Holocene earthquake history and slip rate of the southern Teton fault, Wyoming, USA
Holocene earthquake history and slip rate of the southern Teton fault, Wyoming, USA
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美国怀俄明州提顿断层南部全新世地震历史和滑动率
DOI：
10.1130/b35363.1
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发表时间：
2020
影响因子：
4.9
通讯作者：
S. Mahan
中科院分区：
文献类型：
--
作者：
C. DuRoss;R. Gold;R. Briggs;J. Delano;D. Ostenaa;M. Zellman;Nicole Cholewinski;S. Wittke;S. Mahan
72公里长的提顿正断层位于美国怀俄明州西北部的提顿山脉东部。尽管断层沿着地貌面记录了最晚更新世至全新世的断层运动，但该断层的冰后期地震历史仍然是个谜。我们在布法罗碗遗址沿着断层最南端挖掘了一条古地震沟，以确定其全新世破裂历史和滑动速率。在该地点，位移量为6.3米，晚于全新世早期（约100米）。10.5 ka）冲积扇面。我们记录的证据，三个表面断层地震的基础上包的悬崖衍生的崩积层晚于冲积扇单位。放射性碳和释光年龄的贝叶斯模型得出了约1000年的地震年代。9.9卡河7.1卡和CA。4.6 ka，形成了提顿断层最长、最完整的古地震记录。我们将这些数据与花岗岩峡谷东北方向4公里处的冰消期位移面相结合，计算出冰后期至全新世中期（14.4-4.6 ka）的滑动速率为1.1 mm/年。我们的分析还表明，冰后期至全新世早期（14.4-9.9 ka）的滑动速率超过全新世（9.9-4.6 ka）的速率的1/2（最大为3）的因素;然而，考虑到95%的滑动速率误差，断层的均匀速率是可能的。第500章K.Y.从最南端的提顿断层最后一次破裂以来所经过的时间意味着目前的滑动赤字为104 -5米，这可能是由空间/时间上不完整的古地震数据，不规则的地震复发，和/或可变的事件位移解释。我们的研究强调了通过整合古地震和地貌数据集和捕获多个地震周期来最大限度地减少滑动率不确定性的重要性。
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.
怀俄明州大提顿国家公园利湖中央提顿断层全新世断裂历史
影响因子：
3
作者：
Zellman, Mark S.;DuRoss, Christopher B.;Thackray, Glenn D.;Personius, Stephen F.;Reitman, Nadine G.;Mahan, Shannon A.;Brossy, Cooper C.
通讯作者：
Brossy, Cooper C.