KDI: Large-Scale Inversion-Based Modeling of Complex Earthquake Ground Motion in Sedimentary Basins

KDI：沉积盆地复杂地震地面运动的大规模反演建模

• 批准号: 9980063
• 负责人: Jacobo Bielak
• 金额: $ 213.1万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9980063&HistoricalAwards=false
• 关键词: KDI; Large; Scale; Inversion; Based

The main objective of this research program is to develop the capability to generate realistic inversion-based models of complex basin geology and earthquake sources "by computer simulation" and to use this capability to model and forecast strong ground motions during earthquakes in Los Angeles Basin and the San Francisco Bay Area. This problem is of great importance to earthquake hazard mitigation, since assessing the ground motion experiences by structures during their lifetimes is an essential first step in designing earthquake-resistant facilities, and retrofitting existing structures: ground motion modeling and forecasting are a necessary precursor to the design process. This project involves collaboration between researchers at Carnegie Mellon University, University of California at Berkeley and San Diego State University. The research team, centered at Carnegie Mellon University, consists of earthquake engineers, seismologists, geologists, computational mechanists, computer scientists, and computer graphics and visualization specialist.Computer modeling and forecasting earthquake ground motions in large basins, is a challenging and complex task, with the complexity arising from several sources: multiple spatial scales characterize the basin response (the shortest wavelengths are measured in tens of meters, the longest in kilometers, and basin dimensions are on the order of tens of kilometers); temporal scales vary from the hundredths of a second necessary to resolve the highest frequencies of the earthquake source up to a couple of minutes of shaking within the basin; many basins have highly irregular geometry; the soils; material properties are highly heterogeneous; and geology and source parameters are only indirectly observable, and thus introduce uncertainty into the modeling process. Current earthquake simulations provide much useful information, but are not always capable of adequately reproducing observed seismograms. The likely reason is that these models use a number of restrictive assumptions to reduce the computational requirements. Motivated by the need for greater fidelity in earthquake ground motion modeling the research team is developing enhance models by incorporating the following: (1) The ability to represent physical domains an order of magnitude larger than current models; (2) The ability to model frequencies higher than currently possible; (3) Improved earthquake source models derived from available observation by solving 3D inverse problems; (4) improved basin material models based on the inversion of observations of ground motion within the basin; and (5) The ability to resolve boundary surfaces and sharp interfaces.The drive toward greater fidelity in earthquake modeling introduces computational challenges in all states of the simulation process: from preprocessing, to solving, to postprocessing. This is addressed through a concerted, unified effort in parallel 3D mesh generation, parallel 3D seismic inversion, and large-scale distributed visualization. It is expected that this will result in important advances in physical modeling and algorithm and software tool development for multi-teraflops computers, while gaining physical insight into earthquake ground motion. Because of the critical role that ground motion plays in infrastructure design, the accelerated availability of suitable simulation methodologies will have a direct impact on public safety and welfare.

这项研究计划的主要目标是开发能力，以产生现实的复杂盆地地质和地震源的反演模型“通过计算机模拟”，并使用这种能力来模拟和预测强烈的地面运动在地震期间在洛杉矶盆地和旧金山弗朗西斯科湾区。 这个问题是非常重要的，以减轻地震灾害，因为评估地面运动的经验结构在其寿命是一个重要的第一步，在设计抗震设施，改造现有的结构：地面运动建模和预测是一个必要的先决条件的设计过程。 该项目涉及卡内基梅隆大学、加州大学伯克利分校和圣地亚哥州立大学的研究人员之间的合作。 该研究团队以卡内基梅隆大学为中心，由地震工程师、地震学家、地质学家、计算力学家、计算机科学家以及计算机图形和可视化专家组成。计算机建模和预测大盆地地震地面运动是一项具有挑战性和复杂性的任务，复杂性来自以下几个方面：多个空间尺度表征流域响应（最短波长以几十米为单位测量，最长波长以千米为单位测量，盆地尺寸为几十千米的量级）;时间尺度从解析震源最高频率所需的百分之一秒到盆地内几分钟的震动不等;许多盆地具有高度不规则的几何形状;土壤;材料特性高度不均匀;地质和震源参数只能间接观测，因此在建模过程中引入了不确定性。 目前的地震模拟提供了许多有用的信息，但并不总是能够充分再现观测到的地震图。 可能的原因是，这些模型使用了一些限制性的假设，以减少计算的要求。 由于地震地面运动模拟需要更高的保真度，研究小组正在开发增强模型，包括以下内容：（1）表示比当前模型大一个数量级的物理域的能力;（2）模拟比当前可能的频率更高的频率的能力;（3）通过解决三维逆问题从现有观测中获得的改进的震源模型;（4）基于盆地内地面运动观测反演的改进盆地物质模型;（5）解决边界表面和尖锐界面的能力。地震模拟中对更高保真度的追求在模拟过程的所有状态中引入了计算挑战：从预处理到求解，再到后处理。 这是通过一个协调一致的，统一的努力，并行三维网格生成，并行三维地震反演，大规模分布式可视化。 预计这将导致物理建模和算法的重要进展和软件工具开发的多万亿次计算机，同时获得物理洞察地震地面运动。 由于地面运动在基础设施设计中起着至关重要的作用，因此，适当的模拟方法的加速可用性将对公共安全和福利产生直接影响。