Long term behaviour of Australian stable continental region (SCR) faults, and implications for earthquake hazard assessment  

Authors / CoAuthors

Clark, D.J. | McPherson, A. | Van Dissen, R.

Abstract

Australia boasts arguably the richest Quaternary faulting record of all the world's SCR crust. Extensive consultation with the earth science community, and recent advances in digital elevation model coverage, have allowed the compilation of an inventory of over 200 landscape features consistent with fault scarps relating to Quaternary surface breaking earthquakes. This record, together with a growing database of palaeoseismicity data, permits analysis of the long term behaviour of SCR faults in different geologic settings. Details of variations in palaeoearthquake magnitude (including maximum magnitude), recurrence characteristics (given appropriate scaling relations and assumptions relating to landscape modification rates) and spatial relationships between scarps in different deforming regions are recoverable. A common characteristic across Australia appears to be the temporal clustering of large earthquakes. Active periods of earthquake activity comprising a finite number of large events are separated by much longer periods of seismic quiescence. This episodic behaviour poses problems for probabilistic seismic hazard assessments (PSHAs) in that it implies that recurrence of large earthquake events is not random (Poisson). The points critical to understanding the hazard posed by such faults, and modelling this hazard probabilistically, become: 1) is the SCR fault in question about to enter an active period, in the midst of an active period, or in a quiescent period, 2) how many large events might constitute an active period, and how many previous ruptures has the fault generated in its current active period (should it be in one), and 3) what is the 'average' recurrence interval in an active period, and what is the variability around this average. This 'average' can be incorporated statistically into PSHAs, and must be considered when palaeoearthquake catalogues are combined with historic records.

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nonGeographicDataset

eCat Id

71406

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Keywords

• External PublicationConference Paper

( Theme )

• geohazards

( Theme )

• earthquakes

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

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2011-01-01T00:00:00

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Australian Government Security ClassificationSystem    

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Creative Commons Attribution 4.0 International Licence    

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Spatial Resolution

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