Collaborative Research: High resolution passive seismic imaging beneath Valles caldera

合作研究：Valles破火山口下的高分辨率被动地震成像

• 批准号: 2113367
• 负责人: Julien Chaput
• 金额: $ 15.4万
• 依托单位: University of Texas at El Paso
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2113367&HistoricalAwards=false
• 关键词: Collaborative; Research; resolution; passive; seismic

The Valles caldera is one of three supervolcanoes in North America and has a long history of volcanism with documented magma flows as recent as ~70,000 years. Seismic imaging allows visualization of volcanic subterranean structures by using seismic waves in a similar way ultrasound sonography in medical imaging. Seismic imaging of the Valles Caldera was lacking until recently, which in turn has hindered estimate of melt volumes, melt extent, and understanding of the plumbing system. A joint University of Texas at El Paso (UTEP)/University of New Mexico (UNM) deployment in 2019 resulted in a 97-seismometer line crossing the entire caldera for 1 month. A primary objective of this initiative is to resolve the spatial extent and concentration of melt under the caldera, with other standing questions including the depth of any magma body underlying the dome, the thickness of intra-caldera fill and fractured basement blocks, and the nature of the crust/mantle boundary. Using cutting edge techniques, researchers probe and unveil the subterranean magmatic system of the volcano and foster a collaboration between UTEP and UNM, two minority serving institutions. The outcomes of this project improve earthquake and volcanic hazard assessment in the region, and support the training of graduate and undergraduate students from underrepresented minorities in science. The Valles caldera, a Quaternary-active supervolcanoes, is the textbook example of a resurgent caldera. It has largely escaped seismic scrutiny in the past two decades. Here the researchers probe the magmatic system beneath Valles caldera. They quantify the spatial extent of melt structures, the depth and emplacement of scattering boundaries, and assess the assumed aseismic nature of the caldera system. Ambient noise seismic interferometry is leveraged to estimate dispersion curves for long period Rayleigh and Love waves; these will be jointly inverted in a transdimensional Bayesian scheme with receiver functions, H/V ratios, and noise autocorrelations. The goal is to accurately estimate velocity structures under the Valles caldera. Targets include bounding the spatial extent and concentration of melt through shear-wave velocity and Vp/Vs estimates, depth to magmatic structures and caldera fill under the resurgent dome through scattered wave analysis, and detection and location of any local seismicity that may reveal magma and fluid movements. This project complements sparser long-term seismic monitoring efforts by Los Alamos National laboratory. It serves as an educational primer and complement to frequent geophysics field camps using the caldera as a natural laboratory. Its outcomes improve the assessment of the volcano life-cycle stage and allow better comparison with other Quaternary supervolcanoes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Valles Caldera是北美三大超级火山之一，具有悠久的火山活动历史，记录了近7万年的岩浆流动。地震成像可以通过使用地震波以类似于医学成像中的超声超声波检查的方式可视化火山地下结构。 直到最近，Valles Caldera的地震成像仍然缺乏，这反过来又阻碍了对融化量，融化范围和管道系统的理解的估计。 德克萨斯大学埃尔帕索分校（UTEP）/新墨西哥州大学（UNM）在2019年的联合部署导致97个地震仪线穿过整个破火山口1个月。 这一举措的主要目标是解决空间范围和火山口下的熔体浓度，与其他长期存在的问题，包括圆顶下的任何岩浆体的深度，火山口内填充和破裂的基底块的厚度，以及地壳/地幔边界的性质。研究人员利用尖端技术探索并揭示了火山的地下岩浆系统，并促进了UTEP和UNM这两个少数民族服务机构之间的合作。 该项目的成果改善了该地区的地震和火山灾害评估，并支持对来自代表性不足的少数民族的研究生和本科生进行科学培训。Valles破火山口是一座百年活跃的超级火山，是破火山口复活的教科书范例。在过去的二十年里，它基本上逃脱了地震的审查。在这里，研究人员探测Valles破火山口下的岩浆系统。 他们量化的空间范围内的熔体结构，散射边界的深度和定位，并评估假设的火山口系统的asepersion性质。利用环境噪声地震干涉测量来估计长周期瑞利波和Love波的频散曲线;这些将在具有接收器函数、H/V比和噪声自相关的跨维贝叶斯方案中联合反演。 其目标是准确地估计下的Valles破火山口的速度结构。目标包括通过剪切波速度和Vp/Vs估计，通过散射波分析，以及可能揭示岩浆和流体运动的任何当地地震活动的检测和定位，确定岩浆结构和复兴圆顶下的破火山口填充的深度。该项目补充了洛斯阿拉莫斯国家实验室较稀疏的长期地震监测工作。它作为一个教育初级读本和补充，经常使用的破火山口作为一个天然实验室物理野外营地。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。