We use high‐resolution earthquake locations to characterize the three‐dimensional structure of active faults in California and how it evolves with fault structural maturity. We investigate the distribution of aftershocks of several recent large earthquakes that occurred on continental strike slip faults of various structural maturity (i.e. various cumulative fault displacement, length, initiation age and slip rate). Aftershocks define a tabular zone of shear deformation surrounding the mainshock rupture plane. Comparing this to geological observations, we conclude that this results from the re‐activation of secondary faults. We observe a rapid fall off of the number of aftershocks at a distance range of 0.06‐0.22 km from the main fault surface of mature faults, and 0.6‐1.0 km from the fault surface of immature faults. The total width of the active shear deformation zone surrounding the main fault plane reaches 1.0‐2.5 km and 6‐9 km for mature and immature faults, respectively. We find that the width of the shear deformation zone decreases as a power law with cumulative fault displacement. Comparing with a dynamic rough fault model, we infer that the narrowing of the shear deformation zone agrees quantitatively with earlier estimates of the smoothing of faults with displacement, both of which are aspects of fault wear. We find that earthquake stress drop decreases with fault displacement and hence with increased smoothness and/or slip rate. This may result from fault healing or the effect of roughness on friction.

中文翻译：

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剪切变形带和带位移的断层平滑

我们使用高分辨率地震位置来描述加利福尼亚活动断层的三维结构及其随着断层结构成熟度的演化。我们调查了在各种结构成熟度（即各种累积断层位移，长度，起始年龄和滑移率）的大陆走滑断层上发生的几次近期大地震的余震分布。余震在主震破裂平面周围定义了一个剪切变形的表格区域。将其与地质观测结果进行比较，我们得出结论，这是由于次生断层的重新活化所致。我们发现，距成熟断层主断面0.06-0.22 km，距未成熟断层0.6-1.0 km，余震数量迅速下降。围绕主断层平面的活动剪切变形带的总宽度分别为成熟断层和未成熟断层的1.0-2.5 km和6-9 km。我们发现，随着变形断层的累积，剪切变形带的宽度随着幂律的减小而减小。与动态粗断层模型相比，我们推断剪切变形带的变窄与断层带位移的断层平滑的早期估计在数量上是一致的，这两个都是断层磨损的方面。我们发现，地震应力下降随着断层位移的增加而减小，从而随着光滑度和/或滑动率的增加而减小。这可能是由于故障修复或粗糙度对摩擦的影响所致。我们发现，剪切变形带的宽度随着幂律的增加而减小，并伴随累积断层位移。与动态粗断层模型相比，我们推断剪切变形带的变窄与断层带位移的断层平滑的早期估计在数量上是一致的，这两个都是断层磨损的方面。我们发现，地震应力下降随着断层位移的增加而减小，从而随着光滑度和/或滑动率的增加而减小。这可能是由于故障修复或粗糙度对摩擦的影响所致。我们发现，剪切变形带的宽度随着幂律的增加而减小，并伴随累积断层位移。与动态粗断层模型相比，我们推断剪切变形带的变窄与断层带位移的断层平滑的早期估计在数量上是一致的，这两个都是断层磨损的方面。我们发现，地震应力下降随着断层位移的增加而减小，从而随着光滑度和/或滑动率的增加而减小。这可能是由于故障修复或粗糙度对摩擦的影响所致。两者都是断层磨损的方面。我们发现，地震应力下降随着断层位移的增加而减小，从而随着光滑度和/或滑动率的增加而减小。这可能是由于故障修复或粗糙度对摩擦的影响所致。两者都是断层磨损的方面。我们发现，地震应力下降随着断层位移的增加而减小，从而随着光滑度和/或滑动率的增加而减小。这可能是由于故障修复或粗糙度对摩擦的影响所致。