Late Pleistocene and Holocene slip rate of the Northern Wadi Araba fault, Dead Sea Transform, Jordan
Late Pleistocene and Holocene slip rate of the Northern Wadi Araba fault, Dead Sea Transform, Jordan
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约旦死海变换北瓦迪阿拉巴断层的晚更新世和全新世滑动率
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发表时间：
2001
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影响因子：
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通讯作者：
J. Harrison
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作者：
T. Niemi;Hongwei Zhang;M. Atallah;J. Harrison
瓦迪阿拉巴谷是沿着死海转换 (DST) 板块边界部分的地貌构造凹陷，将东部的阿拉伯板块与西部的西奈亚板块分开。瓦迪阿拉巴断层 (WAF) 是亚喀巴湾和东向库奈吉拉 (Amatzayahu) 断层之间的主要走滑断层之一，该断层界定死海南端。就在死海以南，WAF 横穿了几代冲积扇，这些冲积扇是在晚更新世利桑湖 (Lake Lisan) 退缩后在达哈尔干河 (Wadi Dahal) 的支流上形成的。 15 ka。活动断层的地貌和地层证据，包括左旋偏移河道和冲积扇表面，产生了 WAF 北段的断层滑动率数据。通过详细的地质和地形测绘，测量了跨断层的河道和冲积扇表面的典型累积位移为 54 m、39 m 和 22.5 m。 最古老的冲积扇表面 (Qf1) 的 54 m 偏移发生在里三湖最终下降之后 (16-15 ka) 和 11 ka 之前，产生了 3.4 mm/年至 4.9 mm/年的滑移率范围。根据断层上挖掘的沟渠中暴露的埋藏 Qf2 冲积扇沉积物中的木炭和蜗牛壳样本的放射性碳分析，39 m 和 22.5 m 的偏移分别发生在 9 ka 和 5.8 ka 后。这些数据得出的滑移率范围在 3.9 毫米/年到 6.0 毫米/年之间。不同时期滑移率估计值的微小变化表明，瓦迪阿拉巴断层北部在过去 15 ka 中保持了相对恒定的滑移率。我们根据三个单独的位移和年龄估计，计算出自 15 ka 以来的平均滑移率为 4.7± 1.3 毫米/年。从沟道和小型断层陡坡冲积扇的偏移量测量了 5 个 3 m 的独立偏移量。这些位移数据表明最近一次地震的同震滑移为 3 m，或者过去几次地震的累积滑移为 3 m。 3 米的最大滑移相当于 7 级地震，断裂长度约为 49 公里。使用 4.7 ± 1.3 毫米/年的平均滑动率以及每次事件 3 米的滑动表明该断层段的最大地震复发间隔为 500 至 885 年。
The Wadi Araba Valley is a morphotectonic depression along part of theDead Sea Transform (DST) plate boundary that separates the Arabian plateon the east from the Sinai subplate on the west. The Wadi Araba fault(WAF) is the main strike-slip faults one of between the Gulf of Aqaba and the E-Wtrending Khunayzira (Amatzayahu) fault that bounds the southern end ofthe Dead Sea. Just south of the Dead Sea, the WAF cuts across severalgenerations of alluvial fans that formed on tributaries to the Wadi Dahalafter the regression of Late Pleistocene Lake Lisan ca. 15 ka. Geomorphicand stratigraphic evidence of active faulting, including left-laterally offsetstream channels and alluvial-fan surfaces, yielded fault slip-rate data for thenorthern segment of WAF. Typical cumulative displacements of 54 m,39 m, and 22.5 m of stream channels and alluvial-fan surfaces acrossthe fault were measured from detailed geologic and topographic mapping.The 54 m offset of the oldest alluvial-fan surface (Qf1) occurredafter the final lowering of Lake Lisan (16–15 ka) and before 11 ka yieldinga slip-rate range of 3.4 mm/yr to 4.9 mm/yr. Based on radiocarbonages of charcoal and landsnail shell samples from the buried Qf2alluvial-fan deposits exposed in trenches excavated across the fault, the39 m and 22.5 m offsets occurred after 9 ka and 5.8 ka, respectively. These data yield a slip-rate range between 3.9 mm/yr and 6.0 mm/yr.The small variability in these slip-rate estimates for different time periodssuggests that the northern Wadi Araba fault has maintained a relativelyconstant slip rate in the past 15 ka. We calculate an average slip rate of 4.7± 1.3 mm/yr since 15 ka based on the three separate displacementsand age estimates. Five separate offsets of 3 m were measured from gullybends and the offset of small fault-scarp alluvial fans. These displacementdata suggest a coseismic slip of 3 m in the last earthquake, or acumulative slip of 3 m in the past few earthquakes. A maximum slip of3 m correspond to a Mw 7 earthquake that ruptures about 49 km offault length. Using an average slip rate of 4.7 ± 1.3 mm/yr togetherwith a 3-m slip-per-event suggests a maximum earthquake recurrence intervalof this fault segment of 500 to 885 years.