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区之一，每200 - 400年间破裂〜7.9地震一次。深磨损的钻孔 - 标准 - 阿尔卑斯座（DFDP-AF）提议在深度钻，采样和监视高山故障，以利用出色的表面暴露和相对较浅的地质过渡深度，因此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。在这种情况下，高山断层构成了国际上重要的自然实验室，用于研究围绕板块的大陆断层，尤其是地震产生的性质。 该项目的第一阶段（DFDP-1）于2011年通过Gaunt Creek的高山断层进行了两个浅孔进行钻孔。现在正在为将在Whataroa山谷进行的项目的第二阶段（DFDP-2）进行准备，并将达到约1.4公里的深度。后者将根据我们的Active-Source seismic seil钻头表征调查（WhatAdusie）在2011年获得的成像结果，在大约1.2 km的深度通过高山断层钻出后一种钻孔（DFDP-2）。使用这个新的钻孔（DFDP-2），使用固定的钻孔传感器和表面接收器进行扩展的走路垂直地震分析（W-VSP）实验，以记录主要沿着上一个Adadusie Profile Line分布的主动地震源。结果将是高山断层及其地下环境的几何形状和结构的高分辨率图像，尤其是在建议的钻井操作可能针对的深度。所得的图像将使井眼记录结果以及核心和物理性质测量结果与高山断层的相邻部分及其更大规模的几何形状和结构相关联。这对于更好地理解当地构造环境和评估地震破裂情景和相关的地质扎华同样重要，从而为大多数相关的DFDP-AF-AF研究小组提供了重要的基础。

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