A general view of the hard-surfaced advanced recording base PEA "Denise" in the north zone of the Moruroa (Mururoa) atoll, southern Pacific ocean, where French forces have conducted 138 nuclear weapon tests until 1996. In order to prevent a potential collapse of the atoll, the ministry of Defense have scheduled improvement works on all its telesurveillance system, named Telsite, starting late 2014 and up to 2017, to monitor the sismic activity of the base. The Telsite system includes a network of sismic captors placed on the surface but also in wells hundreds of meters deep.

Gregory Boissy/AFP

PEA ‘Denise’ in the north zone of the Mururoa Atoll, in the southern Pacific Ocean, where the French military conducted nuclear weapons tests until 1996. The Ministry of Defence has scheduled improvement works starting in late 2014 to monitor the seismic activity of the base amid fears the atoll may collapse