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?

世界各地的火山观测站使用地震活动来监测火山并设置警报级别以保护生命和财产，但并不完全了解地震信号是如何产生的。这项研究将更好地阐明火山动乱和喷发期间的震源过程，潜在地提高火山灾害监测和减灾的能力。长周期(LP)地震活动是火山地震活动的一种特殊类型，火山监测科学家经常使用它来预测和评估喷发并减轻灾害，但其来源仍有争议。Lp事件序列和更连续的火山震动信号(统称为Lp地震活动)通常出现在喷发前的地震图上，提供即将喷发的警告，但不是保证。该项目将对一种有趣的、基本上被忽视的额外类型的火山地震活动的起源进行详细调查：伴随着常规低压事件的许多微小幅度的低压子喷发。LP子喷口可能是监测火山的一个有用的新信号。这项研究将改进对多个火山的地震活动的描述和目录，生成一个公共信息数据库，供其他研究人员研究火山和地震活动时使用。这些产品将引起地球物理学、地质学、地震学和火山学领域的兴趣。该项目启动了加州大学圣巴巴拉分校、加州大学圣地亚哥分校和美国地质调查局之间的合作。它通过为研究生提供资助来支持加州大学圣巴巴拉分校的教育项目。火山-地震事件编目代码将公之于众，将有助于火山地震学家进行研究和监测。该项目将利用从南加州和夏威夷地区地震活动研究中采用的新的计算密集型处理方法。世界各地的多座火山显然都记录到了微小的LP子喷口，但它们的起源仍然是个谜。在2004-2008年圣海伦斯火山(MSH)喷发期间，密集的地震台网非常好地记录了数百万个微小的LP子喷发，但没有被编目或分析。这些低压子事件包含丰富的、未开发的信息，有可能更好地阐明火山地震活动的过程。这项研究将高精度地绘制数百万个微小低压子喷口的时空分布和震源机制图，并确定它们与其他火山地震活动和喷发活动的关系。主要数据集来自MSH，但来自加利福尼亚州猛犸山、基拉韦厄火山、HI和其他火山的其他数据集将用于多个火山系统的比较分析和假设检验。该项目将使用匹配和定位模板匹配方法系统地检测和定位微小的LP子事件，执行高精度的重新定位和聚类分析，叠加相似事件(多重)组，并执行全波形反演以揭示力矩张量和单力等效点震源。综合这些结果将有助于解决地震活动与岩浆、热液和固体挤压导管过程之间的关系。结果将解决以下问题：(1)重新定位的地震活动可能聚集成致密的体积，或沿着断层、岩浆管道或热液结构排列：这些结构揭示了潜在的火山-地震过程的什么？(2)次喷口的震源机制和位置是否揭示了火山地下水系统中的树枝状裂隙丛，或管道边缘的固体挤压过程？(3)LP和次喷口之间的关系？(4)LP和次喷口是否相互触发？(5)MSH的这些现象是独一无二的，还是在其他火山中观察到的类似行为？(6)导致地震活动的潜在物理过程是什么？(7)次喷口能否用于改进喷发预测？

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

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

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