from a sun-synchronous orbit over a period of one year. 

 I have no doubt that this is true for a shorter period 

 (with resolvability depending on an extremely high signal 

 to noise ratio) but, as long as there is at least one 

 synodic period within the observation period, I believe 

 such a frequency can be resolved as well as any other 

 of comparable signal to noise ratio. This could be 

 readily tested by a -omputer experiment similating a sun- 

 synchronous orbit and real tide data. 



3. TSUNAMIS 



We have many tide gauge records showing tsunamis and 

 these data have been supplemented by visual reports, damage 

 estimates and rnjn-up studies. 



Usually tsunamis are generated by an abrupt vertical 

 shift of the sea floor associated with an earthquake. The 

 displacement is transmitted to the sea surface as a crest 

 or a trough. The wave then propagates in all directions 

 but with some directivity (conservation of energy) near the 

 source normal to the fault line of the earthquake. 



On the open ocean a tsunami, which travels with a speed 

 of about 400 to 500 knots, is believed to be only about 30 

 cm high whereas the wave-length may be as long as several 

 hundred kilometers. With a slope of only 10 , it is not 

 observed by ships at sea. As the wave impinges on coastal 



26-22 



