COLLABORATIVE RESEARCH: Geodetic measurements and mechanical models of rifting in onshore segments of mid-ocean ridges.

合作研究：洋中脊陆上部分裂谷的大地测量和力学模型。

• 批准号: 0810148
• 负责人: Timothy Masterlark
• 金额: $ 9.24万
• 依托单位: University of Alabama Tuscaloosa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0810148&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Geodetic; measurements; mechanical

The research supported by this proposal is an international collaboration between U.S. scientists from the University of Wisconsin and the University of Alabama-Tuscaloosa and their Icelandic colleagues that is aimed at quantifying the role of magmatism in accommodating spreading at mid-oceanic ridges. The investigators are performing an impulse-response experiment, in which the impulse is the injection of magma at the rift, and the response is the deformation recorded by geodesic and seismological methods. The research focuses on extension related to an intrusive event from the northern volcanic zone of Krafla in Iceland in 1975-1984, where the width of the axial valley was increased by several meters due to the intrusion of dikes, resulting in a century?s worth of spreading at the long-term average rate of about two centimeters per year. After the magma supply diminishes, the extension continues over years or decades, and finally slows as the stresses relax. The research is addressing the following questions: (1) What is the geometry of the magmatic plumbing? (2) How does the magmatic pressure in the plumbing evolve with time? (3) What are the material properties of the rift structure? Providing quantitative answers to these questions requires answering a more fundamental question: which constitutive relation (rheology) best describes the rock below the lithosphere? Accordingly, the primary goal of the research is determining the constitutive relations and rheologic properties governing rifting. The research is contributing to the understanding of the mechanics of rifting at mid-ocean ridges, a fundamental process in plate tectonics. The research is fostering the training of a doctoral graduate student and is supporting the research efforts of an early career scientist. Research results and the modeling protocols developed during this study will be disseminated among the geological community. From a societal standpoint, the research is leading to a broader understanding of magmatic and seismological hazards associated with rifting events. The research is supported by the Geophysics Program and Marine Geology and Geophysics Programs.

这项提案支持的研究是来自威斯康星州大学和塔斯卡卢萨大学的美国科学家及其冰岛同事之间的国际合作，旨在量化岩浆活动在洋中脊扩张中的作用。研究人员正在进行一项脉冲响应实验，其中脉冲是裂谷处岩浆的注入，而响应是大地测量和地震学方法记录的变形。研究重点是与1975年至1984年冰岛克拉弗拉北方火山区侵入事件相关的延伸，由于岩脉的侵入，轴向谷的宽度增加了数米，导致了一个世纪？It’以每年两厘米的长期平均速度传播是值得的。 在岩浆供应减少后，伸展会持续数年或数十年，最后随着应力的放松而减缓。本研究旨在解决以下问题：（1）岩浆垂向的几何特征是什么？(2)管道中的岩浆压力如何随时间演变？(3)裂谷结构的物质属性是什么？要对这些问题提供定量的答案，需要回答一个更基本的问题：哪种本构关系（流变学）最能描述岩石圈以下的岩石？因此，研究的主要目标是确定本构关系和流变性能的裂谷。这项研究有助于了解洋中脊断裂的力学机制，这是板块构造的一个基本过程。 这项研究正在培养一名博士研究生，并支持一名早期职业科学家的研究工作。研究结果和建模过程中开发的协议将在地质界传播。从社会的角度来看，这项研究正在导致对与裂谷事件有关的岩浆和地震危险的更广泛的理解。这项研究得到了地球物理计划和海洋地质与地球物理计划的支持。