You did not drop the pebble into the pond ten seconds ago in the past; you dropped it in the present moment, and the ripples are an echo, or trace, of that event, which are also occurring in the present. (Actually, dropping pebble and ripples are a single event). There never was a past or future. Both dropping the pebble and ripples occur in the present, as all events do.
Now if you say that you dropped the pebble into the pond and ripples resulted, you are speaking from memory, which is where all past events are stored. There is no past as such; there is only the trace, or memory, of expired present events.
You might argue that you can predict the future by dropping the pebble into the pond by saying that ripples will result, but you are basing the statement on known behavior, which is based on the past, or repeatable data stored in memory. All you can really say is that ripples will result in the present, which is actually when they occur.
When you say 'ten seconds ago' you are not speaking about a past that exists in reality, but about the system of measurement you are employing to record the event, and that is where the general confusion lies when most of us think that past events create the present. We mistake the linear system of measurement employed of an event for the actual reality. 'Ten seconds ago' is a point on that linear scale which was actually an event in the present moment, but because of a flaw in the mind, we associate the event with the scale to measure it called Time.
If you look closely, what is trailing off and fading away are at the outer edges of the ripples, away from the center where the original event occurred. The analogy is not exactly comparable to the ship/wake analogy since the ship cutting the wake is an ongoing event in the present.