Collaborative Research: Earthquake Catalog and Waveform Analysis to Assess the Evolution of Axial Seamount Surrounding the 2015 Eruption

合作研究：地震目录和波形分析以评估 2015 年火山喷发周围轴状海山的演化

• 批准号: 1635276
• 负责人: DelWayne Bohnenstiehl
• 金额: $ 18.78万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635276&HistoricalAwards=false
• 关键词: Collaborative; Research; Earthquake; Catalog; Waveform

Axial seamount is an active submarine volcano located off the west coast of the US on the Juan de Fuca midocean ridge spreading center. Axial has recently been instrumented for continuous real-time data monitoring as part of the cabled ocean observatory network of the NSF-sponsored Ocean Observatory Initiative (OOI) that includes high-quality ocean bottom seismic data, as well as an unrivaled set of seafloor geodetic and hydrothermal measurements. The seamount has erupted periodically in the past but the most recent eruption in April/May 2015 was captured by the local seismic network and provides a unique dataset with which to investigate the eruption and magmatic mechanisms associated with submarine volcanoes. The project will analyze the evolution of earthquake properties and statistical patterns in space and time, as well as how these changes are correlated with deformation and hydrothermal outputs throughout the eruption cycle. These data will be used to track changes in stress and the movement of magma within the volcanic edifice, leading to a better understanding of the mechanics of submarine volcanoes and the dynamics of eruptions on the seafloor. This project takes advantage of the recently enabled OOI Axial seamount cabled array data portal and will contribute to scientific infrastructure for undersea monitoring. The project provides research experience for community college students, undergraduates and graduate students, and training for middle-school science teachers in the areas of earthquake physics and submarine volcanic processes.This project will utilize the compiled Axial Seamount seismic catalog and carry out waveform analysis to assess the evolution of the volcanic system before, during and after the April and May 2015 eruption including the many linkages between earthquakes, seafloor deformation and hydrothermal activity. Stress states will be inferred by monitoring changes in seismicity rate and variations in earthquake statistical patterns. The strength of the faults and/or the movement of fluids will be constrained through earthquake source parameter studies. This project will advance three technical goals: 1) Study the evolution of stress within the volcanic crust through the 2015 eruption at Axial Seamount using a novel combination of techniques, including seismicity/stressing rate changes, earthquake stress drop measurements and seismic b-value studies. 2) Investigate the response of fault systems within the caldera to dynamic stresses in the context of their local stressing history, and by incorporating hydrothermal time series observations that provide new constraints on the role of fluids in dynamic triggering. 3) Explore the exceptional record of explosive acoustic events associated with the 2015 eruption. Although there is increasing evidence that explosive volcanism is common in the deep-sea, there are few direct observations. Understanding the distribution and scaling of these signals may transform our views on eruption dynamics in mid-ocean ridge environments.

轴向海山是位于美国西海岸胡安德富卡洋中脊扩张中心的一座海底活火山。作为美国国家科学基金会（nsf）赞助的海洋观测计划（OOI）的有线海洋观测网络的一部分，Axial最近被用于连续实时数据监测，该网络包括高质量的海底地震数据，以及无与伦比的海底大地测量和热液测量数据。海山过去曾周期性喷发，但最近一次在2015年4月/ 5月的喷发被当地地震网络捕捉到，并提供了一个独特的数据集，用于研究与海底火山相关的喷发和岩浆机制。该项目将分析地震性质和时空统计模式的演变，以及这些变化如何与整个喷发周期的变形和热液输出相关联。这些数据将用于追踪火山大厦内的应力变化和岩浆运动，从而更好地了解海底火山的力学和海底喷发的动力学。该项目利用了最近启用的OOI Axial海底山电缆阵列数据门户，将为海底监测的科学基础设施做出贡献。本项目为社区大学生、本科生和研究生提供地震物理和海底火山过程领域的研究经验，并为中学科学教师提供培训。该项目将利用编制的轴向海山地震目录并进行波形分析，以评估火山系统在2015年4月和5月喷发之前，期间和之后的演变，包括地震，海底变形和热液活动之间的许多联系。应力状态将通过监测地震活动性的变化和地震统计模式的变化来推断。断层的强度和/或流体的运动将通过震源参数研究得到约束。本项目将推进三个技术目标：1)利用地震活动性/应力速率变化、地震应力降测量和地震b值研究等新技术组合，通过2015年轴向海山喷发研究火山地壳内部应力演化。2)通过结合热液时间序列观测，研究火山口内断层系统在其局部应力历史背景下对动态应力的响应，为流体在动态触发中的作用提供新的约束。3)探索与2015年火山喷发相关的爆炸声事件的特殊记录。尽管有越来越多的证据表明，深海中爆发性火山活动是常见的，但很少有直接的观察。了解这些信号的分布和尺度可能会改变我们对中洋脊环境中火山喷发动力学的看法。

项目成果

The Recent Volcanic History of Axial Seamount: Geophysical Insights into Past Eruption Dynamics with an Eye Toward Enhanced Observations of Future Eruptions

轴状海山的近期火山历史：对过去喷发动力学的地球物理洞察，着眼于加强对未来喷发的观测

• DOI: 10.5670/oceanog.2018.117
• 发表时间: 2018
• 期刊: Oceanography
• 影响因子: 2.8
• 作者: Wilcock, William;Dziak, Robert;Tolstoy, Maya;Chadwick, William;Nooner, Scott;Bohnenstiel, DelWayne;Caplan-Auerbach, Jacqueline;Waldhauser, Felix;Arnulf, Adrien;Ballard, Christian
• 通讯作者: Ballard, Christian

Seismic constraints on caldera dynamics from the 2015 Axial Seamount eruption

• DOI: 10.1126/science.aah5563
• 发表时间: 2016-12
• 期刊: Science
• 影响因子: 56.9
• 作者: W. Wilcock;M. Tolstoy;F. Waldhauser;Charles Garcia;Yen Joe Tan;D. Bohnenstiehl;J. Caplan‐Auerbach;R. Dziak;A. Arnulf;M. E. Mann

Mechanics of fault reactivation before, during, and after the 2015 eruption of Axial Seamount

2015 年轴海山喷发之前、期间和之后的断层再活动机制

• DOI: 10.1130/g39978.1
• 发表时间: 2018
• 期刊: Geology
• 影响因子: 5.8
• 作者: Levy, S.;Bohnenstiehl, D.R;Sprinkle, P.;Boettcher, M.S.;Wilcock, W.S.D.;Tolstoy, M.;Waldhauser, F.
• 通讯作者: Waldhauser, F.

Explosive processes during the 2015 eruption of Axial Seamount, as recorded by seafloor hydrophones: EXPLOSIVE ACTIVITY AT AXIAL SEAMOUNT

海底水听器记录的 2015 年轴向海山喷发期间的爆炸过程：轴向海山的爆炸活动

• DOI: 10.1002/2016gc006734
• 发表时间: 2017
• 期刊: Geosystems
• 作者: Caplan-Auerbach, J.;Dziak, R. P.;Haxel, J.;Bohnenstiehl, D. R.;Garcia, C.
• 通讯作者: Garcia, C.