Authors / CoAuthors
Townsend, D. | Nicol, A. | Mouslopoulou, V. | Begg, J.G. | Beetham, R.J. | Clark, D. | Giba, M. | Heron, D. | Lukovic, B. | McPherson, A. | Seebeck, H. | Walsh, J.J.
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 slip/earthquake ranging from ~0.3-1.5 m (average ~0.7 m). Recurrence intervals and slip/earthquake 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 possibly relieving stress and decreasing the likelihood of additional earthquakes across the system. Earthquake magnitudes are estimated to be M 6.5-6.7. The dating resolution of paleoearthquakes is generally ±1-2 kyr and is presently too imprecise to test the temporal relations between seismic events and either volcanic eruptions or lahars formed by debris avalanches during cone collapse. It is unlikely, however, that formation of the ~7.8 kyr Opua Formation lahar was triggered by a large earthquake on the Rahotu, Oaonui or Kina faults which, of the faults studied, are farthest from the Mt Taranaki volcanic cone.
Product Type
nonGeographicDataset
eCat Id
69327
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
-
- External Publication
- ( Theme )
-
- earthquakes
- ( Theme )
-
- risk assessment
- ( Theme )
-
- geohazards
-
- NZ
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Earth Sciences
-
- Published_Internal
Publication Date
2009-07-23T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Lineage
Unknown
Parent Information
Extents
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not available.