Answer:
Some say that a tsunami's sea wave can scotch an entire island. All you will hear is a sudden silence, shadowed by the roar of a wave and then Splash! You are drowned in debri and dampened by dirty water.
Explanation:
Alliteration: "Some say...tsunami's sea...scotch" "sudden silence" "drowned in debri....dampened by dirty"
Onomotoppoeia: "Splash"