The earthquake which supposedly caused this incident was a Mb 4.4 in Central
Chile on 3 July, 2001. This is supposed to have had enough effect on Irkutsk to
have downed the plane. Earthquakes of this size occur about 20 times a day
on average - it's a wonder any planes are left in the sky.
In another problem, the exact opposite point to Irkutsk (50N 105E) is 50S 75E
an area in the Strait of Magellen at the southern tip of South America, and an area
which has never had a sizable earthquake. The earthquake in Central Chile
occurred at 29S 71W, nearly 2500 km away from the antipode - hardly exactly
opposite Irkutsk.