Petra,
I think you are being a bit generous in accepting the event in the eastern Mediterranean
today as having been predicted by Antonio. It does not fall within his predicted parameters
which were within 150 km of 38.5N 22.5E. The epicenter in the eastern Mediterranean
is about 507 km away from this epicenter. This is like saying a earthquake north of
San Francisco was properly predicted by a prediction for an earthquake south of Los
Angeles.
Anyway, we can see what chances Antonio has for getting this prediction right
by random guessing. During the past 35 years 112 earthquakes have occurred with M>=5
within 150 km of his stated epicenter. During that time there were 12775 days. This
averages to a probability of 0.009 for an event of this size in this radius on a given
day (about 1 in 100 odds). Since his time window was 11 days, his odds are about
11 times this or around 1 in 9 or 1 in 10 of a correct prediction by chance. If such
an event were to occur before May 6, there would probably be reason to congratulate
him.
On the other hand there have been 443 events within 510 km of this epicenter with M>=5
in the past 35 years. The daily probability of an event in this area of M>=5 is therefore
about 0.035 (about 1 in 35), but in an 11-day window this is a probability of success
with a random guess of about 0.38 (nearly 1 in 2).
If you were playing Russian Roulette, I'd bet you might be willing to continue playing
if you knew your odds of hitting the bullet were 1 in 10, but I think you would have
second thoughts if you know that the odds were 1 in 2.