ABSTRACT

The M_w 7.8 Kaikōura earthquake of November 14th, 2016 provided rare opportunities to evaluate ground deformation during a large strike-slip earthquake. Following the earthquake, both halves of a displaced paleoseismic trench were re-excavated and extended to test, refine, and extend the known late Holocene chronology of surface rupturing earthquakes on the Kekerengu Fault. 28 organic-bearing samples were collected during these excavations. Of these, six samples provided new ¹⁴C ages that could be superimposed on the preferred age model of (Little VDR, Kearse J, Norton K, Benson A, Wang N. 2018. Kekerengu fault, New Zealand: Timing and size of Late Holocene surface ruptures. Bulletin of the Seismological Society of America. 108(3B):1556–1572) to derive an expanded, updated age model of earthquake events on the fault that is now based on 16 dated samples. Including the 2016 earthquake, we recognise six surface rupturing earthquakes on the Kekerengu Fault since ∼2000 cal. B.P. Based on the last five events, our analysis yields an updated estimate of the mean recurrence interval for surface rupturing on the fault of 375 ± 32 yrs (1σ) since ∼1650 cal. B.P. An older, sixth event (E5) was not included in the preferred age model due to uncertainties in interpretation; however, incorporating this event into an alternative, six-event age model would adjust the recurrence interval estimate to 433 ± 22 yrs (1σ) since ∼2000 cal. B.P.

摘要

_{2016 年 11 月 14 日发生的 7.8 级}凯库拉地震为评估大型走滑地震期间的地面变形提供了难得的机会。地震发生后，重新挖掘并扩建了一个移位的古地震沟槽的两半，以测试、改进和扩展已知的全新世晚期 Kekerengu 断层地表破裂地震的年代学。在这些挖掘过程中收集了 28 个有机样品。其中，六个样本提供了新的¹⁴ C 年龄，可以叠加到首选年龄模型（Little VDR、Kearse J、Norton K、Benson A、Wang N. 2018。新西兰 Kekerengu 断层：晚全新世的时间和大小地表破裂。美国地震学会公报。108(3B):1556–1572) 推导出一个扩展的、更新的断层地震事件年龄模型，该模型现在基于 16 个有日期的样本。包括 2016 年地震在内，我们认识到自 2000 年以来在 Kekerengu 断层上发生了六次地表破裂地震。BP 基于最近五个事件，我们的分析得出了自 ∼1650 cal 以来 375 ± 32 年 (1σ) 断层表面破裂的平均复发间隔的更新估计。BP 由于解释的不确定性，较早的第六次事件 (E5) 未包含在首选年龄模型中；然而，将此事件纳入替代的六事件年龄模型会将复发间隔估计调整为 433 ± 22 岁 (1σ)，因为 ∼2000 cal。英国石油公司