The Kamchatka earthquake in 1952, & the quake last year off the western coast of Sumatra were both 9s.

The 1960 quake in Prince William Sound (AK) in 1960 was a 9.2.

The worst one was in Chile, also in 1960, and it was a 9.5.

But these are only the ones recorded with modern equipment.

The New Madrid, MO quakes of 1811 & 1812 made a lot of changes in the terrain, but is estimated to have been "only" an 8+. They affected the topography more than any other earthquake on the North American continent, and were felt from east of the Rockies to the Atlantic seaboard. Large areas sank into the earth, new lakes were formed, the course of the Mississippi River was changed, and forests were destroyed over an area of 150,000 acres. They also caused the Mississippi River to flow backwards for a while, and rang church bells in Boston, MA.

It isn't just the magnitude that does the damage, it's the depth, the direction, and what's built on top of it, plus what else it can affect, like volcanoes & tsunamis, plus myriad other conditions.

Bob Hope once referred to an earthquake as a mountain range doing the Funky Chicken.

Sue