Extending the Spatiotemporal Scales of Physics-Based Seismic Hazard Analysis

扩展基于物理的地震灾害分析的时空尺度

• 批准号: 1440085
• 负责人: Thomas Jordan
• 金额: $ 4万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1440085&HistoricalAwards=false
• 关键词: Extending; Spatiotemporal; Scales; Physics; Based

Earthquake simulations at the spatiotemporal scales required for probabilistic seismic hazard analysis (PSHA) present some of the toughest computational challenges in geoscience. PSHA is the scientific basis for many engineering and social applications: performance-based design, seismic retrofitting, resilience engineering, insurance-rate setting, disaster preparation and warning, emergency response, and public education. This project will extend deterministic earthquake simulations to seismic frequencies of 2 Hz and greater with the goal of reducing the epistemic uncertainties in physics-based PSHA. The research will address fundamental scientific problems that limit the scale range in current representations of source physics, anelasticity, and geologic heterogeneity. The research will improve the physical representations of earthquake processes and the deterministic codes for simulating earthquakes, which will benefit earthquake system science worldwide. The consequent decrease in mean exceedance probabilities, which could be up to an order of magnitude at high hazard levels, would have a broad impact on the prioritization and economic costs of risk-reduction strategies.Previous research on Blue Waters has verified the scalability and computational readiness of the simulation codes. These codes will be used to advance physics-based PSHA through a coordinated program of numerical experimentation and large-scale simulation targeted at three primary objectives: (1) validation of high-frequency simulations against seismic recordings of historical earthquakes; (2) computation of high-frequency CyberShake hazard models for the Los Angeles region to support the development of high-resolution urban seismic hazard maps by the U. S. Geological Survey and the Southern California Earthquake Center (SCEC), and (3) high-frequency simulation of a M7.8 earthquake on the San Andreas fault to revise the 2008 Great California ShakeOut scenario and improve the risk analysis developed in detail for that scenario. The plan to accomplish this research has five computational milestones: (a) dynamic rupture simulations up to 8 Hz that include fault roughness and near-fault plasticity; (b) simulations of historic earthquakes up to 4 Hz for model validation; (c) simulations of the 1994 Northridge Earthquake up to 8 Hz for verification and validation; (d) extension of the 2008 ShakeOut scenario to 4 Hz; and (e) calculation of a complete CyberShake hazard model for the Los Angeles region up to 2 Hz.

概率地震危险分析 (PSHA) 所需的时空尺度的地震模拟提出了地球科学中一些最艰巨的计算挑战。 PSHA 是许多工程和社会应用的科学基础：基于性能的设计、抗震改造、复原力工程、保险费率设定、备灾和预警、应急响应和公共教育。该项目将把确定性地震模拟扩展到 2 Hz 及更高的地震频率，目标是减少基于物理的 PSHA 中的认知不确定性。该研究将解决限制当前源物理、迟弹性和地质异质性表示的尺度范围的基本科学问题。该研究将改进地震过程的物理表示和模拟地震的确定性代码，这将有利于全世界的地震系统科学。由此产生的平均超出概率的下降（在高危险水平下可能会达到一个数量级）将对风险降低策略的优先顺序和经济成本产生广泛的影响。Blue Waters 之前的研究已经验证了可扩展性和计算能力模拟代码的准备情况。这些代码将用于通过数值实验和大规模模拟的协调程序来推进基于物理的 PSHA，其目标是三个主要目标：（1）根据历史地震的地震记录验证高频模拟； (2) 计算洛杉矶地区的高频 Cyber​​Shake 灾害模型，以支持美国地质调查局和南加州地震中心 (SCEC) 开发高分辨率城市地震灾害图，以及 (3) 高频模拟圣安德烈亚斯断层上的 M7.8 地震，以修正 2008 年加州大地震情景并改进针对该情景详细开发的风险分析。完成这项研究的计划有五个计算里程碑：(a) 高达 8 Hz 的动态破裂模拟，包括断层粗糙度和近断层塑性； (b) 模拟高达 4 Hz 的历史地震以验证模型； (c) 模拟 1994 年北岭地震，频率高达 8 Hz，以进行验证和确认； (d) 将 2008 年 ShakeOut 情景扩展至 4 Hz； (e) 计算洛杉矶地区完整的 Cyber​​Shake 危险模型，频率高达 2 Hz。