Molten Salt Thorium Reactors are earthquake safe. Thorium reactors have a very simple and compact design where gravity is the only thing needed to stop the nuclear reaction. Conventional nuclear reactors depend on external power to shut down after a SCRAM, where poison rods fall down to halt the reaction. The next figure shows the concept of a Thorium reactor.
The idea is to empty the fissile U-233 core through gravity alone. All that is needed is a melt-plug that is constantly cooled by cold air. In an earthquake the cold air flow automatically shuts off, and since the fuel is already molten, it will then run down into channels like pig-iron into cooling heat exchangers with water supplied through gravity alone.
As we can see the reactor hardened structure is compact, and can be completely earthquake and tsunami proof. What can be sheared off are the steam pipes and external power, but the reactor shutdown will complete safely without additional power, even if the earthquake is so bad the reactor is broken into pieces.