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

美国已经有20多年没有发生过大规模破坏性地震了。 然而，通过在具有类似抗震设计标准和良好基础设施的国家观察大地震的影响，地震工程继续取得进展。 新西兰有着严格的建筑规范和类似于美国的基础设施，提供了最大的机会，以吸取将直接转移到我国的经验教训。 Mw7.8凯库拉地震提供了一个独特的机会，以评估地震震动对不同类型的基础设施的影响，在不同的人口密度的城市，由各种类型的土壤剖面，受到广泛的震动强度。 这些情况为研究场地、盆地和地形效应引起的地面震动放大以及断层诱发的地面破坏提供了宝贵的机会，这些情况将直接适用于美国城市，如洛杉矶、旧金山弗朗西斯科、西雅图和湖城。 由于私人投资者目前可以使用一些关键设施，例如惠灵顿的中心港口，因此需要紧急处理。例如，在他们重建港口后，将不再有通道，并将失去描述地震后立即发生的地面特征的机会。 此外，新西兰研究人员正在迅速动员起来，在关键地点开展初步研究。 为了将联合收割机资源和专门知识结合起来，该项目还需要迅速调动。 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，可持续性和可承受性，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相关问题。 简而言之，这项工作的广泛影响远远超出了新西兰的边界，并将积极影响美国和国外的地震灾害实践。研究计划的知识价值包括：（1）复杂岩土工程环境中的地面运动地层学，盆地和地形效应;（2）砾石土的液化反应;（3）地震的影响。（3）非液化覆盖层对液化破坏潜力的影响;（4）建筑物和重要港口基础设施对液化土壤的反应。 特别令人感兴趣的是在首都惠灵顿距断层破裂60公里的天然和再生土壤场地上记录到的远高于预期的长周期地面运动。 据推测，高度可变的地形，无论是上面和下面的谷底，导致地层，盆地和地形效应之间的复杂的相互作用，放大地面运动。 需要以深层剪切波速度（Vs）剖面和地形阵列研究的形式进行高级场地表征，以调查这些现象。 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察结果放在背景中。 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小尺度上研究所有这些地面运动效应。 惠灵顿的港口设施也需要先进的场地特性，在那里，在中等震动下发生了令人惊讶的严重液化破坏（PGA值为0.13 - 0.24g）从这个相对遥远的地震除了记录损坏码头和航运起重机由于地震引起的横向蔓延运动，在CentrePort有一些罕见的砾石液化事件需要记录。南岛上其他重要的地面破坏地点也应该迅速描述，以增加价值，易腐数据到美国土壤液化触发和横向传播经验数据库。 计划在惠灵顿和南岛的关键案例历史现场进行高级场地特性研究，综合使用：（1）单站水平-垂直频谱比噪声测量，以调查基本场地周期，（2）联合有源和环境波场表面波测试，以开发深层Vs剖面;（3）圆锥贯入测试，以揭示详细的场地地层;（4）直推式井间测试，获得高分辨率的Vs和Vp剖面。 收集和分析这些数据将有助于更好地了解宝贵的经验教训，这些经验教训可直接用于改进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.