A minor 3.1 magnitude earthquake was detected in North Korea early Monday, South Korea's state weather agency said, adding that there was no indication it was related to a nuclear test.According to the Korea Meteorological Administration (KMA), the quake struck at 5:17 am (2017 GMT Sunday) near the southwestern North Korean city of Songlim.It was not believed to be the result of a nuclear test as the affected area was far from the North's Punggye-ri underground test site in the country's northeast."It is a natural earthquake. We don't think it is another nuclear test. Nothing special has been detected," a KMA official told AFP.There were no immediate reports of any damage.The Korean peninsula is not an area of strong seismic activity, although minor earthquakes are quite common.Any moderate seismic shock usually sets off alarm bells, as it could be the first signal of a nuclear test.The first indication of the North's last test on January 6 was a 5.1 magnitude tremor at Punggye-ri that was detected by international seismic monitors.