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Tracking high‐frequency seismic source evolution: 2004 M w 8.1 Macquarie event
Author(s) -
Kennett B. L. N.,
Gorbatov A.,
Spiliopoulos S.
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058935
Subject(s) - intraplate earthquake , seismology , geology , ridge , fault (geology) , event (particle physics) , paleontology , physics , quantum mechanics , tectonics
The 2004 M w 8.1 event on 23 December 2004 near the Macquarie Ridge is a very large intraplate event that has been overshadowed by the M w 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.