Friction and Microstructure of the Papaku Fault, Hikurangi

This study focuses on the Pāpaku fault, a major splay fault in the Hikurangi prism which shows evidence of both brittle and ductile in-situ deformation. The Hikurangi subduction zone, located off the eastern coast of New Zealand's North Island, is known for regularly repeating slow slip events which occur at very shallow depths, possibly reaching the seafloor. We performed laboratory friction experiments on 8 intact core samples spanning the Pāpaku fault from 237-450 mbsf, recovered during IODP Expedition 375. The experiments were conducted at in-situ effective normal stress and driving velocities as low as the plate convergence rate of 5 cm/yr. Following the shearing experiments, the samples were analyzed for microstructure with scanning electron microscopy.

本研究聚焦于帕帕库断层，该断层位于希库兰迪棱镜中，是一处主要的分支断层，表现出脆性和韧性原地变形的证据。位于新西兰北岛东海岸的希库兰迪俯冲带，以其规律性重复发生的浅层慢滑事件而闻名，这些事件可能达到海底深度。我们对IODP 375航次中回收的237至450米海底以下帕帕库断层处的8个完整岩心样本进行了实验室摩擦实验。实验在原地有效正应力和驱动速度下进行，驱动速度低至板块汇聚速率的5厘米/年。在剪切实验之后，样本经扫描电子显微镜分析，以研究其显微结构。