Just a quick thought on an old thread.
What if ...
The "earthquake" [greek: 'seismos', which, besides "earthquake" can also mean a shake, riot, upheaval, comotion] that splits the great city in three may refer to the endless social-military upheavals that have involved Jerusalem, resulting in it today being a "great city" split into three parts, the three so-called monotheistic religions: Judaism, Christianity, Islam?
In this case, Jerusalem would be "Babylon the Great".
Eden