Assuming you're not just yanking my chain, using the phrase logarithmically in this context is supposed to convey that it isn't a straight line progression over time. The further in time you go from the event the MUCH further out the odds are of something happening. In this case you have a pretty good chance of a bigger quake within a few hours, but that dwindles to almost nothing over a short period of time. A linear progression would be much more straight forward, where the likelyhood goes down, say, by half in an hour, then another half of that in another hour and so on.
"the hawaiian islands are sinking every day". this is what FNC is saying. its going to take a while of course.
Thanks.