Island (Figure 63d), Yuzhno, Kuril Islands (Figure 6i^c ) and Hanasaki, 

 Japan (Figure 65c). At Lyttleton there is an amplitude increase of these 

 long waves toward the end of the beat suggesting that energy was being 

 accumulated at the period of about 2.75 hours. Since the natural period 

 of oscillation of the inlet of Port Lyttelton is about 3.35 hours, it is 

 possible that sufficient energy was being stored by the incoming waves 

 at or near this frequency to produce resonance in the fundamental mode 

 of the inlet. 



At Hanasaki, Japan, the effect is similar (Figure 65c) but details 

 of Hanasaki Bay on Kokkaido Island, Japan, are unknown. Similar responses 

 are found also at Yuzhno, Kurilsk (Figure 6i+c ) . 



At Poronaysk, Sakhalin Island, the long waves of U.9 hours period 

 are dominant from the moment of arrival of the tsunami and show all the 

 features of a dispersive, evanescent wave system. At Hilo, Hawaii, a 

 decaying, strongly dispersive long -wave system of initial period T == 3.5 

 hours is apparent in the record (Figure 59c). 



This feature occurs too frequently in the subjective analyses to be 

 considered an error of interpretation. We believe that these long-wave 

 systems are real and may have relation to the horizontal thrust of the 

 Alaskan landmass in the earthquake region. They were obviously of very 

 low amplitude and therefore required some degree of resonance to be 

 recorded at remote stations. The possibility that the waves are a non- 

 linear subharmonic derivation from the main tsunami cannot be overlooked. 



9. Heights of Runup Along the North American Coast 



Here we use the final column of figures in Table B-1 of Appendix 

 B to define the maximum height of the wave derived either as a rise or 

 fall above tide level of the time to give an idea of runup along the 

 Worth American seaboard. Table B-2 gives some particulars of effects 

 recorded at remote stations outside the Pacific Theater. The locations 

 of the stations for both these tables are shown in Figure B-1. 



The maximum recorded wave heights along the U. S. and Canadian 

 coastline from Alaska to Vancouver Island are shown in greater detail 

 in Figure 77. Figure 78 provides added detail in the Vancouver Island 

 region. The data are derived from Spaeth and Berkman (1967), Wigen and 

 White (196U) and from White (1966). In general. Figures 77 and 78 show 

 that the tsunami penetrated deeply into the farthest reaches of the 

 fjord-like coastline, even to Pitt Lake, about 135 nautical miles from 

 the mouth of the Juan de Fuca Strait at the south end of Vancouver 

 Island. On the seaward side of Vancouver Island wave height© registered 

 from 8 to 17 feet according to location. Port Alberni , along with Shields 

 Bay in Queen Charlotte Islands, suffered the highest waves. 



FigTire 77 shows the approximate positions on the hour reached by 

 the tsunami front and the approximate positions on the hour of the 

 crest of the spring tide sweeping in toward the Gulf of Alaska. The 

 tsunami front reached the shore between Prince Rupert and Vancouver 



18 



