Derivation of direct on-fault submarine paleoearthquake records from high-resolution seismic reflection profiles, Cook Strait, New Zealand: Implications for fault interactions and stress loading
Abstract
Under favourable conditions, direct on-fault submarine paleoearthquake records can be derived from high-resolution seismic reflection profiles of active fault growth sequences. The most ideal conditions are when the long-term rate of sedimentation exceeds the rate of fault vertical displacement, and coseismic vertical increments of displacement and fault scarp development are preserved in the architecture of the growth sequence. In this case the interseismic period of sedimentation may comprise a post-seismic growth interval, covered by a uniformly thick sedimentation interval that developed after burial of the fault tip. Such intervals can be recognised on vertical displacement history curves, and from particular seismic stratigraphic relationships. In the generally less favourable situation where the long-term fault vertical displacement rate exceeds the sedimentation rate, it is still possible in some cases to recognise coseismic vertical displacements based on the specific architecture of the post-seismic growth sequence. We present a conceptual model, methodologies, and examples of paleoearthquake records for the offshore Wairau, Cloudy and Vernon faults in Cook Strait, New Zealand. We compile the offshore interpretations with onshore paleoearthquake records, and model Coulomb static stress loading, to investigate regional fault interactions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMOS43C1839P
- Keywords:
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- 3075 MARINE GEOLOGY AND GEOPHYSICS / Submarine tectonics and volcanism;
- 5475 PLANETARY SCIENCES: SOLID SURFACE PLANETS / Tectonics;
- 7221 SEISMOLOGY / Paleoseismology