I've got 26 pages in my research notes dedicated to this subject. I don't know what triggers the induced fluidity in the asthenosphere nor does anyone else, however there are a lot of very difficult to explain curiosities on Earth that, all of a sudden, make sense in light of the pole flip hypothesis.

Pole flips mean every tectonic plate shifts, with the ice caps getting mediated to the equator.

Imagine you took a baking sheet from your kitchen and created a reasonably accurate topographical model of earth’s surface out of sand or dirt or whatever. You shaped continents and mountain ranges, carved out seas and major lakes, and then filled in the rest of the baking pan with water to model the oceans. Now imagine that baking sheet was placed on an airport travelator: those horizontal moving walkways one might find most often in airport terminals. Imagine that this particular travelator has a random 45 degree offset at a certain point. As the baking pan scale topographical model of Earth’s land and water bodies traverses that 45-degree turn, one should notice some cataclysmic sloshing of the water in that pan. The model’s ocean water would be expected to slosh violently across the modeled lands. Scale sized observers on that model would experience incredibly tall waves that completely inundate the lands, flooding everything, wiping out most life, most structures, most signs of civilization, etc.