Volcano Deformation and Magma Migration in Galapagos Shield Volcanoes

加拉帕戈斯盾火山的火山变形和岩浆迁移

• 批准号: 9814312
• 负责人: Dennis Geist
• 金额: $ 27.58万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2003-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814312&HistoricalAwards=false
• 关键词: Volcano; Deformation; Magma; Migration; Galapagos

9814312GeistGalapagos shield volcanoes are some of the most active volcanoes in the world and constitute one of the most widespread volcano types in the ocean basins and on other planets. The internal plumbing, the mechanisms of magma migration, and the role of deformation in the evolution of Galapagos-type shield volcanoes are all poorly known, particularly in their type locality. The state of strain within the volcanoes and the emplacement of magma will be monitored through GPS geodetic and microgravity surveys at 51 stations at Fernandina and Sierra Negra volcanoes. After the initial deployment, the GPS networks will be reoccupied annually for two years to measure surface response to active subsurface processes and any eruptive activity. Microgravity measurements will also be carried out at the same stations each year, in order to detect changes in the gravity signal related to internal mass redistribution. This integrated investigation will address: 1) the origin of the characteristic morphology of Galapagos-type shields, 2) the mechanisms of caldera collapse, 3) the strain associated with emplacement of magma, 4) the long-term space accommodation from repeated dike intrusions, and 5) the geometry of magmatic intrusions underlying calderas. The results from this study should provide data useful in distinguishing between competing and poorly-constrained models of volcano evolution, and will greatly increase our understanding of the internal structure and active processes associated with morphologic and eruptive styles of Galapagos volcanism

加拉帕戈斯盾状火山是世界上最活跃的火山之一，也是海洋盆地和其他星球上最广泛的火山类型之一。内部管道，岩浆迁移的机制，变形在加拉帕戈斯型盾状火山演化中的作用都知之甚少，特别是在它们的典型位置。将通过在费尔南迪纳火山和内格拉山脉火山的51个观测站进行全球定位系统大地测量和微重力测量，监测火山内部的应变状态和岩浆的就位情况。在初步部署之后，全球定位系统网络将每年重新启用两年，以测量地表对活跃的地下过程和任何喷发活动的反应。每年还将在同一台站进行微重力测量，以探测与内部质量重新分布有关的重力信号变化。这项综合调查将解决：1）加拉帕戈斯型盾的特征形态的起源，2）破火山口坍塌的机制，3）与岩浆侵位相关的应变，4）重复岩墙侵入的长期空间容纳，以及5）破火山口下的岩浆侵入体的几何形状。这项研究的结果应该提供有用的数据，以区分火山演化的竞争和约束条件差的模型，并将大大增加我们对内部结构和活动过程与加拉帕戈斯火山活动的形态和喷发风格的理解