Tracking high-frequency seismic source evolution: 2004 Mw 8.1 Macquarie event
Article first published online: 22 FEB 2014
©2014 Commonwealth of Australia.
Geophysical Research Letters
Volume 41, Issue 4, pages 1187–1193, 28 February 2014
How to Cite
2014), Tracking high-frequency seismic source evolution: 2004 Mw 8.1 Macquarie event, Geophys. Res. Lett., 41, 1187–1193, doi:10.1002/2013GL058935., , and (
- Issue published online: 19 MAR 2014
- Article first published online: 22 FEB 2014
- Accepted manuscript online: 17 JAN 2014 10:07PM EST
- Manuscript Accepted: 15 JAN 2014
- Manuscript Received: 2 DEC 2013
- earthquake sources;
- energy projection;
- source evolution
The 2004 Mw 8.1 event on 23 December 2004 near the Macquarie Ridge is a very large intraplate event that has been overshadowed by the Mw 9.3 Sumatra-Andaman event only 3 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 subevent 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 subparallel to that inferred from long-period studies. This composite fault behavior with displaced triggered failure appears to be a characteristic of large intraplate events beneath the oceans.