The ability has multiple charges (up to 10+) of bolts, which can be fired in rapid succession.
The bolts leave behind a shiny trace and emit light when stuck to something, allowing players to spot them easily.
They get a visual indication to roughly show the remaining time until explosion (basically "light pulse version" of the beeping with increasing rate that is being used in movies, or in CounterStrike, when a time bomb is about to blow up).
The detonations are simple (smokey) explosions.
Resonating Bolts are not included in the video posted by Tragedy, so here is one:
The targeted area is being marked by a vertical laser beam/hologram above, and a circle on the ground.
The attack itself is made up of a bunch of explosions hitting different places within the targeted area (all of them covering the entire area with damage, independent on where their animation shows them to take place).