Collaborative research: acoustic logging of the WAIS Divide borehole

0944199/ matsuoka该奖项支持一个项目，该项目测试了织物突变存在的假设，并与气候变化和火山爆发有关。它需要对织物进行深度连续测量。在完成岩心钻探后，通过将一种新的测井工具放入WAIS Divide井眼，该项目将测量声波速度作为深度的函数，并根据冰结构进行解释。这种解释将以稀疏深度的冰芯测量织物为指导。该项目将应用现有的冰盖测井分析技术，并在短间隔（~ 1米）估计纵波和横波速度的深度剖面。以前的测井项目只测量了平均5-7米间隔的压缩波速度。因此，新的记录器将支持更精确的结构解释。利用薄片对织物进行测量，发现了不同的织物图案，相隔不到几米；在较短的时间内测量织物是至关重要的。在WAIS Divide井眼，将使用不同的观测参数进行六次双向测井，以便识别多种波传播模式，从而获得纵波和横波速度的估计。每次作业大约需要24小时才能完成；我们建议总共占用8天的钻孔时间。WAIS分水岭的测井临时计划在2011年12月进行，但时间并不重要。这个项目吗?S的范围仅限于完成日志记录和结构解释。结果将立即与其他WAIS Divide研究人员共享。这种数据共享的直接好处包括指导进一步的薄层分析，推导出精确的减薄函数，从而获得更准确的积累历史和深度年龄尺度。该项目的pi在该地区进行了雷达和地震调查，该项目将为这些区域冰内部的遥感评估提供基础事实。反过来，这些遥感手段可以将结果从钻孔扩展到南极洲中西部的更大地区。本项目资助两名地球物理、冰川学、古气候和极地物流专业的研究生。本项目将获得的仪器可用于其他钻孔的冰结构特征和冰川水文（温带冰的湿度）。

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).