中国被指进行地下核试验，或重启核试验竞赛

As new global arms race looms, accusation highlights limits to monitoring low-yield tests RICHARD STONE I n the afternoon on 22 June 2020, a seismic station in eastern Kazakhstan registered two small earthquakes 12 seconds apart near China’s Lop Nur nuclear test site. Closely spaced jolts can arise from underground explosions followed by a cavity collapse, or simply from earthquakes. But U.S. officials this month asserted the shaking was from a clandestine nuclear detonation—an accusation that could sound the starting gun for a new global arms race. Thomas DiNanno, the State Department’s under secretary for arms control and international security, made the accusations against China at a disarmament meeting in Geneva on 6 February. …