Collaborative Research: Earthquake swarms and aseismic slip in the Salton Trough: High-resolution imaging of the upper frictional stability transition.

合作研究：索尔顿海槽中的地震群和抗震滑移：上部摩擦稳定性转变的高分辨率成像。

• 批准号: 0943906
• 负责人: Rowena Lohman
• 金额: $ 11.43万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0943906&HistoricalAwards=false
• 关键词: Collaborative; Research; Earthquake; swarms; aseismic

Efforts to understand the build-up and release of stress along active fault zones require detailed studies of individual faults and placement of those results in a physical framework consistent with our knowledge about rock mechanics. One particularly intriguing fault zone behavior that has been observed with increasing frequency in recent years involves the interplay between aseismic slip and seismic swarm activity. Slow fault slip has been observed to trigger earthquake swarms in a variety of tectonic environments including subduction zones, volcanic systems, and continental strike-slip faults such as those in close proximity to population centers in Southern California. One region that provides a prime environment to study seismic swarms and aseismic creep is the Imperial Valley/Salton Trough in Southern California. Seismic swarms, large (Mw7) earthquakes, and transient episodes of fault creep are all frequent occurrences along the plate boundary faults within the Salton Trough. The Salton Trough offers a prime opportunity to examine the interplay between these varied types of fault activity, since so many of them are observed within a relatively small geographic area, which also has had very detailed geologic studies and contains one of the world?s densest seismic and geodetic station networks. Detailed studies of aseismic and seismic events offer an opportunity to connect physical properties of the fault-zone such as rock type, depth, and temperature with rock-mechanical properties such as frictional stability, and will allow us to better understand the temporal evolution of seismic hazard associated with individual fault zones.We propose a combination of an active source seismic study of the 2005 swarm's primary fault zone, and a more detailed analysis of the existing seismic and geodetic data. The core of our effort is a one-week seismic survey using the high-res profiling techniques developed by the USGS-Menlo Park group that will provide constraints on the details of fault-zone geometry and rigidity structure. These results will be used to improve our studies of the 2005 swarm. The combination of these studies will allow us to study the relations between rock-type, rigidity, thermal structure and frictional stability. Because shallow creep and earthquake swarms are general properties of major faults in the Salton Trough, our results will provide inputs to physics based earthquake hazard models in the region.

了解沿主动断层区域的压力的积累和释放的努力需要详细研究单个断层和放置这些结果，结果与我们对岩石力学的了解一致的物理框架。 近年来频率增加的一种特别有趣的断层区行为涉及无性滑移与地震群活动之间的相互作用。已经观察到缓慢的断层滑动是在各种构造环境中触发地震群的，包括俯冲带，火山系统和大陆走滑断层，例如与南加州南部人口中心非常接近的那些。 一个为研究地震群和无性蠕变提供的主要环境的地区是南加州的帝国山谷/萨尔顿槽。 地震群，大（MW7）地震和断层蠕变的瞬态发作都是沿着萨尔顿槽内的板边界断层的频繁出现的。 Salton槽提供了一个主要的机会来检查这些不同类型的断层活动之间的相互作用，因为在相对较小的地理区域中观察到了其中许多的相互作用，该区域也具有非常详细的地质研究，并包含世界上最密集的地震和地球座网络。 Detailed studies of aseismic and seismic events offer an opportunity to connect physical properties of the fault-zone such as rock type, depth, and temperature with rock-mechanical properties such as frictional stability, and will allow us to better understand the temporal evolution of seismic hazard associated with individual fault zones.We propose a combination of an active source seismic study of the 2005 swarm's primary fault zone, and a more detailed analysis of the existing seismic and geodetic 数据。 我们努力的核心是使用USGS-Menlo Park集团开发的高分辨率分析技术进行的为期一周的地震调查，该技术将对断层区域几何形状和刚性结构的细节提供约束。 这些结果将用于改善我们对2005年群的研究。这些研究的结合将使我们能够研究岩石型，刚性，热结构和摩擦稳定性之间的关系。 由于浅蠕变和地震群是萨尔顿槽中主要断层的一般特性，因此我们的结果将为该地区基于物理的地震危险模型提供输入。