Taking the Lyttelton position in th.e inlet ag x = 8 miles, we derive the 

 resiiLts listed in Table II. 



TABLE II 

 Computed Amplification Effects in Port Lyttelton, New Zealand 



Period of Tsunami 

 Excitation 



T 



(hours ) 



Observed Inferred 

 Amplification Wave Height Wave Height at 

 Factor at Lyttelton Mouth of Inlet 



H 

 (feet) 



Hi 

 ( feet ) 



1.8 

 1.6 



0.8k 

 6.3 



1.0 

 3.8 



1.2 

 0.6 



The inference drawn from Table II is that the beat-shape of tsunami 

 waves entering Port Lyttelton was quite different from the rocket-shape 

 of Figure 60c . The later waves in the beat would have been less prominent 

 in relation to the leading waves, and the beat-shape at the mouth may have 

 been more in accord with Figure 6lc , applicable to Moen Island, Truk, in 

 the Caroline Islands. 



West of the Tonga Trench the tsunami had to filter through much 

 thicker island clusters whose strength in depth prevented much penetration 

 of energy into the Tasman Sea, despite a focusing tendency brought about 

 by wave refraction (Figure 27). The waves reaching Fort Denison and Camp 

 Cove, Australia, were about 1.2 feet high (Spaeth and Berkman, 196?) . 



The analyses of Figures 62 to 66 relate to the tsunamis that emanated 

 from the extreme southwest end of the source region (Figure 27). In five 

 cases covering a boundary spread from the Aleutian Islands to Japan, the 

 tsunami signal is still characteristically a long bullet-shaped beat com- 

 prising 6 to 8 waves with periods of about 1.9 hours. The complexity of 

 the records in most of these cases made their analysis a considerable 

 challenge. For example, in the records for Japan, the presence of the 

 primary waves is not readily apparent (Figures 65 and 66). Nevertheless, 

 strong similarities fo\and in primary wave systems for Poronaysk (Sakhalin 

 Island), Yuzhno, Kurilsk (Kuril Islands), Hanasaki and Ofxmato, Japan, 

 indicate the same origin. (Figures 63c, 6Hc, 65c, 66c) 



Table III summarizes some of the salient features evolved from the 

 analyses of the marigrams in Figures 1+3 through 66. 



97 



