Seismic site characterization - Alpine Fault drilling project

阿尔卑斯断裂带（新西兰南岛）是地球上最大的活动断裂带之一。它每200-400年发生一次7.9级地震，据认为最后一次破裂是在公元1717年，这意味着具有重大的地质灾害潜力。除了具有地震危险性之外，阿尔卑斯断层还构成了一个国际上重要的天然实验室，用于研究活跃的板块边界大陆断层是如何工作的，特别是地震产生的性质。“深断层钻探项目-阿尔卑斯断层（DFDP-AF）”建议对阿尔卑斯断层进行深度钻探、取样和监测，以利用良好的地表暴露和相对较浅的地质转换深度，从而更好地了解岩石变形、地震发生（地震起震和破裂）和地震变形的基本过程。该计划钻井作业可行性的关键是提高对高山断层详细几何形状和结构的了解，特别是在拟议钻井作业可能针对的深度。我们建议对现有和新获得的主动和被动地震数据集进行处理，以确定高山断裂系统的几何形状和结构。主要结果将是断层带深层结构的高分辨率图像，这将主要作为详细选择DFDP-AF钻探地点的地震场地特征研究，以及更好地了解构造和地球动力学背景。随后，研究结果也可被其他研究人员用于相关地质灾害的可靠评估，为大多数相关的DFDP-AF研究小组提供了重要的依据。

The Alpine Fault (South Island, New Zealand) is one of the largest active fault zones on earth. It ruptures every 200-400 years in a magnitude ~7.9 earthquake, and is thought to have last ruptured in AD 1717, which implies a significant geohazard potential. In addition to its seismic hazard, the Alpine Fault constitutes an internationally significant natural laboratory for research into how active plate-bounding continental faults work and, in particular, the nature of earthquake generation. The "Deep Fault Drilling Project - Alpine Fault (DFDP-AF) proposes to drill, sample, and monitor the Alpine Fault at depth, to take advantage of excellent surface exposures and the relatively shallow depths of geological transitions, and hence to better understand fundamental processes of rock deformation, seismogenesis (earthquake initiation and rupture), and earthquake deformation. Key to the viability of this planned drilling operation is an improved knowledge of the detailed geometry and structure of the Alpine Fault, especially at the depths which the proposed drilling operation might target. We propose to process existing and newly acquired active and passive seismic data sets to determine the geometry and structure of the Alpine Fault system. The principal results will be high-resolution images of the fault zone structure at depth, which will serve primarily as a seismic site characterization study for the detailed selection of the DFDP-AF drill site as well as for a better understanding of the tectonic and geodynamic setting. Subsequently the results can also be used by other researchers for reliable assessment of the related geohazard, providing an important basis for most of the associated DFDP-AF research groups.