(The Seattle Times)—The earthquake that lashed the Pacific Northwest in 1700 ranks among the mightiest the Earth can yield. Scientists today call it a megaquake — a magnitude 9 monster that ripped the full length of the offshore fault where seafloor and continent collide, and unleashed a killer tsunami. Only a few seismic disasters in modern times have approached that level of fury.
No one who saw the videos from the 2004 Indian Ocean megaquake and tsunami will ever forget the wall of water that pulverized cities and muscled through resorts as if they were made of cardboard. More than 200,000 people died. The force of the fault rupture made the Earth wobble on its axis.
In March 2011, an offshore fault ripped loose off Japan. The magnitude 9 quake shoved the island of Honshu eight feet to the east and triggered a tsunami that reached the closest shores in 20 minutes. A nation whose leaders thought they were prepared for the worst watched in horror as waves poured over sea walls and swept nearly 20,000 people to their deaths. Nuclear reactors crippled by the flood melted down and spewed enough radiation to turn the surrounding countryside into a no man’s land.