(n + l)At 

 n At 

 »~S 



-as — ■ 



BOUNDARY 



Figure 12. Graphical representation of the total 

 transmission open boundary condition 

 (from Hwang and Divoky, 1975) . 



Houston and Garcia (1974) and Hwang and Divoky (1975) used numerical 

 techniques to obtain predicted wave heights for the 1964 tsunami originat- 

 ing in Prince William Sound, Alaska. The uplifting and subsidence deter- 

 mined from field surveys (Plafker, 1965; Berg, et al., 1970) was used as 

 the initial deformation of the water surface. Predicted wave heights 

 13,000 seconds (3.61 hours) after the time of generation are shown in 

 Figure 13. 



The assumptions that complete reflection occurs at a solid boundary 

 (i.e., at a shoreline) and that equation (125) will describe an open 

 boundary introduce errors into the computations which limit the length 

 of real-time records which can be simulated numerically. At a shoreline, 

 some amount of wave energy may be trapped so that complete reflection does 

 not occur. Wave trapping is discussed later in this report. 



59 



