Abstract - The tectonic origin, paleoearthquake histories and slip rates of six normal faults
(referred to here as the Rahotu, Oaonui, Kina, Kiri, Ihaia and Pihama faults) have been
examined for up to ~26 kyr within the Taranaki Rift, New Zealand. A minimum of 13
ground-surface rupturing paleoearthquakes have been recognised on four of the faults
using analysis of displaced late Quaternary stratigraphy and landforms. These data, in
combination with 21 new radiocarbon dates, constrain the timing, slip and magnitude of
each earthquake. The faults have low throw rates (~0.1–0.8 mm/yr) and appear to be
buried near the Mt Taranaki volcanic cone. Recurrence intervals between earthquakes on
individual faults typically range from 3–10 kyr (average ~6 kyr), with single event
displacements ranging from ~0.3–1.5 m (average ~0.7 m) and corresponding magnitudes incorporating estimated fault rupture areas of Mw 6.1-6.6. Recurrence intervals and
single event displacements typically vary by up to a factor of three on individual faults,
with only the Oaonui Fault displaying near-characteristic slip (of about 0.5 m) during
successive earthquakes. The timing and slip of earthquakes on individual faults appear to
have been interdependent, with each event decreasing the likelihood of additional
earthquakes across the system.
New Zealand Journal of Geology and Geophysics, 53, 1-20, 2010.