Guys, it's simple physics.
Godzilla, as large as he is, cannot displace enough water on his own to create a tsunami.
What causes a tsunami? Vertical displacement of a large colmumn of water, and to date, the only forces capable of creating a tsunami are medium to high scale earthquakes, rare underwater volcanic eruptions, and large meteorite impacts within the ocean.
Godzilla, as large as he is, cannot displace the kind of water or create the kind of kinetic energy it takes to start a tsunami.
@ BTBETTA35 - Yes, Godzilla is not a part of the tsunami. As I just explained, because of the laws of physics and how a tsunami is created, Godzilla could be swimming in front of or behind a tsunami, but would not be the cause. There's nothing terribly 'interesting' about that fact.
@ DRAGONLORD TEVIN - Godzilla is not a God, he's an animal. As powerful as he is, he's not powerful enough to create a tsunami regardless of his size. Your lack of logic and education regarding physics confounds me, but is entertaining in its own kind of way.
Again, physics demand respect and Godzilla is not above them (barring the fact that physically he could never exist anything). As much as we love him, he'll not be the cause of a tsunami anytime soon (nor will he ever).