Thanks for posting the pic.
The story from Down Under also indicated local rescue crews on site.
Big hole for sure, I would have said a Mk 82, tops.
My guess would be crater 30 feet by 6 feet. However, samples have been taken to test for radioactivity and will be ready in 7 days. If it is radioactivity (a fallen piece of radioactive space junk of human manufacture?) then it is incredibly strong and people will start dying long before the test results are in. Otherwise, if radioactivity is weak, they would not have gotten sick that quickly. Perhaps the boiling of the water set off gases from buried matter in the soil. Certainly an object large enough to make such a crater would also heat up the subsoil and boil the ground water. On the other hand, the area looks awfully dry to have groundwater that close to the surface.