[HakTaisanip]

Seems to me that a "friendly" Alien species would be aware of the ground affects of their spacecraft and either land in sparsely populated areas or, more likely, remain in orbit and send some smaller vessels down that would not have such a severe ground affect and be less likely to cause widespread panic and damage.
Seems to be that either they really don't care, or that it is a deliberate tactic! Assuming it isn't just the usual director's "let's make it a huge dramatic spectacle!" and not a writers decision!