The 72-km-long Teton normal fault bounds the eastern base of the Teton Range in northwestern Wyoming, USA. Although geomorphic surfaces along the fault record latest Pleistocene to Holocene fault movement, the postglacial earthquake history of the fault has remained enigmatic. We excavated a paleoseismic trench at the Buffalo Bowl site along the southernmost part of the fault to determine its Holocene rupture history and slip rate. At the site, ∼6.3 m of displacement postdates an early Holocene (ca. 10.5 ka) alluvial-fan surface. We document evidence of three surface-faulting earthquakes based on packages of scarp-derived colluvium that postdate the alluvial-fan units. Bayesian modeling of radiocarbon and luminescence ages yields earthquake times of ca. 9.9 ka, ca. 7.1 ka, and ca. 4.6 ka, forming the longest, most complete paleoseismic record of the Teton fault. We integrate these data with a displaced deglacial surface 4 km NE at Granite Canyon to calculate a postglacial to mid-Holocene (14.4–4.6 ka) slip rate of ∼1.1 mm/yr. Our analysis also suggests that the postglacial to early Holocene (14.4–9.9 ka) slip rate exceeds the Holocene (9.9–4.6 ka) rate by a factor of ∼2 (maximum of 3); however, a uniform rate for the fault is possible considering the 95% slip-rate errors. The ∼5 k.y. elapsed time since the last rupture of the southernmost Teton fault implies a current slip deficit of ∼4–5 m, which is possibly explained by spatially/temporally incomplete paleoseismic data, irregular earthquake recurrence, and/or variable per-event displacement. Our study emphasizes the importance of minimizing slip-rate uncertainties by integrating paleoseismic and geomorphic data sets and capturing multiple earthquake cycles.

中文翻译：

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美国怀俄明州南部提顿断裂的全新世地震历史和滑移率

提顿正断层长72公里，位于美国怀俄明州西北部提顿山脉的东部基地。尽管沿断层的地貌表面记录了最新的更新世至全新世断层运动，但该断层的冰期后地震历史仍然令人迷惑。我们在沿断层最南端的布法罗碗遗址开挖了一条古地震沟槽，以确定其全新世的破裂历史和滑移率。在该地点，约6.3 m的位移是早于全新世（约10.5 ka）的冲积扇表面的。我们记录了三个以冲断扇单元为基础的陡坡派生的崩塌包裹的表面断层地震的证据。放射性碳和发光年龄的贝叶斯模型产生的地震时间约为。约9.9 ka 7.1 ka，以及 4.6 ka，形成最长的 提顿断裂的最完整的古地震记录。我们将这些数据与位于花岗岩峡谷东北4 km的位移冰河表面进行整合，计算出冰川后至全新世（14.4–4.6 ka）的滑移速率约为1.1毫米/年。我们的分析还表明，冰川后至全新世（14.4–9.9 ka）滑移速率比全新世（9.9–4.6 ka）滑移速率高约2倍（最大值为3）。但是，考虑到95％的滑差率误差，可以实现统一的故障率。自最南端的Teton断层最后一次破裂以来经过的约5 ky时间表明当前的滑移赤字为约4-5 m，这可能由空间/时间上不完整的古​​地震数据，不规则的地震复发和/或每个事件的变化解释移位。