Collaborative Research: FEM-based inverse methods to estimate nonlinear geometric source parameters of volcano deformation from geodetic data

合作研究：基于有限元的反演方法从大地测量数据估计火山变形的非线性几何源参数

• 批准号: 1316082
• 负责人: Timothy Masterlark
• 金额: $ 32.08万
• 依托单位: South Dakota School of Mines and Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1316082&HistoricalAwards=false
• 关键词: Collaborative; Research; FEM; based; inverse

The migration of magma within a volcano produces a deformation signature at the Earth's surface. The location, shape, and pressurization of the magma chamber, as well as the internal structure of the rocks surrounding the magma chamber, control the specific deformation pattern that can be observed at the surface of the volcano. Quantifying the characteristics of magma migration is important, because the upward migration of magma is a precursor to volcanic eruptions. This project will develop finite element models (FEMs), a type of numerical method, to simulate volcanoes as a dynamic system that accounts for the interaction of migrating magma within the complex internal structure of an active volcano. These FEMs will be used in inverse methods that seek to quantify estimates and uncertainties of a few characteristic parameters that describe magma migration into, or out of, a magma chamber. These methods will be developed in the context of two volcanoes (Okmok, Alaska, and Tungurahua, Ecuador) that will serve as natural laboratories. Both of these active volcanoes have known internal structures in the form of tomography models estimated using data from ground-based seismic instruments, as well as surface deformation histories that were recorded with geodetic data (e.g., GPS data and satellite radar imagery) over the past decade. More specifically, this project will use FEM-based inverse analyses of geodetic data to determine estimates and uncertainties for the location, shape, and pressurization of magma chambers embedded in the complex internal structures of these two active volcanoes. More generally, this project will develop methods to integrate volcano geodesy and seismology, two traditionally disparate geophysical fields of study. This integration is poised to advance the fundamental understanding of active volcanoes.This project comprises collaborative research among early-career and mid-career faculty and graduate education at the South Dakota School of Mines and Technology (SDSMT), an EPSCoR institution. SDSMT is a regional center for science and engineering research and is ideally located to interface with a substantial local Native American community. The proposed methods will provide powerful numerical techniques to combine different types of information that are customarily used independently from one another to assess volcano hazards. This ability to simultaneously analyze different types of information will provide a more complete picture of the internal processes for a given active volcano and will likely lead to more reliable predictions of volcanic behavior. The methods developed by this project will be designed to be generally amenable for other analyses of volcano deformation and ultimately provide important societal benefits of more reliable natural hazards assessments. Another impact of this project is its direct relevance to studies of earthquake deformation, which are driven by analogous configurations of deformation sources embedded in complex structures associated with active faults. Thus, the techniques developed for this project may be readily extended to studies of earthquake deformation and may have important implications for future analyses of seismic and tsunami hazards worldwide.

岩浆在火山中的迁移在地球表面产生变形特征。岩浆室的位置，形状和加压以及岩浆腔周围岩石的内部结构，控制在火山表面上可以观察到的特定变形模式。量化岩浆迁移的特征很重要，因为岩浆的向上迁移是火山喷发的前体。该项目将开发有限元模型（FEMS），一种数值方法，以模拟火山作为动态系统，该系统解释了在活动火山的复杂内部结构中迁移岩浆的相互作用。这些FEM将用于试图量化一些特征参数的估计和不确定性的反相反方法，这些特征参数描述了岩浆迁移到岩浆腔中或之外。这些方法将在两个火山（Okmok，Alaska和Tungurahua，Ecuador）的背景下开发，这些火山将用作天然实验室。这两种活跃的火山都以使用地面地震仪器的数据估算的层析成像模型的形式以及在过去十年中用大地数据（例如GPS数据和卫星雷达图像）记录的表面变形历史估计的内部结构。更具体地说，该项目将使用基于FEM的大地测量数据逆分析来确定嵌入在这两个活跃火山的复杂内部结构中的岩浆腔的位置，形状和加压的估计和不确定性。更一般而言，该项目将开发整合火山地理学和地震学的方法，这是两个传统上不同的地球物理研究领域。这种整合有望提高对活动火山的基本理解。该项目包括南达科他州矿业与技术学院（SDSMT）的早期职业和中期教师和研究生教育的合作研究。 SDSMT是科学与工程研究区域中心，理想地与与美国当地本地社区进行交往。提出的方法将提供强大的数值技术，以结合不同类型的信息，这些信息通常彼此独立地使用以评估火山危害。这种同时分析不同类型信息的能力将为给定的活跃火山提供更完整的内部过程，并可能导致对火山行为的更可靠的预测。该项目开发的方法将被设计为通常用于其他火山变形的分析，并最终为更可靠的自然危害评估提供重要的社会利益。该项目的另一个影响是它与地震变形研究的直接相关性，该研究是由嵌入与活动断层相关的复杂结构中的变形源的类似构型驱动的。因此，为该项目开发的技术很容易扩展到地震变形的研究，并可能对全球地震和海啸危害的未来分析具有重要意义。