It has been said that today Puerto Rico(If I heard right)has had 30 3.5 tremors?

Actually these little tremors are harmless but it has been frequent today. These past months small tremors have occurred. The top seismologist have subtly said,(in my own words, she didn't say it)that the big one is really coming and it's time to get ready for it'.so as not to cause panic. But it's coming and the question is when. Question: Let's say that in the Puerto Rican trench a 8.3 to 9.0 comes up and the canyon of the miles long trench pushes up displacing water....how many minutes till the tsunami reaches San Juan and how high will be the waves and will it flow all the way to the Cordillera Mountains killing the densely populated north? Can there be a possibility? I feel that there can be a possibility.