By doing some geometry and guessing, we can assume that the nuke landed in open water. When Trigger shot the Alicorn, I'm guessing it didn't move horizontally that much, if at all, but it definitely moved down. Due to there not being really any land east of Oured, the shell probably landed in the water.
After playing with Desmos online grapher, I've found a few things. Ideally, it shouldn't overshoot by lowering its angle since it's already less than 45 degrees. Since the disruption to the angle wasn't significant, all that remained was the water between Oured and Sapin. That's a narrow miss right there. A degree lower or two would've hit Sapin. That probably added a lot more fuel to why David became so enraged at Torres.
EDIT: I've just realized that Trigger came so close to saying "Aw shit. I ain't going back to jail."