RAPID: Multiplexed Distributed Acoustic Sensing (DAS) at the Ocean Observatory Initiative (OOI) Regional Cabled Array (RCA)

分布式声学传感（DAS）是学术界相对较新的观测技术，其利用重复的激光脉冲询问光纤，并利用反向散射光的相位变化来测量沿光纤的应变率沿着。如果成功，这项测试将证明海洋观测计划（OOI）区域电缆阵列（RCA）上多路复用DAS的可行性，并将为使用众多现有电信电缆进行大规模海底监测打开大门。永久性的海上DAS阵列有可能大大提高卡斯卡迪亚俯冲带两次大地震的预警时间。2021年11月，NSF资助的试点实验证明了在俄勒冈州近海海洋观测计划（OOI）区域电缆阵列（RCA）的两条海底电缆中使用光纤进行DAS观测的可行性。该测试将利用计划的短暂维护停机，在同一电缆上使用同一仪器采集亮光纤和暗光纤DAS数据，以评估系统性能。它将于2024年3月在OOI RCA上进行为期4天的DAS测试，使用L波段DAS在照明光纤上进行记录，而不会中断普通RCA数据遥测。包括关机在内的测试的优点是，我们将观察有和没有电信数据的DAS数据质量，以及有和没有DAS的电信数据质量。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Distributed Acoustic Sensing (DAS) is a relatively new observational technique in academia that interrogates an optical fiber with repeated laser pulses and utilizes changes in the phase of backscattered light to measure the strain rate along the fiber. If successful, this test will demonstrate the feasibility of multiplexed DAS on the Ocean Observatory Initiative’s (OOI) Regional Cabled Array (RCA)and would open the door for large-scale seafloor monitoring using the numerous existing telecom cables. Permanent, offshore DAS arrays have the potential to dramatically improve warning times for both great earthquakes in the Cascadia subduction zone. University of Washington postdocs will get experience leading data acquisition and quality control analysis.In November 2021 NSF-funded pilot experiment demonstrated the feasibility of making DAS observations using optical fibers in the two submarine cables of the Ocean Observatory Initiative’s (OOI) Regional Cabled Array (RCA) offshore Oregon. This test will take advantage of a planned brief maintenance shutdown to acquire both lit-fiber and dark-fiber DAS data on the same cable and with the same instrument to evaluate system performance. It will consist of a 4-day test of DAS on the OOI RCA in March 2024 using L-band DAS to record on lit fiber without interrupting ordinary RCA data telemetry. The advantage of a test that includes a shutdown is that we will observe both the DAS data quality with and without telecom data, as well as the telecom data quality with and without DAS.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.