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Landslides in the Sydney Basin - Geoscience Australia

Landslides in the Sydney Basin - Geoscience Australia

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Seismic Hazard <strong>in</strong> <strong>Sydney</strong>Proceed<strong>in</strong>gs of <strong>the</strong> one day workshopEvidence for recent and cont<strong>in</strong>u<strong>in</strong>g activity on faults of <strong>the</strong> nor<strong>the</strong>rn LSC is also provided by <strong>the</strong>impedance of Burralow Creek by <strong>the</strong> Burralow Fault, and by disequilibrium stream profiles whereeasterly flow<strong>in</strong>g dra<strong>in</strong>age crosses <strong>the</strong> LSC (Rawson 1990; Rawson and Clark, this volume). Anevolutionary model for <strong>the</strong> LSC is proposed which reconciles this evidence for late Cenozoic upliftacross <strong>the</strong> LSC and <strong>the</strong> observation that <strong>the</strong> Rickaby’s Creek Gravels overlie shale on <strong>the</strong>Cumberland Pla<strong>in</strong> and sandstone on <strong>the</strong> Lapstone Monocl<strong>in</strong>e. This model, while prelim<strong>in</strong>ary,suggests that <strong>the</strong> f<strong>in</strong>d<strong>in</strong>gs of a major seismic hazard assessment of <strong>the</strong> <strong>Sydney</strong> Bas<strong>in</strong> which suggestsmagnitude M W 7.0 and greater earthquake events might be expected on <strong>the</strong> LSC on average every15-30 ka should be treated with caution. This expectation of regular recurrence must be temperedby <strong>the</strong> possibility that a large part of <strong>the</strong> relief relat<strong>in</strong>g to <strong>the</strong> complex may have formed <strong>in</strong> <strong>the</strong> lateMiocene (e.g. Sandiford et al. 2004), and evidence from o<strong>the</strong>r <strong>Australia</strong>n <strong>in</strong>traplate faults suggest<strong>in</strong>gthat large earthquake occurrence is markedly temporally clustered (e.g. Crone et al. 1997, 2003;Clark 2007; Clark et al., <strong>in</strong> press).ACKNOWLEDGMENTSThanks to John Pickett for a very constructive critique of <strong>the</strong> model presented here<strong>in</strong>. He and KerrieTomk<strong>in</strong>s are also thanked for animated discussions related to <strong>the</strong> evolution of <strong>the</strong> LSC. Thismanuscript benefited from constructive reviews by Dr. Andrew McPherson and Dr Clive Coll<strong>in</strong>s.This paper is published with <strong>the</strong> permission of <strong>the</strong> Chief Executive Officer, <strong>Geoscience</strong> <strong>Australia</strong>REFERENCESABEL R.S. 1985. Geology of <strong>the</strong> Lake George Bas<strong>in</strong>, N.S.W. Bureau of M<strong>in</strong>eral Resources,Geology and Geophysics Record 1985/4, 57p.AHMADI R., OUALI J., MERCIER E., MANSY J.-L., VAN-VLIET LANOE B., LAUNEAU P.,RHEKHISS F. AND RAFINI S. 2006. The geomorphologic responses to h<strong>in</strong>ge migration <strong>in</strong><strong>the</strong> fault-related folds <strong>in</strong> <strong>the</strong> Sou<strong>the</strong>rn Tunisian Atlas. Journal of Structural Geology 28, 721-728.ALLMENDINGER R. W. 1998. Inverse and forward numerical modell<strong>in</strong>g of trishear faultpropagationfolds. Tectonics 17, 640-656.AUSTRALIAN OIL AND GAS CORPORATION LTD, 1966. Putty-Oakdale Seismic Survey, SectionA-B-C-D through Kurrajong Heights No. 1 Well, Map.BERRYMAN K., ET AL. [INSTITUTE OF GEOLOGICAL AND NUCLEAR SCIENCES LIMITED], 1999.Seismic hazard analysis, Lucas Heights, site of <strong>the</strong> high flux <strong>Australia</strong>n reactor. <strong>Australia</strong>nNuclear Science and Technology Organisation (ANSTO) report(http://www.ansto.gov.au/<strong>in</strong>fo/library/wnaugust2004.html), Call number: 621.039.583/16.BISHOP P., HUNT P. AND SCHMIDT P.W. 1982. Limits to <strong>the</strong> age of <strong>the</strong> Lapstone Monocl<strong>in</strong>e,N.S.W. - a palaeomagnetic study. Journal of <strong>the</strong> Geolical Society of <strong>Australia</strong>, 29, 319-326.BISHOP P. 1986: Horizontal stability of <strong>the</strong> <strong>Australia</strong>n cont<strong>in</strong>ental dra<strong>in</strong>age divide <strong>in</strong> South CentralNew South Wales dur<strong>in</strong>g <strong>the</strong> Ca<strong>in</strong>ozoic. <strong>Australia</strong>n Journal of Earth Sciences 33, 295-307.BRANAGAN D. F. AND PEDRAM H. 1990. The Lapstone Structural Complex, New South Wales.<strong>Australia</strong>n Journal of Earth Sciences 37, 23-36.BRANAGAN D. F., 1969. The Lapstone Monocl<strong>in</strong>e and associated structures. Advances <strong>in</strong> <strong>the</strong>Study of <strong>the</strong> <strong>Sydney</strong> Bas<strong>in</strong>, 4th Symposium. Department of Geology, University ofNewcastle. pp. 61-62BRYAN J. H. 1966. Geology of <strong>the</strong> <strong>Sydney</strong> 1:250 000 sheet. Geological Survey of New SouthWales 1:250 000 Geological Series Explanatory Notes, 46 pp.CARNE J. E. 1908. Geology and m<strong>in</strong>eral resources of <strong>the</strong> western coalfield. Memoir of <strong>the</strong>Geological Survey of New South Wales. 6.CHESNUT W. S. 1982. Notes on <strong>the</strong> occurrence of lateritic gravels (?Rickaby’s Creek Gravel) at <strong>the</strong>RAAF Base, Lapstone, NSW. Geological Survey of New South Wales Report GS 1980/473.43

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