Most houses downtown were old buildings . In fact , prior to the 

 quake, plans had been made for urban renewal of this section. These old 

 light wooden frame buildings , generally were inadequately connected to 

 their foundations. Many were floated atfay and damaged by the flowing 

 water. They were also damaged by impacts when they stranded, or by im- 

 pacts from other houses, boats and other floating objects. Many of the 

 houses, affected by the waves but still remaining on their foundations, 

 were partly damaged by impacts from floating objects, and all had damage 

 due to inundation. 



Damage in the downtown area is shown in the series of photographs, 

 Figiores lOU to 106. On these and on the map (Figure 103), several 

 buildings are marked with identifying numbers I to X. These buildings, 

 although lying in the path of the tsunami, were unmoved, but all suffered 

 damage and some were unsalvable. The type of structure in these buildings 

 and the extent of damage are summarized in Table V. The waves caused 

 minor erosion of roads and sidewalks downtown. 



Serious scour occurred in the channel between Kodiak and Near Island 

 where, in some places, 10 feet of sediment was washed away. This presented 

 a major postquake construction problem because no sediment foundation 

 remained for the piles of new waterfront structures (Kachadoorian and 

 Plafker, 196?). 



All boat floats in the small boat harbor were totally damaged. The 

 boat floats were held in place by approximately 100 guide pile?, all of 

 which were broken. Estimating pile diameter at 12 inches and water depth 

 at 12 feet, the ultimate lateral load capacity of one pile is calculated 

 to be 2.5 tons, assuming the load is applied 2 feet above stillwater level. 

 Acting in unison, the piles would have had an effective load capacity of 

 250 tons. If water moved through this array at 25 feet per second, the 

 drag force alone would have been of the order of 700 tons . Failure of the 

 system is thus easily explained, particularly since water velocities may 

 have been higher, and pressure and inertia forces from the wave slope may 

 have been additional to drag. 



Damage to the breakwaters was partly due to compaction settlement 

 caused by the tremors and partly due to the tsunami. Figure 89 shows 

 typical sections of the breakwaters as they were measured after the quake, 

 as well as cross sections of the rebuilt breakwaters (U. S. Army Corps of 

 Engineers, Anchorage, Alaska). The exact weight of the cover-layer stones 

 and the core material of the breakwater are not known. However, to judge 

 from Figure 102, the armor stones were too light to resist any great 

 degree of overtopping. 



At the City Dock (Figiire 89), submergence from the "second" wave of 

 some 6 to 8 feet apparently buoyed the decking off the pile caps, because 

 the deck stringers were merely driftpinned to the pile caps. Subsequent 

 vertical motion accompanied by lateral movement destroyed the decking. 

 When the bulkhead and about 25 piles at the approach to City Dock were 

 destroyed, pres\jmably with the third wave, the approach decking floated 

 away (Tudor, 196^). 



162 



