Three Compliance Instruments for Axial Volcano to Observe Long Term Evolution of the Magma Chamber and in Support of OOI Observations

用于轴状火山观测岩浆室长期演化并支持 OOI 观测的三种顺应性仪器

• 批准号: 1924024
• 负责人: Spahr Webb
• 金额: $ 62.78万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924024&HistoricalAwards=false
• 关键词: Three; Compliance; Instruments; Axial; Volcano

Despite decades of observations, how magma migrates and is stored within volcanoes remains poorly understood because there are few means to continuously monitor changes within magma chambers beneath volcanoes. Such measurements are needed to understand when and how the gradual emplacement of magma finally triggers an eruption. The instrumentation developed will provide the potential to monitor changes in the magma content continuously beneath undersea volcanoes and thereby provide a better understanding of volcano processes that can also be applied to volcanos on land that pose a major hazard to millions of people.Axial Volcano, a large, very active undersea volcano offshore the US West Coast is currently monitored using sensors that transmit data through the NSF supported Ocean Observatories Initiative cable to shore. Sensors on these cables measured changes in the compliance of seafloor preceding and following an eruption in 2015 associated with changes in the magma chamber, but the noise level of these sensors limited the sensitivity of the observations and the observation period to the winter months when the compliance signal was larger. New compliance sensors with better sensitivity and a lower noise level will be constructed using more optimal sensors and placed on the seafloor beneath large shields that protect the sensors from noise from ocean currents. Compliance, a measure the deformation of the seafloor under the loading of long period ocean waves, depends on the elastic properties of the underlying Earth and thereby to the fraction of magma within the magma chamber. The current shielding developed will also have applicability for reducing the noise levels for the horizontal components of broadband seismometers installed on the seafloor. Ocean bottom seismometers are critical to understanding many Earth processes, but the high noise levels due to ocean floor currents limits the types and quality of observations that can be made.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.

尽管经过几十年的观察，岩浆是如何在火山中迁移和储存的，人们仍然知之甚少，因为几乎没有办法持续监测火山下岩浆房的变化。这样的测量对于了解岩浆的逐渐就位最终触发喷发的时间和方式是必要的。开发的仪器将提供持续监测海底火山岩浆含量变化的潜力，从而提供对火山过程的更好理解，也可以应用于对数百万人构成重大威胁的陆地火山。轴向火山是美国西海岸近海的一个非常活跃的大型海底火山，目前正在使用传感器进行监测，这些传感器通过美国国家科学基金会支持的海洋观测倡议电缆将数据传输到岸上。这些电缆上的传感器测量了2015年火山喷发前后海底顺应性的变化，这些变化与岩浆室的变化有关，但这些传感器的噪声水平限制了观测的灵敏度，并且观测周期仅限于顺应性信号较大的冬季月份。采用更优的传感器，将建造灵敏度更高、噪音水平更低的新型合规传感器，并将其放置在海底的大屏蔽层下，以保护传感器免受洋流的噪音影响。顺应性是衡量海底在长周期海浪作用下变形的一种方法，它取决于地下地球的弹性特性，从而取决于岩浆房中岩浆的比例。目前开发的屏蔽也将适用于降低安装在海底的宽带地震仪水平组件的噪声水平。海底地震仪对了解许多地球过程至关重要，但由于海底洋流产生的高噪声水平限制了观测的类型和质量。该奖项反映了美国国家科学基金会的法定使命，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。