Seismic characterization of the DFDP-2 drill hole environment

DFDP-2钻孔环境的地震特征

• 批准号: 270821955
• 负责人: Professor Dr. Stefan Buske
• 金额: --
• 依托单位: Institut für Geophysik und Geoinformatik
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/270821955?language=en
• 关键词: Seismic; characterization; DFDP; drill; hole

The Alpine Fault (South Island, New Zealand) is one of the largest active fault zones on earth, which ruptures every 200-400 years in a magnitude ~7.9 earthquake. 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. In that context 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 first phase of the project (DFDP-1) was undertaken in 2011 with drilling of two shallow boreholes through the Alpine Fault at Gaunt Creek. Preparations are now under way for the second phase of the project (DFDP-2) which will be conducted in the Whataroa Valley, and will reach a depth of approximately 1.4 km. The latter borehole (DFDP-2) will be drilled through the Alpine Fault at a depth of about 1.2 km, based on the imaging results of our active-source seismic drill site characterization survey (WhataDUSIE) acquired in 2011.Here it is proposed to use this new borehole (DFDP-2) to conduct an extended walkaway vertical seismic profiling (W-VSP) experiment using fixed borehole sensors as well as surface receivers to record active seismic sources distributed mainly along the previous WhataDUSIE profile line. The result will be a high-resolution image of the geometry and structure of the Alpine Fault and its subsurface environment, especially at those depths which the proposed drilling operation might target. The resulting images will enable to relate borehole logging results as well as core and physical property measurements to the adjacent parts of the Alpine Fault and its larger-scale geometry and structure. This is equally important for a better understanding of the local tectonic setting and for evaluating earthquake rupture scenarios and the related geohazard, thereby providing an important basis for most of the associated DFDP-AF research groups.

高山断层（新西兰南岛）是地球上最大的活动断层带之一，每 200-400 年就会发生一次 7.9 级地震。深部断层钻探项目高山断层（DFDP-AF）提出对高山断层进行深部钻探、采样和监测，利用良好的地表暴露和相对较浅的地质转变深度，从而更好地了解岩石变形、地震发生（地震引发和破裂）和地震变形的基本过程。在这种背景下，阿尔卑斯断层构成了一个国际重要的自然实验室，用于研究活动的板块边界大陆断层如何工作，特别是地震产生的性质。 该项目的第一阶段 (DFDP-1) 于 2011 年开始，在冈特溪的阿尔卑斯断层上钻了两个浅井。该项目第二阶段（DFDP-2）的准备工作正在进行中，该项目将在 Whataroa 山谷进行，深度约为 1.4 公里。根据我们2011年获得的主动源地震钻探现场特征调查（WhataDUSIE）的成像结果，后一个钻孔（DFDP-2）将穿过阿尔卑斯断层约1.2公里的深度。这里建议使用这个新钻孔（DFDP-2）并使用固定钻孔传感器进行扩展无人垂直地震剖面（W-VSP）实验 作为地面接收器来记录主要沿先前 WhataDUSIE 剖面线分布的活动地震源。结果将是阿尔卑斯断层及其地下环境的几何形状和结构的高分辨率图像，特别是在拟议钻探作业可能目标的深度。生成的图像将能够将钻孔测井结果以及岩心和物理特性测量结果与阿尔卑斯断层的邻近部分及其更大规模的几何和结构联系起来。这对于更好地了解当地构造环境以及评估地震破裂情景和相关地质灾害同样重要，从而为大多数相关的 DFDP-AF 研究小组提供了重要基础。

项目成果

Comparison of fiber-optic sensor and borehole seismometer VSP surveys in a scientific borehole: DFDP-2b, Alpine Fault, New Zealand

• DOI: 10.1190/segam2016-13946302.1
• 发表时间: 2016
• 期刊: Seg Technical Program Expanded Abstracts
• 作者: A. Constantinou;D. Schmitt;R. Kofman;R. Kellett;J. Eccles;D. Lawton;M. Bertram;K. Hall;John Townend;M. Savage;S. Buske;V. Lay;A. Gorman