RAPID/Collaborative Research: Dynamic Site Characterization Following Mw 7.1 Puebla Earthquake for Development of a Refined 3D Shallow Crust Velocity Model of the Mexico City Basin

RAPID/协作研究：普埃布拉 7.1 级地震后的动态场地特征，用于开发墨西哥城盆地的精细 3D 浅地壳速度模型

• 批准号: 1822482
• 负责人: Clinton Wood
• 金额: $ 9.37万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-15 至 2020-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1822482&HistoricalAwards=false
• 关键词: RAPID; Collaborative; Research; Dynamic; Site; RAPID; Collaborative; Research; Dynamic; Site

The 2017 Mw 7.1 Puebla-Mexico City Earthquake caused numerous building collapses, ground failures, and over 300 casualties. Documented field evidence revealed damage distribution patterns that have been recognized in published studies of previous earthquakes in the region, specifically that the complex regional and local geology, hydrology and geotechnical conditions play a decisive role in shaping the ground shaking characteristics of the clay sediments in Mexico City. While ground motion recordings showed clear evidence of one-dimensional (1D) site amplification in the lake zone of the basin, the uneven damage distribution and ground motion variability in areas of reportedly similar deposit depths and structural characteristics in the transition zone suggest that three-dimensional (3D) site effects played a significant role in the observed damage. The documented evidence of the role of site effects in Mexico City combined with the high density instrumentation and decades of site characterization research provide an excellent opportunity for engineers and earth scientists to study in real scale the coupling of 3D basin effects and 1D local (shallow) site response, and the interaction between hydrological conditions and seismic amplification. Advances in our understanding of these phenomena can be used to develop better prediction models for seismically active regions, including U.S. metropolitan areas such as Los Angeles, San Francisco and Seattle. The overarching goal of this Grant for Rapid Response Research (RAPID) project is to combine instrumentation and monitoring, ata collection and analysis, and numerical modeling to better characterize regional basin and local site effects during earthquakes. The rapid response framework maximizes the project resources by aligning its goal with ongoing and upcoming activities of Mexican researchers and engineers to refine the geological and geotechnical site characterization of the basin, and map the evolution of dynamic geotechnical properties with time to the rapidly changing hydrologic conditions in the area. This award addresses the NSF mission to promote the progress of science and to advance the national health, prosperity, and welfare. On a technical level, this project focuses on conducting dynamic site characterization of strong motion stations and other key places in Mexico City using active source and ambient wavefield surface wave methods along with horizontal-to-vertical spectral ratios. The goal of conducting these measurements is to develop seismic shear wave velocity profiles and estimate site periods that can lead to improved microzonation maps for the city and regional hazard assessment. Combining field measurements with the spatial variability of shallow deposits and geological information of the deeper sediments from Mexican research databases, a 3D shallow crust velocity model of Mexico City will be developed. This model is essential for physics based ground motion simulations, given the known influence that small-scale lateral heterogeneities in very soft materials have on ground motions, especially in cases of complex resonance interaction between the deeper geologic formations, the shallow sediments, and the structural vibration characteristics of buildings. A better understanding of these phenomena contributes by extension to improved seismic hazard estimates not only for Mexico City, but also for U.S. cities that lie on similar sedimentary basins.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.

2017 MW 7.1普韦布拉 - 墨西哥城市地震造成了许多建筑物倒塌，地面故障和300多人伤亡。 有记录的现场证据显示，在该地区以前的地震的发表研究中已经确认了损伤分布模式，特别是，复杂的区域和局部地质，水文学和岩土技术条件在塑造墨西哥城粘土沉积物的地面震动特征方面起着决定性的作用。 虽然地面运动记录显示了盆地湖区中一维（1D）位点放大的明确证据，但据报道，在过渡区域中相似的沉积物深度和结构特征的区域的损伤分布和地面运动变化表明，三维（3D）位点在观察到的损害中起着重要作用。 墨西哥城现场影响作用的证据与高密度仪器和数十年的现场表征研究相结合，为工程师和地球科学家提供了一个绝佳的机会，可以在实际规模上研究3D盆地效应和1D局部（浅水）现场反应的耦合，以及水力学条件和地震扩增之间的相互作用。 我们对这些现象的理解的进步可用于开发更好的地震活跃地区的更好的预测模型，包括洛杉矶，旧金山和西雅图等美国大都市地区。 该赠款对快速响应研究（快速）项目的总体目标是将仪器和监视，ATA收集和分析以及数值建模相结合，以更好地表征地震期间区域盆地和本地现场效应。 快速响应框架通过将其目标与墨西哥研究人员和工程师的持续和即将进行的活动保持一致，从而使项目资源最大化，以完善盆地的地质和岩土技术场所的表征，并将动态岩土特性的演变与时间的时间绘制到该地区快速变化的水文条件。 该奖项旨在解决NSF的使命，以促进科学进步并促进国家健康，繁荣和福利。在技​​术层面上，该项目着重于使用主动源和环境波场表面波法以及水平与垂直光谱比进行强大运动站和墨西哥城其他关键位置的动态场所表征。 进行这些测量值的目的是开发地震剪力波速度曲线并估算地点周期，从而可以改善城市和区域危害评估的微分解图。 将现场测量与墨西哥研究数据库中更深沉积物的浅层沉积物的空间变异结合在一起，将开发出墨西哥城的3D浅层外壳速度模型。 鉴于已知的影响，该模型对于基于物理的地面运动模拟至关重要，因为已知的影响是，在深层地质地层，浅层沉积物，浅层沉积物和建筑物的结构振动特征之间，非常柔软的材料中的小规模侧向异质性对地面运动具有相互作用。 对这些现象的更好理解促进了改善墨西哥城的地震危险估计，而且对属于类似沉积盆地的美国城市也有贡献。这奖反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来获得支持的。