In order to reduce the detonation, the earthquake as well as other vibration disasters, the underground structure should have the enough anti - dynamic load ability.

为了减少爆炸、地震以及其它的振动灾害，地下结构应具有足够的抗动载能力。

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In February, the country conducted its third underground detonation of a nuclear device, possibly using enriched uranium rather than the plutonium employed in previous tests.

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Months after North Korea's latest underground detonation, U.S. intelligence is still unable to determine what material actually exploded -- uranium or other radioactive materials.

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They have long since outlived their design life and for at least 18 years none of them has been tested in an operationally realistic way (that is, with an underground nuclear detonation).

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