i think that wherever the pole is, it aggregates a very strong field alignment due to how powerful the field is, and the rock around it will tend to align north to south in that position. so, it seems logical to me that it would tend to be a pair of poles that you find during each period there is magnetic anomalies in those areas even though they may not be especially thick parts of the crust, it just used to be the pole point.

the field is from the highly compressed, high iron containing core of the planet, and the pressure and gravity makes it more or less directly turn the gravity into a magnetic field, like a dynamo, imparting magnetism from the forces going into it.

the crust is just dotted with material in various patterns of magnetic permeability and there are numerous dense areas in various layers of the crust and even the mantle has high and low magnetic permeable areas in it, these have been measured and estimated their shape from the field effects.

the main thing is that normally the viscosity of the material the earth sits on is higher, and when more electricity gets into the earth, it gets hotter, and that lowers viscosity and then at a certain point, the magnetic field outside, from the galaxy, couples with these anomalies and pushes them into alignment with the gravitational pole, ie north/south pole of the core.

in the process, there can be shifting of plates as well as new faults forming so some land as well as being flooded, may rise or fall compared to its current location. the himalayas and mongolian plateau are examples of land that uplifted a lot at one point, pressing plates together.

yeah, it's probably pretty rough time to be around on the planet lol. that's why i am planning to be inland and up high sometime in the next 3-5 years.