An Integrated Analysis of Seismicity, Infrasound, and High-Resolution SO2 Measurements to Determine the Source of Low-Frequency Seismicity at Villarrica Volcano, Chile

对地震活动、次声和高分辨率 SO2 测量进行综合分析，以确定智利比亚里卡火山低频地震活动的来源

• 批准号: 0948526
• 负责人: Gregory Waite
• 金额: $ 22.22万
• 依托单位: Michigan Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948526&HistoricalAwards=false
• 关键词: Integrated; Analysis; Seismicity; Infrasound; Resolution

Volcanoes produce a rich variety of seismic signals that are unlike those generated during typical earthquakes. While great improvements in the ability to forecast volcanic eruptions have come from recognizing precursory seismic signals, knowledge of the specific mechanisms responsible for the volcanic signals is only generally understood. For example, low-frequency seismic tremor is linked to fluid movement, but many models can explain seismic tremor at any one volcano. By integrating high-resolution seismic, acoustic, and gas emission data, this study will determine the relationship between gas flux and the characteristics of seismic tremor at Villarrica volcano. Villarrica has had persistent gas emission and an active lava lake with continuous, mild, explosive activity since 1984. Because of the continuous low-level activity, direct measurements of emissions of gas, seismicity, and low-frequency sound (infrasound) can safely be made from the summit crater. This study will use simultaneous measurements of seismicity, infrasound and gas emissions. The researchers will deploy arrays of broadband stations to locate and track the depth of low-frequency and volcano-tectonic seismicity, along with distributed infrasonic microphones to characterize the explosive outgassing activity. During 2-3 week field campaigns, they will also collect high-time resolution SO2 emission data, and thermal and visual video of the outgassing activity. All these data will be interpreted jointly to characterize and quantify different styles of outgassing. A 15-month deployment of seismometers and microphones will assure that a significant portion of the outgassing styles is well sampled. The classification scheme for outgassing style they develop during the shorter field campaigns will allow them to calculate a proxy data set for gas emission during the full duration of the deployment so that they may address questions about long-term cycles of activity and the relationship between both deeper local volcanic earthquakes and distant earthquakes on the volcanic system.The transformative potential of this project lies in the integration of these data. The seismic analysis will be based on the strong foundation of established techniques. Infrasound analysis is now seen as critical for monitoring open-vent systems, yet some aspects of infrasound data are not well understood. A novel UV camera, recently developed with support from the National Science Foundation, can image SO2 emission at a rate comparable to eruptive processes. By establishing empirical links between the data, this study will test theoretical models for the generation of seismicity and sound from gas emission and generate important new knowledge on eruptive processes.

火山产生了各种各样的地震信号，这些地震信号与典型地震期间产生的地震信号不同。虽然预测火山喷发的能力的大大改善来自于认识到前寿命的地震信号，但仅了解对火山信号的特定机制的了解。例如，低频地震震颤与流体运动有关，但是许多模型可以解释任何一座火山的地震震颤。通过整合高分辨率的地震，声学和气体发射数据，这项研究将确定Villarrica火山的气体通量与地震震颤的特征之间的关系。比利亚里卡（Villarrica）自1984年以来一直具有持久的气体排放和一个活跃的熔岩湖，具有连续，轻度，爆炸性的活性。由于连续的低水平活性，直接测量气体排放，地震性和低频声音（频音）可以安全地从山顶界面上进行。 这项研究将同时测量地震性，反向和气体排放。研究人员将部署宽带站的阵列，以定位和跟踪低频和火山施加性地震性的深度，以及分布式的基源麦克风，以表征爆炸性的超出活动。在2-3周的现场活动中，他们还将收集高级分辨率SO2排放数据，以及供气活动的热和视频。所有这些数据将被共同解释，以表征和量化不同风格的排气方式。 15个月的地震仪和麦克风部署将确保对大部分额外的样式进行了很好的采样。他们在较短的现场活动期间开发的超出气体风格的分类方案将使他们能够在部署的整个过程中计算出气体排放的代理数据集，以便他们可以解决有关活动的长期周期的问题，以及在该项目中列出这些项目的变革性潜能。地震分析将基于既定技术的强大基础。现在，插向分析对于监视开放式系统至关重要，但是侵权数据的某些方面尚不清楚。最近在美国国家科学基金会（National Science Foundation）的支持下开发的一种新型紫外摄像头可以以可与喷发过程相当的速度成像SO2发射。通过建立数据之间的经验联系，本研究将测试理论模型，以产生气体发射中的地震性和声音，并在喷发过程中产生重要的新知识。