And the former Defense Nuclear Agency (now called the Defense Special Weapons Agency) has reported that there are several techniques that could be employed to reduce the likelihood that covert nuclear tests will be reliably identified even by in-country seismic monitoring.
CENTERFORSECURITYPOLICY: Center for Security Policy | Clinton??s CTB And Other Placebos Won??t Stop, Will Compound The Danger Of Proliferating Weapons Of Mass Destruction