or the increased area resulting from this debris may result in 

 sufficient force from the tsunami to cause the entire structure 

 to be swept away. 



"structures that were sufficiently anchored (generally on 

 noncontinuous footings) floated off their foundations and were 

 seriously wrecked or rendered useless when they finally settled 

 on the ground. 



"The third major cause of loss was the general lack of 

 resistance to horizontal forces in many structures, normally 

 provided by shear walls in buildings and cross bracing in 

 open-pile structures. 



"Generally, the more substantially constructed structures, 

 particularly multistory wood, hollow block, and reinforced 

 concrete, withstood the tsunami. These structures required 

 considerable internal refurbishing due to water damage, but 

 are in use today". 



Figure 221 shows, fairly typically, how buildings were moved from 

 their original locations by the force of moving water downtown. A 25- 

 ton concrete tetrapod mounted loosely on 'a pedestal as a monument to the 

 harbor development at Front Street (Figure 210) was moved bodily through 

 a distance of about 10 feet by wave forces. Tudor (l96^) calculated the 

 velocity of flow required, and arrived at a water speed of 20 feet per 

 second. However, the calculation is not likely to be very meaningful be- 

 cause it is known that the tetrapod had been pushed by a large diameter, 

 long log which lay astraddle of it when it was found out of place. 



Tudor (196^+) also calculated probable water flow velocities based 

 on the evidence of the bending of the supports of a detached light box. 

 His calculation is given in Figure 222, in which the direction of bend 

 would be normal to the paper. Here he tends to find a velocity of flow 

 of about 11 feet per second and a pressure force of about i+3 pounds per 

 square foot. 



The total estimated cost of tsunami damage at Crescent City was 

 $7,^1^, 000.-* Details are given in Table E-T of Appendix E. Approximately 

 30 blocks of the city were devastated, and the area was strewn with rubble 

 and logs swept in by the waves. Automobiles were heaped in scattered 

 piles, and stock from damaged stores scattered widely. Quoting Spaeth 

 and Berkman (196T): 



"The third wave picked up a gasoline tank truck parked at 

 the Texaco station and slammed it through the garage door of 

 the Nickels Pontiac building. The impact knocked loose an 

 electrical junction box j^st inside the door and a fire started 

 which destroyed the building, and spread back to the Texaco 

 tank farm, which burned for three days". 



* This figure is now revised upward to $11 million (see Table B-5) 



344 



