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: 1822484
• 负责人: Domniki Asimaki
• 金额: $ 8.5万
• 依托单位: California Institute of Technology
• 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 2019-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1822484&HistoricalAwards=false
• 关键词: 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 年墨西哥城普埃布拉 7.1 级地震造成多处建筑物倒塌、地面塌陷，造成 300 多人伤亡。 记录在案的现场证据揭示了损害分布模式，该模式已在该地区先前发表的地震研究中得到认可，特别是复杂的区域和当地地质、水文和岩土条件在塑造墨西哥粘土沉积物的地面震动特征方面发挥着决定性作用城市。 虽然地面运动记录显示了盆地湖区一维 (1D) 场地放大的明显证据，但据报道，过渡区沉积深度和结构特征相似的区域的不均匀损害分布和地面运动变化表明，三-维度（3D）位点效应在观察到的损伤中发挥了重要作用。 墨西哥城场地效应作用的记录证据与高密度仪器和数十年的场地特征研究相结合，为工程师和地球科学家提供了绝佳的机会，以实际规模研究 3D 盆地效应和 1D 局部（浅层）的耦合场地响应以及水文条件和地震放大之间的相互作用。 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预测模型，包括洛杉矶、旧金山和西雅图等美国大都市区。 该快速响应研究资助 (RAPID) 项目的总体目标是将仪器和监测、ATA 收集和分析以及数值建模结合起来，以更好地表征地震期间的区域盆地和局部场地影响。 快速响应框架通过将其目标与墨西哥研究人员和工程师正在进行和即将进行的活动相结合，以最大限度地利用项目资源，以细化盆地的地质和岩土工程场地特征，并绘制动态岩土特性随时间的演变以适应快速变化的水文条件在该地区。 该奖项体现了 NSF 促进科学进步和促进国民健康、繁荣和福利的使命。在技​​术层面上，该项目的重点是使用主动源和环境波场表面波方法以及水平与垂直谱比对墨西哥城的强运动站和其他关键地点进行动态现场表征。 进行这些测量的目的是开发地震剪切波速度剖面并估计站点周期，从而改进城市和区域灾害评估的微分区图。 将现场测量与墨西哥研究数据库中浅层沉积物的空间变化和深层沉积物的地质信息相结合，将开发墨西哥城的 3D 浅层地壳速度模型。 该模型对于基于物理的地震动模拟至关重要，因为众所周知，非常软的材料中的小尺度横向不均匀性对地震动有影响，特别是在较深的地质构造、浅层沉积物和结构之间存在复杂的共振相互作用的情况下。建筑物的振动特性。 对这些现象的更好理解不仅有助于改进墨西哥城的地震灾害估计，也有助于改善位于类似沉积盆地的美国城市的地震灾害估计。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，被认为值得支持。智力价值和更广泛的影响审查标准。

项目成果

Mexico City Basin Effects: Past, Present, and Future

墨西哥城盆地效应：过去、现在和未来

• DOI: 10.1061/9780784482100.043
• 发表时间: 2019-03
• 期刊: Eighth International Conference on Case Histories in Geotechnical Engineering
• 作者: Asimaki, Domniki;Villa, Juan Mayoral;Ayoubi, Peyman;Franke, Kevin;Hutchinson, Tara
• 通讯作者: Hutchinson, Tara