The relationship between distance and time is shown in Figure 70, 

 which gives, for x = 6.1 meters, 



t = 2.02 seconds 



(b) From equation (345) , 



u 14 



u, = u =14 



D out + 1 (0.021 x 14 x 2.02) + 1 



u, = 5.22 meters (17.1 feet) per second 



Substituting equations (342) and (341) into equation (338) , 



F = pVa (u - u, ) 2 



F = 1,026 x 216 x 0.021(14 - 5.22) 2 



= 3.59 x 10 5 kilogram-meters per second squared 



F = 3.59 x io 5 newtons (8.1 x 10 1 * pounds) 



(c) Momentum, M , at impact is 



M = u, x mass 



taking the mass of the building equal to the mass of the displaced 

 water for a partially submerged building which is floating (the mass 

 includes water within the building), 



mass = pV = 1,026 kilograms per cubic meter x 216 cubic meters 



and the momentum is 



M = u, x mass = 5.22 x 1,026 x 216 

 o b 



= 1.16 x io 5 kilogram-meters per second 

 (2.56 x 10 5 pound-seconds) 

 ************************************* 



Magoon (1965) indicates that substantial damage occurred at Crescent 

 City during the 1964 tsunami as a result of debris impacting on structures. 

 This debris included logs, automobiles, and baled lumber. The impact 

 forces either destroyed the load-carrying capacity of walls, or caused 

 bending or breaking of light columns. 



Wilson and T^rum (1968) discussed some instances of impact damage 

 resulting from the 1964 Alaskan tsunami. Figure 72 illustrates the damage 

 at the Union Oil Company tank farm at Whittier. Buildings and larger 

 tanks were able to withstand the force of the tsunami; however, smaller 



190 



