Collaborative Research: Simultaneous Imaging of the Megathrust and Volcanic Systems in the Aleutian Islands Using Hybrid Mini Seismic Arrays

合作研究：使用混合微型地震阵列对阿留申群岛的巨型逆冲断层和火山系统进行同步成像

• 批准号: 1358619
• 负责人: Clifford Thurber
• 金额: $ 21.91万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1358619&HistoricalAwards=false
• 关键词: Collaborative; Research; Simultaneous; Imaging; Megathrust

The Alaska-Aleutian subduction zone is one of the most active areas in the world, in terms of its seismic and volcanic activity. The megathrust experiences large damaging fast (normal) earthquakes, slow earthquakes and associated tectonic tremor revealing a wide spectrum of slip behavior. The volcanoes show a complex blend of seismicity, from volcanic tremor to deep long-period (DLP) events. Many of these tectonic and volcanic natural systems remain relatively unexplored because of the challenging logistics leading to poor instrumentation. We propose to install 4 hybrid mini seismic arrays and 6 stand-alone seismic stations on Unalaska and Akutan Islands, to capture this rich variety of seismic activity, both tectonic and volcanic, and image earth structure in high resolution. The experiment is designed such that it simultaneously images multiple sources, thereby illuminating both megathrust and volcanic systems at the same time. Deployment of mini arrays is logistically convenient in this challenging environment compared to conventional network-style deployments with similar number of stations maximizing scientific gain with relatively low cost. This study will be an important step forward in our understanding of the complex volcanic and tectonic systems and their interplay in Alaska-Aleutian subduction complex. This intertwined natural system will be investigated by combining novel array techniques to image multiple sources with an augmented conventional seismic network. This study will examine a wide spectrum of fault slip dynamics, volcanic plumbing system and earth structure in this area. It will not only enrich our knowledge of the subduction system in this area but also might be extrapolated to other areas like Cascadia that are not so productive seismically.The Alaska-Aleutian subduction zone has witnessed a number of large damaging earthquakes in instrumental history. The Unalaska-Akutan area is located near the eastern edge of the 1957 M8.6 megathrust rupture zone. The proposed study will help better understand the dynamics of the subduction fault, and therefore aid in seismic hazard analyses. In addition, Akutan and Makushin are among the most frequently active volcanoes in the United States and are defined as ?very high threat?. They both pose threat to nearby population centers. This study will help us image and understand the volcanic plumbing systems leading to improved monitoring of precursory phenomena. Moreover, this project will help advance the career of an early-career faculty member, post doctoral researchers, and graduate students, and foster collaboration between educational and government institutions.

就地震和火山活动而言，阿拉斯加-阿留申俯冲带是世界上最活跃的地区之一。巨型逆冲经历了大的破坏性的快速(正常)地震、慢地震和相关的构造震动，揭示了广泛的滑动行为。这些火山表现出复杂的地震活动混合，从火山震动到深部长周期(DLP)事件。这些构造和火山自然系统中的许多仍然相对未被勘探，因为具有挑战性的后勤导致仪器设备不佳。我们建议在乌纳拉斯卡和阿库坦群岛安装4个混合微型地震台阵和6个独立地震台站，以捕捉这种丰富的构造和火山活动，并以高分辨率成像地球结构。该实验被设计成同时拍摄多个来源的图像，从而同时照亮巨型逆冲和火山系统。在这种具有挑战性的环境中，与具有相似数量的站点的传统网络式部署相比，微型阵列的部署在后勤方面更加方便，从而以相对较低的成本最大限度地提高科学成果。这项研究将是我们理解阿拉斯加-阿留申俯冲杂岩中复杂的火山和构造系统及其相互作用的重要一步。这种相互交织的自然系统将通过将新的阵列技术与增强的常规地震网络相结合来研究，以成像多个震源。这项研究将考察该地区广泛的断层滑动动力学、火山管道系统和地球结构。这不仅将丰富我们对该地区俯冲系统的认识，而且还可能外推到其他地震活动不太活跃的地区，如卡斯卡迪亚。阿拉斯加-阿留申俯冲带在仪器历史上见证了许多大的破坏性地震。Unalaska-Akutan地区位于1957年M8.6级巨型逆冲断裂带的东部边缘附近。拟议的研究将有助于更好地了解俯冲断层的动力学，从而有助于地震危险性分析。此外，阿库坦火山和马库申火山是美国最频繁的活火山之一，被定义为“非常高的威胁”。它们都对附近的人口中心构成了威胁。这项研究将有助于我们想象和了解火山管道系统，从而改进对前兆现象的监测。此外，该项目将有助于促进职业生涯早期的教师、博士后研究人员和研究生的职业生涯，并促进教育机构和政府机构之间的合作。