Estimating Frictional Properties of Faults from Geodetic Data

根据大地测量数据估计断层的摩擦特性

• 批准号: 0911467
• 负责人: Kaj Johnson
• 金额: $ 12.1万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0911467&HistoricalAwards=false
• 关键词: Estimating; Frictional; Properties; Faults; Geodetic

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)Large faults that generate earthquakes exhibit a wide range of slip behaviors including stick-slip motion resulting in episodic earthquakes, stable and steady sliding without fast earthquake slip, and oscillatory or non-steady slip sliding without earthquakes. This range in slip behaviors can be understood and modeled through the application of friction laws derived from laboratory sliding experiments with natural or synthetic rock samples. The friction parameters obtained from these experiments are implemented in numerical models of faults imbedded in the earth in order to predict the slip behavior of faults. Small changes in the friction parameters implemented in these models can lead to dramatically different sliding behaviors. For example, small changes in parameters can change from stick-slip, earthquake producing slip behavior to steady, stable sliding behavior without earthquakes. Knowledge of the distribution of these parameters on faults is therefore essential for earthquake hazard assessment. The object of this work is to use measurements of motions of the Earth?s surface near faults to infer friction parameters on faults. Measurements from the Hayward fault in the eastern San Francisco Bay Area and from the San Andreas fault near San Juan Bautista will be compared with numerical models of fault slip. Data from these locations recorded transient slip episodes on the faults triggered by distant earthquakes. Also, various existing methodologies for modeling fault creep will be systematically examined to assess the influence of simplifying assumptions on model inferences and therefore provider a clearer understanding of how well the frictional properties of faults can be resolved using such approaches.Models incorporating rate-state friction have been remarkably successful in explaining a wide range of observations reflecting the nature of fault slip including afterslip, decay rates of aftershocks, episodic slip at subduction zones, spontaneous silent earthquakes, as well as general features of the earthquake cycle. Numerical studies invoking rate-state friction employ laboratory-derived friction parameters which are often assumed, for simplicity, to vary only with depth. It remains unclear to what extent the laboratory friction values are relevant to real faults.

该奖项是根据2009年美国恢复和再投资法案（公法111 - 5）资助的，产生地震的大断层表现出广泛的滑动行为，包括导致幕式地震的粘滑运动，稳定和稳定的滑动而没有快速地震滑动，以及振荡或非稳定滑动而没有地震。这种范围内的滑动行为可以理解和模拟，通过应用摩擦定律，从实验室滑动实验与天然或合成岩石样品。从这些实验中获得的摩擦参数实施在数值模型中的断层埋在地球中，以预测断层的滑动行为。在这些模型中实现的摩擦参数的微小变化可以导致显着不同的滑动行为。例如，参数的微小变化可以从粘滑、地震产生的滑动行为改变为稳定的、稳定的滑动行为而没有地震。因此，了解这些参数在断层上的分布对于地震危险性评估至关重要。这项工作的目的是使用测量地球的运动？断层附近的S面来推断断层上的摩擦参数。 从弗朗西斯科湾区东部的海沃德断层和圣胡安鲍蒂斯塔附近的圣安德烈亚斯断层的测量结果将与断层滑动的数值模型进行比较。来自这些地点的数据记录了由远距离地震触发的断层上的瞬时滑动事件。此外，各种现有的方法来模拟断层蠕动将系统地检查，以评估简化假设模型推论的影响，因此提供了一个更清晰的理解如何以及断层的摩擦性能可以解决使用这样的approaches.Models纳入速率状态摩擦已经非常成功地解释了广泛的意见，反映了断层滑动，包括后遗滑动的性质，余震的衰减率、俯冲带的幕式滑动、自发无声地震以及地震周期的一般特征。数值研究调用率态摩擦采用实验室推导的摩擦参数，通常假设，为简单起见，只随深度而变化。目前还不清楚实验室摩擦值与真实的断层的相关程度。