boundaries.

[7] The earthquake occurred at a shallow depth and had a moment magnitude of 8.1, with its epicentre being located roughly 250 km (155 mi) south of the boundary between the Antarctic and Australian plates.

[8] The earthquake ruptured in a sinistral (left lateral) strike-slip manner, oriented east–west for a length of roughly 200 km (124 mi).

[9] Studies found that the stresses imparted into the interior of the Antarctic plate from the Macquarie triple junction were not consistent with the rupture pattern that was observed.