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.

When a magnitude 8.8 earthquake rocked Russia's Kamchatka Peninsula on Tuesday, officials warned that damaging tsunami waves could follow. Instead, the waves that reached Hawaii and the U.S. West Coast proved smaller than initially feared.

One of the largest earthquakes ever recorded happened off the Russian coast, triggering tsunami warnings from the U.S. west coast to South America. In Hawaii, people clamored to the top of high-rises and a traffic rush headed away from the coast.