@ j_h and kael: Uzushiogakure was near the Land of Waves, off the coast of the Land of Fire in an island. The thing is, it's south from the coastal line Hashirama is in (he's on the border of the Land of Frost with the Land of Hot Springs), meaning the Bijuudama did blow up in an yet unknown continent.
Edit:that map has too much anime data to be considered, I prefer this one.
Look at the bay on the border of the Land of Frost and Land of Hot Springs (edited my post for accuracy). It's the exact same one as this chapter, so it either hit that island south of the Land of Lightning or that continent east of the Land of Lightning.