Earth's layers remain stable, and the entire planet tips over as a whole.
Either unknown extraterrestrial forces are at play, or the Earth is becoming unbalanced.
Mars probably experienced a similar unbalancing event.
The largest gravity anomaly in our solar system is located along its equator, a massive volcano known as Tharsis.
Due to centrifugal forces, either this volcano formed on the equator and has remained there ever since, or it formed elsewhere and migrated there.
In a spinning globe, centrifugal forces will shift heavier points toward the equator if they are heavier than average