Probabilistic Tectonic Hazard Analysis of the Otway Basin, Australia: Groundwork for the CO2CRC Otway Project  


Authors / CoAuthors

Stilring, M. | Litchfield, N. | Gerstenberger, M. | Clark, D. | Bradley, B. | Beavan, J. | McVerry, G. | Van Dissen, R. | Nicol, A. | Wallace, L. | Buxton, R.

Abstract

We present a probabilistic tectonic hazard analysis of a site in the Otway Basin,Victoria, Australia, as part of the CO2CRC Otway Project for CO2 storage risk. The study involves estimating the likelihood of future strong earthquake shaking and associated fault displacements from natural tectonic processes that could adversely impact the storage process at the site. Three datasets are used to quantify the tectonic hazards at the site: (1) active faults; (2) historical seismicity, and; (3) GPS surface velocities. Our analysis of GPS data reveals strain rates at the limit of detectability and not significantly different from zero. Consequently, we do not develop a GPS-based source model for this Otway Basin model. We construct logic trees to capture epistemic uncertainty in both the fault and seismicity source parameters, and in the ground motion prediction. A new feature for seismic hazard modelling in Australia, and rarely dealt with in low-seismicity regions elsewhere, is the treatment of fault episodicity (long-term activity versus inactivity) in the Otway model. Seismic hazard curves for the combined (fault and distributed seismicity) source model show that hazard is generally low, with peak ground acceleration estimates of less than 0.1g at annual probabilities of 10-3-10-4/yr. The annual probability for tectonic displacements of greater than or equal to 1m at the site is even lower, in the vicinity of 10-8-10-9/yr. The low hazard is consistent with the intraplate tectonic setting of the region, and unlikely to pose a significant hazard for CO2 containment and infrastructure.

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nonGeographicDataset

eCat Id

71583

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EGD  

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Commonwealth of Australia (Geoscience Australia)  
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Australia

Keywords

  • External PublicationScientific Journal Paper
( Theme )
  • earthquakes
( Theme )
  • geohazards
( Theme )
  • CO2 capture
Australian and New Zealand Standard Research Classification (ANZSRC)
  • Earth Sciences
  • Published_Internal

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2011-03-01T00:00:00

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