1000 I— 



100 — 



e 10 - 



E 

 u 



--v^. 



FREQUcMCY mc/scc 



Figure 16. Spectra of tsunamis recorded at Honolulu. 



estimated arrival times are distributed to all areas in the 

 system. For localities near an epicenter, warnings may be 

 issued on seismological evidence only. 



If a tsunami could be detected on the open ocean from 

 a spacecraft, an estimate of its dimensions would be very 

 valuable to the warning system. However, if the slope of a 

 large tsunami is truly only 10 , this is roughly equal to 

 a slope of a moderate ocean current system and an order of 

 magnitude smaller than the slope of a major current such as 

 the Gulf Stream. Therefore, a detectable anomaly from the 

 geostrophic slopes in the ocean must be determined. Further- 

 more, this would require an orbit that happened to be in the 



26-27 



