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

拟议的研究将有可能研究与火山活动有关的地热和热液特征，并监测未来的火山活动。原位Vp/VS方法将为现有的泊松-S比地震测绘技术提供一个新的、强有力的补充。与其他技术相比，Vp/VS比具有更高的精度和简单性，将使其成为地震学中更强大的工具，将有助于跟踪火山内岩浆和挥发分的运动，并有助于估计活动断裂带中破裂和流体含量的空间变化。火山是一种自然灾害，会产生多种破坏性现象，如熔岩流、泥石流、有毒气体排放和空中灰云。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。为了更好地了解火山喷发过程和火山-地震相互作用，减少生命和财产损失，我们需要提高数据质量和更稳健的估计方法来研究火山系统。在这里，我们建议对几个火山岩田进行波形互相关的综合应用，以评估精细尺度的近源火山构造的空间和时间变化。将应用于该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差异时间；(2)复合事件方法，以减少地震层析成像中的随机拾取误差，并最大限度地增加每个事件的可能观测数；(3)利用初至绝对时间和差异时间的三维和四维地震层析；(4)相似事件簇分析和互相关重新定位；(5)利用波形数据估计高分辨率的原位泊松？S比。科索地热区和黄石公园。精细的层析成像速度结构可以用来成像整个火山系统，并解析管道和岩浆室。高分辨率泊松-S比值将有助于追踪岩浆运动和研究未来喷发灾害的可能性，高精度的地震重新定位也是绘制岩浆迁移图所必需的。这些研究都有助于今后对火山系统的地震数据进行实时分析，并有助于调查火山和火山口的历史和现状。

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.