I live in Colorado–some of you may remember the earthquake near the Colorado-New Mexico border not too long ago. One of the news reports said that the strongest earthquake ever recorded in Colorado was a 6.5 (sometime around 1880, I believe).
We also get tornadoes, although they’re quite rare in the specific area where I live. The eastern part of the state, which is the western end of the Great Plains, gets more of them, although they’re generally F2 or lower.
In other words, significant earthquakes and tornadoes are both rare but entirely possible.
If you wanted to build a house to withstand anything that would be even quasi-semi-likely to happen, and you had it built to withstand a 5.0 earthquake (for example), would it automatically also withstand a (for example) F3 tornado? What about the other way around–would a tornado-resistant building automatically withstand an earthquake?
Totally different builds. Example was my house in Japan. Little more than sticks, some mortar, glass sliding doors, and rice paper. Swayed just fine without falling down in 6.0+ earthquakes. A strong wind would utterly destroy the structure.
For an earthquake, you want either the building to be able to sway on its own (house size) or be built on a suspension system that absorbs the motion (large buildings). Depending on the earthquake; you could have a rapid up/down strike, a back/forth sway, or some combination.
Tornado damage is from the wind and flying debris. You’d want to limit glass area, have strong walls possibly with some aerodynamic shaping (dome home or arch shaped). Reinforced garage doors fared better in hurricanes in a post storm study in Florida. You don’t want to get the wind into the house structure as it will blow out the walls (weakest direction). Florida houses where the garage doors held up had less damage.