Open AccessLatest Pleistocene–Holocene Incremental Slip Rates of the Wairau Fault: Implications for Long‐Distance and Long‐Term Coordination of Faulting Between North and South Island, New Zealand
Author(s) -
Zinke R.,
Dolan J. F.,
Rhodes E. J.,
Van Dissen R. J.,
Hatem A. E.,
McGuire C. P.,
Brown N. D.,
Grenader J. R.
Publication year - 2021
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2021gc009656
Subject(s) - geology , seismology , slip (aerodynamics) , active fault , holocene , fault (geology) , pleistocene , sinistral and dextral , paleontology , physics , thermodynamics
We use high‐resolution lidar microtopographic data and luminescence dating to constrain incremental Holocene–latest Pleistocene slip rates for the Wairau fault, a major dextral strike‐slip fault in the Marlborough Fault System, South Island, New Zealand. Our data come from two closely spaced study areas along the structurally simple, central portion of the fault: The well‐known Branch River terrace flight, and a previously undated series of offset risers and channel features several km to the east that we refer to as the Dunbeath site. Field work and mapping using lidar‐derived topography yields revised or novel measurements of nine fault offsets. We date those features using a post‐IR 50 ‐IRSL 225 infrared stimulated luminescence dating method, and a stratigraphically informed Bayesian age model. The dated slip history of the Wairau fault is further constrained using newly cataloged offset measurements collected along a ∼35 km stretch of the fault, and available paleoseismic data. Incremental slip rates are precisely computed using a Monte Carlo resampling scheme. Our results provide a nearly earthquake‐by‐earthquake record of incremental slip, with pronounced variations in incremental slip rate spanning multiple millennia and tens of m of slip. These extreme, multi‐millennial variations in fault slip rate have basic implications for earthquake occurrence, plate boundary lithosphere behavior, and probabilistic seismic hazard assessment.