RAPID/Collaborative Research: Advanced Site Characterization of Key Ground Motion and Ground Failure Case Histories Resulting from the Mw7.8 Kaikoura, New Zealand, Earthquake

20多年来，美国从未发生过破坏性大的地震。然而，通过在具有类似地震设计标准和良好基础设施的国家观察大地震的影响，地震工程方面继续取得进展。在像新西兰这样有着严格的建筑规范和与美国相似的基础设施的国家，记录地震的影响提供了最大的学习机会，这些经验教训将直接适用于我们的国家。Mw7.8 Kaikoura地震提供了一个独特的机会，可以在相当深度上评估地震对不同人口密度的城市中不同类型的基础设施的影响，这些城市受不同类型的土壤剖面的影响，受到各种震动强度的影响。这些情况提供了一个宝贵的机会来研究由场地、盆地和地形效应引起的地面震动放大，以及液化引起的地面破坏案例，这将直接适用于洛杉矶、旧金山、西雅图和盐湖城等美国城市。紧急需要，因为pi目前可以使用一些关键设施，如惠灵顿的中心报告。例如，在他们重建港口之后，将不再有机会进入，并且将失去描述地震后地面的机会。此外，新西兰研究人员正在迅速动员起来，在关键地点进行初步研究。为了将资源和专业知识结合起来，该项目还需要迅速动员起来。该项目的最终目标是通过改进抗震设计，提高民用基础设施的弹性、可持续性和可负担性，从而使整个社会受益。这项工作还将有助于加强美国和新西兰之间的国际研究合作，并将为美国研究生提供有益的国际旅行经验，这将有助于平衡他们的技术教育，并使他们接触到地震工程中仍然存在的全球联系问题。简而言之，这项工作的广泛影响远远超出了新西兰的边界，并将对美国和国外的地震灾害实践产生积极影响。该研究计划的智力优势包括：(1)复杂岩土环境下的地震动地层学、盆地和地形效应；(2)砂砾土液化响应；(3)不可液化盖层对液化损伤潜力的影响；(4)建筑物和关键港口基础设施对液化土的响应。特别令人感兴趣的是，在距离首都惠灵顿断层破裂60公里的自然和开垦土壤上记录的长时间地面运动比预期的要高得多。据推测，谷底上下高度变化的地形导致地层、盆地和地形效应之间复杂的相互作用，放大了地面运动。为了研究这些现象，需要以深横波速度（Vs）剖面和地形阵列研究的形式进行先进的现场表征。如果没有这些信息，就不可能将凯库拉地震造成的结构破坏和地面破坏的观测结果与实际情况联系起来。惠灵顿是这项研究的完美试验台，因为突然变化的地形允许在几公里的非常小的范围内研究所有这些地面运动的影响。除了记录液化引起的横向扩散运动对码头和船舶起重机造成的损害外，还需要对惠灵顿港口设施进行先进的现场描述，因为在这次相对较远的地震中，中度震动（PGA值为0.13 - 0.24g）对港口设施造成了严重的液化破坏。在南岛其他重要的地面故障地点也应该迅速进行特征描述，以便为美国土壤液化触发和横向扩散经验数据库添加有价值的易腐烂数据。计划在惠灵顿和南岛的关键案例历史站点进行先进的站点特征研究，使用以下组合进行：(1)单站水平与垂直频谱比噪声测量，用于调查基本站点周期；(2)结合有源和环境波场表面波测试，用于开发深部v剖面；(3)锥贯试验揭示场址详细地层；(4)高分辨率v、Vp剖面直推井间试验。收集和分析这些数据将有助于更好地理解有价值的经验教训，这些经验教训可直接用于改善美国的抗震设计实践

A large and widely-damaging earthquake has not occurred in the U.S. for over 20 years. However, advancements have continued to be made in earthquake engineering by observing the effects of large earthquakes in countries that have similar seismic design standards and well-constructed infrastructure. Documenting the effects of earthquakes in a country like New Zealand, which has rigorous building codes and similar infrastructure to the U.S., provides the greatest opportunities for learning lessons that will be directly transferable to our country. The Mw7.8 Kaikoura earthquake provides a unique opportunity to evaluate in considerable depth the effects of earthquake shaking on diverse types of infrastructure, in cities of different population densities, underlain by various types of soil profiles, subjected to a wide range of shaking intensities. These circumstances provide an invaluable opportunity to study ground shaking amplification caused by site, basin and topographic effects, and cases of liquefaction-induced ground failure, that will be directly applicable to U.S. cities such as Los Angeles, San Francisco, Seattle and Salt Lake City. Urgency is required because the PIs currently have access to some key facilities, such as the CentrePort of Wellington. After they have rebuilt the port, for example, there will no longer be access and the opportunity to characterize the ground as it was immediately after the earthquake will be lost . Moreover, New Zealand researchers are rapidly mobilizing to carry out initial studies at key sites. In order to combine resources and expertise, the project will need to also mobilize quickly. The end-goal of this project is to benefit society at-large through increased resiliency, sustainability and affordability of civil infrastructure via improved seismic design. This work will also serve to strengthen international research collaborations between the U.S. and New Zealand, and will provide U.S. graduate students with rewarding international travel experiences that will serve to balance their technical education and expose them to the globally-connected problems that still exist in earthquake engineering. In short, the broader impacts of this work stretch far beyond the borders of New Zealand and will positively impact seismic hazard practices in the U.S. and abroad.The intellectual merits of the research plan include an improved understanding of: (1) ground motion stratigraphy, basin and topographic effects in complex geotechnical settings; (2) liquefaction response of gravelly soils; (3) the influence of non-liquefiable capping layers on liquefaction damage potential; and (4) the response of buildings and critical port infrastructure on liquefiable soil. Of particular interest are the much-higher-than-expected long period ground motions recorded on natural and reclaimed soil sites 60 km from the fault rupture in the capital city of Wellington. It is hypothesized that highly variable topography, both above and below the valley floor, resulted in complex interactions between stratigraphy, basin and topographic effects, amplifying ground motions. Advanced site characterization is needed in the form of deep shear wave velocity (Vs) profiling and topographic array studies to investigate these phenomena. Without this information, it will be impossible to place observations of structural damage and ground failure caused by the Kaikoura earthquake in context. Wellington is the perfect test bed for this study, because abruptly changing topography allows all of these ground motion effects to be studied on a remarkably small scale of several kilometers. Advanced site characterization is also needed at Wellington's port facility, where surprisingly severe liquefaction damage occurred under moderate shaking (PGA values of 0.13 - 0.24g) from this relatively distant earthquake In addition to documenting the damage to wharves and shipping cranes due to liquefaction-induced lateral spread movements, there are rare incidents of gravel liquefaction to document at CentrePort Other important ground failure sites on the South Island should also be characterized rapidly to add valuable, perishable data to the U.S. soil liquefaction triggering and lateral spreading empirical databases. Advanced site characterization studies are planned at key case history sites in Wellington and the South Island using a combination of: (1) Single-station horizontal-to-vertical spectral ratio noise measurements for investigating fundamental site periods, (2) Combined active-source and ambient-wavefield surface wave testing for developing deep Vs profiles; (3) Cone penetration tests for revealing detailed site stratigraphy; and (4) Direct-push crosshole tests for high-resolution Vs and Vp profiles. Collecting and analyzing these data will help to better understand valuable lessons-learned that are directly transferrable to improved seismic design practices in the U.S.