UPDATE: National Seismological Centre said that the tremor recorded at 00:38 am was a minor aftershock of local magnitude 3.7. Its epicentre was in Kathmandu Valley itself. The NSC generally gives magnitude of significant earthquakes of local magnitude 4.0 or above. KATHMANDU: A tremor was felt in the Kathmandu Valley at around  00:38 am. Its magnitude and epicentre were not known immediately. Earlier, the National Seismological Centre recorded a light aftershock of the April 25 earthquake at 7:26 pm on Sunday evening. The 328th significant aftershock (ML 4.0 or above) was of local magnitude 4.3 with its epicentre in Sindhupalchok district, according to the NSC.