To understand the magnitude of the force, the Hiroshima and Nagasaki blasts were 13 and 20 kilotons. Compare that to the 120 kilotons detonated by the French on January 27 and the destructive 6.5 to 7.0 Chinese quake February 3, six days later. Anti-nuke groups often discuss the danger of the Mururoa test site. In a 1989 documentary, the Costeau Society showed man-made fractures along the sides of the atoll. The island is built, as is the Fangataufa Atoll, on a dormant volcano.
Tests take place in the volcano's core.
Costeau warned further testing could cause more fracturing and leakage of radioactivity into the ocean. One prediction was fulfilled. Measurements of further fracturing are hampered by the French government. However, the public was enlightened to the fact a blast vaporizes the stone around it for hundreds of feet then melts about the same amount of the surrounding rock. Minutes later it hardens to a kind of radioactive glass ball.