Earlier, South Korea's weather agency said the quake is presumed to have been a natural one, the country's Yonhap news agency reportedThey concluded that SBet实博Saturday's quake is a natural one, the seismic service said4 on the Richter scale that occurred Saturday in the Democratic People's Republic of Korea (DPRK) is not the result of a nuclear test, the China Earthquake Networks Center (CENC) said"The quake is presumed to have occurred naturally," the report quoted an agency official as sayingThe epicenter was roughly the same with a similar shallow earthquake on Sept 3, which turned out to be caused by a nuclear test by the DPRKSBet实博4 on the Richter scale in the Democratic People's Republic of Korea(DPRK)