One of the benefits Cold War ending was the establishment of the Comprehensive Test Ban Treaty Organization (CTBTO). The treaty itself, banned all nuclear detonations. The treaty went into effect in the 1990s, as a system of 75 monitoring stations (eventually to be over 300) was established around the world. The CTBTO stations use seismic sensors, as well as radiation sniffers and other equipment, to detect nuclear explosions anywhere on the planet. Their equipment picked up the December 26, 2004 quake within minutes. There's now a proposal to integrate the CTBTO stations into a global tsunami alert network. It'd really be a cheap measure; the equipment is already there, all that's needed is to develop some procedures and communications links to connect it with the Pacific tsunami alert system. It would also be good PR, since the agency seems to be mostly funded by the US. The CTBTO is regularly tested by earthquakes and large volcano eruptions. In the late 1990s, there was also a spate of nuclear tests of Pakistan and India. These were all picked up by the CTBTO network. If North Korea, Iran, or anyone else, sets off a nuclear weapon underground, CTBTO will most likely catch it. There have been calls to cut the CTBTO budget, so giving the system additional useful tasks is one way to keeping it alive.