43777c97-c388-40d1-9155-2a503ab5988c urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2025-10-16T08:34:21 creation ISO 19115 2016 Tracking high-frequency seismic source evolution: 2004 Mw 8.1 Macquarie event 43777c97-c388-40d1-9155-2a503ab5988c The 2004 Mw 8.1 event on 2004 December 23 near the Macquarie Ridge is a very large intraplate event that has been overshadowed by the Mw 9.3 Sumatra-Andaman event only three days later. We are able to track the progress of source evolution by estimating the progression of the points of energy emission, exploiting the good azimuthal distribution of available stations. The results indicate that this event ruptured on two nearby fault systems reactivating fossil fracture zones, with the second sub-event to the west triggered by the first. The total duration of high-frequency radiation is quite short, about 60 s, for such a large event. Much of the high-frequency radiation occurs on a fault sub-parallel to that inferred from long-period studies. This composite fault behaviour with displaced triggered failure appears to be a characteristic of large intraplate events in the oceans. Earth Sciences External Publication Published_External Scientific Journal Paper Link to Publication documentDigital Link to Publication HTML Unnamed resource documentDigital HTML