Palau has ratified the Comprehensive Nuclear Test Ban Treaty, raising to 139 the number of full member states.
Officials of the organistaion administering the treaty say Palau's infrasound station will be part of a global alarm system being built to help ensure compliance with the treaty.
The treaty, which prohibits all nuclear explosions, will not take formal effect before it is ratified by all 44 states listed in an annex that took part in the 1996 treaty negotiations and have nuclear power or research reactors.
34 of the 44 have both signed and ratified the pact, including Russia, Britain and France.
The 10 laggards include Iran, Israel, North Korea, India, Pakistan, China and the United States.