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年的《美国恢复和再投资法》（公共法第111-5）的资助，产生地震的大缺点表现出广泛的滑移行为，包括粘粘运动，导致情节地震，稳定且稳定的滑动，而无需固定地震，而无需地震就没有振荡或非稳定的滑动滑动。可以通过使用自然或合成岩石样品的实验室滑动实验得出的摩擦定律来理解和建模滑动行为的范围。从这些实验中获得的摩擦参数是在地球上嵌入的故障的数值模型中实现的，以预测断层的滑移行为。这些模型中实现的摩擦参数的小变化可能会导致截然不同的滑动行为。例如，参数的微小变化可以从棍棒滑落，地震产生滑移行为转变为无地震的稳定，稳定的滑动行为。因此，对这些参数在断层上的分布的了解对于地震危害评估至关重要。这项工作的目的是使用地球表面靠近断层的运动的测量来推断故障上的摩擦参数。 旧金山湾地区海沃德断层的测量以及圣胡安包蒂斯塔附近的圣安德烈亚斯断层的测量将与断层滑移的数值模型进行比较。这些位置的数据记录了远处地震触发的断层上的瞬态滑移发作。另外，将系统检查各种现有的用于建模故障蠕变的现有方法，以评估简化假设对模型推断的影响，因此，提供者可以更清楚地理解故障的摩擦属性如何使用这种方法来解决。纳入速率摩擦的模型在包括频率的范围中取得了极大的成功，这些速度在范围内表现出了很大的成功。俯冲带，自发的无声地震以及地震周期的一般特征。数值研究调用速率状态摩擦采用实验室衍生的摩擦参数，这些参数通常是为了简单而被假定仅随深度而变化。目前尚不清楚实验室摩擦值在多大程度上与实际断层有关。