Investigating the seismic signatures of volcanic unrest and eruption: Spatiotemporal distribution and source origin of tiny long-period seismicity

研究火山活动和喷发的地震特征：微小长周期地震活动的时空分布和震源起源

• 批准号: 1620576
• 负责人: Robin Matoza
• 金额: $ 29万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1620576&HistoricalAwards=false
• 关键词: Investigating; seismic; signatures; volcanic; unrest

Volcano observatories worldwide use seismicity to monitor volcanoes and set alert levels to protect life and property, but do not fully understand how the seismic signals are generated. This research will better elucidate seismic source processes during volcanic unrest and eruption, potentially improving capability in volcanic hazard monitoring and mitigation. Long-period (LP) seismicity, a particular type of volcanic seismicity, is used routinely by volcano monitoring scientists to forecast and assess eruptions and mitigate hazards, but its source origin remains controversial. Sequences of LP events and more continuous volcanic tremor signals (collectively called LP seismicity) commonly appear on seismograms before eruptions, providing a warning, but not a guarantee, of impending eruption. This project will perform detailed investigations into the origin of an intriguing and largely overlooked additional type of volcanic seismicity: numerous tiny-amplitude LP subevents that accompany the regular LP events. LP subevents could be a useful new signal for monitoring volcanoes. This research will lead to improved descriptions and catalogs of seismicity for multiple volcanoes, generating a public database of information suitable for other researchers in their studies of volcanoes and seismicity. These products will be of interest to the geophysics, geology, seismology, and volcanology communities. This project initiates collaboration between UC Santa Barbara, UC San Diego, and the USGS. It supports the educational program at UC Santa Barbara by providing funds for graduate student support. The volcano-seismic event cataloging code will be made publicly available and will be useful to volcano seismologists for research and monitoring.This project will utilize novel computationally intensive processing methods adapted from studying regional seismicity in Southern California and Hawaii. Tiny LP subevents have apparently been recorded at multiple volcanoes worldwide, but their origin remains mysterious. Millions of tiny LP subevents were exceptionally well recorded by a dense seismic network during the 2004-2008 eruption of Mount St. Helens (MSH), but were not cataloged or analyzed. These LP subevents contain rich, unexploited information that has the potential to better elucidate the processes generating volcanic seismicity. This research will map the spatiotemporal distribution and source mechanisms of millions of tiny LP subevents to high precision and determine their relation to other volcanic seismicity and eruptive activity. The primary dataset is from MSH, but additional datasets from Mammoth Mountain, CA, Kilauea Volcano, HI, and other volcanoes will be exploited for comparative analyses and hypothesis testing across multiple volcanic systems. This project will systematically detect and locate tiny LP subevents using a match-and-locate template matching approach, perform high-precision relocation and cluster analysis, stack groups of similar events (multiplets), and perform full-waveform inversion to reveal the moment-tensor and single-force equivalent point-sources. Integrating these results will help to resolve the relationships between seismicity and magmatic, hydrothermal, and solid extrusion conduit processes. The results will address the following questions: (1) Relocated seismicity will likely cluster into compact volumes, or align along fault, magma conduit, or hydrothermal structures: what do these structures reveal about the underlying volcano-seismic processes? (2) Do source mechanisms and locations of subevents reveal a dendritic plexus of cracks in the volcano groundwater system, or solid extrusion processes at the conduit margin? (3) What is the relationship between LPs and subevents? (4) Do LPs and subevents trigger each other? (5) Are these phenomena at MSH unique or is similar behavior observed at other volcanoes? (6) What is the underlying physical process causing this seismicity? (7) Can subevents be used to improve eruption forecasting?

世界各地的火山天文台使用地震性来监测火山并设定警报水平以保护生命和财产，但不完全了解如何产生地震信号。这项研究将更好地阐明在火山动乱和喷发期间的地震源过程，从而有可能提高火山危害监测和缓解的能力。长期（LP）地震性是一种特殊类型的火山地震性，通常通过火山监测科学家来预测和评估喷发和减轻危害，但其源头仍然有争议。 LP事件的序列和更连续的火山震颤信号（统称为LP地震行为）通常出现在喷发前的地震图上，提供了警告，但不能保证即将发出。该项目将对引人入胜且在很大程度上被忽视的其他类型的火山震荡的起源进行详细研究：伴随常规LP事件的许多微小振幅LP子事件。 LP子事件可能是监测火山的有用新信号。这项研究将导致对多个火山的地震性的描述和目录改进，从而在其火山和地震性研究中产生适合其他研究人员的信息的公共数据库。这些产品将吸引地球物理，地质学，地震学和火山学社区。该项目启动了加州大学圣塔芭芭拉分校，加州大学圣地亚哥分校和USGS之间的合作。它通过提供研究生支持的资金来支持加州大学圣塔芭芭拉分校的教育计划。火山性事件编目代码将被公开可用，对火山地震学家进行研究和监测非常有用。该项目将采用新颖的计算密集型处理方法，这些处理方法适用于研究南加州和夏威夷的区域地震性。 Tiny LP子事件显然是在全球多个火山上记录的，但它们的起源仍然很神秘。在2004 - 2008年在圣海伦斯山（MSH）爆发期间，密集的地震网络（MSH）的密集地震网络记录了数百万个小的LP子事件，但未对其进行分类或分析。这些LP子事件包含丰富的，未开发的信息，有可能更好地阐明产生火山地震的过程。这项研究将绘制数百万种LP子事件的时空分布和源机制，以高精度，并确定其与其他火山地震性和喷发活性的关系。主要数据集来自MSH，但是来自加利福尼亚州猛mm山，Kilauea火山，HI和其他火山的其他数据集将被利用，以在多个火山系统上进行比较分析和假设测试。该项目将使用匹配和仪表模板匹配方法系统地检测和定位小的LP子事件，执行高精度重定位和集群分析，类似事件（多重事件）的堆叠组，并执行全波倒置以揭示矩量调整和单力量等价点源。整合这些结果将有助于解决地震性与岩浆，水热和固体挤出导管过程之间的关系。结果将解决以下问题：（1）重新定位的地震性可能会聚集成紧凑的量，或沿断层，岩浆导管或水热结构对齐：这些结构揭示了有关潜在的火山震荡过程的内容？ （2）子事件的来源机制和位置是否揭示了火山地下水系统中裂缝的树突丛，还是导管边缘处的固体挤出过程？ （3）LPS和子事件之间的关系是什么？ （4）LPS和子事件是否互相触发？ （5）这些现象是在MSH唯一的，还是在其他火山上观察到相似的行为？ （6）导致这种地震性的根本物理过程是什么？ （7）是否可以使用子事件来改善喷发预测？

项目成果

Investigating Spectral Distortion of Local Volcano Infrasound by Nonlinear Propagation at Sakurajima Volcano, Japan

• DOI: 10.1029/2019jb018284
• 发表时间: 2020-03
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: S. Maher;R. Matoza;C. Groot‐Hedlin;K. Gee;D. Fee;A. Yokoo

Volcano infrasound: progress and future directions

• DOI: 10.1007/s00445-022-01544-w
• 发表时间: 2022-04
• 期刊: Bulletin of Volcanology
• 影响因子: 3.5
• 作者: L. M. Watson;A. Iezzi;L. Toney;S. Maher;D. Fee;Kathleen F. McKee;H. Ortiz;R. Matoza;J. Gestrich;J. Bishop;Alex J. C. Witsil;Jacob F. Anderson;Jeffrey B. Johnson

High-rate very-long-period seismicity at Yasur volcano, Vanuatu: source mechanism and decoupling from surficial explosions and infrasound

瓦努阿图亚苏尔火山的高频率超长周期地震活动：震源机制以及与地表爆炸和次声的解耦

• DOI: 10.1093/gji/ggab533
• 发表时间: 2022
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Matoza, Robin S.;Chouet, Bernard A.;Jolly, Arthur D.;Dawson, Phillip B.;Fitzgerald, Rebecca H.;Kennedy, Ben M.;Fee, David;Iezzi, Alexandra M.;Kilgour, Geoff N.;Garaebiti, Esline
• 通讯作者: Garaebiti, Esline

Seismo-acoustic characterisation of the 2018 Ambae (Manaro Voui) eruption, Vanuatu

2018 年瓦努阿图 Ambae（Manaro Voui）喷发的地震声学特征

• DOI: 10.1007/s00445-021-01474-z
• 发表时间: 2021
• 期刊: Bulletin of Volcanology
• 影响因子: 3.5
• 作者: Park, Iseul;Jolly, Arthur;Matoza, Robin S.;Kennedy, Ben;Kilgour, Geoff;Johnson, Richard;Garaebiti, Esline;Cevuard, Sandrine
• 通讯作者: Cevuard, Sandrine

Evaluating the state-of-the-art in remote volcanic eruption characterization Part I: Raikoke volcano, Kuril Islands

评估远程火山喷发特征的最新技术第一部分：千岛群岛的莱科克火山

• DOI: 10.1016/j.jvolgeores.2021.107354
• 发表时间: 2021
• 期刊: Journal of Volcanology and Geothermal Research
• 影响因子: 2.9
• 作者: McKee, Kathleen;Smith, Cassandra M.;Reath, Kevin;Snee, Eveanjelene;Maher, Sean;Matoza, Robin S.;Carn, Simon;Mastin, Larry;Anderson, Kyle;Damby, David
• 通讯作者: Damby, David