Chronology of tectonic, geomorphic, and volcanic interactions and the tempo of fault slip near Little Lake, California
Chronology of tectonic, geomorphic, and volcanic interactions and the tempo of fault slip near Little Lake, California
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加利福尼亚州小湖附近的构造、地貌和火山相互作用的年代学以及断层滑动的速度
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
A. Jayko
中科院分区：
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作者：
C. Amos;S. Brownlee;D. Rood;G. Fisher;R. Bürgmann;P. Renne;A. Jayko
新的地质年代学和地貌的限制在东部加州剪切带的小湖断层显示稳定，适度的右旋滑动率在中更新世和自晚更新世。我们专注于一套补偿河流地貌在更新世欧文斯河通道，形成响应周期性的相互作用与附近的玄武岩流，从而记录位移在多个时间间隔。40 Ar/ 39 Ar年龄之间的重叠最年轻的intracanyon玄武岩流和10 Be表面暴露测年的下游阶地表面表明广泛的通道切口在一个突出的突出洪水通过小湖通道约。64 ka。位于峡谷边缘上部和下部两侧的较古老的玄武岩流表明欧文斯河在212 ± 14和197 ± 11 ka之间的当前位置的定位。再加上地面光探测和测距（激光雷达）和数字地形测量的右旋偏移，修订后的小湖年表表明，平均右旋滑动率至少为0.6-0.7毫米/年和4至105年。尽管以前的大地测量观测相对快速的震间应变沿着小湖断层，我们没有发现证据的持续时间波动的滑动率在多个地震周期。相反，我们的研究结果表明，加速故障加载可能是短暂的，在更短的时间内（1010 - 1年），并可能指示与东部加州剪切带断层与时间相关的地震危险。
New geochronologic and geomorphic constraints on the Little Lake fault in the Eastern California shear zone reveal steady, modest rates of dextral slip during and since the mid-to-late Pleistocene. We focus on a suite of offset fluvial landforms in the Pleistocene Owens River channel that formed in response to periodic interaction with nearby basalt flows, thereby recording displacement over multiple time intervals. Overlap between 40 Ar/ 39 Ar ages for the youngest intracanyon basalt flow and 10 Be surface exposure dating of downstream terrace surfaces suggests widespread channel incision during a prominent outburst flood through the Little Lake channel at ca. 64 ka. Older basalt flows flanking the upper and lower canyon margins indicate localization of the Owens River in its current position between 212 ± 14 and 197 ± 11 ka. Coupled with terrestrial light detection and ranging (lidar) and digital topographic measurements of dextral offset, the revised Little Lake chronology indicates average dextral slip rates of at least ∼0.6–0.7 mm/yr and 4 to 10 5 yr. Despite previous geodetic observations of relatively rapid interseismic strain along the Little Lake fault, we find no evidence for sustained temporal fluctuations in slip rates over multiple earthquake cycles. Instead, our results indicate that accelerated fault loading may be transient over much shorter periods (∼10 1 yr) and perhaps indicative of time-dependent seismic hazard associated with Eastern California shear zone faults.