The center previously issued a notice saying it suspected another test because the epicenter was located on the surface4 magnitude quake would be much smaller than the quakes caused by previous DPRK nuclear tests, the report saidWelcome官方网站After the incident, the center quickly organized seismological bureaus and geological institutions to evaluate the situation, it saidSeismologists from the Chinese Academy of Sciences and the University of California Santa Cruz also published a joint report on Saturday that said tests had shown the quake "clearly falls in the natural phenomena category" and was similar to the last natural earthquake in the region, which was recorded in December 20043 magnitude quake, while the strongest, this month, resulted in a 6Welcome官方网站"The incident was not a nuclear explosion, but had the characteristics of a natural quake," the China Earthquake Networks Center said late Saturday in a statement released online