A magnitude 6.0 earthquake releases approximately 1.3×1017J of energy, equivalent to the explosion of a 100-megaton Russian nuclear submarine Poseidon. It is well known that magnitude 6 earthquakes do not generate tsunamis. On July 29, 2025, an 8.8 magnitude earthquake occurred, which generated a tsunami wave 4 m high.
That is, to generate such a wave, 15850 nuclear Poseidons would have to be detonated.
So nuclear Poseidons do not pose a threat?