CAREER: Global Assessment of Aseismic Faulting: The Search For a Common Mechanism Among the World's Faults

无震滑动描述的是与弹性波的产生无关的断层运动，这是一种尚未完全理解的现象。虽然已经提出了潜在的解释，如蛇纹岩的存在或断层上正应力的横向变化，但社区一直无法解释为什么一个活动断层表现出无地震行为，而另一个只表现出地震行为。尚未完全解决的一项关键知识是，无地震滑动在世界断层中是否普遍存在。由于在没有安装当地仪器(即蠕变仪)的情况下很难识别现场的断层蠕动，也很难注意到城市结构相对于断层运动的偏转，地震滑动的报告仍然很少。PI正在使用干涉合成孔径雷达(InSAR)评估全球范围内无地震滑动的流行度。这项技术非常适合于以一致的方式识别全球范围内的断层蠕变和其他无震瞬变。越来越多的合成孔径雷达数据提供了对地球的全球覆盖，从而能够对主要断层系统进行系统评估。在建立了地震和地震断层的全球目录后，我们进行了与断层相关的特征分析，以努力确定哪些因素与抗震行为最相关。感兴趣的特征包括近断层地质、宏观几何以及区域应力场的方向。这些比较可以识别或排除允许断层蠕动的可能机制，并提供关于为什么一个断层显示无地震滑动而其他断层不显示的洞察。收集和综合几个全球数据集提供了一个理想的机会，让本科生和研究生都参与到一个大型研究项目中。该项目的模块化性质允许具有广泛技术和地质技能的学生参与其中。为了促进对学生的培训，开发了一系列课程，涵盖InSAR处理和理论、提取断层特征的地理信息系统技能，以及参与者在特定地理区域进行合作研究的焦点小组。

Aseismic slip, which describes fault movement that is not associated with the production of elastic waves, is a phenomenon that is not fully understood. While potential explanations, such as the presence of serpentinite or lateral variations in normal stress on the fault have been suggested, the community has been unable to explain why one active fault exhibits aseismic behavior while another only behaves seismically. One key piece of knowledge that has not been fully addressed is whether aseismic slip is prevalent among the world's faults. Aseismic slip remains largely under-reported because of the difficulty in identifying fault creep in the field without installing local instrumentation (i.e. creepmeters) or by noting the deflection of urban structures from fault movement.The PI is evaluating the prevalence of aseismic slip around the globe using Interferometric Synthetic Aperture Radar (InSAR). This technique is ideally suited to identify fault creep and other aseismic transients on a global scale in a consistent manner. The growing catalogue of synthetic aperture radar data provides global coverage of the planet allowing for a systematic assessment of major fault systems. After a global catalogue of aseismic and seismic faults is established, we perform an analysis of fault related characteristics in an effort to identify which factors are most correlated with aseismic behavior. Characteristics of interest include near-fault geology, macroscopic geometry, as well as the orientation of the regional stress field. These comparisons allow the identification or exclusion of likely mechanisms that allow faults to creep and provide insight as to why one fault exhibits aseismic slip while others do not. The collection and synthesis of several global data sets provides an ideal opportunity to involve both undergraduate and graduate students in a large research project. The modular nature of the project allows students with a wide range of technical and geological skill sets to participate. To facilitate the training of students, a series of courses are developed that cover InSAR processing and theory, GIS skills for extracting fault characteristics, and focus groups where participants perform collaborative research on a particular geographic region.