Near‐field observations of tsunami waves generated by the M _w9.2 1964 Alaska earthquake reveal a complex relationship between coseismic slip and the tsunami wavefield in the source area. The documented times and amplitudes of first arrivals, measured run‐up heights and inundation areas along the coasts of the Kenai Peninsula and Kodiak Island show that secondary splay faults played an important role in generating destructive tsunami waves. We find that a splay fault extending to about 150°W is required to fit tsunami first arrivals on the Kenai Peninsula but that the splay fault did not rupture along the entire length of the Kenai Peninsula. This extent supports the connection of splay faulting to a persistent Prince William Sound asperity. Our results also show that the contribution of coseismic horizontal displacements into the initial tsunami wavefield does not change the pattern of tsunami arrivals much but increases the amplitude. The coseismic deformation model of Suito and Freymueller (2009, https://doi.org/10.1029/2008JB005954) explains the pattern of tsunami arrivals in the Kodiak Island region well, indicating that it provides a good estimate of slip on the megathrust in the Kodiak asperity. The sensitivity of the near‐field arrival information to the coseismic slip model shows that such data are important in distinguishing between slip on splay faults and on the megathrust and in discriminating between competing slip models.

中文翻译：

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1964年阿拉斯加海啸的近场建模：扇形断层和水平位移的作用

M _w产生的海啸波的近场观测1964年的9.2阿拉斯加地震揭示了震源区同震滑动和海啸波场之间的复杂关系。记录下来的首次到达的时间和幅度，沿基奈半岛和科迪亚克岛沿岸测得的上升高度和淹没区域表明，次级张开断裂在产生破坏性海啸波中起着重要作用。我们发现，为了适应基奈半岛海啸的初次到达，需要扩展到大约150°W的张裂断层，但是张裂断层并没有在基奈半岛的整个长度上破裂。此范围支持将张开断层与持续存在的威廉王子声音的粗糙联系起来。我们的结果还表明，同震水平位移对初始海啸波场的贡献不会改变海啸到达的方式，但会增加振幅。Suito和Freymueller的同震形变模型（2009，https://doi.org/10.1029/2008JB005954）很好地解释了科迪亚克岛地区海啸的到来模式，表明它可以很好地估计海底巨推力的滑移。科迪亚克粗糙。近震到达信息对同震滑动模型的敏感性表明，这些数据对于区分张开断层和超大推力上的滑动以及区分不同的滑动模型非常重要。1029 / 2008JB005954）很好地解释了科迪亚克岛地区海啸的到来模式，表明它提供了对科迪亚克凹凸不平巨型推力滑动的良好估计。近震到达信息对同震滑动模型的敏感性表明，这些数据对于区分张开断层和超大推力上的滑动以及区分不同的滑动模型非常重要。1029 / 2008JB005954）很好地解释了科迪亚克岛地区海啸的到来模式，表明它提供了对科迪亚克凹凸不平巨型推力滑动的良好估计。近震到达信息对同震滑动模型的敏感性表明，这些数据对于区分张开断层和超大推力上的滑动以及区分不同的滑动模型非常重要。