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Assessing the contribution of off‐fault deformation to slip‐rate estimates within the Taupo Rift, New Zealand, using 3‐D ground‐penetrating radar surveying and trenching
Author(s) -
McClymont Alastair Fergus,
Villamor Pilar,
Green Alan G.
Publication year - 2009
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2009.00901.x
Subject(s) - geology , trench , seismology , ground penetrating radar , rift , geodetic datum , slip (aerodynamics) , interferometric synthetic aperture radar , fault (geology) , radar , geodesy , tectonics , remote sensing , synthetic aperture radar , telecommunications , chemistry , physics , organic chemistry , layer (electronics) , computer science , thermodynamics
We demonstrate that conventional palaeoseismic trenching and mapping techniques that do not account for the effects of off‐fault deformation can significantly underestimate a fault’s slip rate. Using combined interpretations of 3‐D ground‐penetrating radar (GPR) and palaeoseismic trench data, we show that drag folding and hangingwall and footwall horizontal‐axis rotations have accommodated up to 41% of total extension across a normal fault within the Taupo Rift, New Zealand, over the past 24.6 ± 1.0 cal. ka BP. Our results may explain why geologically determined fault‐slip rates for the central and southern Taupo Rift are anomalously low when compared with geodetic estimates. We suggest that a combination of GPR surveying and palaeoseismic trenching may help resolve differences between geodetically and geologically determined strain rates observed across active extensional regimes worldwide.