and went on to be recorded at the Argentine Islands on the west side of 

 the Palmer Peninsula of Antarctica, on the east coasts of New Zealand and 

 Australia, on the eastern seaboard of Japan and even on Sakhalin Island 

 in the Sea of Okhotsk. 



Mercifully, the earthquake occurred at a period of low tide; also 

 in most of Prince William Sound the land was raised h to 10 feet in 

 elevation and mitigated the full damage potential of the first waves. 

 Fortunately too, Alaska's indented coastline is sparsely populated so 

 that the dissipation of wave energy occurred with far less loss of life 

 and property than would have occurred on a well-populated coastline. 

 Nevertheless, Valdez, Whittier, Seward, and Kodiak were tragically inun- 

 dated and suffered severe damage (Life Magazine, April 10, I96U; National 

 Geographic Magazine, July 196^+; Grantz, Plafker and Kachadoorian, I96U ; 

 U. S. Coast and Geodetic Survey, I96U; Brown, I96U). 



The earthquake also stimulated remote seiche and wave effects in 

 the Gulf of Mexico and various parts of the United States. These effects 

 were complete^', dissociated from the Pacific Ocean tsunamis, yet in their 

 own right may be logically called seismic sea waves or seismic seiches. 



This study is an attempt to assemble and assimilate the work of 

 many investigators who in one way or another have been concerned with 

 the task of recording what happened, specifically as regards the effects 

 of the tsunami. More importantly it seeks to reconstruct the mechanisms 

 whereby the tsunamis were generated, to identify the nature and propaga- 

 tion of the waves, and to determine the damage they caused. We shall 

 take the liberty of injecting some new ideas and considerations that may 

 or may not be in agreement with the explanations advanced by others. 



Section II. THE NATURE OF EARTH DISLOCATION AND MOVEMENT 



1. The Geological Character of Faults in Alaska 



The geological structure of Alaska has been discussed in detail 

 in the now voluminous literature dealing with the Alaskan Earthquake 

 (cf. Wood, et al, 1966; Hansen, et al, 1966; Marlette, et al, I965) so 

 that we shall dwell only on those features pertinent to our theme. 



The State of Alaska may be broadly divided into four physiographic 

 regions which band the area in a approximate east-west direction (Figure 

 2a). In the south, the Pacific Mountain system forms an arcuate belt 

 of rugged terrain and encompasses the system of faults within which the 

 earthquake epicenter was located. The region is typified by a serration 

 of geanticlines and geosynclines which roughly parallel the coast and 

 penetrate laterally into the next northerly region of intermontane 

 plateaus and beyond. North of this is another mountainous region, a 

 continuation of the continental Rocky Mountain System. Still further 

 north is a comparatively narrow Arctic Coastal Plain. 



