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.

研究人员将在阿留申弧的Okmok火山进行大地电磁（MT）调查，以表征火山下的岩浆系统。将收集新的陆上被动地震和大地电磁学数据以及海上大地电磁学数据，以验证关于板块流体在弧熔体产生、地壳内熔体迁移以及活跃火山口下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。这个项目的数据计划被纳入本科地球科学课程和报告中。第二部分阿留申火山弧是地球地质学的主要调查点，是研究火山弧岩浆作用的理想构造活动区。Okmok是一座位于阿留申岛弧中心的活火山，距离荷兰港仅100公里，这使得它在后勤上具有优势，可以对岛弧进行陆上和海上两栖地球物理成像。S岩浆系统。选择Okmok也是因为它已知的火山活动，根据以前的研究推断，地壳岩浆储层的存在，以及它所呈现的火山危险性，2008年爆发前缺乏预警证明。它已经举办了两次火山口形成喷发（CFE），是阿留申弧内和世界范围内经历长时间喷涌喷发的火山的代表，其间穿插着更大的爆炸性CFE。该项目将测试关于流体在熔融地幔楔中所起作用的假设，以及熔体如何通过地幔楔的角流状态上升。它还将测试关于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的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，为温度、矿物学和流体含量提供独特的约束条件。这些约束条件将用于研究地幔熔体通量及其可能在地壳底部的储存，部分熔体/岩浆体在中上部地壳的分布以及火山口下上部地壳的热力学性质。更广泛的影响：拟议的工作将有助于提高我们对Okmok火山岩浆储存和运输及其对火山危害的影响的理解。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）将得到支持。7名本科生将获得资助（部分来自本项目资金和Scripps NSF REU支持的SURF项目）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学校进行演示，并通过在线研讨会向一些阿拉斯加学校进行演示。威斯康星大学麦迪逊分校将开设一门关于MT方法的短期课程，并将为威斯康星大学地质博物馆创建一个计算机显示器。主动地球显示。