The initial swells weren't what did it - there was the drawback, then a flowforward, meaning the recesssion and then an advance past the old
coastline, coming in with several waves - these waves were moving at almost the speed of sound, but were not large at all.
Then larger waves would have come, and a great torrent would have existed as this mass of water was drawing backwards across a place it had never
been, while larger waves were ripping through it at near the speed of sound.
Then, after the 'normal', second-hand* waves had grown to immense heights, the true first-hand Tsunami would strike and cause massive damage,
flowing forwards through the already advanced sea, and ripping through debris, killing many.
* By 'second hand', I mean that you are starting with a large displacement of water, causing the initial first hand Tsunami, but the second it is
moving, it is affecting all of the other particles in the ocean, similarly to the way that spinning one end of a pole, the other end, no matter how
far away, will instantaneously be affected, because they are in direct contact with each other.
So, within instants of the earthquake, nth-generation waves would begin affecting the shores, decreasing, and as n decreases the direct power and
volume of water would increase, until generation-1, which was the first hand wave of water being directly displaced. 'Second hand' would be the
water displaced by the displaced water, from the earthquake.
-- Now, as for 'seeing the waves come at them' - by the time the largest wave was on the horizon, the initial swell would have hit, and most of the
people around would have been running long ago, or swept away. The waves were moving incredibly fast, and were also under the water until they came
very near to the shore - it would be within 2-3 kilometers, quite closer than the horizon, that you noticed any real change in wave height/size.
At any rate, it is amazing that she warned those people. It is definitely good to see one bit of human success in this tragedy. And FredT takes the
longest title he can, again.