Most if not all of these “pits” are in relative wilderness and not on or near approved hiking paths. They were dug hundreds to thousands of years ago for water collection. Most of these are unknown to the public or the authorities, and there are probably hundreds to thousands of them. They are quite deep, this one apparently being 10 meters deep, which is not at all unusual.
Hechochom einav b’rosho. When one goes hiking, always follow approved paths, especially if rough terrain is not your specialty. These tragedies can be avoided.