The Walker Lane is a zone of distributed transtension where normal faults are overprinted by strike-slip motion. We use two newly acquired, high-resolution seismic reflection profiles and a reprocessed Consortium for Continental Reflection Profiling (COCORP) deep crustal reflection profile to assess the subsurface geometry of the Holocene-active, transtensional Warm Springs Valley fault zone (WSVFZ) near Reno, Nevada, USA. Our multiscale observations extend to 12 km depth and suggest that the WSVFZ is more complex in the subsurface than implied by late Pleistocene surface fault traces. Two 4-km-long high-resolution profiles image to a depth of ∼2 km and reveal moderately dipping reflections and truncations, some of which project to mapped scarps formed in late Pleistocene surfaces. The shallow lines are collocated with COCORP profile NV 08 along ∼40°N latitude. Reanalysis of the COCORP data reveals previously unidentified coherent reflections to a depth of ∼12 km and a previously mapped ∼30° west-dipping fault at 8–12 km. From these seismic profiles, the WSVFZ is not a simple, subvertical fault zone extending through the entire seismogenic crust. Instead, the reflections are consistent with a zone of steeply and moderately dipping faults that simplify and steepen with depth before intersecting a mid-crustal, low-angle (∼25–30°) fault. The complex fault geometry of the WSVFZ implies that crustal shear is accommodated by a mix of dipping and subvertical faults in the transtensional northern Walker Lane. If so, transtensional fault zones may present challenges to paleoseismic and geodetic studies and require careful treatment when included in seismic hazard analyses.

中文翻译：

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美国西内华达州北沃克巷横张暖泉谷断层带地壳结构的地球物理约束

沃克巷是一个分布的张力带，在那里正断层被走滑运动覆盖。我们使用两个新获得的高分辨率地震反射剖面和一个重新处理的大陆反射剖面 (COCORP) 深地壳反射剖面来评估里诺附近全新世活动的、跨张的暖泉谷断层带 (WSVFZ) 的地下几何形状，美国内华达州。我们的多尺度观测延伸至 12 公里深度，表明 WSVFZ 在地下比晚更新世地表断层痕迹所暗示的更复杂。两个 4 公里长的高分辨率剖面成像到约 2 公里的深度，并显示出适度倾斜的反射和截断，其中一些投射到在更新世晚期表面形成的映射陡坡。浅线沿~40°N纬度与COCORP剖面NV 08搭配。对 COCORP 数据的再分析揭示了先前未识别的 12 公里深度的相干反射和先前绘制的 8-12 公里处的 30°西倾断层。从这些地震剖面来看，WSVFZ 并不是一个简单的、贯穿整个发震地壳的近垂直断层带。相反，反射与陡峭和中等倾斜断层的区域一致，在与中地壳、低角度（~25-30°）断层相交之前，这些断层随着深度而简化和变陡。WSVFZ 复杂的断层几何形状意味着地壳剪切受沃克巷北部横向张拉的倾斜断层和近垂直断层的混合影响。如果是这样的话，