My sense is that the L~rd is not nearly as ambivalent or indecisive as Mr. Snodgrass. Although his vision may be true, emphasis in his interpretation should be on repentance. Too many people who say they are saved by grace treat it as an excuse for continuing in sin. The L~rd is calling for genuine repentance and not for prayer to change His mind about judgment or relocation of the epicenter.
I can't conceive of where one would pray that He send the epicenter of a 9.+ quake and it not hurt a lot of people badly.
FWIW, about 20 years ago I constructed a building in the middle of the Mojave Desert. Near its completion I looked out upon a vista of extremely remote barren terrain, terra incognita which time had forgotten and made a simple prayer that should a massive earthquake occur in that area , perhaps it might be made in that area so as not to harm too many innocent victims. Some 16 years later the epicenter of the Hector Mines earthquake happened to hit within about 500m of the area I had been glancing prior to my simple passing prayer 16 yrs earlier. (I want to say within 100m, but the general area I remember was about a 3 mile x 3 mile area in an expanse of about 35 x 70 miles.
Mind you, this doesn't mean my prayer caused anything, For all glory goes to Him, and He has such power not myself, but I have noticed that those passing simple prayers can sometimes seemingly be the most powerful with respect to later events.
As for a 9.0+ event,...far better it occur in a rural area than in a metropolitan area,.....unless of course we're speaking about a number of different homosexual communities in the US.