The Russian earthquake, which hit off of the coast of the Kamchatka Peninsula, was one of the most powerful earthquakes ever recorded.

The 8.8 magnitude quake off Russia that triggered tsunami warnings across the Pacific occurred on what is known as a "megathrust fault", where the denser Pacific Plate is sliding underneath the lighter North American Plate,

Russia's magnitude-8.8 earthquake spawned serious tsunami warnings, but waves have been moderate so far. Here's the geological reason why