The National Data Buoy Center at: https://www.ndbc.noaa.gov/ shows you where the buoys are positioned. Unfortunately, not all areas of the ocean are equally covered. You will notice that from the Canary Islands heading westward towards the United States, you will go a long stretch before you cross a buoy, more than halfway across the distance between the two.
And currently, the two closest buoys are 'offline' which means we will have very little notice of an impending tsunami, unless it begins during daylight hours and other parties alert us.
I am wondering why hasn't the U.S. NOAA sent out a crew to repair or replace the 'non-reporting' buoys?