Relative velocity changes using ambient seismic noise at Okmok and Redoubt volcanoes, Alaska

使用阿拉斯加奥克莫克火山和堡垒火山周围地震噪声的相对速度变化

• 批准号: 1246975
• 负责人: Clifford Thurber
• 金额: $ 7.96万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1246975&HistoricalAwards=false
• 关键词: Relative; velocity; changes; using; ambient

The PIs will improve the ability to detect precursory activity leading to activevolcanism at both Okmok caldera and Redoubt volcano, Alaska, as well as increase understanding ofthe complexity of magma storage at Redoubt. They will investigate important questions at Redoubtregarding (1) the spatial extent of the magma chamber, (2) if magma migrates from a primary magmachamber to a second magma reservoir located somewhere between 2 and 4.5 km depth, (3) if temporaryperturbations to the upper crustal velocity structure of Redoubt, reflecting CO2 degassed at mid-crustaldepths, can be observed, possibly as early as several months prior to the 2009 event, thus serving as anearly indicator of the eruption. At Okmok, they will examine important questions including (1) theexistence of early signs of volcanic unrest preceding the 2008 eruption and/or (2) early indicators that theeruption would emanate NW of Cone D instead of an expected eruption at Cone A, (3) if there wereindications of shallow magma movement (1-3 km depth) within the caldera in the months leading up tothe 2008 eruption. One promising approach to improve detection of precursory activity leading to activevolcanism at Okmok and Redoubt is to carry out seismic interferometry using ambient noise recorded atthese volcanoes (specifically pre- through post-eruption for the 2008 Okmok and 2009 Redoubteruptions).Okmok and Redoubt are two of the most active volcanoes in the Aleutian Arc and, assuch, pose major hazards to people living within these regions, air traffic, local fisheries, and local oilproduction facilities. This study will improve our ability to detect precursory activity leading to activevolcanism at both Okmok and Redoubt as well as increase our understanding of the complexity of magmastorage at Redoubt. The proposed study will also broaden the experience of an early career femalescientist.

PI将提高检测导致阿拉斯加Okmok火山口和Redoubt火山活动的火山活动的能力，并增加对Redoubt岩浆储存复杂性的理解。他们将在里道顿研究一些重要问题，包括（1）岩浆房的空间范围，（2）岩浆是否从一个原始岩浆房迁移到位于2到4.5公里深处的第二个岩浆库，（3）如果能观察到里道顿上地壳速度结构的暂时扰动，反映出在地壳中部深度脱气的CO2，可能早在2009年事件之前的几个月，因此可以作为火山爆发的早期指标。在Okmok，他们将研究重要的问题，包括（1）2008年爆发前火山动荡的早期迹象的存在和/或（2）早期指标，火山喷发将发出锥D的西北部，而不是预期的喷发锥A，（3）如果有迹象表明，在2008年爆发前的几个月内，火山口内的浅岩浆运动（1-3公里深）。一个有希望的方法，以改善探测的火山活动，导致活跃的火山在奥克莫克和堡垒是进行地震干涉测量使用环境噪音记录在这些火山（特别是2008年Okmok和2009年Redoubteruptions的喷发前和喷发后）。Okmok和Redoubter是阿留申弧中最活跃的两座火山，因此对生活在这些地区的人们构成重大危险，空中交通、当地渔业和当地石油生产设施。这项研究将提高我们的能力，以检测导致activevolcanism在Okmok和堡垒，以及增加我们的理解的复杂性，在堡垒的岩浆储存。拟议的研究还将扩大早期职业女性科学家的经验。