Collaborative Research: Quantifying Explosive Volcanism in Alaska Using Seismo-acoustic Wavefields Recorded by USArray

合作研究：利用 USArray 记录的地震声波场量化阿拉斯加的火山爆发

• 批准号: 1614323
• 负责人: David Fee
• 金额: $ 7.88万
• 依托单位: University of Alaska Fairbanks Campus
• 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: 2016-06-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1614323&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; Explosive; Volcanism

Collaborative Research: Quantifying explosive volcanism in Alaska using seismo-acoustic wavefields recorded by USArrayAlaska is home to 130 potentially active volcanoes, of which more than 50 have been active in historical times. On average 2 volcanoes are in a state of eruption every year. Volcanoes in the Aleutian Islands, Alaska Peninsula, and Cook Inlet are capable of sudden, explosive, ash-cloud forming eruptions, which are potentially hazardous to passenger and freight aircraft along this heavily travelled air corridor. Many of Alaska?s volcanoes are in remote locations with harsh environments. Monitoring these volcanoes represents a formidable challenge and many of the volcanoes are not instrumented. Infrasound (acoustic waves with frequencies below the 20 Hz hearing threshold of the human ear) is a rapidly developing technology to understand and monitor explosive volcanic eruptions. Modest-sized explosive eruptions produce powerful infrasound signals that propagate efficiently over thousands of kilometers in the atmosphere. However, to date, these signals have been recorded by sparse infrasound sensor networks, limiting our understanding of their source generation and propagation through the atmosphere. The EarthScope Transportable Array (TA) is currently being deployed in Alaska, bringing the densest ever combined seismic and infrasonic network to one of the world?s most active volcanic regions. Exploiting this novel dataset, this project will advance the capability of acoustic early warning systems of volcanic eruptions for aviation safety and will assess the potential contribution of large sensor networks such as the TA to volcano monitoring. At the end of the project, an operational volcano-acoustic monitoring system resulting from this work will be implemented at the Alaska Volcano Observatory.This work will capitalize on the unprecedented seismo-acoustic dataset starting to become available as the TA records Alaska?s routine explosive volcanism with dense spatial wavefield sampling. Volcano seismo-acoustics is a rapidly advancing research field, where basic questions remain on the source mechanisms, source directionality, atmospheric propagation, and seismo-acoustic coupling from explosive volcanic eruptions. This project will focus on detection, discrimination, and location of the signals using novel methods; quantifying the seismo-acoustic wavefield; investigating the source mechanisms; quantifying seismo-acoustic wave coupling; and understanding infrasound propagation in the spatio-temporally varying atmosphere. Through a combination of data analysis and modeling, we will characterize and quantify diverse seismic and infrasonic signals recorded at a range of distances and directions from the explosive eruption source. We will address the following questions: (1) How do observed acoustic and seismic signals from explosive volcanic eruptions vary with distance and azimuth to the source? (2) How does acoustic propagation differ for various types of explosive eruptions? (3) What kind of volcanic source information can be determined from long-range seismo-acoustic data? (4) What are the wavefield sampling limitations in previous volcano infrasound studies? (5) What other infrasound sources are present in Alaska? Our team will work with the EarthScope National Office at the University of Alaska Fairbanks to help highlight this research and its impacts. Multi-media products illustrating seismo-acoustic wavefields from volcanic eruptions in Alaska will be distributed via the web for use in public information packets and education and outreach. Event catalogs and related data products will be publically available, with notable infrasound events uploaded to the IRIS TA Infrasound Reference Event Database (TAIRED).

协作研究：使用USARRAYALASKA记录的Seismo-Acoustic Wavefields在阿拉斯加量化爆炸性火山，是130座潜在活跃的火山的家园，其中50多个在历史时期一直活跃。平均每年有2个火山处于爆发状态。阿留申群岛，阿拉斯加半岛和库克入口的火山能够突然，爆炸性，灰云形成爆发，这可能会沿着这座旅行的空中走廊沿途危害乘客和货运飞机。阿拉斯加的许多火山都在偏远地区，环境恶劣。监测这些火山代表着巨大的挑战，许多火山没有得到仪器。反射（频率低于20 Hz听力阈值的声波）是一项迅速发展的技术，可以理解和监测爆炸性的火山喷发。适中的爆炸爆发产生强大的伸出信号，在大气中有效地传播了数千公里。但是，迄今为止，这些信号已通过稀疏的插向传感器网络记录，从而限制了我们对它们通过大气中的源产生和传播的理解。目前正在阿拉斯加部署Earthscope可运输阵列（TA），将有史以来最密集的地震和室内式网络带到世界上最活跃的火山区域之一。利用这个新颖的数据集，该项目将提高火山喷发的声学预警系统对航空安全的能力，并将评估大型传感器网络（例如TA）对火山监测的潜在贡献。在该项目结束时，这项工作导致的运营火山声音监测系统将在阿拉斯加火山天文台实施。这项工作将利用前所未有的地震声学数据集开始，随着TA Records Alaska的常规爆炸性爆炸性的爆炸性爆炸性的爆炸性爆发力，并具有密集的Spatial Spatial spatial spatial sppling sampling sampling。火山地震声学是一个迅速发展的研究领域，在该领域中，基本问题仍然存在于爆炸性火山喷发中的来源机制，来源方向性，大气传播和地震声音耦合上。该项目将着重于使用新方法的信号的检测，歧视和位置。量化地震声波场；研究源机制；量化地震声波耦合；并了解时空变化的大气中的非传播传播。通过数据分析和建模的组合，我们将表征和量化在爆炸性喷发来源的一系列距离和方向上记录的多样化地震和室内信号。我们将解决以下问题：（1）观察到来自爆炸性火山喷发的声学和地震信号如何随远距离和方位角而变化？ （2）在各种类型的爆炸性喷发中，声学传播有何不同？ （3）可以从远程地震声学数据中确定哪种火山源信息？ （4）先前火山侵蚀研究中的波场采样限制是什么？ （5）阿拉斯加还有哪些其他临时资源？我们的团队将与阿拉斯加Fairbanks大学的Earthscope国家办公室合作，以帮助强调这项研究及其影响。多媒体产品说明了阿拉斯加火山爆发的地震声波场，将通过网络分发，以用于公共信息数据包以及教育和外展。事件目录和相关数据产品将公开可用，显着的插曲事件上传到Iris TA Infrasound参考事件数据库（Taired）。