The Southern California Earthquake Center, Phase 4 (SCEC4): Tracking Earthquake Cascades

该合作协议为南加州地震中心（SCEC）提供资金，为期5年，从2012年2月1日至2017年1月31日（SCEC4）。该中心是一个全国性的大型机构联盟，其分布范围越来越广，以南加州为主要的自然实验室，协调地震科学的基础研究。该地区数据丰富，城市化人口超过2000万，构成了全国地震风险的最大份额。SCEC的地震系统科学主题强调通过传感器网络收集信息、实地工作和实验室实验之间的联系；通过基于物理的系统级建模来形成知识；提高对地震危害的认识；以及减少地震风险和促进社区恢复力的行动。地震产生于活动断层系统中复杂的、多尺度的相互作用，这些系统在自然和建筑环境中作为混沌连锁反应级联。当前的5年研究计划正在开发通过随时间变化的地震灾害分析来跟踪地震级联所需的地球科学，并通过跨科学学科和研究机构协调的高度集成合作，以及高性能计算和先进的信息技术，推动这一科学向前发展。这些合作集中在地震物理学的六个基本问题上：(a)从板块运动到地壳断层的应力转移：长期断层滑动率。(b)应力介导的断层相互作用和地震聚类：机制评价。(c)地震滑动过程中断层阻力的演化：破裂模型的尺度适宜规律。(d)断裂带和系统的结构和演化：与地震物理学的关系。(e)瞬态变形的原因和影响：慢滑事件和构造震动。(f)地震波的产生和散射：强地面运动的预测。这些问题是相互关联的，需要跨学科、多机构的方法。SCEC4跨学科研究计划包括分布在南加州的特殊断层研究区域；开发南加州社区大地测量模型，该模型结合了GPS和InSAR数据；建立了社区应力模型，这是一个整合地震产生应力的各种约束的新平台。该中心正在将基础研究转化为实用产品，以减少风险和提高社区的复原力。SCEC4项目旨在将长期地震危害分析转变为一门基于物理的科学。它正在帮助美国地质勘探局和其他负责任的政府机构发展可操作的地震预报能力，以提供有关地震灾害时间依赖性的权威信息，帮助社区为潜在的破坏性地震做好准备。它为地震早期预警提供了科学依据——提前通知地震正在发生，并预测强震何时会到达更远的地方——并改善了有关强地面运动和次生灾害的事后信息的传递。SCEC的沟通、教育和外展项目是围绕创建一个具有地震和海啸韧性的加州这一主题建立的。通过ShakeOut演习，个人和组织准备应对不断变化的地震灾害，并向他们介绍操作地震预报和地震预警的新技术。它正在教育所有年龄段的人——在加州，全国各地，和国际上——关于地震，并激励他们做好准备。一项K-14地震教育倡议旨在改善地球科学教育和学校地震安全。SCEC的体验式学习和职业发展计划为学生和早期职业科学家提供了不同的研究机会和网络，以鼓励和维持科学和工程的职业生涯。

This cooperative agreement funds the Southern California Earthquake Center (SCEC) for the 5-year period from 1 Feb 2012 to 31 Jan 2017 (SCEC4). The Center is a large consortium of institutions with a national, and increasingly worldwide, distribution that coordinates basic research in earthquake science using Southern California as its principal natural laboratory. The region is data-rich and, with an urbanized population exceeding 20 million, comprises the lion's share of national earthquake risk. SCEC's theme of earthquake system science emphasizes the connections between information gathering by sensor networks, fieldwork, and laboratory experiments; knowledge formulation through physics-based, system-level modeling; improved understanding of seismic hazard; and actions to reduce earthquake risk and promote community resilience. Earthquakes emerge from complex, multiscale interactions within active fault systems that cascade as chaotic chain reactions through the natural and built environments. The current 5-year research program is developing the geoscience required to track earthquake cascades through time-dependent seismic hazard analysis, and it is moving this science forward through highly integrated collaborations that are coordinated across scientific disciplines and research institutions and enabled by high-performance computing and advanced information technology. The collaborations are focused on six fundamental problems of earthquake physics: (a) Stress transfer from plate motion to crustal faults: long-term fault slip rates. (b) Stress-mediated fault interactions and earthquake clustering: evaluation of mechanisms. (c) Evolution of fault resistance during seismic slip: scale-appropriate laws for rupture modeling. (d) Structure and evolution of fault zones and systems: relation to earthquake physics. (e) Causes and effects of transient deformations: slow slip events and tectonic tremor. (f) Seismic wave generation and scattering: prediction of strong ground motions. These problems are interrelated and require an interdisciplinary, multi-institutional approach. The SCEC4 interdisciplinary research initiatives include special fault study areas, which are distributed throughout Southern California; the development of a community geodetic model for Southern California, which combines GPS and InSAR data; and a community stress model, which is a new platform for integrating the various constraints on earthquake-producing stresses.The Center is translating basic research into practical products for reducing risk and improving community resilience. The SCEC4 program aims to transform long-term seismic hazard analysis into a physics-based science. It is helping the USGS and other responsible government agencies develop operational earthquake forecasting into a capability that can provide authoritative information about the time dependence of seismic hazards to help communities prepare for potentially destructive earthquakes. It is providing the science to enable earthquake early warning -- advanced notification that an earthquake is underway and predictions of when strong shaking will arrive at more distant sites -- and to improve the delivery of post-event information about strong ground motions and secondary hazards.SCEC's Communication, Education and Outreach program is built around the theme of creating an earthquake and tsunami resilient California. Through ShakeOut exercises, it is preparing individuals and organizations to respond to changing seismic hazards and introducing them to the new technologies of operational earthquake forecasting and earthquake early warning. It is educating people of all ages -- in California, across the country, and internationally -- about earthquakes, and motivating them to become prepared. A K-14 earthquake education initiative seeks to improve earth science education and school earthquake safety. SCEC's experiential learning and career advancement program provides a diverse cross-section of students and early-career scientists with research opportunities and networking to encourage and sustain careers in science and engineering.