Collaborative research: acoustic logging of the WAIS Divide borehole

合作研究：WAIS Divide 钻孔的声波测井

• 批准号: 0944285
• 负责人: Sridhar Anandakrishnan
• 金额: $ 16.45万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944285&HistoricalAwards=false
• 关键词: Collaborative; research; acoustic; logging; WAIS

0944199/MatsuokaThis award supports a project to test the hypothesis that abrupt changes in fabric exist and are associated with both climate transitions and volcanic eruptions. It requires depth-continuous measurements of the fabric. By lowering a new logging tool into the WAIS Divide borehole after the completion of the core drilling, this project will measure acoustic-wave speeds as a function of depth and interpret it in terms of ice fabrics. This interpretation will be guided by ice-core-measured fabrics at sparse depths. This project will apply established analytical techniques for the ice-sheet logging and estimate depth profiles of both compressional- and shear-wave speeds at short intervals (~ 1 m). Previous logging projects measured only compressional-wave speeds averaged over typically 5-7 m intervals. Thus the new logger will enable more precise fabric interpretations. Fabric measurements using thin sections have revealed distinct fabric patterns separated by less than several meters; fabric measurements over a shorter period are crucial. At the WAIS Divide borehole, six two-way logging runs will be made with different observational parameters so that multiple wave-propagation modes will be identified, yielding estimates of both compressional- and shear-wave speeds. Each run takes approximately 24 hours to complete; we propose to occupy the boreholes in total eight days. The logging at WAIS Divide is temporarily planned in December 2011, but the timing is not critical. This project?s scope is limited to the completion of the logging and fabric interpretations. Results will be immediately shared with other WAIS Divide researchers. Direct benefits of this data sharing include guiding further thin-section analysis of the fabric, deriving a precise thinning function that retrieves more accurate accumulation history and depth-age scales. The PIs of this project have conducted radar and seismic surveys in this area and this project will provide a ground truth for these regional remote-sensing assessments of the ice interior. In turn, these remote sensing means can extend the results from the borehole to larger parts of the central West Antarctica. This project supports education for two graduate students for geophysics, glaciology, paleoclimate, and polar logistics. The instrument that will be acquired in this project can be used at other boreholes for ice-fabric characterizations and for englacial hydrology (wetness of temperate ice).

0944199/Matsuoka该奖项支持一个项目，以测试存在结构突变的假设，并与气候转变和火山爆发有关。它需要对织物进行深度连续测量。在岩心钻探完成后，通过将一个新的测井工具下放到WAIS分水岭钻孔中，该项目将测量作为深度函数的声波速度，并根据冰组构对其进行解释。这种解释将指导冰芯测量织物在稀疏的深度。 该项目将应用既定的冰盖测井分析技术，并估计短间隔（~ 1 m）的压缩波和剪切波速度的深度剖面。以前的测井项目仅测量通常5-7米间隔内的平均压缩波速度。因此，新的记录器将实现更精确的织物解释。使用薄切片的织物测量揭示了不同的织物图案，其间隔小于几米;在较短的时间内进行织物测量至关重要。 在WAIS分水岭井眼，将用不同的观测参数进行六次双向测井，以便确定多种波传播模式，得出压缩波和剪切波速度的估计值。每次钻探大约需要24小时完成;我们建议总共占用钻孔8天。WAIS分水岭的伐木工作暂定于2011年12月进行，但时间并不重要。 这个项目？的范围仅限于完成测井和结构解释。 研究结果将立即与其他WAIS Divide研究人员分享。这种数据共享的直接好处包括指导进一步的组构薄片分析，得出精确的变薄函数，检索更准确的积累历史和深度年龄尺度。该项目的主要研究人员在这一地区进行了雷达和地震调查，该项目将为这些冰内部的区域遥感评估提供地面实况。反过来，这些遥感手段可以将钻孔的结果扩大到西南极洲中部的更大部分地区。 该项目为两名研究生提供了地球物理学、冰川学、古气候学和极地物流学方面的教育。本项目将获得的仪器可用于其他钻孔，用于冰组构表征和冰川水文学（温带冰的湿度）。