Development of a New Broadband Optical Seismometer

世界范围内的地震台网越来越复杂，需要能够探测到大范围振幅和频率的地球振动的地震仪。过去二十年来全球地震网使用的主要天文台级地震仪已不再生产，目前市场上也没有其他质量足够的商用产品。对于这种高质量的仪器，开发风险高，开发时间长，市场小，显然不足以提供商业可行性。为了满足全球地震学的仪器要求，我们将设计、建造和测试一种新的观测级地震仪，该地震仪将使用光纤干涉测量法记录悬挂在弹簧上的小质量的运动。使用光纤干涉测量而不是传统的电子位移传感器具有显著的优势。在这个计划的最后，我们期望开发、建造和测试一种新的天文台级地震仪，适用于拱顶或钻孔安装。这项拟议中的研究对于提高我们对地球的认识非常重要，因为它最终将产生更清晰的地球内部地震图像。它还将提供更好的井内观测，井内固有的地震信噪比更好。在此过程中，我们将进一步开发出具有足够灵敏度、动态范围和带宽的位移传感器，不仅可以满足观测级地震学的要求，而且还可以应用于其他领域。

EAR-0352877Zumberge World-wide seismic networks are increasingly complex and require seismometers that can detect Earth vibrations spanning a wide range of amplitude and frequency. The mainstay observatory-class seismometer used by global networks for the past two decades is no longer manufactured and there is no other commercially available product of sufficient quality on the market today. For such quality instruments, the development risk is high, the development time long, and the market small and apparently not sufficient to provide commercial viability. To meet the instrumentation requirements of global seismology, we will design, build and test a new observatory-class seismometer that will use optical fiber interferometry to record the motion of a small mass suspended on a spring. The use of optical fiber interferometry rather than traditional electronic displacement transducers affords significant advantages. At the conclusion of this proposed program, we expect to have developed, built and tested a new observatory-class seismometer suitable for either vault or borehole installation. The proposed research is important to advancing our knowledge of Earth because it will ultimately result in clearer seismic images of the interior. It will also provide for better observations from within boreholes, where the inherent seismic signal-to-noise ratio is better. In the process, we will have further developed a displacement sensor of sufficient sensitivity, dynamic range and bandwidth not only to satisfy the requirements of observatory-class seismology but with applications to other fields as well.