2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)

Paper No. 272-4
Presentation Time: 8:50 AM

TILTING OF MARINE TERRACES ABOVE A LISTRIC THRUST FAULT


DUFFY, Brendan Gilbert, Department of Geological Sciences, University of Canterbury, 20 Kirkwood Avenue, Christchurch, 8041, New Zealand, brendan.duffy@clear.net.nz

A LiDAR survey over the Kaikoura Peninsula in the South Island of New Zealand provides new insight into the deformation and tilting of Kaikoura’s flight of uplifted shore platforms. The present terrace stratigraphy is incompatible with measured terrace tilts. This paper revises the terrace stratigraphy and reconciles measured tilting with a listric fault model. Geometric analysis of the tilt, and assignment of ages based on sea level curves, suggests that the fault has a slip rate of 3.33±0.12 mm/yr. Young uplifted beaches on the peninsula suggest a characteristic slip of 3.62±0.6 m on an offshore fault of the interpreted geometry. Based on calculated slip rates, the fault has a recurrence interval of 1.08±0.18ka. This represents an important and under-estimated, proximal seismic and tsunami hazard to Kaikoura.
Handouts
  • Duffy_Kaikoura.pptx (9.4 MB)