Earthquake Triggering and Synchronization on Oceanic Transform Faults

海洋转换断层的地震触发与同步

• 批准号: 1357433
• 负责人: Meng Wei
• 金额: $ 16.79万
• 依托单位: University of Rhode Island
• 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: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1357433&HistoricalAwards=false
• 关键词: Earthquake; Triggering; Synchronization; Oceanic; Transform

Strike-slip faults can cause major damage when they rupture near population centers. While the basic mechanism of slip along a single fault strand is relatively well understood, behavior of multi-strand faults within a historically active zone can be complex. Progress towards a quantitative and predictive understanding of fault behavior can be achieved by studying two types of fault system activity: 1) earthquake triggering- a distant earthquake triggers slip on a local fault; 2) earthquake synchronization- two large earthquakes occur close in time and space over many earthquake cycles on a given fault zone. Oceanic transform faults are ideal for studying such behavior because of their simple tectonic setting and relatively short earthquake cycle. This research helps establish a young researcher in a new university position, allowing him to extend his expertise to submarine faults, and it provides training for an undergraduate student.Investigation of earthquake triggering at oceanic transform faults takes advantage of the short cycle of loading and rupture (~20 yrs) for these systems. Coverage is sparse but a combination of ocean bottom seismographs, hydrophones, buoys, and near-shore land seismic stations do provide data. Earthquake catalogs will be searched for events that correspond with passage of waves from large teleseismic earthquakes or that indicate synchronous regional activity, suggesting events that are dynamically triggered by stress transfer between fault segments. In an effort to advance knowledge from conceptual to quantitative models, numerical modeling that incorporates rate and state friction parameters will be performed. A new development will be to include along-fault variations in 2-D models of fault properties and evolution. Fairly detailed data from the Blanco, Quebrada-Discovery-Gofar, Romanche and Eltanin fault systems will be employed, in contrast to previous work that depended on sparse teleseismic data for global studies of oceanic transform fault behavior.

走滑断层在人口中心附近破裂时会造成重大破坏。虽然沿着单一断层链滑动的基本机制相对较好地理解，但历史活动区内多链断层的行为可能是复杂的。通过研究两种类型的断层系统活动，可以实现对断层行为的定量和预测性理解的进展：1）地震触发-远距离地震触发当地断层的滑动; 2）地震同步-两个大地震在给定断层带上的许多地震周期中在时间和空间上接近发生。大洋转换断层由于构造环境简单，地震周期相对较短，是研究这种行为的理想场所。这项研究有助于在一个新的大学职位上建立一个年轻的研究人员，使他能够扩展他的专业知识，海底断层，它提供了一个本科生的培训。调查地震触发在海洋转换断层利用这些系统的加载和破裂的短周期（~20年）。覆盖范围很小，但海底地震仪、水听器、浮标和近岸陆地地震站的组合确实提供了数据。将搜索地震目录，以寻找与大地震波的传播相对应的事件，或者表明同步区域活动的事件，这些事件表明是由断层段之间的应力转移动态触发的。在努力推进知识从概念到定量模型，数值建模，结合率和状态摩擦参数将进行。一个新的发展将包括沿断层的变化在2-D模型的断层性质和演变。相当详细的数据，从布兰科，Quebrada-Discovery-Gofar，Romanche和Eltanin断层系统将被雇用，与以往的工作，依赖于稀疏的地球物理数据的海洋转换断层行为的全球研究。