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Tracking high-frequency seismic source evolution: 2004 Mw 8.1 Macquarie event

Created 16/10/2025

Updated 16/10/2025

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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.

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Field Value
Title Tracking high-frequency seismic source evolution: 2004 Mw 8.1 Macquarie event
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/43777c97-c388-40d1-9155-2a503ab5988c
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 22/04/2018
Geospatial Coverage Australia
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Tracking high-frequency seismic source evolution: 2004 Mw 8.1 Macquarie event". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/tracking-high-frequency-seismic-source-evolution-2004-mw-8-1-macquarie-event