Obviously, being next to explosions is bad. The farther away one is from the explosion, the larger the hemisphere of the shock wave is, and so the more the energy from the explosion is dissipated. Typically, this rate of loss of energy density is modeled as $1/r^2$, where $r$ is the distance from the detonation.
However, this model misses an interesting effect that occurs (at least hypothetically) for sufficiently large explosions. Supposing that the explosion in question occurred at the north pole, once the shock wave moves past the equator, the size of the circle formed by the shock wave moving along the ground decreases, and eventually converges on the south pole (i.e. the antipodal point), resulting in constructive interference that could seemingly pose more of a danger to someone who's there than someone who's much closer to the explosion.
Can this phenomenon occur in practice in cases of extremely large explosions, such as the Tsar bomb? If so, then how close to the north pole would one have to be to feel the same effects that someone on the south pole feels?
I know this question is somewhat silly, but I don't think it's completely absurd, either. The blast wave from the Tsar bomb circled the Earth three times, and the atmosphere can focus blast waves in such a way as to make them more deadly to somebody who's far away from the explosion. The difference in this case is that the focusing mechanism is the shape of the atmosphere, not local/regional differences in atmospheric density. Finally, I'm aware of this question, but it has a different focus than mine, and the question and answers don't address the antipodal focusing principle that I'm asking about.