Radar reveals details of mountain collapse after North Korea’s most recent nuclear test

(University of California – Berkeley) North Korea's Sept. 3, 2017, underground nuclear test — it's latest and biggest — created a 5.2 magnitude earthquake and 4.5 magnitude aftershock. Researchers from Singapore, UC Berkeley, Germany and China combined synthetic aperture radar with seismic measurements to determine that the explosion pushed the mountain surface outward up to 11 feet and left it 20 inches shorter, probably after cavity collapse and subsequent compression of fractured rock. The aftershock may have been a tunnel collapse.