On Numerical Simulation of the Landslide-Generated Tsunami of November 3, 1994 in Skagway Harbor, Alaska
On Numerical Simulation of the Landslide-Generated Tsunami of November 3, 1994 in Skagway Harbor, Alaska
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DOI：
10.1007/978-94-017-3618-3_17
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发表时间：
2001
影响因子：
2
通讯作者：
R. Thomson;A. Rabinovich;E. Kulikov;I. Fine;B. Bornhold
中科院分区：
文献类型：
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作者：
R. Thomson;A. Rabinovich;E. Kulikov;I. Fine;B. Bornhold
具有完全滑波相互作用的粘性滑坡的三维浅水数值模型（Kulikovet等人; 1996; Fineet等人，1998年）进行了修改，以包括滑坡的陆上部分。该模型被用来模拟1994年11月3日在斯卡格威，阿拉斯加州的PARN码头倒塌产生的海啸。结果表明，码头滑坡沿太牙湾陡边坡（30-35°）向下移动，并沿坡底槽沿着移动，与地貌特征一致。在滑坡前方传播的主导海啸波以正波（波峰）冲击了阿拉斯加州渡轮码头和美国国家海洋和大气管理局验潮站，这与验潮记录和Raichlenet等人（1996年）的实验室模拟结果一致。PARN码头故障的计算波高（渡轮码头为13 m，验潮站为7.7 m，小船港为1.3 m）与验潮记录和目击者的描述非常吻合。计算的3.0分钟周期的基本长波模式斯卡格威港几乎是相同的观测周期。Q因子的估计值（Q = 24）与观测值（Q = 21）相当，表明港口中保留了大量海啸能量。能量损失似乎是通过辐射阻尼，而不是从摩擦效应。对PARN码头附近的滑动运动和相关海啸波的详细检查表明，在最初的几秒钟内，码头对面会形成一堵“水墙”，浮动渡轮码头会在事件发生后15至20秒受到影响，与目击者的描述一致。在码头的仍然站立的北方部分观察到的漂浮碎片显然是由来自码头倒塌的南部附近的第二波波峰沿着海岸带的。与世界海洋其他沿海地区的类似现象一样，以及1966年10月在斯卡格威港产生的早期滑坡和海啸，1994年11月的Skagway事件与极端低潮时边坡材料的临界超载有关。对连接海岸滑坡和低潮的物理机制的研究表明，1994年斯卡格威海啸主要是滑坡的亚热带成分造成的。这支持了我们的论点，即滑动是由PARN Dock故障引起的。我们的结论是，我们的滑坡与1994年PARN码头故障在斯卡格威港帐户的各个方面的观察到的波场没有额外的假设，同时，假设，地球物理，地质或水文气象事件在毗邻地区的数值模型。
A three-dimensional, shallow-water numerical model for a viscous landslide with full slide-wave interaction (Kulikovet al.; 1996; Fineet al., 1998) has been modified to include the subaerial component of the landslide. The model is used to simulate the November 3, 1994 tsunami in Skagway, Alaska generated by collapse of the PARN Dock. Results show that the dock slide moved down the steep (30–35°) slope of Taiya Inlet and was guided along the trough at the base of the slope, consistent with geomorphological findings. The leading tsunami wave, propagating in front of the advancing slide, impacted the Alaska State Ferry Terminal and the NOAA tide gauge site as apositive wave(crest), consistent with the tide gauge record and with the results of laboratory modelling by Raichlenet al. (1996). Computed wave heights for the PARN Dock failure (13 m at the Ferry Terminal, 7.7 m at the tide gauge site, and 1.3 in the Small Boat Harbor) agree closely with the tide gauge record and eyewitness accounts. The computed 3.0 min period for the fundamental long-wave mode for Skagway Harbor is nearly identical to the observed period. Estimates of theQ-factor (Q≈24) are comparable to observed values (Q≈21), suggesting significant tsunami energy retention in the harbour. Energy loss appears to be through radiation damping rather than from frictional effects. A detailed examination of the slide motion and associated tsunami waves in the vicinity of the PARN Dock reveals that, in the first few seconds, a “wall of water” would have formed opposite the dock and that the floating Ferry Terminal would have been impacted 15 to 20 s after onset of the event, consistent with eyewitness accounts. The floating debris observed at the still-standing northern portion of the dock was apparently carried alongshore by a secondary wave crest originating near the collapsed southern part of the dock.As with similar phenomena in other coastal regions of the world ocean, and with an earlier landslide and tsunami generated in Skagway Harbor in October 1966, the November 1994 Skagway event is linked to critical overloading of the slope materials at the time of extreme low tide. An examination of the physical mechanism linking coastal landslides and low tides indicates that the 1994 Skagway tsunami was largely the result of asubaerialcomponent of the landslide. This supports our contention that the slide was caused by failure of the PARN Dock. We conclude that our numerical model of the landslide associated with the 1994 PARN Dock failure in Skagway Harbor accounts for all aspects of the observed wave field without additional assumptions concerning simultaneous, hypothetical, geophysical, geological or hydrometeorological events in the adjoining region.