COLLABORATIVE RESEARCH: Geodetic measurements and mechanical models of the volcano deformation cycle

合作研究：火山变形循环的大地测量和力学模型

• 批准号: 0943943
• 负责人: Timothy Masterlark
• 金额: $ 8.9万
• 依托单位: University of Alabama Tuscaloosa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0943943&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Geodetic; measurements; mechanical

Okmok volcano in Alaska appears to erupt every decade or so, most recently in 1997 and again in 2008. Its activity has been monitored using modern methods, forming a rich observational data set. The investigators are developing a geophysical model that should explain the timing and location of most of the observed activity. The new information from this study will be directly relevant to understanding time-dependent volcanic hazard posed by Okmok and other, similar volcanoes lying beneath the heavily-used north Pacific air traffic corridors. The same type of model should be applicable to other volcanoes displaying cyclic activity, such as Westdahl in Alaska or Hekla in Iceland. Okmok is an excellent natural laboratory for such an experiment because a complete cycle of deformation has been monitored using geodetic and seismic means. Using this rich observational data set and a formal protocol for numerical modeling, the investigators are studying Okmok volcano to address the following questions: (1) What is the distribution of material properties within Okmok? (2) How does anelastic rheology modify the temporal evolution of the deformation field? (3) How do material properties at depth influence the deformation observed at the surface? (4) What are the uncertainties of the model parameters that describe the magma chamber?The impulse-response rheological experiment will improve understanding of the volcano deformation cycle. Specifically, the research project will test four hypotheses: (I) Deformation following the 1997 eruption did not reach a steady state before the eruption in 2008. (II) Viscoelastic stress relaxation contributes to the transient deformation observed during the co-and post-eruptive time intervals. (III) The effective viscosity is several orders of magnitude smaller in the rind of the magma chamber than in the surrounding crust. (IV) The lava flow extruded from Cone A during the 1997 eruption produces a stress field that favors dike propagation from the magma chamber to Cone D.The results will be published in the international, peer-reviewed literature. A graduate student from a group under-represented in Science, Technology, Engineering and Mathematics (STEM) will be trained for a career in geophysical research at the intersection of three disciplines: seismology, geodesy and volcanology. The modeling protocol and approach will be disseminated among the scientific community at an operational level. Investigator Masterlark, a junior faculty member from an institution funded by the Office of Experimental Program to Stimulate Competitive Research (EPSCoR), will offer a short course on how to apply the Finite Element Method to volcanic deformation. Applicants from underrepresented groups will be especially encouraged to participate. The project will enhance collaboration between the investigators and scientists at the U.S. Geological Survey

阿拉斯加的Okmok火山似乎每十年左右爆发一次，最近一次是在1997年，在2008年再次爆发。它的活动已使用现代方法进行监测，形成了丰富的观察数据集。研究人员正在开发一个地球物理模型，该模型应解释大多数观察到的活性的时间和位置。这项研究的新信息将与理解俄克斯巨石和其他相似的火山构成的时间依赖的火山危害直接相关。相同类型的模型应适用于其他表现出循环活动的火山，例如阿拉斯加的Westdahl或冰岛的Hekla。 Okmok是这样一个实验的出色自然实验室，因为已经使用地震和地震手段对完整的变形循环进行了监测。使用此丰富的观察数据集和用于数值建模的正式协议，研究人员正在研究Okmok火山来解决以下问题：（1）Okmok内材料特性的分布是多少？ （2）无弹性流变性如何改变变形场的时间演变？ （3）深度的材料特性如何影响在表面观察到的变形？ （4）描述岩浆腔的模型参数的不确定性是什么？冲动反应流变实验将改善对火山变形周期的理解。具体而言，研究项目将检验四个假设：（i）1997年喷发后的变形未达到2008年喷发之前的稳态状态。（ii）粘弹性应激松弛有助于在爆发后时间间隔期间观察到的瞬态变形。 （iii）有效粘度是岩浆腔室的果皮比周围地壳小的几个数量级。 （iv）1997年爆发期间，从锥A挤出的熔岩流产生了一个应力场，有利于岩浆腔到锥体的堤防传播。结果将在国际，同行评审的文献中发表。来自一个科学，技术，工程和数学（STEM）人数不足的小组的研究生将在三个学科的交汇处进行地球物理研究的职业进行培训：地震学，地理学和火山学。建模方案和方法将在运营层面上传播在科学界。研究人员Masterlark是由实验计划办公室资助的刺激竞争研究（EPSCOR）资助的机构的初级教职员工，将提供有关如何将有限元方法应用于火山变形的简短课程。特别鼓励来自代表性不足的团体的申请人参加。该项目将加强美国地质调查局的调查人员与科学家之间的合作