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at a centennial timescale in active intraplate northern China (Kusky et al ., 2007 ; Wheeler,
2011 ) with no recurrence over the 2,000-3,000-year window captured by the Chinese
record of historical seismicity. As crustal deformation rates in this 1,000 km
×
1,000 km
region of China are in the order of 1-2 mm/yr (Liu et al ., 2011 ) , such data might be
considered as a minimum seismicity migration rate for Australia at the neotectonic domain
scale.
There is some indication that the temporal clustering behaviour emerging from single-
fault studies in non-cratonic Australia may be symptomatic of a larger picture of the more-
or-less continuous tectonic activity from the late Miocene to Recent being punctuated by
“pulses” of activity in specific deforming regions (e.g., Quigley et al ., 2010 ; Clark et al .,
2012 ) . For example, major deformation episodes are constrained to the interval 6-4 Ma
in southwest Victoria (D4) (Paine et al ., 2004 ) and 2-1 Ma in the Otway Ranges (D5)
(Sandiford, 2003a ) . An episode of deformation ceased at 1.0 Ma in the offshore Gippsland
Basin (D5) although it continued onshore until
250 ka (Holdgate et al ., 2003 ) . Holdgate
et al .( 2008 ) present evidence from the southeast highlands that resurrects the idea of a
punctuated post-Eocene Kosciuszko Uplift event (Browne, 1967 ) that continued into the
late Pliocene and possibly the Pleistocene.
The Mount Lofty and Flinders Ranges (D2) are perhaps an exception to this rule. The
FRSZ has been associated with diffuse earthquake activity throughout the historic era
(Greenhalgh and Singh, 1988 ; Greenhalgh et al ., 1994 ) . While epicentres cannot in most
cases be confidently associated with neotectonic faults, strain rates and uplift rates estimated
from the seismic catalogue are approximately consistent with the number of neotectonic
faults and their paleoseismologically derived slip rates (e.g., Sandiford, 2003b ; Braun et al .,
2009 ) . Hence, it is possible that seismicity is a long-lived (millions of years) process in this
crustal setting.
While the suite of neotectonic fault behaviours may vary across Australia, as implied by
the neotectonic domains model, one individual fault characteristic appears to be common
to most Australian intraplate faults studied - active periods comprising a finite number
of events are separated by typically much longer periods of quiescence (Crone et al .,
1997 , 2003; Clark et al ., 2007 , 2008, 2011a, 2012; Estrada, 2009 , ) ( Figure 2.6 ) . Data and
modelling from elsewhere in the world identify similar episodic behaviour on faults with
low slip rates (e.g., Wallace, 1987 ; Ritz et al ., 1995 ; Marco et al ., 1996 ; Friedrich et al .,
2003 ) and suggest that the time between successive clusters of events (deformation phases)
is highly variable but significantly longer than the inter-event times between successive
earthquakes within an active phase (Marco et al ., 1996 ; Stein et al ., 1997 ; Chery et al .,
2001 ; Chery and Vernant, 2006 ; Li et al ., 2009 ) . This characteristic has been referred to
as Wallace-type behaviour (see Wallace, 1987 ) , and may be conceptualised using a model
similar to that proposed by Friedrich et al .( 2003 ) ( Figure 2.7 ) .
The sparse data available in Australia suggests that an active period (e.g., t 1 ,t 2 ,t 3 in
Figure 2.7 ) in cratonic central or western Australia (D1) might comprise as few as two
or three events (e.g., Hyden - Crone et al ., 2003 ; Clark et al ., 2008 ) , with interseismic
intervals between large events in an active period in the order of 20-40 ka (Crone et al .,
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