Enhancements to the OOI Cabled Array at Axial Seamount

海洋观测站倡议（OOI）的一部分是一个位于太平洋东北部的电缆观测站，它延伸到离岸的轴向海山，这是一个活跃的海底火山，经常喷发，热液喷口和独特的深海生态系统。由于它是如此活跃和容易接近，轴状海山一直是一个长期的研究地点，监测显示了火山膨胀和收缩的循环，这被用来预测火山爆发的准确性越来越高。该项目将增强轴向海底山的OOI电缆阵列，增加能够探测山顶火山口热液输出变化和火山地面运动的仪器，从而改进喷发预测。这些对轴向海山监测工作的加强将有助于增加我们对活火山岩浆储存系统的了解，导致和触发火山喷发的过程，以及海底火山喷发对热液系统和它们所维持的深海生态系统的影响。一名教师将参与研究巡航部署仪器，教师将在研究巡航之前，期间和之后与教室互动。在纽波特的哈特菲尔德海洋科学游客中心的公开讲座将包括这个项目的结果。2015年轴状海山的喷发是OOI电缆阵列首次实时探测到的。尽管它以前所未有的细节捕捉到了这一事件，但它也表明，仪器网络中缺少了一些关键的观测结果，这限制了人们对火山喷发及其后果的理解。该项目将对电缆观测站进行以下有针对性和及时的补充：(1)一台新的海底CTD（电导、温度、深度）仪器，以增加关键的盐度测量，这是目前缺乏的，但需要测试海底火山喷发期间从地壳释放热液盐水的假设；(2)一台底部压力/倾斜仪器，已经建成并支付了费用。此外，还将建造四个自主（无电缆）微型压力记录仪，并购买一个声学释放传感器，用于现有的自主底压记录系泊。这些仪器将加强对海底火山变形的时空监测，并对其在地下的成因进行建模。

Part of the Ocean Observatories Initiative (OOI) is a cabled observatory in the northeast Pacific Ocean that extends offshore to Axial Seamount, an active submarine volcano that has frequent eruptions, hydrothermal vent fields, and unique deep-sea ecosystems. Because it is so active and accessible, Axial Seamount has been a long-term study site and monitoring has revealed a cycle of volcano inflation and deflation that has been used to forecast eruptions with increasing accuracy. This project will enhance the OOI Cabled Array at Axial Seamount by adding instruments with the capability to detect changes in hydrothermal output in the summit caldera, and to ground movements at the volcano, which will in turn improve eruption forecasts. These enhancements to the monitoring effort at Axial Seamount will help to increase our understanding of magma storage systems at active volcanoes, the processes that lead to and trigger eruptions, and the impacts of submarine eruptions on hydrothermal systems and the deep-sea ecosystems they sustain. A teacher will participate on the research cruise to deploy the instruments, and the teacher will interact with classrooms before, during, and after the research cruise. Public lectures at the Hatfield Marine Science Visitor Center in Newport, OR will include results from this project. The 2015 eruption at Axial Seamount was the first detected in real time by the OOI Cabled Array. Although it captured the event in unprecedented detail, it also showed that there are some key observations missing from the instrument network that limited understanding of the eruption and its consequences. This project will make the following targeted and timely additions to the cabled observatory: (1) one new seafloor CTD (Conductivity, Temperature, Depth) instrument to add critical salinity measurements, which are currently lacking but are needed to test the hypothesis that hydrothermal brine is released from the crust during seafloor eruptions, and (2) one bottom pressure/tilt instrument that has already been built and paid for. In addition, four autonomous (non-cabled) miniature pressure recorders will be built and an acoustic release transducer will be purchased to be used on an existing autonomous bottom pressure recording mooring. These instruments will enhance the spatial and temporal monitoring of volcanic deformation of the seafloor and the modeling of its causes in the subsurface.