Collaborative Research: Magnetotelluric and Seismic Investigations of Arc Melt Generation, Deliver 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研究

• 批准号: 1751099
• 负责人: Kerry Key
• 金额: $ 6万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1751099&HistoricalAwards=false
• 关键词: Collaborative; Research; Magnetotelluric; Seismic; Investigations

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 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，调查人员将在阿留申弧的Okmok火山进行磁铁（MT）调查，以表征火山下面的岩浆系统。将收集新的陆上被动地震和MT数据以及海上MT数据，以测试有关平板流体在ARC熔体产生中的作用，地壳内的熔体迁移以及地壳岩浆岩浆管道和存储系统下方的假设。该项目将支持女性早期的调查员几位毕业生和本科生，为后者提供海上动手研究。计划将该项目的数据纳入本科生的地球科学课程和演示。第2部分Aleutian火山弧是一个地理位主义的主要研究地点，该地点是构造活跃的区域，被认为是研究弧岩岩的理想选择。 Okmok是位于阿留申河中部弧的一座活火山，距离荷兰港口仅约100公里，这对于两栖陆上和近海地球物理成像的逻辑上有利。还选择了Okmok，由于其已知的火山活性，即以前的研究所推断出的地壳岩浆储层的存在以及它所提出的火山危害，这证明了2008年喷发之前缺乏警告证明。它已经举办了2次火山口爆发（CFE），并代表了阿留申弧内的火山和全球范围内的火山，经历了长时间的爆发，并由更大的爆炸性CFE刺破。该项目将测试流体在熔化地幔楔中的作用以及如何通过地幔楔的角流动方式上升的假设。它还将检验有关上地幔和地壳内熔体迁移和存储的竞争假设，以及这如何影响爆炸性CFE。该项目收集的数据将用于绘制ARC内的地震速度和电导率变化，从而对温度，矿物学和流体含量提供了独特的约束。这些约束将用于研究地幔熔体通量，其在地壳底部的可能存储，部分熔体/岩浆体在中型壳中的分布以及上层面包口的热和机械性能在Caldera.boader的影响下的热和机械性能：所建议的工作将有助于提高对Magma储存和运输的认识。将支持一名女性早期职业调查员和三名研究生（1个Scripps； 2个UW-Madison）。将支持七名本科生（部分通过该项目的资金和Scripps NSF REU支持的冲浪计划），以参与陆上/离岸现场工作。该项目的数据将纳入本科生的地球科学课程，并将在当地的K-12学校和通过现场网络研讨会向几所阿拉斯加学校提供演讲。 UW-Madison将提供有关MT方法的简短课程，该项目的计算机显示将为UW地质博物馆的主动地球展示创建。