Collaborative Research: Magnetotelluric and seismic investigation of arc melt generation, delivery, and storage beneath Okmok volcano

合作研究：奥克莫克火山下方电弧熔体产生、输送和储存的大地电磁和地震调查

• 批准号: 1456749
• 负责人: Clifford Thurber
• 金额: $ 83.73万
• 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: 2015
• 资助国家: 美国
• 起止时间: 2015-04-15 至 2022-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1456749&HistoricalAwards=false
• 关键词: Collaborative; Research; Magnetotelluric; seismic; investigation

Part 1The investigators will conduct a magnetotelluric (MT) survey at Okmok volcano in the Aleutian arc in order to characterize the magmatic system beneath the volcano. New onshore passive seismic and MT data and offshore MT data will be collected to test hypotheses regarding the role of slab fluids in arc melt generation, melt migration within the crust, and the crustal magmatic plumbing and storage system beneath an active caldera. The project will support a female early career investigator, and several graduate and undergraduate students providing the latter hands-on research at sea. Data from this project is planned to be incorporated into undergraduate Earth Sciences courses and presentations.Part 2The Aleutian volcanic arc is a GeoPRISMS primary investigation site that is tectonically active region considered to be ideal for studying arc magmatism. Okmok, an active volcano located in the central Aleutian arc, is only about 100 km from Dutch Harbor making it a logistically advantageous for an amphibious onshore and offshore geophysical imaging of the arc?s magmatic system. Okmok is also selected due to its known volcanic activity, the presence of a crustal magma reservoir, as inferred from previous studies, and the volcanic hazard it presents, as evidenced by the lack of warning prior to 2008 eruption. It has hosted 2 caldera-forming eruptions (CFE) and is representative of volcanoes both within the Aleutian arc and worldwide that experience long periods of effusive eruptions punctuated by much larger explosive CFE. The project will test hypotheses on the role fluids play in melting the mantle wedge and how melts ascend through the corner flow regime of the mantle wedge. It will also test competing hypotheses about melt migration and storage within the upper mantle and crust and how this impacts explosive CFE. Data collected by this project will be used to map seismic velocity and electrical conductivity variations within the arc, providing unique constraints on temperature, mineralogy and fluid content. These constraints will be used to study the mantle melt flux, its possible storage at the base of the crust, the distribution of partial melt/magma bodies in the mid-upper crust, and the thermal and mechanical properties of the upper crust beneath the caldera.Broader Impacts: The proposed work would help improve our understanding of magma storage and transport and its implications on volcanic hazards at Okmok volcano. A female early career investigator and three graduate students (1 Scripps; 2 UW-Madison) would be supported. Seven undergraduate students would be supported (partially through funds from this project and via Scripps NSF REU supported SURF program) to participate in onshore/offshore fieldwork. Data from this project will be incorporated into undergraduate Earth Sciences courses and presentations will be given at local K-12 schools and via live webinars to a few Alaskan schools. A short course on MT methods will be given at UW-Madison and a computer display for this project will be created for the UW Geology Museum?s Active Earth display.

第1部分研究人员将在阿留申岛弧的奥克莫克火山进行大地电磁（MT）测量，以描述火山下方的岩浆系统。将收集新的陆上被动地震和MT数据以及海上MT数据，以检验有关板块流体在弧熔体生成、地壳内熔体迁移以及活跃破火山口下的地壳岩浆管道和储存系统中的作用的假设。该项目将支持一名女性早期职业调查员，以及几名研究生和本科生，为后者提供海上实践研究。从这个项目的数据计划纳入本科地球科学课程和presentation.Part 2阿留申火山弧是GeoPRISMS的主要调查网站，是构造活跃的地区被认为是理想的研究弧岩浆作用。Okmok，一个活火山位于阿留申弧中部，只有约100公里，从荷兰港使其成为一个后勤上有利的两栖陆上和海上地球物理成像的弧？岩浆体系奥克莫克之所以被选中，也是因为它已知的火山活动，从以前的研究中推断出的地壳岩浆库的存在，以及它所呈现的火山危险，如2008年爆发前缺乏警告所证明的那样。它曾主办过2次破火山口形成喷发（CFE），是阿留申弧内和世界各地火山的代表，这些火山经历了长时间的喷发，并被更大的爆炸性CFE打断。该项目将测试关于流体在地幔楔熔化中所起作用以及熔体如何通过地幔楔的角流状态上升的假设。它还将测试有关上地幔和地壳内熔体迁移和储存的相互竞争的假设，以及这如何影响爆炸性CFE。该项目收集的数据将用于绘制弧内的地震速度和电导率变化图，提供对温度、矿物学和流体含量的独特限制。这些限制将被用来研究地幔熔体通量，其可能的存储在地壳的底部，部分熔体/岩浆体在中上地壳的分布，以及热和力学性质的上地壳下的破火山口。更广泛的影响：拟议的工作将有助于提高我们的理解，岩浆的储存和运输及其对火山灾害的影响在Okmok火山。将支持一名女性早期职业调查员和三名研究生（1名斯克里普斯; 2名威斯康星大学麦迪逊分校）。七名本科生将得到支持（部分通过本项目的资金和通过斯克里普斯NSF REU支持的SURF计划）参加陆上/海上实地考察。该项目的数据将被纳入本科地球科学课程，并将在当地K-12学校和通过现场网络研讨会向阿拉斯加的一些学校进行演示。一个关于MT方法的短期课程将在威斯康星大学麦迪逊分校举行，并将为威斯康星大学地质博物馆创建一个用于该项目的计算机显示器？s Active Earth显示。