New Zealand Journal of Geology & Geophysics abstracts
Short communication
Reassessment of slip rate and implications for surface rupture
hazard of the Martinborough Fault, South Wairarapa, New Zealand
Nicola Litchfield*
Russell Van Dissen
Andrew Nicol
GNS Science
PO Box 30368
Lower Hutt 5040, New Zealand
*Corresponding author: n.litchfield@gns.cri.nz
Abstract New mapping of the Martinborough Fault utilising
high resolution LIDAR data and orthophotos defines a c. 1.3 km
long active fold trace consisting of a broad (50–150 m wide) warp
crossing dissected alluvial fans. GPS survey profiles across the
fold-scarp reveal vertical separations ranging from 1.2 to 6 m on two
fan surfaces. Published OSL ages imply a Porewan age for the upper fan
(surface age c. 55 ka). We calculate a revised vertical slip rate
of c. 0.1 mm/yr (previously published rates range between 0.3 and
0.67 mm/yr) and a recurrence interval of c. 15 000 yr from these
new data. This places the fault within the Ministry for the Environment
Active Fault Guidelines Recurrence Interval Class V (>10 000 to
≤20 000 yr), to which a medium level of confidence is assigned.
Keywords Martinborough Fault; Wairarapa; reverse fault; slip
rate; alluvial fan; MfE Active Fault Guidelines
G07007; Online publication date 25 July 2007; Received 2 May 2007;
accepted 28 June 2007
New Zealand Journal of Geology & Geophysics, 2007, Vol. 50:
239–243
0028–8306/07/5003–0239 © The Royal Society of New Zealand 2007
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