Integrated Studies of Transient Volcano Deformation in Hawaii

夏威夷瞬时火山变形的综合研究这项研究将高精度全球定位系统（GPS）和干涉合成孔径雷达（干涉合成孔径雷达）测量与地震观测和力学建模相结合，以更好地了解火山系统。 该方法将数据收集和解释与理论和数值分析相结合。 与夏威夷火山观测站（HVO）合作，在过去10年中在夏威夷收集的连续GPS测量结果表明：1）基拉韦厄火山的膨胀和收缩周期与P 'u' O 'o火山的喷发活动相关; 2）莫纳罗亚火山顶峰膨胀的开始; 3）基拉韦厄和莫纳罗亚火山变形之间明显的时间相关性; 4）基拉韦厄火山基拉韦厄和莫纳罗亚山南翼的向海运动; 5）1997年火山爆发前8小时的裂谷伸展;伴随着这次爆发的快速收缩，随后是再膨胀; 6）当山顶恢复到喷发前的状态时，普奥火山的恢复; 7）1997年爆发后6个月的短暂裂谷延伸; 8）一系列的四次无声地震。 无声地震的规模相当于5.7级，但发生在1到2天的时间内，而不是几秒钟。它们似乎在同一个区域重复，紧挨着一个狭窄的地震带。 目前正在分析全球定位系统数据，以确定基拉韦厄长期侧翼变形和地震活动的震源位置。 原始GPS相位数据用于确定事件持续时间。 这项工作的另一个方面是看看无声的事件是否与非火山震颤或其他不寻常的地震信号有关。长期瞬态变形的来源，包括潜在的莫纳罗亚-基拉韦厄相互作用和岩浆构造相互作用也正在分析中。后者涉及干涉合成孔径雷达和全球定位系统的结合，并将测试从地震活动和其他地球物理和地质数据推断的具体结构模型。第二个重点是成像和建模随时间变化的变形伴随着堤防入侵。 分析力学模型探讨阐明的因素，确定是否堤到达表面和喷发或结束与入侵，以及它是否是在原则上可以确定这一点，而过程正在发生。时间相关的反演方法已经发展，但大地测量数据的空间分辨率是有限的。包括伴随侵入体的震群活动的位置有助于提高空间分辨率。迪特里希（1994）的理论提供了堤坝诱发应力与地震活动率之间的关键联系。这使得人们可以反演堤防形状的大地测量数据和地震率，多余的堤防压力和其他参数。最后一个目标是与观测的物理模型的堤防传播。这项工作扩展了现有的集总参数模型，包括热效应和岩浆密度的变化引起的泡。这将有助于更好地了解堤坝的生长及其随时间的变形，并量化控制喷发与侵入的因素。最后，该项目将取代合作GPS网络中出现故障的接收器，其中许多已经使用了十多年。该项目将资助两名博士。学生，一个侧重于地震和地震过程，包括无声地震，其他岩浆过程，包括堤防入侵。四个过去或现在的博士。的学生（3名女学生）至少部分基于该项目。此外，还有10名研究生或博士后参与了这项研究。我们的研究与HVO完全合作，在过去的16年里，我们与六位项目科学家合作。

Integrated Studies of Transient Volcano Deformation in Hawaii This study combines high precision Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) measurements with seismic observations and mechanical modeling to better understand volcanic systems. The approach combines data collection and interpretation with theoretical and numerical analysis. Continuous GPS measurements collected over the past 10 years in Hawaii in a collaborative effort with the Hawaiian Volcano Observatory (HVO) have shown: 1) inflation and deflation cycles on Kilauea volcano correlated with eruptive activity at P'u 'O'o; 2) the onset of summit inflation at Mauna Loa volcano; 3) apparent temporal correlations between deformation at Kilauea and Mauna Loa; 4) seaward motion of both Kilauea and Mauna Loa south flanks; 5) eight hours of rift extension preceding an eruption in 1997; rapid deflation accompanying this eruption followed by re-inflation; 6) recovery of the P'u 'O'o eruption when the summit regained its pre-eruptive state; 7) six months of transient rift extension following the 1997 eruption; and 8) a series of four silent earthquakes. The silent earthquakes are equivalent in size to a magnitude 5.7 but occur over a period of 1 to two days, rather than a few seconds. They appear to repeat in the same area, immediately seaward of a narrow band of earthquakes. The GPS data are being analyzed to determine the source locations with respect to the sources of long-term flank deformation and seismicity on Kilauea. The raw GPS phase data are used to determine event durations. Another aspect of the work is to see if the silent events are associated with non-volcanic tremor or other unusual seismic signals. The sources of longer-term transient deformation, including potential Mauna Loa-Kilauea interactions and magmatic tectonic interactions are also being analyzed. The latter involve the integration of InSAR and GPS and will test specific structural models inferred from seismicity and other geophysical and geologic data. A second focus is imaging and modeling time dependent deformation accompanying dike intrusion. Analytical mechanical models are explored to elucidate the factors that determine whether a dike reaches the surface and erupts or ends with intrusion, and whether it is in principal possible to determine this while the process is occurring. Time dependent inversion methods have been developed, but the spatial resolution of geodetic data is limited. Including the locations of swarm seismicity accompanying intrusions helps to improve spatial resolution. Dieterich's (1994) theory provides the key link between dike induced stress and seismicity rate. This allows one to invert geodetic data and earthquake rates for the shape of the dike, the excess dike pressure, and other parameters. The final objective is relating the observations to physical models of dike propagation. This work extends extends existing lumped parameter models by including thermal effects and magma density changes induced by vesiculation. This should allow better understanding of the growth of dikes and their induced deformation with time, and to quantify the factors that govern eruption vs. intrusion. Lastly, the project will replace failing receivers in the collaborative GPS network, many of which are more than a decade old. This project will support two Ph.D. students, one focusing on seismic and aseismic processes including silent earthquakes, the other magmatic processes including dike intrusion. Four past or present Ph.D.'s (3 female students) were based at least in part on this project. In addition, 10 other graduate students or Postdocs have participated in this research. Our research is fully collaborative with HVO where we have worked with six project scientists over the past 16 years.