Abstract In this work we present a review of the current state of knowledge of the active faults in El Salvador and its seismo-tectonic implications. An updated map of active fault traces is combined with the spatial analysis of shallow seismicity, focal mechanisms, recent geodetic GPS velocities, local strain estimations and morpho-tectonic features to provide a synoptic view of the active tectonics of the El Salvador. The major faults selected as potential seismic sources bound tectonic blocks or regions that include GPS sites with consistent relative velocity vectors. We propose several active tectonic domains along El Salvador controlled by three current deformation regimes: a crustal block in the forearc sliver dominated by rigid westward translation with the faster and more homogeneous GPS velocities; three zones dominated by E-W distributed extensional coaxial deformation; and two bands with a deformation compatible with transtensional regime. In the Western sector of the ESFZ, GPS velocities and local structure suggest that E-W extension concentrates along the NNW-SSE oriented Santa Ana volcanic axis and it could connect to the north with the extensional region of the Ipala Graben. This is consistent with to the eastward shift of the North America-Cocos-Caribbean triple junction and “the closing of the zipper” proposed in recent models that progressively slows down the strike-slip movement along the northern limit of the forearc sliver. In the central sector large GPS velocity gradient parallel to the volcanic arc may be associated to complex and discontinuous structure of the ESFZ driving slowdown of the westward movement of local tectonic blocks. The southeaster sector of the ESFZ is an incipient large pull-apart structure affecting a pre-existing extensional N-S oriented fabric that induces two tectonic subdomains, the eastern one undergo E-W coaxial extension and the western one characterized by transtensional strain regime. We propose a new structural segmentation of the ESFZ considering that this fault zone includes all those structures that accommodate the relative velocity between the forearc sliver and the Chortis block. The 38 active faults with surface traces that are mapped for more than 5 km long proposed in this work, with maximum potential magnitude Mw ranging from 5.98 to 7.94, will contribute to improve regional and local seismic sources databases and seismic hazard assessment.

中文翻译：

---

萨尔瓦多活动断层

摘要 在这项工作中，我们回顾了萨尔瓦多活动断层的现状及其地震构造影响。更新的活动断层轨迹图与浅层地震活动、震源机制、近期大地测量 GPS 速度、局部应变估计和形态构造特征的空间分析相结合，以提供萨尔瓦多活动构造的概要视图。被选为潜在地震源的主要断层限制了包括具有一致相对速度矢量的 GPS 站点的构造块或区域。我们提出了萨尔瓦多沿线的几个活动构造域，由三种当前变形机制控制：弧前裂片中的地壳块，主要是刚性向西平移，具有更快和更均匀的 GPS 速度；三个以 EW 分布的同轴拉伸变形为主的区域；和两个变形与拉伸状态兼容的带。在 ESFZ 的西段，GPS 速度和局部结构表明 EW 延伸沿 NNW-SSE 取向的 Santa Ana 火山轴集中，它可以与 Ipala Graben 的延伸区连接到北部。这与最近模型中提出的北美-科科斯-加勒比三重交界处的东移和“拉链的关闭”是一致的，它们逐渐减缓了沿前弧长条北部边界的走滑运动。在中央部分，与火山弧平行的 GPS 速度梯度大可能与 ESFZ 的复杂和不连续结构驱动局部构造块向西运动的减速有关。ESFZ 的东南部是一个初期的大型拉开结构，影响了预先存在的拉伸 NS 取向结构，该结构诱导了两个构造子域，东部一个经历 EW 同轴延伸，西部一个以跨张应变状态为特征。我们建议对 ESFZ 进行新的结构分割，因为该断层带包括所有那些适应前弧条带和 Chortis 块之间相对速度的结构。在这项工作中提出的 38 个具有表面痕迹的活动断层超过 5 公里长，