On the basis of the continuous and dense GPS observations covering the northern segment of the Xiaojiang fault zone (n-XJFZ) from March 2012 to March 2016, we present the velocity field, spatiotemporal deformation, slip rate and locking depth of the n-XJFZ. The results provide strong support for achieving a better understanding of the deformation behavior of this fault. The heterogeneity of the GPS velocity field and relatively nonuniform distribution of seismicity suggest that the observational area is fragmented. Shear strain has been accumulating with an almost constant azimuth, which is consistent with the trends of the mapped major faults. The 2014 M s 6.5 Ludian earthquake produced a sudden change in the dilatational strain, which was almost constant prior to the event, and an increase in the shear strain rate. The near-field deformation of the n-XJFZ estimated with the near-field data was larger than expected, revealing that the n-XJFZ is becoming more locked. These results imply that the seismic risk in the study area is currently rising and that, similar to the 2014 M s 6.5 Ludian earthquake, future earthquakes will possibly occur away from mapped faults.

中文翻译：

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最新和最近 GPS 观测对小江北部断裂带地震风险的影响

基于2012年3月至2016年3月小江断裂带北段（n-XJFZ）连续密集的GPS观测，我们给出了n-XJFZ的速度场、时空变形、滑动速率和锁定深度. 结果为更好地理解该断层的变形行为提供了强有力的支持。GPS 速度场的不均匀性和地震活动的相对不均匀分布表明观测区是支离破碎的。剪切应变以几乎恒定的方位角累积，这与绘制的主要断层的趋势一致。2014 年 6.5 级鲁甸地震引起了震前几乎恒定的膨胀应变的突然变化，以及剪切应变率的增加。用近场数据估计的 n-XJFZ 的近场变形大于预期，表明 n-XJFZ 变得更加锁定。这些结果表明目前研究区的地震风险正在上升，与2014年鲁甸6.5级地震类似，未来地震可能发生在远离已测绘断层的地方。