Millions of people were evacuated, as minds cast back to the devastating tsunami of Boxing Day 2004 in the Indian Ocean and Japan 2011, both triggered by similarly large earthquakes. But today's tsunami has been much less severe, even though it's brought some damage.

A magnitude 8.2 earthquake caused a tsunami that killed more than 5,200 people on Dec. 30, 1703, according to NOAA data. The event occurred off the southwest Boso Peninsula, which is just south of Tokyo, Japan.

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