e. The worst effects of (c) occurred during and immediately 

 following the earthquake. The worst effects of (d) were 

 contingent upon the concurrence of highest tsunami waves 

 with highest tide, several hours after the earthquake. 



f. Tectonic regional subsidence of the land increased the 

 damage potential of the tsunami, as at Kodiak, Seward, 

 and Whittier, and mildly at Valdez; uplift of the land 

 decreased the damage potential, as at Cordova. 



g. Submarine sliding and collapse of waterfront areas at 

 Seward, Valdez, and Whittier, were probably promoted by 

 drawdown of the water table as a result of seismic seiches 

 generated by the earthquake or initial seismic sea waves 

 of displacement. Primary cause of collapse was the un- 

 stable nature under vibration of the glacial deposits on 

 which these towns are founded. 



h. Small boats and marina docks suffered severely from the 

 waves. If beached and caught by turbulent water they 

 were frequently rolled and waterlogged or otherwise 

 smashed. If anchored fore and aft, they were often 

 keeled by broadside currents, and sunk at their moorings. 



i. Larger boats usually floated and had a better chance of 

 survival, but were usually damaged by battery. Vessels 

 of ship size showed best survival abilities. 



j . Pile-supported dock structures and decking were frequently 

 buoyed off their piles as a consequence of inadequate 

 connections (usually driftpins) and were carried away and 

 destroyed. Inadequately braced pilings were ready victims 

 for destruction. Some piles were pulled from their sockets 

 because of inadequate adhesion in the foundation. Usually 

 these piles had insufficient penetration in the foundation. 



k. At Kodiak, the breakwaters were severely damaged by com- 

 paction-settling of the foundation, regional subsidence, 

 resultant wave overtopping and severe scour from high 

 velocity flows probably exceeding kO feet per second. 



1. Land-based structures of timber construction, insecurely 

 fastened to their foundations, suffered severely. They 

 were usually floated off and beached near the high water 

 limit, or were splintered and smashed by impacts against 

 obstacles or by momentum from behind. 



m. At Kodiak Naval Station, the value of hold-down cables 

 was demonstrated when a small building, so provided, 

 withstood the waves in an area where others of its 

 kind were swept away. 



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