This famous video clip is from a Civil Defense Effects test at the Nevada Test Site. It first shows the test house with the tower holding the nuclear device in the background. Then the effects of the detonation are shown. This video is silent.
The test took place at the Nevada Test Site on 17 March 1953 and was nationally televised. The broadcast as well as this film suggests that it is possible to survive an a-bomb blast, as long as you have a good fallout shelter or other protection. Unfortunately, just a few years after this film was made, larger and larger yield nukes and the H-bomb made the proposition of survival quite unlikely.
The Trinity Atomic Web site