High-Resolution Seismic Imaging: A Comprehensive Application of Waveform Cross-Correlation to Volcanic Fields

拟议的研究将为今后研究与火山活动有关的地热和热液特征以及监测火山活动提供可能性。原位Vp/Vs方法将提供一个新的和强大的补充现有的地震技术映射泊松？s比率。与其他方法相比，Vp/Vs比具有更高的精度和更简单的特点，这将使它成为地震学中一个更有力的工具，有助于跟踪火山内部岩浆和挥发物的运动，估计活动断裂带破裂和流体含量的空间变化。火山是一种自然灾害，它产生多种破坏性现象，如熔岩流、岩屑崩落、有毒气体排放、和空中的火山灰云随着火山附近地区的发展，更多的人和财产面临火山活动的风险。为了提高我们对火山喷发过程和火山-地震相互作用的理解，以减少生命和财产损失，我们需要提高数据质量和更强大的估计方法来研究火山系统。在这里，我们建议追求波形互相关几个火山领域的全面应用，以评估细尺度近源的空间和时间的火山结构变化。将应用于拟议项目的主要五项研究是：（1）波形互相关，以获得纵波和横波的微分时间，（2）复合事件方法，以减少随机拾取误差并最大化地震层析成像反演中每个事件的可能观测数，（3）使用初至绝对时间和微分时间的三维和四维地震层析成像，（4）相似事件聚类分析和互相关重定位;（5）高分辨率原位泊松分布估计。建议的工作将被应用到几个火山领域，包括长谷火山口，科索地质区，黄石公园。细尺度层析速度结构可用于成像整个火山系统，并解决管道和岩浆房。高分辨率泊松分布？S比值将有助于追踪岩浆运动和研究未来喷发危险的可能性，高精度的地震重新定位也是绘制岩浆迁移图的必要条件。这些研究对今后火山系统地震数据的实时分析以及调查火山和破火山口的历史和现状都是有用的。

The proposed research will provide a potential to study the geothermal and hydrothermal features related to volcanic activities and to monitor volcanic activity in the future. The in situ Vp/Vs method will provide a new and robust complement to the existing seismic techniques for mapping Poisson?s ratio. The higher precision of results and the simplicity compared with other techniques will make Vp/Vs ratio a more powerful tool in seismology and will help to track movement of magma and volatiles within a volcano and to estimate spatial variations in fracturing and fluid content in active fault zones.Volcanoes are a natural hazard that produces many kinds of destructive phenomena, such as lava flows, debris avalanches, noxious gas emissions, and airborne ash clouds. With the development of areas near volcanoes, more people and property are at risk of volcanic activity. In order to improve our understanding of eruption process and volcano-earthquake interactions to reduce life and property loss, we need improved data quality and more robust estimation methods to study volcanic systems. Here we propose to pursue a comprehensive application of waveform cross-correlation to several volcanic fields to assess fine-scale near-source spatial and temporal volcanic structural variations. The main five studies that will be applied to the proposed project are: (1) waveform cross-correlation to obtain both compressional and shear wave differential times, (2) composite event method to reduce the random picking error and maximize possible number of observations for each event in seismic tomographic inversions, (3) three- and four-dimensional seismic tomography using first-arrival absolute and differential times, (4) similar event cluster analysis and cross-correlation relocation, and (5) estimate of high-resolution in situ Poisson?s ratio using waveform data.The proposed work will be applied to several volcanic fields, including the Long Valley Caldera, the Coso Geothermal Area, and the Yellowstone. Fine-scale tomographic velocity structure can be used to image the entire volcanic systems and to resolve conduits and magma chambers. High-resolution Poisson?s ratios will be helpful to track magma moving and investigate the possibility of future eruption hazards and high-precision earthquake relocations are also essential for mapping magma migration. These studies are all useful for future real-time analysis of seismic data in volcanic systems and for investigating the history and current states of volcanoes and calderas.