One of this century's most powerful earthquakes struck off the coast of Russia and generated tsunami warnings and advisories for a broad section of the Pacific, including Alaska, Hawaii and the U.S. West Coast and as far south as New Zealand.

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.

An 8.8-magnitude undersea earthquake struck early Wednesday off the coast of Russia's Petropavlovsk-Kamchatsky, triggering tsunami waves in parts of Russia and Japan, and prompting alerts across the Pacific region.