the fundamental period is: 



T^ = li.UU L/ /^d^ (T) 



in which L is the length of the channel from the mouth and d the depth 

 at the mouth. For L = iiO miles, d-^ = 600 feet, Tj_ is 1.85 hours, which 

 clearly suggests that pseudo-resonance occurred. 



Ass-uming a uniformly sloping channel "bed, which is still a fair 

 approximation, an estimate of the amount of amplification a of the waves 

 ■between the mouth and the head of Alberni Inlet may be obtained (Lamb, 

 1932), without consideration of friction. 



Amplitude at head ^ /^ _i_ Hl)^ (8) 



" ~ Amplitude at mouth 2 



in which K is a wave number defined by 



K = a2L/gd^ (9) 



and is the angular frequency of the incident waves. For the 1.7-hour 

 waves of Figure Ujc , a is about 10, suggesting that the tsionami waves 

 entering Barkley Sound (Figure 68) were about 2.7 feet high and therefore 

 of the same order as the waves reaching Victoria (Figure i+8d). 



We shall confine our attention here to what are considered the 

 essential tsunami signatures in Figures k3 to 66 and reserve comment on 

 secondary features (such as the wave systems (c) and (e) in Figure U8, 

 for example) for a later stage. 



Analysis of the limited data for Crescent City suggests that the 

 second principal wave (Figiire U9c ) , of 1.8 hours period and 13 feet 

 effective wave height, made the tide gage inoperative and caused the 

 great destruction and tragedy (Griffin, et al, 196i+). This wave was 

 assisted by a local oscillation with an effective height of 17.5 feet 

 and a period of about 30 minutes exactly phased to occur on the crest 

 of the- monster 1.8-hour wave. In addition, these waves rolled in on 

 the high spring tide just as at Prince Rupert and Port Alberni, Canada, 

 (see Figures h6 and ^7). 



The waves reaching Crescent City came from the southwest extremity 

 of the source region near Kodiak Island (Figure 27). A paper recently 

 received (von Huene, et al, I967) indicates that this part of the sovirce 

 region had the highest concentration of strain-energy release over the 

 period March 27 through May 1, 196i+ of any area tectonically affected 

 by the earthquake. The wave rays of Fig\ire 27 suggest that energy from 

 that region was spreading through overlapping wave systems, presumably 

 as a result of the vertical uplift and the horizontal thrust of the sea- 

 bed or from some other cause. The line of progression of the "caustic" 

 or intersection of the slightly oblique wave systems has the appearance 

 of bearing directly on Crescent City and might account for the large 



93 



