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Paleoseismicity of two historically quiescent faults in Australia: Implications for fault behavior in stable continental regions

Bulletin of the Seismological Society of America

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Abstract

Paleoseismic studies of two historically aseismic Quaternary faults in Australia confirm that cratonic faults in stable continental regions (SCR) typically have a long-term behavior characterized by episodes of activity separated by quiescent intervals of at least 10,000 and commonly 100,000 years or more. Studies of the approximately 30-km-long Roopena fault in South Australia and the approximately 30-km-long Hyden fault in Western Australia document multiple Quaternary surface-faulting events that are unevenly spaced in time. The episodic clustering of events on cratonic SCR faults may be related to temporal fluctuations of fault-zone fluid pore pressures in a volume of strained crust. The long-term slip rate on cratonic SCR faults is extremely low, so the geomorphic expression of many cratonic SCR faults is subtle, and scarps may be difficult to detect because they are poorly preserved. Both the Roopena and Hyden faults are in areas of limited or no significant seismicity; these and other faults that we have studied indicate that many potentially hazardous SCR faults cannot be recognized solely on the basis of instrumental data or historical earthquakes. Although cratonic SCR faults may appear to be nonhazardous because they have been historically aseismic, those that are favorably oriented for movement in the current stress field can and have produced unexpected damaging earthquakes. Paleoseismic studies of modern and prehistoric SCR faulting events provide the basis for understanding of the long-term behavior of these faults and ultimately contribute to better seismic-hazard assessments.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Paleoseismicity of two historically quiescent faults in Australia: Implications for fault behavior in stable continental regions
Series title:
Bulletin of the Seismological Society of America
Volume
93
Issue:
5
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Bulletin of the Seismological Society of America
First page:
1913
Last page:
1934
Number of Pages:
22