Intraplate earthquakes in Australia - Intraplate Earthquakes - page 11

Figure 2.2 Indo-Australian Plate with plate boundary forces and orientation of modelled maximum
and minimum horizontal stresses used in the finite element stress modelling of Reynolds et al .
( 2002 ) . Much of the southern part of the continent has an east-west-oriented maximum horizontal
compressive stress oriented at a high angle to the NNE-oriented plate velocity vector. Solid triangles
indicate the direction of subduction and open triangles delineate the Banda Arc. TK, Tonga-Kermadec
Trench; AAD, Australian-Antarctic discordance. (Modified after Reynolds et al ., 2002 and Hillis
et al ., 2008 . )
which records remain were four Milne seismographs established between 1901 and 1909
(Doyle and Underwood, 1965 ; McCue, 2004 ) . The seismograph network remained sparse
until 1962-3, after which time the Australian catalogue could be considered complete for
magnitude ( M ) 5.0 and above earthquakes, and instrumental records largely replaced felt
reports as the primary information source (McCue, 2004 ; Leonard, 2008 ) . Doyle et al .
( 1968 ) summarised the history of earthquakes and seismological research in Australia up
to 1966, and prepared a comprehensive reference list of historical earthquake sources. The
authors tabulated over 160 Australian earthquakes, which formed the core of the preliminary
digital Australian earthquake catalogue (Denham et al ., 1975 ) . Despite enhancements
resulting in the lowering of the completeness magnitude for the national catalogue to