I think it’s highly unlikely that even half the pressure waves would simultaneously reach a single point on earth. The waves get reflected in all kinds of ways by the ground, mountain ranges, difference in air temperature, etc.

If they did, however, I wonder how strong the force would be at its focus (if that’s the proper name)

(If I did my math right, the antipodes of Tonga live in the south of Algeria, near the Niger/Mali/Algeria tripoint. I haven’t heard of weird phenomena happening there, but then, I don’t think that is the most populated and most twitter-addicted part of the world)