God can do whatever He likes whether in the past, the present or the future.
That's not true, He has to stick to the prophecies He has already given.
Isa:42:9: Behold, the former things are come to pass, and new things do I declare: before they spring forth I tell you of them.
Jer:4:28: For this shall the earth mourn, and the heavens above be black: because I have spoken it, I have purposed it, and will not repent, neither will I turn back from it.
For Japan to be part of the end time prophecies it would have to be within 3 1/2 years of Christ's return. In that time Jerusalem is still the focus of the prophecies. If the disaster is not in that time-frame mentioned it cannot pinpoint any timing, it becomes part of a general reference to an undetermined length of time.
M't.24:7
For nation shall rise against nation,
and kingdom against kingdom:
and there shall be famines,
and pestilences,
and earthquakes,
in divers places.
The first quake that is part of the start of the end also has to see other events be fulfilled just as literally. The first 4 trumps of Revelation could happen within 4 days, The deaths associated with wormwood start at the end of that period and continue until Christ's return.
Re.8:6-12
And the seven angels which had the seven trumpets prepared themselves to sound.
The first angel sounded,
and there followed hail and fire mingled with blood,
and they were cast upon the earth:
and the third part of trees was burnt up,
and all green grass was burnt up.
And the second angel sounded,
and as it were a great mountain burning with fire was cast into the sea:
and the third part of the sea became blood;
And the third part of the creatures which were in the sea,
and had life,
died;
and the third part of the ships were destroyed.
And the third angel sounded,
and there fell a great star from heaven,
burning as it were a lamp,
and it fell upon the third part of the rivers,
and upon the fountains of waters;
And the name of the star is called Wormwood:
and the third part of the waters became wormwood;
and many men died of the waters,
because they were made bitter.
And the fourth angel sounded,
and the third part of the sun was smitten,
and the third part of the moon,
and the third part of the stars;
so as the third part of them was darkened,
and the day shone not for a third part of it,
and the night likewise.
If I was to try and apply Japan to the first trump it would still have to happen on a scale that is already too long. It might still have all 6 radiate for months and years. Could the verse mean radiation maybe if 1/3 of commercial shipping ended, that might be because of no freight or it could be damage to the ships that made them unsafe. I'm going to admit I would scratch my chin if 1/3 of all 737-300 were grounded but that is still one point and the 1/3 that die in the seas would be dead rather than being given something that will eventually kill them. Revelation is also written in such a way that some of the bigger disasters claim a portion, like 1/3, over a specific number. Revelation only need a world population of about 600,000 to be fulfilled according to the numbers listed. Granted this JMHO but attitude is the way to survive in those days compared to being able to life in some specific area. For a Christian it is the same thing as before those days begin. Faith through works rather than false lip service.
Jas.2:14
What doth it profit,
my brethren,
though a man say he hath faith,
and have not works?
can faith save him?
Jas.2:15
If a brother or sister be naked,
and destitute of daily food,
Jas.2:16
And one of you say unto them,
Depart in peace,
be ye warmed and filled;
notwithstanding ye give them not those things which are needful to the body;
what doth it profit?
Jas.2:17
Even so faith,
if it hath not works,
is dead,
being alone.
I have no idea how well that part of the operation is going, I would assume as caring as any Gov is the exodus will be a day alter than it should be or the people will simply be sacrificed and the total silently added at a later date when everybody is watching something else.