Collaborative research: acoustic logging of the WAIS Divide borehole

0944199/Matsuoka该奖项支持一个项目，该项目旨在测试这样一个假设，即织物的突然变化存在，并与气候转变和火山喷发有关。它需要对织物进行深度连续测量。在岩心钻探完成后，通过将一台新的测井仪器放入WAIS分隔孔，该项目将测量声波速度作为深度的函数，并根据冰组构对其进行解释。这种解释将以稀疏深度的冰芯测量织物为指导。该项目将对冰盖测井应用既定的分析技术，并估计短间隔(约1米)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为5-7米间隔的纵波速度。因此，新的记录仪将能够更准确地解释织物。使用薄片的织物测量显示了不同的织物图案，相隔不到几米；较短时间内的织物测量是至关重要的。在WAIS分隔孔，将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，得出纵波和横波速度的估计。每次运行大约需要24小时才能完成；我们建议总共占用8天的井眼。WAIS Divide的伐木工作暂时计划在2011年12月进行，但时间并不关键。这个项目？S的范围仅限于完成测井和组构解释。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对织物进行进一步的薄片分析，得出精确的细化函数，从而检索更准确的累积历史和深度-年龄标尺。该项目的私人投资机构在这一地区进行了雷达和地震调查，该项目将为这些对冰层内部进行的区域遥感评估提供基本事实。反过来，这些遥感手段可以将钻孔的结果扩展到西南极洲中部的更大部分。该项目支持两名研究生的地球物理、冰川学、古气候和极地物流方面的教育。在该项目中将获得的仪器可用于其他钻孔，以确定冰层结构的特征，并用于气候水文学(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).